An Efficient Synthesis of Pyrazolo[3,4-b]quinolin-3-amine and Benzo[b][1,8]naphthyridine Derivatives

Abstract

2-Oxo-4-phenyl-1,2,5,6,7,8-hexahydroquinoline-3-carbonitrile (10) reacted with hydrazine hydrate, phenylisothiocyanate or benzoyl chloride to give derivatives 12, 13 and 15, respectively. The latter two products were treated with hydrazine hydrate to afford pyrozole[3,4-b]quinolines derivatives 14 and 16, respectively. Compound 10 also reacted with acetonitrile dimer or malononitrile dimer to yield benzo [b][1,8]-naphthyridine derivatives. A single crystal X-ray crystallographic analysis was performed on compound 10, confirming its structure.

Efficient One-Step Synthesis of Substituted-pyrazolo[3,4-b]pyridine from Substituted-3-cyano-2(1H)-pyridone

“…It is worth mentioning that standard procedures for the conversion of 3-cyano-2(1H)-pyridones into pyrazolo [3,4-b]pyridines usually involves a chlorination step of the amidic carbonyl [4] or its conversion into a 2-thione [8], followed by reaction with hydrazine hydrate. However, a recent report outlined a single-step conversion of 3-cyano-2-quinolone derivative into the 3-aminopyrazolo[3,2-b]quinoline analog via reaction with hydrazine hydrate, which further supported our finding [9]. On the other hand, when 1 was allowed to react with hydrazine hydrate (98%) under pressure, in a sealed reaction tube at 130 o C (oil bath), the starting material was consumed within 40 h and we obtained the unexpected product 3-amino-6-methyl-4-phenyl-1H-pyrazolo [3,4-b]pyridine (8).…”

Synthesis, reactions and pharmacological studies of new series of selenolo [2,3-b]tetrahydroquinoline

“…To attempt our target, we start with 2-oxo-4-(4-substituedphenyl)-1, 2, 5, 6, 7, 8-hexahydroquinoline-3-carbonitrile (5a-c) which were prepared as according to known method [1]. Reaction of 5c with POCl 3 affording 2-Chloro-4-(4-methoxyphenyl)-5, 6, 7, 8-tetrahydro quinoline-3-carbonitrile (6) and reacted directly with sodium hydrogenselenide in ethanol to give 4-(4-methoxyphenyl)-5, 6, 7, 8-tetrahydroquinoline-2(1H) selenone-3-carbonitrile (7).…”

“…2-Oxo-4-(4-substitutedphenyl)-1, 2, 5, 6, 7, 8-hexahydroquinoline-3-carbonitrile (5a-c), were prepared as according to previously procedure [1]. See physical properties and elemental analyses (Table 1).…”

“…IR (KBr, cm −1 ) spectra were recorded on a Pye-Unicam SP3-100 instrument at Taif University. 1 H NMR spectra were obtained on a Varian (400 MHz) EM 390 USA instrument at Cairo University by using TMS as internal reference. 13C NMR spectra were recorded on a GEMINI-200 NMR200 at Cairo University.…”

“…Tetrahydroquinolines are used as a precursor for synthetic many of heterocyclic compounds for examples their use in the synthesis of pyrazolo [3,4-b]quinolines and benzo [b] [1,8] naphthyridines derivatives [1][2][3][4][5][6] which possess antitumor, trypanocidal and DNA binding properties [7,8] and are antimicrobial agents [9]. While pyrazolo [3,4-b]quinoline derivatives are used as pharmaceutical agents and as inhibitors of oncogenic Ras [10,11].…”