For a guy born and raised in Mexico, Roberto Gallardo has an exquisite knack for Southern manners. That’s one of the first things I notice about him when we meet up one recent morning at a deli in Starkville, Mississippi. Mostly it’s the way he punctuates his answers to my questions with a decorous “Yes sir” or “No sir”—a verbal tic I associate with my own Mississippi upbringing in the 1960s.
Gallardo is 36 years old, with a salt-and-pepper beard, oval glasses, and the faint remnant of a Latino accent. He came to Mississippi from Mexico a little more than a decade ago for a doctorate in public policy. Then he never left.
I’m here in Starkville, sitting in this booth, to learn about the work that has kept Gallardo in Mississippi all these years—work that seems increasingly vital to the future of my home state. I’m also here because Gallardo reminds me of my father.
Gallardo is affiliated with something called the Extension Service, an institution that dates back to the days when America was a nation of farmers. Its original purpose was to disseminate the latest agricultural know-how to all the homesteads scattered across the interior. Using land grant universities as bases of operations, each state’s extension service would deploy a network of experts and “county agents” to set up 4-H Clubs or instruct farmers in cultivation science or demonstrate how to can and freeze vegetables without poisoning yourself in your own kitchen.
State extension services still do all this, but Gallardo’s mission is a bit of an update. Rather than teach modern techniques of crop rotation, his job—as an extension professor at Mississippi State University—is to drive around the state in his silver 2013 Nissan Sentra and teach rural Mississippians the value of the Internet.
In sleepy public libraries, at Rotary breakfasts, and in town halls, he gives PowerPoint presentations that seem calculated to fill rural audiences with healthy awe for the technological sublime. Rather than go easy, he starts with a rapid-fire primer on heady concepts like the Internet of Things, the mobile revolution, cloud computing, digital disruption, and the perpetual increase of processing power. (“It’s exponential, folks. It’s just growing and growing.”) The upshot: If you don’t at least try to think digitally, the digital economy will disrupt you. It will drain your town of young people and leave your business in the dust.
Then he switches gears and tries to stiffen their spines with confidence. Start a website, he’ll say. Get on social media. See if the place where you live can finally get a high-speed broadband connection—a baseline point of entry into modern economic and civic life.
Even when he’s talking to me, Gallardo delivers this message with the straitlaced intensity of a traveling preacher. “Broadband is as essential to this country’s infrastructure as electricity was 110 years ago or the Interstate Highway System 50 years ago,” he says from his side of our booth at the deli, his voice rising high enough above the lunch-hour din that a man at a nearby table starts paying attention. “If you don’t have access to the technology, or if you don’t know how to use it, it’s similar to not being able to read and write.”
These issues of digital literacy, access, and isolation are especially pronounced here in the Magnolia State. Mississippi today ranks around the bottom of nearly every national tally of health and economic well-being. It has the lowest median household income and the highest rate of child mortality. It also ranks last in high-speed household Internet access. In human terms, that means more than a million Mississippians—over a third of the state’s population—lack access to fast wired broadband at home.
Gallardo doesn’t talk much about race or history, but that’s the broader context for his work in a state whose population has the largest percentage of African-Americans (38 percent) of any in the union. The most Gallardo will say on the subject is that he sees the Internet as a natural way to level out some of the persistent inequalities—between black and white, urban and rural—that threaten to turn parts of Mississippi into places of exile, left further and further behind the rest of the country.
And yet I can’t help but wonder how Gallardo’s work figures into the sweep of Mississippi’s history, which includes—looking back over just the past century—decades of lynchings, huge outward migrations, the fierce, sustained defense of Jim Crow, and now a period of unprecedented mass incarceration. My curiosity on this point is not merely journalistic. During the lead-up to the civil rights era, my father worked with the Extension Service in southern Mississippi as well. Because the service was segregated at the time, his title was “negro county agent.” As a very young child, I would travel from farm to farm with him. Now I’m here to travel around Mississippi with Gallardo, much as I did with my father. I want to see whether the deliberate isolation of the Jim Crow era—when Mississippi actively fought to keep itself apart from the main currents of American life—has any echoes in today’s digital divide.
My father was an outsider too. Warren Eubanks arrived in Mississippi in 1949 at the age of 26, armed with an agronomy degree from the Tuskegee Institute. He came from just across the border in Alabama, not Mexico, but even that was enough to arouse suspicion. “Mississippi works more like a club than a state,” I once overheard someone say at a cocktail party in Jackson, the state capital. And in those days, white elites went to great lengths to protect the prerogatives of the club. Civil rights activists called Mississippi “the closed society.”
My father came to the Extension Service, and to Mississippi, in part out of a conviction that teaching black Southerners how to profit from their own land was the clearest way to lift them out of poverty. Some were leaving behind lives of sharecropping to farm independently, often in the face of great resistance from white communities. And my father was there to help.
The idea that prosperity could come from a small plot of land wasn’t as far-fetched then as it might seem now. My father’s first home in the state was on the broad swath of farmland that is the Mississippi Delta—some 200 miles long, 70 miles across at its widest point, and flat for as far as the eye can see—with topsoil that can go down almost 18 feet. It was known as some of the richest farmland in the world, and its cotton had helped mint some of the largest fortunes in America. Surely, then, a small farm on such productive land could provide plenty of income for a family.
I pulled over at a McDonalds to use its Wi-Fi. A fellow customer asked me what kind of computer I was using. She had never seen a Mac before.
My father’s first assignment was in the small Delta communities of Mileston and Tchula. By the time I was born in 1957, the family had moved farther south, off the Delta, to a town called Mount Olive. And between the ages of about 4 and 6, I spent most of my days accompanying my father out on the road. What stands out in my memory—aside from the portraits of FDR and Jesus Christ that adorned so many farmers’ walls and the crumbly molasses cakes I was sometimes served—is the way my father’s speech and manner would change when he walked onto a poor family’s piece of land. He’d code-switch from educated man to fellow farmer, in a shift that seemed calculated to put people at ease. He’d sit patiently at a farmer’s side as they reviewed whatever Extension Service pamphlet he was leaving with them. As an outsider and an educated man, he did not want to lord over the people he encountered.
During my trip to meet with Gallardo, I pass through Tchula. Of course, a great deal has changed for the better in the 60 years since my father was assigned to the town: Jim Crow is dead and buried. Tchula no longer rings a bell on Saturdays to warn black citizens that it’s time to leave the streets, as happened back in the 1950s. Election posters dot the streets, and every candidate is African-American.
But the end of segregation also set off a crippling exodus of white residents and white capital. Today every face I see on the streets is black. The town, which ranks as one of the poorest municipalities in the state, is in conspicuous disrepair. The unemployment rate is 9.1 percent, nearly double the Mississippi average.
The entire Delta’s economic base is rickety. The region didn’t develop much industrially in the early 20th century, as white elites were determined to fence out any competition for black sharecropping labor. Of the few factories that did set up shop, most have closed down over the past few decades with the decline of US manufacturing. Small-scale farming didn’t become the path to prosperity my father had hoped it would, owing to mechanization and consolidation in agriculture. And after the long fight for integration, the region’s schools effectively resegregated into a public system for black children and private academies for whites. Recently, a Mississippi judge ruled that the legislature is not obliged to fully fund schools in the state, a decision that hits poor districts like Tchula and other Delta towns with a wallop.
Increasingly, there are two main paths out of high school in the Delta, and both of them lead to the same place. The biggest employer in the area today is a network of local prisons whose population—of both inmates and guards—is largely African-American and drawn from the Delta’s native sons and daughters.
