4-Alkylamino-2-chloroquinoline-3-carbonitriles 4a - c react with NaN3 to give the corresponding tetrazolo[1,5-a]quinoline-4-carbonitriles 5a - c which are converted into 2-amino-quinoline-3-carbonitriles 8a - c by reaction with PPh3 via an iminophosphorane and subsequent hydrolysis. On the other hand, the new 3,4-diamino-1H-pyrazolo[4,3-c]quinoline (11) was prepared by fusion of the aminoquinolines 8a - c with hydrazine hydrate. Diazotization of 11 followed by reaction with NaN3 yielded the novel tetracyclic ring system 3-azido-1H-1,2,4,5,6,6a-hexaazabenzo[a]indacene (13)
2-Substituted ylidene-N-phenylhydrazinecarbothioamides 1a-f reacted with 2,3-dicyano-5,6-dichloro-1,4-benzoquinone, 2,3,5,6-tetrachloro-1,4-benzoquinone, 2,3-dichloro-1,4-naphthoquinone, 2,3-dicyano-1,4-naphthoquinone and 3,4,5,6-tetrachloro-1,2-benzoquinone to form substituted N-phenylindazolecarbothioamides, substituted benzindazolecarbothioamides and substituted benzophthalazinediones. Rationales for the role of benzo-and naphthoquinones in heterocyclization of compounds 1a-f are presented.
Reaction of 2,4-dichloroquinoline-3-carbonitrile (1) with 4-methylpiperidine gave 2-chloro-4-(4-methylpiperidin-1-yl)quinoline-3-carbonitrile(2). Acid hydrolysis of 2 afforded the corresponding 2-quinolinones 3, which were N-alkylated in DMF to form the 1-methyl, -ethyl and -phenacyl quinolinones 6a-c. Fusion of 6a-c with hydrazine hydrate gave the 3-aminopyrazolo[4,3-c]quinolin-4-ones 8a-c. Diazotisation of 8a,b followed by reaction with sodium azide afforded the novel 3-azidopyrazolo[4,3-c]quinolin-4-ones 9a,b.
Fused pyridine derivatives R 0450 Fused Quinoline Heterocycles. Part 8. Synthesis of Polyfunctionally Substituted Pyrazolo[4,3-c]quinolin-4(5H)-ones. -A new, efficient and convenient procedure for the synthesis of pyrazolo[4,3-c]quinolinone derivatives such as (VII) and (VIII) starts from readily available dichloroquinoline-3-carbonitrile (I). -(MEKHEIMER*, R. A.; REFAEY, S. M.; SADEK, K. U.; HAMEED, A. M. A.; IBRAHIM, M. A.; SHAH, A.; J. Chem. Res. 2008, 12, 735-737; Dep. Chem., Fac. Sci.,
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