Pyridazine-fuzed carbazoles: Synthesis, reactivity, and antitumor activity

Syntheses of Methyl 4,5-Dihydro-2H-Pyrazolo[3,4-a]Carbazole-3-Carboxylates

The syntheses of methyl 4,5-dihydro-2 H-pyrazolo[3,4- a]carbazole-3-carboxylates (4a–e) from 1-oxo-1,2,3,4-tetrahydrocarbazoles (1a–e) using the intermediates, methyl 2-(1-oxo-2,3,4,9-tetrahydro-1 H-carbazol-2-yl)-2-oxoacetates (3a–e) are discussed. The formation of the end products was characterised using spectral and analytical techniques.

Synthesis of pyrazolino- and thiopyrimido- fused carbazoles from 2-ethylidene-3,4-dihydrocarbazol-1(2H)-ones

Annelated carbazoles namely, 3-methyl-1,2,3,3a,4,5,5a,10,10a,10b-decahydropyrazolino[4,5-a]carbazoles, 4a–e and 4-methyl-1,3,4,5,6,11-hexahydropyrimido[4,5-a]carbazole-2-thiones 5a–e were synthesised in excellent yields from 2-ethylidene-3,4-dihydrocarbazol-1(2H)-ones 2a–e, derived from the easily accessible 3,4-dihydrocarbazol-1(2H)-ones 1a–e.

Synthesis, Antibacterial, and Antifungal Activities of Novel Pyridazino Carbazoles

Strategy to synthesize novel carbazole, that is, 2,3-dihydro-2-phenyl-6H-pyridazino[4, 5-b]carbazole-1,4-dione (2), is developed as key reaction. This novel compound showed ideal reactivity toward different functional groups like methyl, carboxylic, nitro, piperazine, and amine; thus series of its derivatives are synthesized sequentially with the aim to fuel up the carbazole compounds with new versatile derivatives. All compounds were investigated for their activity against bacteria (MRSA andS. typhi) and fungi (Candida albicans). Among tested compounds3,6, and8exhibited pronounced antibacterial activities while2,5, and9also showed moderate activities.2,3,5,7, and9showed stronger antifungal activity againstCandida albicanscomparable to positive control.

Synthesis and in-vitro antitumor activity of 1-[3-(indol-1-yl)prop-1-yn-1-yl]phthalazines and related compounds

A series of novel 3-(indol-1-yl)prop-1-yn-1-yl-substituted phthalazines and related azines was prepared via a concise pathway by palladium-catalyzed cross-coupling of appropriate halo-azines and N-propargylindoles. Some of the compounds exhibited significant antitumor activity in an in-vitro assay.

Synthetic Utility of 2-Benzylidene-1,2,3,4-tetrahydrocarbazol-1-ones. A Facile Syntheses of Pyrano[2,3-a]carbazoles, Pyrido[2,3-a]carbazoles and Pyridazino[3,4-a]carbazoles

2-Benzylidene-1,2,3,4-tetrahydrocarbazol-1-ones 1, synthons easily accessible from the corresponding 1,2,3,4-tetrahydrocarbazol-1-ones, were utilized in the synthesis of fused carbazoles. In accordance, the reaction of 1 with malononitrile yielded pyrano[2,3-a]carbazoles 2a and 2d or pyrido[2,3-a]carbazoles 2b, 2c and 2e. The reaction of 1 with thiocarbohydrazide or thiosemicarbazide under basic conditions afforded pyridazino[3,4-a]carbazoles 3 or thiol substituted pyridazino[3,4-a]carbazoles 4, respectively, in good yields. The formation of the hitherto unknown compounds was well supported by plausible mechanisms. The products formed were characterized by IR, 1H NMR, 13C NMR, mass spectral methods and by elemental analysis.