Gallardo tells me that many Delta residents are too poor to own a computer or get a wired Internet connection, even if their town has a broadband carrier. Smartphones are fairly pervasive, but so are limited data plans, which put a ceiling on their functionality. And besides, Gallardo asks, have you ever tried, say, filling out a job application on your phone? A few months ago, I pulled over at a McDonalds in the Delta town of Marks to use the restaurant’s Wi-Fi. A fellow customer came up to me to ask what kind of computer I was using. She had never seen a Mac before.
In the small Delta town of Ruleville, the only public space with a strong Wi-Fi connection is the public library, open just two days a week. Sharonda Evans, a 16-year-old student at the local high school, tells me that she’s one of the lucky ones in her town: Her family pays $50 a month for a slow connection. “Those who live outside the center of town can’t get Internet access, even if they can afford it,” she says. And as far as I can tell, there are no plans in the works to bring broadband to Ruleville.
Not every small town in Mississippi is like Tchula or Ruleville, though. Two days after our initial meeting, Gallardo and I pull up to the city hall in Quitman, population 2,300, a former logging and textile town about 200 miles southeast of the Delta. On its face, the town shows some of the telltale marks of rural decline: An abandoned plant sits right in the middle of everything, and the town has lost an estimated 15 percent of its population—which now stands at around 60 percent white, 40 percent black—over the past decade. The official poverty rate stands at about 24 percent. But still, cars are humming down the streets, and people dot the sidewalks. It’s not bustling, exactly, but it’s alive. And kicking.
In 2013 a regional telecommunications company called C Spire announced that it would bring fiber-optic broadband infrastructure to any Mississippi town or neighborhood that could rally between 35 and 45 percent of its residents to commit to signing up for service. The pitch—which mimics Google Fiber’s business model for getting broadband infrastructure to large numbers of homes quickly—set off a flurry of neighborhood organizing campaigns across the state. (In Eudora Welty’s old neighborhood in Jackson not long ago, I saw yard signs dotting the streets that read “I signed up for C Spire broadband. Will you?”) When C Spire announced the first nine towns that had reached critical mass in November 2013, right there on the list was tiny, out-of-the-way Quitman.
Elderly townspeople, black and white alike, were uneasy about the security and privacy implications of entering the Internet age.
The town’s size turned out to be an asset. The pastor of the local First Baptist Church, Gene Neal, made it a personal cause to get his congregation signed up. Toby Bartee, the local judge and a pillar of the town’s black Baptist church, rallied his congregation as well. Between them, that accounted for a significant chunk of Quitman. For anyone who could not afford C Spire’s $10 sign-up charge, the town enlisted local banks and businesses to pay the fee. When it was announced that Quitman would be getting fiber broadband, Gallardo began showing up frequently too, teaching Internet basics at the library, consulting with town leaders, and generally making sure Quitman could make the most of its state-of-the-art Internet connection.
When Gallardo and I arrive at city hall, Eddie Fulton, the avuncular, white-haired mayor of Quitman, meets us outside and promptly cracks a well-worn joke about Gallardo’s green card. Gallardo plays along gamely, then Fulton grabs me by the arm to tell me about signs of hope he already sees in his newly wired town: There’s the local women’s clothing boutique called Simply Irresistible that has an Instagram following more than triple the size of Quitman’s population; 90 percent of its sales come from out of town. There’s a 3-D printer at the public library, hooked up to the town’s broadband connection.
And yet what’s most curious about the broadband project in Quitman is that some residents of the town actually opposed it. Inside city hall, I meet up with some of the local leaders who organized the sign-up campaign. And when I ask the group whether Mississippi’s wariness of outside influences ever stood in the way, nobody has to ask what I mean. They all come back with a resounding yes. Pastor Neal says some of his older, predominantly white parishioners were vocally opposed to the effort. “You people just want to change everything,” they said.
Elderly townspeople, black and white alike, were also uneasy about the security and privacy implications of entering the Internet age. This is understandable; older people everywhere in America have some of these concerns. But fears of surveillance and abuse may be a little less abstract for Mississippians than they are for other Americans.
Sometime around the early 1960s, my father began attending integrated meetings of Extension Service agents. He was also friends with civil rights leader Medgar Evers and worked quietly with the NAACP to register voters in our hometown. Because of all that, his name was entered into the files of something called the Mississippi State Sovereignty Commission. Established in 1956 to help maintain Mississippi’s segregationist way of life, the Sovereignty Commission was originally a kind of public relations shop. But by the early ’60s it became a full-fledged state-run spy agency, keeping tabs on outsiders, subversives, and anyone whose “utterances or actions indicate that they should be watched with suspicion on future racial attitudes.” Thousands of Mississippians were caught up in the effort, either as informers or targets. (There was also censorship to go along with the surveillance: When Nat King Cole sang with Peggy Lee on national television, or Thurgood Marshall appeared on the news, TVs across Mississippi cut to secondary networks or screens that said “Sorry, cable trouble.”)
Today, the state government isn’t actively thwarting efforts to integrate black Mississippians into full participation in the economy. But it isn’t doing much to help, either. Last year the Mississippi Library Commission tried to get the legislature to approve a modest $1.4 million appropriation to place a broadband connection in every public library in the state. The library commission explained to state officials that, with broadband, the libraries could start providing virtual health services to areas with too few doctors. But even that measure didn’t pass.
In a state that has privatized everything from child protective services to nutrition programs for the elderly, broadband access is bound to be regarded pretty much entirely as something for the private sector to sort out, and not as anything like a public need or a civil right.
After my visit to Quitman, I decide that I want to go see how a large Delta town has responded to C Spire’s call for sign-ups. So I set my GPS on Clarksdale, a city of about 17,000 people that is 80 percent black and has one of the highest rates of incarceration in the state. Gallardo can’t make the trip with me, but he puts me in touch with the mayor there, a former Democratic candidate for governor named Bill Luckett.
Luckett has been in touch with Gallardo before and seems genuinely interested in technology. “I do see broadband as a game changer,” Luckett tells me in his office, whose walls are lined with antique maps of Mississippi. “But we’re spread out here in the Delta.” Luckett says he can’t justify committing the time, resources, and political capital it would take to rally his constituents around signing up for a new high-speed broadband network that will ultimately cost them $80 a month. For one thing, he knows that many of them would not be able to afford it. To cite a common measure of poverty, nearly 90 percent of students in public schools here qualify for free or reduced-cost lunches.
Plus, Luckett just has bigger fires to put out as mayor: crime, poverty, and all the social ramifications of families divided by incarceration. At the time of my visit, the local media’s attention is preoccupied with the recent fatal shooting of a Clarksdale attorney—an act of violence that Luckett himself witnessed.
Clarksdale does have at least one high-speed fiber broadband connection, though. The Ground Zero Blues Club, which Luckett owns with the actor Morgan Freeman, uses its fast pipe to live-stream performances by Delta blues performers from its stage. The Ground Zero’s name is a reference to the nearby crossroads of Highways 61 and 49 in Clarksdale, where the bluesman Robert Johnson supposedly sold his soul to the devil in exchange for his musical talents. Mayor Luckett tells me that tourists sometimes come to the Ground Zero not for the blues, especially, but because they hear it has the best Wi-Fi connection in town. As for the rest of the Delta, it seems the Devil isn’t even offering deals there anymore. Like everyone else these days, he probably prefers a faster connection.
Quinoline derivatives have diverse biological activities including anticancer activity. On the other hand, many sulfonamide derivatives exhibited good cytotoxic activity. Hybrids of both moieties may present novel anticancer agents.
