Quinoline derivatives, inhibition

When reacted with dimethyl acetylenedicarboxylate, the amines produced ben-zotriazolylaminobutendioates 188 accompanied by A-benzotriazolyl substituted 2-pyridones only in the case of 5-amino-2-methyl-2//-benzotriazole, the triazolo-9,10-dihydrobenzo[d]azepine and an unusual cyclization product, triazolo-2-oxindole (convertible into 2-methyltriazolo[4,5-/]carbostyril-9-carboxylate) were formed. The quinolones 189 were aromatized to chloroesters 190 these in turn were hydrolyzed to chloroacids 191 and decarboxylated to 9-chlorotriazolo[4, 5-/]quinolines 192 (Scheme 58) (93H259). The chlorine atom could be replaced with 17 various secondary amines to give the corresponding 9-aminoalkyl(aryl) derivatives 193, some of which exhibit both cell selectivity and tumor growth inhibition activity at concentrations between 10 and 10 " M (95FA47). 

It was known that the K+ -competitive imidazopyridine compound, SCH28080, inhibits acid secretion. Then, many reversible inhibitors were developed. These contain protonatable nitrogens but have a variety of core structures such as imidazopyiidines, piperidinopyr-idines, substituted 4-phenylaminoquinolines, pyrrolo [3,2-c]quinolines, guanidinothiazoles, and 2,4-diamino-pyrimidine derivatives. Several reversible inhibitors have been in clinical trials. 

HETE (138) is known to inhibit 5-LO [334]. A group at Revlon created a series of combined 5-LO inhibitors/LT antagonists derived conceptually from the structure of 15-HETE. REV 5901A (139) [335], the best of the series, inhibited 5-HETE release from rat ISN (0.12 //M) and was fairly selective with respect to CO and 12-LO inhibition. The quinoline could be replaced by another lipophilic aromatic group, but potency decreased (naphthalene was 40-fold less potent, and substituted phenyl was 5- to 20-fold less active). Pyridines were active but also less potent 2-pyridyl was only 4-fold less active, while 3- and 4-pyridyl were 20-fold weaker. Ortho-and pnra-substituted phenylene groups were less active. Elimination of the side-chain hydroxyl to the olefin caused a loss of activity, as did the use of shorter alkyl chains. 

Camptothecin (Fig. 4), a quinoline alkaloid, is a potent anti-neoplastic agent that inhibits DNA topoisomerase I. Accumulation of up to 8 mg of camptothecin/L was reported for hairy root cultures of Ophiorriza pumila transformed with A. rhizogenes. Cotyledon-derived calluses of Nothapodytes foetida were able to produce not only camptothecin, but also its derivatives also known to exhibit anticancer activity. 

Partially hydrogenated quinoline cores are also present in some important bioactive compounds. For example, the 4-aza-analogs of Podophyllotoxin, a plant lignan that inhibits microtubule assembly, revealed to be more potent and less toxic anticancer agents. In 2006, Ji s group reported a green multicomponent approach to a new series of these derivatives, consisting of the reaction of either tetronic acid or 1,3-indanedione with various aldehydes and substituted anilines in water under microwave irradiation conditions (Scheme 26) [107]. For this efficient and eco-friendly transformation, the authors proposed a mechanism quite similar to the one that was postulated for the synthesis of tetrahydroquinolines in the precedent section. 

Oxime derivatives of heterocyclic compounds, such as pyrrole and quinoline, were proposed as anti-inflammatory agents, probably due to their ability to inhibit the biosynthesis of leukotrienes . Inhibition of 5-lipogenase by oximes of biphenyl sulfides , and by 0-aIkylcarboxylate oximes of indole " , were suggested as key leads for the development of efficient anti-inflammatory drugs. 

The antitumor activities of indole and isatin oximes and of furan oximes were studied by several investigators. Furan oximes were found to inhibit DNA, RNA and protein synthesis in lipoid leukemia cells. Derivatives of quinoline oximes were also shown to possess antitumor activity , and glucosinolates, 15, were suggested as cancer-preventive agents . ... 

Preparation of a somewhat more complex leukotriene antagonist begins by aldol condensation of the methyl carbanion from quinoline (29-1) with meta-phthalalde-hyde (29-2) to give the stilbene-like derivative (29-3) dimer formation is presumably inhibited by the use of excess aldehyde. Reaction of that product with A,A-dimethyl-3-mercaptopropionamide in the presence of hexa-methylsilazane affords the silyl ether (29-4) of the hemimercaptal. Treatment of that intermediate with ethyl 3-mercaptopropionate leads to the replacement of the silyl ether by sulfur and the formation of the corresponding thioacetal (29-5). Saponification of the ester group leads to the carboxylic acid and thus to verlukast (29-6) [33]. 

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