Chloroquinoline incorporating a biologically active benzene-sulfonamide moieties 5–21 and diarylsulfone derivatives 22 and 23 were prepared using (E)-1-(4-((E)-7-chloro-1-methylquinolin-4(1H)-ylideneamino)phenyl)-3-(dimethyl-amino)prop-2-en-1-one 4 as strategic starting material. The structure of the newly synthesized compounds were confirmed by elemental analyses and spectral data. Compound 4 was confirmed by X-ray crystallographic analysis. The prepared compounds were evaluated for their anticancer activity against Lung, HeLa, Colorectal and breast cancer cell lines. Compounds 2, 4, 7, 11, 14 and 17 showed better or comparable activity to 2′, 7′-dichlorofluorescein (DCF) as reference drug. Molecular docking of the active compounds on the active site of PI3K enzyme was performed in order to explore the binding mode of the newly synthesized compounds.
Compounds 2, 4, 7, 11, 14 and 17 are novel quinoline derivatives that may represent good candidates for further evaluations as anticancer agents. The mechanism of action of these compounds could be through inhibition of PI3K enzyme.
Compound 17 on the active site of PI3K
Keywords: Chloroquinolines, Benzenesulfonamides, Anticancer activities
Quinoline scaffold has been broadly distributed in sundry natural and synthetic compounds with multipurpose biological activities [1–3]. The antitumor activity of the quinoline derivatives for instance camptothecin , luotonin , ascididemin , TAS-103 A that displayed IC50 value of: 0.0030–0.23 microM hostile to various cell lines , CIL-102 B that unveiled IC50 value of: 0.31–2.69 microM hostile to countless cell lines , cryptolepin  and indolo[2,3-b]quinolines  has been described. Numerous mechanisms of action were optional for such action among them was the strong suppression of E2F1 that inhibits growth by thwarting cell cycle progression and fasters differentiation by creating a permissive environment for cell distinction . Chloroquinolines were valuable in sundry cancer sorts remarkably, breast cancer with high aptitude to induce apoptosis . Heterocyclic sulfonamides have publicized good anticancer bustle with diversity of mechanisms embracing cell cycle perturbation at G1 phase, disruption of microtubules assembly and the eminent carbonic anhydrase inhibition activity with selectivity to the tumor allied isoforms hCA IX and hCA XII [13–17]. Merging quinoline scaffold with the biologically active benzene-sulfonamide moiety has received immense attention as PI3K inhibitor which is an vital enzyme regulatory signal transduction [16, 18–20]. Freshly, diaryl sulfones that were prepared from Dapson have shown respectable cytotoxic activity on breast cancer cell line . Based on the aforementioned and as a continuation for our effort to synthesize a novel anticancer agents [18–25], we have prepared novel quinolone-sulfonamide and diarylsulfone derivatives. Prepared compounds were subjected to cytotoxic assay on lung, hela, colorectal and breast cancer cell lines. Likewise, “the highest active compounds were docked on the active site of PI3K enzyme” to recommend their binding mode in a trial to explore their mechanism of action expecting to reach innovative anticancer agents.
Results and discussion
The ambition of this effort was to prepare a new series of chloroquinolines carrying biologically active benzene-sulfonamide moieties and to assess their anticancer activity. Thus, interaction of 2  with dimethylformamide-dimethylacetal (DMF-DMA) in dry xylene yielded the unexpected 4 instead of expected 3. “The structural assignments to synthesized compounds were based on their physico-chemical characteristics and spectroscopic (FT-IR, 1H-NMR, 13C-NMR, and mass spectroscopy) investigations”. Structure of 4 was confirmed by X-ray crystallographic analysis  (Figs. 1, 2). IR of 4 revealed the disappearance of NH band and presence of absorption bands for (aromatic), (aliphatic), (CO), (CN), (CCl). 1H-NMR showed the presence of a singlet at 2.4 ppm attributed to N-(CH3)2, singlet at 3.4 ppm assigned to N-CH3, two doublet at 5.4, 6.5 ppm for CH = CH of quinolone ring, two doublet at 6.1,7.4 ppm assigned to CH = CH group. Enaminones are highly reactive intermediates extensively used for the preparation of heterocyclic derivatives. Thus, treatment of 4-(7-chloro-1-methylquinolin-4-(1H)-ylideneamino) phenyl-3-(dimethyl-amino)-prop-2-en-1-one 4 with sulfonamide derivatives in refluxing ethanol/acetic acid mixture (2:1) afforded the sulfonamide derivatives 5–21 (Scheme 1). “Structures of the latter products were assigned on the basis of their analytical and spectral data”. 1H NMR of 5–21 support the assumption that these structures were in E-form and not in Z form, while the coupling constant of doublet signals for olefinic protons was equal to 6.1–7.7 Hz. IR of the reaction products showed in each case three absorption bands for 2NH functions in the 3446–3143 cm−1 region, in addition to carbonyl functions 1654–1635 cm−1 region and CCl functions 883–763 cm−1 (Scheme 1). 1H-NMR of 5 showed singlet at 12.0 ppm assigned to NH group, while 13C NMR revealed singlet at 189.3 ppm for CO group. 1H-NMR of 6 exhibited singlet at 2.0 ppm according to COCH3 group.1H-NMR of 7 revealed singlet at 9.4 ppm for NH group. 1H-NMR of 8 showed singlet at 2.3 ppm for CH3 group, while 1H NMR of 9 exhibited two signals at 1.9, 2.6 assigned to 2CH3 groups. 1H NMR of 10 revealed two signals at 10.2, 12.0 ppm assigned to NH, SO2NH groups. 1H-NMR of 11 exhibited two signals at 6.6, 6.8 ppm for CH = CH of thiazole ring. 1H-NMR of 12 exhibited singlet at 2.4 ppm for CH3 of thiadiazole ring. 13C NMR of 13 showed signal at 186.6 ppm due to CO group. 1H-NMR of 15 exhibited singlet at 2.3 ppm for CH3 of pyrimidine ring. 1H-NMR of 16 revealed singlet at 2.2 ppm for 2CH3 of pyrimidine ring. 1H-NMR of compound 17 exhibited singlet at 3.9 ppm for OCH3 group. 1H-NMR of 18 showed singlet at 3.7 ppm assigned to 2OCH3 groups, while 1H NMR of 19 exhibited two signals at 3.6, 3.8 ppm attributed to 2OCH3 groups. 1H NMR of 20 revealed singlet at 12.0 according to NH group of indazole ring. 13C-NMR of 21 showed singlet at 186.7 ppm for CO group. Interaction of 4 with Dapson in molar ratio (1:1 mol) afforded the mono compound 22, while the bis-compound 23 was achieved in the same condition but in molar ratio (2:1 mol). Compounds 22 and 23 were confirmed by microanalyses, IR, 1H-NMR, 13C-NMR and mass spectral data. IR of 22 revealed the characteristic bands at 3446, 3348, 3213 cm−1 (NH2, NH), 1635 cm−1 (CO), 1591 cm−1 (CN), 1369, 1180 cm−1 (SO2), 821 cm−1 (CCl). 1H-NMR of 22 exhibited signals at 3.4 ppm corresponding to N-CH3 group, 5.9 ppm due to NH2 group, two doublet at 6.1, 7.4 ppm for 2 CH quinoline, two doublet at 6.5, 6.6 ppm assigned to CH = CH groups, singlet at 12.0 NH. 13C-NMR of 22 showed singlet at 186.6 ppm attributed to (CO) group. Mass of 22 revealed a molecular ion peak m/z at 569 [M+] (19.87) with a base peak appeared at 90 (100). IR of 23 showed a characteristic bands at 3143 cm−1 (2NH), 1635 cm−1 (2CO), 1570 cm−1 (2CN), 1375, 1180 cm−1 (SO2), 819 cm−1 (2CCl). 1H-NMR of 23 revealed signals at 3.4 ppm for N-CH3, two doublets at 6.2, 7.3 ppm due to 4CH quinoline, two doublets at 6.6, 7.2 assigned to 2CH = CH, two singlet’s at 9.3, 12.0 for 2NH groups. 13C-NMR of 23 revealed singlet at 186.7 ppm for (2CO) groups. Mass of 23 showed a molecular ion peak m/z at 889 [M+] (6.48) with a base peak appeared at 272 (100) (Scheme 2).
ORTEP diagram of the title compound 4 drawn at 40 % ellipsoids for non-hydrogen atoms
Crystal packing of compound 4 showing the intermolecular hydrogen bonds
In vitro cytotoxic screening
The newly synthesized compounds were evaluated for their in vitro cytotoxic activity against human lung (A549-Raw), hela, colorectal (lovo) and breast (MDA-MB231) cancer cell lines and 2′,7′-dichlorofluorescein (DCF) was used as the reference drug in this study. The relationship between surviving fraction and drug concentration was plotted to obtain the survival curve of cancer cell lines. The response parameter calculated was the IC50 value, which corresponds to the concentration required for 50 % inhibition of cell viability. Table 1 shows the in vitro cytotoxic activity of the newly synthesized compounds. In a closer look to Table 1, we can see that compounds 1, 2, 4, 7, 11, 14 and 17 were active towards all the tested cell line while the rest of compounds were inactive. Regarding the activity towards lung cancer cell line (A549-Raw), all the aforementioned compounds were more active than DCF as reference drug. Compound 2 was the most active compound with IC50 value of 44.34 μg/ml. For Hela cancer cell line, the same compounds were active. Compounds 7 and 17 were more active than DCF and compound 17 was the most active compound with IC50 value of 30.92 μg/ml. In case of lovo cancer cell line, all seven compounds were more active than DCF. Compound 2 was the most active compound with IC50 value of 28.82 μg/ml. Finally, the activity towards breast cancer cell line (MDA-MB231) was better than that of DCF for the aforementioned compounds except for compound 14. Compound 17 again was the most active compound with IC50 value of 26.54 μg/ml. In the light of biological results, we can see that the 4,7-dichloroquinoline 1 showed moderate anticancer activity that were enhanced upon converting it to 1-(4-(7-chloloquinoline-4-ylamino) phenyl)ethanone 2. The activity still exists upon preparation of (E)-1-(4-((E)-7-chloro-1-methylquinolin-4(1H)-ylideneamino) phenyl)-3-(dimethylamino) prop-2-en-1-one 4. Further preparation of the sulfonamide derivatives 5–21 using various sulfa drugs only succeeded to obtain active derivatives with the guanidine derivative 7, the thiazole derivative 11, the pyrimidine derivative 14 and the 5-methoxypyrimidine derivative 17. Combination with diaryl sulfone moieties as in compounds 22 and 23 did not yield active compounds.
In vitro anticancer screening of the newly synthesized compounds against four cancer cell lines
Phosphoinositide 3-kinases (PI3K) comprises an important class of enzymes that phosphorylates the 3 hydroxyl group of inisitol and play a major role in signal transduction through the cell cycle. Targeting PI3K by inhibitors has become a well-known strategy in seeking for new anticancer agents . Quinolinesulfonamide derivatives were reported to express good inhibitory activity on PI3K enzyme . In our present investigation and in a trial to suggest the mechanism of action of the active compounds, molecular docking of compounds 1, 2, 4, 7, 11, 14 and 17 was performed on the active site of PI3K to explore their binding modes to amino acids of the active site of the enzyme. The protein data bank file (PDB: 3S2A) was selected for this purpose. The file contains PI3K enzyme co-crystallized with a quinoline ligand. All docking procedures were achieved by MOE (Molecular Operating Environment) software 10.2008 provided by chemical computing group, Canada. Docking on the active site of PI3K enzyme was performed for all synthesized compounds. Docking protocol was verified by redocking of the cocrystallized ligand in the vicinity of the active site of the enzyme with energy score (S) = −29.8249 kcal/mol and root mean standard deviation (RMSD) = 1.9094 (Fig. 3). The quinoline ligand interacts with the active site of PI3K by six interactions: Val 882 with a hydrogen bond of 2.90 Å, Tyr 867 with a hydrogen bond of 3.33 Å, Asp 864 with a hydrogen bond of 3.33 Å, Lys 833 with a hydrogen bond of 3.33 Å, Ser 806 with a hydrogen bond of 3.74 Å and Asp 841 with a hydrogen bond of 2.79 Å through a water molecule. All the docked compounds were fit in the active site of enzyme. Energy scores (S) as well as amino acids interactions were listed in Table 2. The best docking score was achieved by compound 17 with a value = −27.1666 kcal/mol. Compound 17 interacted with Val 822 with a hydrogen bond of 3.20 Å, with Asp 964 with a hydrogen bond of 2.48 Å, with Ser 806 with a hydrogen bond of 3.38 Å and finally with His 984 with a hydrogen bond of 2.70 Å (Figs. 4, 5).
Co-crystallized quinoline ligand on the active site of phosphoinisitol kinase (PI3K)
Binding scores and amino acid interactions of the docked compounds on the active site of phosphoinisitol kinase (PI3K)
2D interactions of compound 17 on the active site ofphosphoinisitol kinase (PI3K)
3D interactions of compound 17 on the active site of phosphoinisitol kinase (PI3K)
Melting points (uncorrected) were determined in open capillary on a Gallen Kamp melting point apparatus (Sanyo Gallen Kamp, UK). Precoated silica gel plates (Kieselgel 0.25 mm, 60 F254, Merck, Germany) were used for thin layer chromatography. A developing solvent system of chloroform/methanol (8:2) was used and the spots were detected by ultraviolet light. IR spectra (KBr disc) were recorded using an FT-IR spectrophotometer (Perkin Elmer, USA). 1H-NMR spectra were scanned on an NMR spectrophotometer (Bruker AXS Inc., Switzerland), operating at 500 MHz for 1H- and 125.76 MHz for 13C. Chemical shifts are expressed in δ-values (ppm) relative to TMS as an internal standard, using DMSO-d6 as a solvent. Elemental analyses were done on a model 2400 CHNSO analyser (Perkin Elmer, USA). All the values were within ±0.4 % of the theoretical values. All reagents used were of AR grads.
1-(4-(7-chloroquinoline-4-ylamino)phenyl)ethanone 2 (2.97 g, 0.01 mol) and dimethylformamide-dimethylacetal (1.19 g, 0.01 mol) was added into dry xylene (30 mL). Reaction was refluxed for 10 h, and the solid product recrystallized from ethanol to give 4.
Yield, 89 %; m.p.268.1 °C. IR: 3100 (arom.), 2966, 2856 (aliph.), 1696 (CO), 1618 (CN), 776 (CCl).). 1HNMR: 2.4 [s, 3H, N(CH3)2], 3.6 [s, 1H, N-CH3], 5.4, 6.5 [2d, 2H, CH = CH quinoline, J = 7.1, 7.3 Hz], 6.1,7.4 [2d, 2H, CH = CH, J = 7.5, 7.4 Hz], 6.9–7.6 [m, 3H, Ar–H]. 13CNMR: 36.3, 44.5 (2), 91.5, 114.6, 115.3, 116.9, 121.4 (2), 131.7, 132.8 (2), 133.0, 135.9, 136.6, 141.4, 146.2, 152.5, 161.4, 166.4, 191.3. MS m/z (%): 365 (M+) (2.84), 74 (100). Anal.Calcd. For C21H20ClN3O (365.86): C, 68.94; H, 5.51; N, 11.49. Found: C, 68.66; H, 5.22; N, 11.74.
Synthesis of sulfonamide derivatives 5–21
4-(7-chloro-1-methylquinolin-4-(1H)-ylideneamino) phenyl-3-(dimethylamino)-prop-2-en-1-one 4 (3.65 g, 0.01 mol) and sulfa-drugs (0.012 mol) was added into ethanol (10 mL) and acetic acid (5 mL). The mixture was refluxed for 18 h. The solid product formed was recrystallized from dioxane to give 5–21.
4-(E)-3-(4-(E)-7-chloro-1-methylquinolin-4(1H)-ylideneamino) phenyl)-3-oxoprop-1-en-ylamino)benzenesulfonamide (5)
Yield, 88 %; m.p. 299.0 °C. IR: 3381, 3209 (NH2, NH), 3078 (arom.), 2937, 2869 (aliph.), 1635 (CO), 1593 (CN), 1373, 1182 (SO2), 867 (CCl). 1HNMR: 3.6 [s, 3H, N-CH3], 6.2, 7.3 [2d, 2H, 2CH quinoline, J = 7.2 Hz], 6.1, 7.6 [2d, 2H, CH = CH, J = 7.4 Hz], 7.7–8.6 [m, 13H, Ar–H + SO2NH2], 12.0 [s, 1H, NH]. 13CNMR: 40.5, 95.1, 99.8, 104.9 (2), 112.5, 115.4, 116.2, 119.5 (2), 125.8 (2), 127.9, 128.2 (2), 133.8, 137.6, 138.4, 143.1, 144.6, 146.7, 152.5, 172.5, 189.3. MS m/z (%): 492 (M+) (4.72), 91 (100). Anal. Calcd. For C25H21ClN4O3S (492.98): C, 60.91; H, 4. 29; N, 11.36. Found: C, 61.19; H, 4.52; N, 11.01.
Yield, 76 %; m.p. 310.0 °C. IR: 3367 (NH), 3066 (arom.), 2939, 2877 (aliph.), 1724, 1635 (2CO), 1593 (CN), 1369,1184 (SO2), 833 (CCl). 1HNMR: 2.0 [s, 3H, COCH3], 3.5 [s, 3H, N-CH3], 6.3, 7.3 [2d, 2H, 2CH quinoline, J = 7.4 Hz], 6.6, 7.6 [2d, 2H, CH = CH, J = 7.6 Hz], 7.7–8.6 [m, 12H, Ar–H + SO2NH], 12.0 [s, 1H, NH]. 13CNMR: 23.6, 40.5, 97.8, 101.3, 112.7(2), 115.1, 116.0, 119.5, 120.2 (2), 125.9 (2), 128.1, 129.5 (2), 130.2, 134.6, 142.8 (2), 144.5, 146.9, 150.0, 152.4, 163.1, 186.7, 189.6. MS m/z (%): 535 (M+) (9.36), 74 (100). Anal. Calcd. For C27H23ClN4O4S (535.01): C, 60.61; H, 4.33; N, 10.47. Found: C, 60.29; H, 4.59; N, 10.19.
N-carbamimidoyl-4-(E)-3-(4-(E)-7-chloro-1-methylquinolin-4(1H)-ylideneamino)- phenyl)-3-oxoprop-1-enylamino)benzenesulfonamide (7)
Yield, 81 %; m.p. 146.6 °C. IR: 3431, 3336, 3209 (NH2, NH), 3100 (arom.), 2957, 2858 (aliph.), 1635 (CO), 1593 (CN), 1373, 1178 (SO2), 827 (CCl). 1HNMR: 3.4 [s, 3H, NCH3], 6.2, 7.6 [2d, 2H, 2CH quinoline, J = 7.3 Hz], 6.1, 7.4 [2d, 2H, CH = CH, J = 7.4 Hz], 7.7–8.6 [m, 13H, Ar–H + NH2], 9.4 [s, 1H, NH imino], 10.3, 12.0 [2s, 2H, NH + SO2NH]. 13CNMR: 40.5, 94.9, 99.4, 112.8 (2), 115.2, 116.1, 119.5, 120.2 (2), 125.8 (2), 127.8, 129.5 (2), 131.2, 133.8, 134.6, 138.0, 142.9, 144.8, 145.1, 158.2, 158.5, 172.8, 189.2. MS m/z (%): 535 (M+) (7.74), 76 (100). Anal. Calcd. For C26H23ClN6O3S (535.02): C, 58.37; H, 4. 33; N, 15.71. Found: C, 58.55; H, 4.09; N, 15.47.
4-(E)-3-(4-(E)-7-chloro-1-methylquinolin-4(1H)-ylideneamino) phenyl)-3-oxoprop-1-en-ylamino)-N-(3-methylisoxazol-5-yl)benzenesulfonamide (8)
Yield, 86 %; m.p. 192.5 °C. IR: 3446, 3215 (NH), 3088 (arom.), 2970, 2883 (aliph.), 1635 (CO), 1616 (CN), 1369,1159 (SO2), 821 (CCl). 1HNMR: 2.3 [s, 3H, CH3], 3.4 [s, 3H, NCH3], 6.1, 7.3 [2d, 2H, 2CH quinoline, J = 7.7 Hz], 6.6, 7.6 [2d, 2H, CH = CH, J = 7.4 Hz], 6.7 [s, 1H, CH isoxazole], 7.7–8.5 [m, 12H, Ar–H + SO2NH], 12.0 [s,1H, NH]. 13CNMR: 12.4, 40.5, 95.5, 100.4, 104.7, 113.0 (2), 115.5, 116.3, 119.5, 120.1 (2), 125.8, 129.2 (2), 132.9 (2), 133.7, 134.6, 142.8, 144.9, 145.2, 146.8, 147.4, 153.7, 154.3, 158.5, 170.5, 186.9. MS m/z (%): 574 (M+) (1.62), 58 (100). Anal. Calcd. For C29H24ClN5O4S (574.05): C, 60.68; H, 4. 21; N, 12.20. Found: C, 60.39; H, 4.54; N, 12.49.
4-(E)-3-(4-(E)-7-chloro-1-methylquinolin-4(1H)-ylideneamino) phenyl)-3-oxoprop-1-en-ylamino)-N- (3,4-dimethylisoxazol-5-yl)benzenesulfonamide (9)
Yield, 77 %; m.p. 212.1 °C. IR: 3381, 3230 (NH), 3099 (arom.), 2926, 2819, 2763 (aliph.), 1635 (CO), 1589 (CN), 1373, 1180 (SO2), 810 (CCl). H1 NMR: 1.9, 2.6 [2s, 6H, 2CH3], 3.4 [s, 3H, NCH3], 6.2, 7.3 [2d, 2H, 2CH quinoline, J = 7.6 Hz], 6.6, 7.5 [2d, 2H, CH = CH, J = 7.5 Hz], 7.6–8.6 [m, 11H, Ar–H], 10.4, 12.0 [2s,2H, NH +SO2NH]. 13CNMR: 6.4, 10.8, 40.5, 95.5, 100.3, 102.9, 104.4 (2), 115.5, 116.4, 119.2, 120.7 (2), 126.1, 127.3 (2), 129.5 (2), 133.6, 134.1, 135.2, 142.9, 144.4, 145.4, 147.7, 157.4, 157.9, 161.5, 172.5, 189.3. MS m/z (%): 588 (M+) (11.22), 55 (100). Anal. Calcd. For C30H26ClN5O4S (588.08): C, 61.27; H, 4. 46; N, 11.91. Found: C, 61.01; H, 4.17; N, 11.64.
4-(E)-3-(4-(E)-7-chloro-1-methylquinolin-4(1H)-ylideneamino) phenyl)-3-oxoprop-1-en-ylamino)-N-(1-phenyl-1H-pyrazol-5-yl)benzenesulfonamide (10)
Yield, 80 %; m.p. 94.3 °C. IR: 3417, 3230 (NH), 3064 (arom.), 2966, 2827 (aliph.), 1635 (CO), 1591 (CN), 1373, 1180 (SO2), 763 (CCl). 1HNMR: 3.4 [s, 3H, NCH3], 6.2, 7.5 [2d, 2H, 2CH quinoline, J = 7.5 Hz], 6.5, 7.2 [2d, 2H, CH = CH, J = 7.7 Hz], 7.8–8.6 [m, 18H, Ar–H], 10.2, 12.0 [2s, 2H, NH +SO2NH]. 13CNMR: 40.5, 97.3, 100.0, 103.5, 111.6 (2), 113.0, 116.2, 118.6, 123.7 (2), 124.7 (2), 125.1, 129.0 (2), 129.1, 129.2 (2), 129.3 (2), 129.4, 129.5, 135.1, 136.2, 137.7, 138.9, 140.2, 142.7, 144.3, 146.1, 156.8, 172.4, 186.8. MS m/z (%): 635 (M+) (4.43), 103 (100). Anal. Calcd. For C34H27ClN6O3S (635.13): C, 64.30; H, 4. 28; N, 13.23. Found: C, 64.56; H, 4.52; N, 13.49.
4-(E)-3-(4-(E)-7-chloro-1-methylquinolin-4(1H)-ylideneamino) phenyl)-3-oxoprop-1-en-ylamino)-N-(thiazol-2-yl) benzenesulfonamide (11)
Yield, 69 %; m.p. 172.7 °C. IR: 3341, 3219 (NH), 3101 (arom.), 2937, 2869 (aliph.), 1635 (CO), 1589 (CN), 1373, 1180 (SO2), 773 (CCl). 1HNMR): 3.4 [s, 3H, N-CH3], 5.8, 7.6 [2d, 2H, 2CH quinoline, J = 7.0 Hz], 6.2, 7.2 [2d, 2H, CH = CH, J = 7.3 Hz], 6.6, 6.8 [2d, 2CH thiazole, J = 7.9 Hz], 7.7–8.6 [m, 11H, Ar–H], 10.2, 12.0 [2s, 2H, NH + SO2NH]. 13CNMR: 40.5, 95.1, 99.8, 108.5, 112.9(2), 115.3, 116.2, 119.5, 120.1 (2), 125.9, 128.3 (2), 129.5 (2), 133.0, 134.6, 135.7, 136.9, 143.0, 144.6, 145.1, 146.9, 152.6, 168.4, 172.5, 186.6. MS m/z (%): 576 (M+) (8.99), 101 (100). Anal. Calcd. For C28H22ClN5O3S2 (576.09): C, 58.38; H, 3.85; N, 12.16. Found: C, 58.23; H, 4.11; N, 12.46.
4-(E)-3-(4-(E)-7-chloro-1-methylquinolin-4(1H)-ylideneamino) phenyl)-3-oxoprop-1-en-ylamino)-N-(5-methyl-1,3,4-thiadiazol-2-yl)benzenesulfonamide (12)
Yield, 82 %; m.p. 304.3 °C. IR: 3246, 3115 (NH), 3088 (arom.), 2937, 2859 (aliph.), 1635 (CO), 1589 (CN), 1383, 1182 (SO2), 769 (CCl). 1HNMR: 2.4 [s, 3H, CH3 thiadiazole], 3.4 [s, 3H, N-CH3], 6.2, 7.6 [2d, 2H, 2CH quinoline, J = 7.6 Hz], 6.6, 7.2 [2d, 2H, CH = CH, J = 7.8 Hz], 7.7–8.5 [m, 11H, Ar–H], 10.3, 12.0 [2s, 2H, NH + SO2NH]. 13CNMR: 16.4, 40.5, 95.2, 99.9, 115.4 (2), 116.3, 120.2, 120.4, 125.2 (2), 127.9, 128.2 (2), 129.5 (2), 133.1, 134.8, 135.3, 143.0, 143.8, 144.6, 144.8, 152.1, 154.7, 168.3, 172.4, 189.3. MS m/z (%): 591 (M+) (25.7), 178 (100). Anal. Calcd. For C28H23ClN6O3S2 (591.10): C, 56.89; H, 3.92; N, 14.22. Found: C, 56.59; H, 3.68; N, 14.49.
Yield, 91 %; m.p. 177.1 °C. IR: 3323, 3219 (NH), 3080 (arom.), 2939, 2849 (aliph.), 1654 (CO), 1596 (CN), 1375, 1178 (SO2), 773 (CCl). 1HNMR: 3.4 [s, 3H, NCH3], 6.2, 7.6 [2d, 2H, 2CH quinoline, J = 7.6 Hz], 6.6, 7.3 [2d, 2H, CH = CH, J = 7.1 Hz], 7.7–8.6 [m, 15H, Ar–H],10.3, 12.0 [2s, 2H, NH +SO2NH]. 13CNMR: 40.5, 95.3, 100.0, 104.9, 112.9 (2), 113.7, 115.3, 116.4, 119.5, 120.2 (2), 128.2, 129.5 (2), 132.9 (2), 133.7, 134.4, 135.7, 140.3, 142.9, 143.9, 144.6, 145.2, 146.7, 152.4, 153.4, 172.5, 186.6. MS m/z (%): 570 (M+) (18.2), 79 (100). Anal. Calcd. For C30H24ClN5O3S (570.06): C, 63.21; H, 4. 24; N, 12. 29. Found: C, 63.47; H, 4.52; N, 12.55.
Yield, 65 %; m.p. 212.9 °C. IR: 3367, 3179 (NH), 3078 (arom.), 2937, 2870 (aliph.), 1635 (CO), 1577 (CN), 1375,1178 (SO2), 883 (CCl). 1HNMR: 3.4 [s, 3H, N-CH3], 6.2, 7.3 [2d, 2H, 2CH quinoline, J = 7.4 Hz], 6.6, 7.6 [2d, 2H, CH = CH, J = 7.5 Hz], 7.0–8.6 [m, 15H, Ar–H + SO2NH], 12.0 [s, 1H, NH]. 13CNMR: 40.5, 95.5, 100.3, 112.6 (2), 115.9, 116.0, 119.5, 120.2 (2), 125.8, 128.1 (2), 130.3 (2), 132.9, 133.7, 134.3, 134.6, 142.8, 144.3, 145.2, 146.9, 157.6 (2), 157.7, 158.6, 172.5, 186.6. MS m/z (%): 571 (M+) (33.2), 158 (100). Anal. Calcd. For C29H23ClN6O3S (571.05): C, 60.99; H, 4. 06; N, 14.72. Found: C, 61.28; H, 4.32; N, 14.47.
Yield, 78 %; m.p. 274.8 °C. IR: 3366, 3259 (NH), 3076 (arom.), 2962, 2870 (aliph.), 1635 (CO), 1562 (CN), 1373, 1182 (SO2), 773 (CCl). 1HNMR: 2.3 [s, 3H, CH3], 3.4 [s, 3H, NCH3], 6.2, 7.6 [2d, 2H, 2CH quinoline, J = 7.3 Hz], 6.6, 7.3 [2d, 2H, CH = CH, J = 7.4 Hz], 7.5–8.5 [m, 13H, Ar–H], 10.3, 12.0 [2s, 2H, NH + SO2NH]. 13CNMR: 23.7, 40.5, 95.4, 100.2, 104.9, 112.4 (2), 114.9, 115.2, 115.8, 119.6 (2), 128.2, 129.5 (2), 130.5 (2), 132.9, 134.4, 134.6, 142.8, 144.3, 145.3, 146.7, 152.4, 157.4, 158.0, 168.6, 172.5, 186.6. MS m/z (%): 585 (M+) (9.36), 172 (100). Anal.Calcd. For C30H25ClN6O3S (585.08): C, 61.59; H, 4.31; N, 14.36. Found: C, 61.29; H, 4.59; N, 14.09.
Yield, 91 %; m.p. 97.9 °C. IR: 3354, 3239 (NH), 3055 (arom.), 2947, 2861 (aliph.), 1635 (CO), 1593 (CN), 1371, 1180 (SO2), 864 (CCl). 1HNMR: 2.2 [s, 6H, 2CH3], 3.4 [s, 3H, NCH3], 5.8, 7.2 [2d, 2H, 2CH quinoline, J = 7.3 Hz], 6.6, 7.7 [2d, 2H, CH = CH, J = 7.5 Hz], 7.8–8.5 [m, 13H, Ar–H + SO2NH], 12.0 [s, 1H, NH]. 13CNMR: 23.4 (2), 40.2, 95.3, 100.1, 104.7, 112.3 (2), 113.8, 114.6, 115.4, 120.6 (2), 125.7, 129.4 (2), 130.8 (2), 132.9, 133.7, 134.8, 144.8, 145.0, 146.9, 157.1, 167.7, 167.8 (2), 172.7, 189.3. MS m/z (%): 599 (M+) (2.71), 109 (100). Anal. Calcd. For C31H27ClN6O3S (599.10): C, 62.15; H, 4. 54; N, 14.03. Found: C, 62.36; H, 4.19; N, 14.29.
Yield, 84 %; m.p. 264.5 °C. IR: 3396, 3221 (NH), 3101 (arom.), 2979, 2865 (aliph.), 1637 (CO), 1593 (CN), 1371, 1178 (SO2), 862 (CCl). 1HNMR: 3.4 [s, 3H, NCH3], 3.9 [s, 3H, OCH3], 5.9, 7.4 [2d, 2H, 2CH pyrimidine, J = 7.1 Hz], 6.2, 7.3 [2d, 2H, 2CH quinoline, J = 7.8 Hz], 6.6, 7.6 [2d, 2H, CH = CH, J = 7.4 Hz], 7.7–8.6 [m, 11H, Ar–H], 10.3, 12.0 [2s, 2H, NH + SO2NH]. 13CNMR: 40.5, 56.7, 95.4, 100.2, 105.0 (2), 112.6, 115.1, 116.0, 119.6 (2), 125.8, 128.2 (2), 129.8 (2), 130.1, 133.7, 134.6, 142.8, 144.2, 144.9, 145.3, 149.9, 151.7, 152.4, 153.3, 172.5, 186.6, 186.9. MS m/z (%): 601 (M+) (11.87), 74 (100). Anal. Calcd. For C30H25ClN6O4S (601.08): C, 59.95; H, 4.19; N, 13.98. Found: C, 60.23; H, 3.81; N, 13.69.
Yield, 87 %; m.p. 232.6 °C. IR: 3387, 3201 (NH), 3097 (arom.), 2980, 2839 (aliph.), 1635 (CO), 1589 (CN), 1352, 1178 (SO2), 771 (CCl). 1HNMR: 3.4 [s, 3H, N-CH3], 3.7 [s, 6H, 2OCH3], 5.9 [s, 1H, CH pyrimidine], 6.2, 7.3 [2d, 2H, 2CH quinoline, J = 7.5 Hz], 6.6, 7.2 [2d, 2H, CH = CH, J = 7.8 Hz], 7.4–8.5 [m, 11H, Ar–H], 10.3, 12.0 [2s, 2H, NH + SO2NH]. 13CNMR: 40.5, 54.1, 54.9, 85.1, 95.6, 100.4, 104.9 (2), 115.4, 116.2, 119.5, 120.2 (2), 128.1, 129.8 (2), 132.7 (2), 132.9, 133.7, 134.6, 142.7, 144.2, 144.9, 145.2, 152.3, 160.8, 161.0, 164.7, 172.0, 186.6. MS m/z (%): 631 (M+) (34.47), 154 (100). Anal. Calcd. For C31H27ClN6O5S (631.10): C, 59.00; H, 4.31; N, 13.32. Found: C, 58.76; H, 4.62; N, 13.03.
Yield, 83 %; m.p. 110.5 °C. IR: 3365, 3230 (NH), 3095 (arom.), 2941, 2863 (aliph.), 1635 (CO), 1577 (CN), 1375, 1159 (SO2), 773 (CCl). 1HNMR: 3.4 [s, 3H, N-CH3], 3.6, 3.8 [2s, 6H, 2OCH3], 6.2, 7.2 [2d, 2H, 2CH quinoline, J = 7.6 Hz], 6.6, 7.6 [2d, 2H, CH = CH, J = 7.7 Hz], 7.7–8.4 [m, 11H, Ar–H], 8.5 [s, 1H, CH pyrimidine], 10.3, 12.0 [2s, 2H, NH + SO2NH]. 13CNMR: 40.5, 54.2, 56.5, 95.3, 100.1, 112.6 (2), 115.8, 119.4, 120.8 (2), 127.9, 129.5 (2), 130.2, 133.0 (2), 133.8, 134.7, 142.9, 144.7, 145.1, 146.9, 149.8, 150.9, 152.0, 154.3, 161.7, 172.5, 186.6. MS m/z (%): 631 (M+) (22.13), 189 (100). Anal. Calcd. For C31H27ClN6O5S (631.10): C, 59.00; H, 4.31; N, 13.32. Found: C, 59.31; H, 4.04; N, 13.10.
Yield, 89 %; m.p. 100.1 °C. IR: 3374, 3231 (NH), 3086 (arom.), 2978, 2848 (aliph.), 1635 (CO), 1589 (CN), 1363, 1151 (SO2), 819 (CCl). 1HNMR: 3.4 [s, 3H, N-CH3], 5.8, 6.6 [2d, 2H, 2CH quinoline, J = 7.2 Hz], 6.2, 6.8 [2d, 2H, CH = CH, J = 7.5 Hz], 7.0–8.5 [m, 16H, Ar–H + SO2NH], 10.8, 12.0 [2s, 2H, 2NH]. 13CNMR: 40.5, 91.1, 95.5, 100.4, 113.0, 115.1 (2), 115.4, 116.3, 119.5, 119.6, 119.8, 120.0, 120.6, 125.8, 129.0 (2), 129.8 (2), 132.1, 132.8, 133.5, 137.3, 140.7, 143.6, 144.3, 145.3, 146.8, 147.0, 154.3, 173.4, 189.8. MS m/z (%): 609 (M+) (51.63), 117 (100). Anal. Calcd. For C32H25ClN6O3S (609.10): C, 63.10; H, 4.14; N, 13.80. Found: C, 62.76; H, 4.40; N, 14.18.
Yield, 66 %; m.p. 209.9 °C. IR: 3334, 3212 (NH), 3064 (arom.), 2981, 2863 (aliph.), 1635 (CO), 1591 (CN), 1375, 1178 (SO2), 767 (CCl). 1HNMR: 3.4 [s, 3H, NCH3], 6.2, 7.3 [2d, 2H, 2CH quinoline, J = 7.0 Hz], 6.6, 7.2 [2d, 2H, CH = CH, J = 7.3 Hz], 7.5–8.6 [m, 16H, Ar–H], 10.3, 12.0 [2s, 2H, NH + SO2NH]. 13CNMR: 40.5, 95.5, 100.3, 112.7 (2), 115.1, 116.0, 119.5,120.2 (2), 125.1, 126.3, 127.2, 127.3, 129.1, 130.1 (2), 131.1 (2), 132.8, 133.0, 133.8, 134.7, 138.0, 138.1, 139.2, 140.3, 142.7, 144.3, 149.7, 152.1, 169.6, 186.7. MS m/z (%): 621 (M+) (10.76), 177 (100). Anal. Calcd. For C33H25ClN6O3S (621.11): C, 63.81; H, 4.06; N, 13.53. Found: C, 63.49; H, 4.34; N, 13.23.
Compound 4 (3.65gm, 0.01 mol) and dapson (2.48 g, 0.01 mol) was added into ethanol (10 mL) and acetic acid (5 mL). The reaction was refluxed for 9 h and the solid obtained while hot was recrystallized from dioxane to give 22.
Yield, 69 %; m.p. 95.2 °C. IR: 3446, 3348, 3213 (NH2, NH), 3100 (arom.), 2956, 2838 (aliph.), 1635 (CO), 1591 (CN), 1369, 1180 (SO2), 821 (CCl). 1HNMR: 3.4 [s, 3H, NCH3], 5.9 [s, 2H, NH2], 6.1, 7.4 [2d, 2H, 2CH quinoline, J = 7.8 Hz], 6.5, 6.6 [2d, 2H, CH = CH, J = 7.9 Hz], 7.5–8.6 [m, 15H, Ar–H], 12.0 [s, 1H, NH]. 13CNMR: 40.5, 95.5, 100.3, 113.3 (2), 113.4, 115.8 (2), 116.6, 119.3, 125.8 (2), 128.9 (4), 129.6 (2), 132.9 (3), 133.7, 135.9, 142.8, 144.2, 145.2, 146.9, 152.4, 154.3, 172.5, 186.6. MS m/z (%): 569 (M+) (19.87), 90 (100). Anal. Calcd. For C31H25ClN4O3S (569.07): C, 65.43; H, 4.43; N, 9.85. Found: C, 65.13; H, 4.71; N, 9.57.
Compound 4 (7.30 gm, 0.02 mol) and Dapson (2.48 g, 0.01 mol) was added into ethanol (20 mL) containing acetic acid (10 mL). Reaction was refluxed for 12 h and the solid obtained while hot was recrystallized from acetic acid to give 23.
Yield, 60 %; m.p. 186.9 °C. IR: 3143 (NH), 3078 (arom.), 2964, 2842 (aliph.), 1635 (CO), 1570 (CN), 1375, 1180 (SO2), 819 (CCl). 1HNMR: 3.4 [s, 6H, 2N-CH3], 6.2, 7.3 [2d, 4H, 4CH quinoline, J = 7.7 Hz], 6.6, 7.2 [2d, 4H, 2CH = CH, J = 7.8 Hz], 7.4–8.5 [m, 22H, Ar–H], 9.3, 12.0 [2s, 2H, 2NH]. 13CNMR: 40.5 (2), 95.8 (2), 100.7 (2), 104.9 (2), 113.4 (4), 115.8 (2), 116.7 (2), 119.6 (4), 125.8 (4), 129.7 (4), 132.8 (4), 133.6 (2), 134.6 (2), 142.6 (2), 144.0 (2), 145.9 (2), 146.7 (2), 152.3 (2), 172.5 (2), 186.7. MS m/z (%): 889 (M+) (6.48), 272 (100). Anal. Calcd. For C50H38Cl2N6O4S (889.85): C, 67.49; H, 4.30; N, 9.44. Found: C, 67.83; H, 4.66; N, 9.12.
The cytotoxic activity in vitro of the novel synthesized compounds was measured using the sulforhodamine B stain (SRB) assay and the method of Skehan et al. . The in vitro anticancer screening was done at pharmacognosy Department, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia. Cells were plated in 96-multiwell plate (104 cells/well) for 24 h before treatment with the compound(s) to allow attachment of cell to the wall of the plate. Test compounds were dissolved in dimethylsulfoxide. Different concentrations of the compound under test (10, 25, 50, and 100 μΜ) were added to the cell monolayer. Triplicate wells were prepared for each individual concentration. Monolayer cells were incubated with the compound(s) for 48 h at 37 °C and in an atmosphere of 5 % CO2. After 48 h, cells were fixed, washed and stained for 30 min with 0.4 % (Wt/vol) SRB dissolved in 1 % acetic acid. Excess unbound dye was removed by four washes with 1 % acetic acid and attached stain was recovered with Trise-EDTA buffer. Color intensity was measured using an enzyme-linked immunosorbent assay ELISA reader. Optical density was read at 510 nm. The relation between the surviving fraction and drug concentration was plotted to get the survival curve after the specified time The molar concentration required for 50 % inhibition of cell viability (IC50) was calculated and compared to the reference drug 2′,7′-dichlorofluorescein (DCF). The results are given in Table 1.
“All the molecular modeling studies were carried out on an Intel Pentium 1.6 GHz processor, 512 MB memory with Windows XP operating system using Molecular Operating Environment (MOE, 10.2008) software. All the minimizations were performed with MOE until a RMSD gradient of 0.05 kcal mol−1 Å−1 with MMFF94X force field and the partial charges were automatically calculated. The protein data bank file (PDB: 3S2A) was selected for this purpose. The file contains PI3K enzyme co-crystallized with a quinoline ligand obtained from protein data bank. The enzyme was prepared for docking studies where: (i) Ligand molecule was removed from the enzyme active site. (ii) Hydrogen atoms were added to the structure with their standard geometry. (iii) MOE Alpha Site Finder was used for the active sites search in the enzyme structure and dummy atoms were created from the obtained alpha spheres. (iv) The obtained model was then used in predicting the ligand enzymes interactions at the active site”.
In summary, we had synthesized a novel series of benzene-sulfonamide derivatives. Seven products 1, 2, 4, 7, 11, 14 and 17 presented sound anticancer activity hostile to lung (A594 Raw), hela, and colorectal (lovo) cancer cell lines with better or comparable activity to DCF. Moreover, molecular docking for these active compounds showed proper fitting on the active site of PI3K enzyme suggesting their action as inhibitors for this enzyme but more investigation should be carried out in the future to explore precisely the mechanism of the action of the synthesized derivatives.
MMG, MSA designed and contributed in synthesis. MSA carried out biological screening. YMN carried out molecular docking study. AAA contributed in experimental interpretation. All authors read and approved the final manuscript.
The authors would like to extend their sincere appreciation to the Deanship of Scientific Research at King Saud University for its funding of this research through the Research Group Project no. RGP-VPP-302.
The authors declare that they have no competing interests.
Mostafa M. Ghorab, Phone: +966-53-4292-860, Email: moc.oohay@barohgsmm.
Mansour S. Alsaid, Email: as.ude.usk@diaslasm.
Mohammed S. Al-Dosari, Email: moc.oohay@irasodsm.
Yassin M. Nissan, Email: email@example.com.
Abdullah A. Al-Mishari, Email: moc.liamtoh@33irahsm.
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