Pyridine → HCID 86746003, compound

Participants

Reaction Steps

A mixture of 4-(benzoylmethyl)-6-cyclohexyl-6,7-dihydro-2-phenyl-4H-pyrazolo[1,5-a]pyrrolo[3,4-d]pyrimidine-5,8-dione (see Example 4), (1.00 g.; 2.15 mmoles) and hydroxylamine hydrochloride (225 mg.; 3.23 mmole), in 4.5 ml of absolute ethanol and 1.5 of pyridine was heated to reflux, becoming homogenous. The solution deposited a precipitate with time, so another 2 ml. of ethanol was added to aid stirring. After a total of eight hours at reflux, the mixture was cooled and diluted with 15 ml. of ethanol. The mixture was suction filtered through a medium glass frit and the collected solid was washed with ethanol and dried in vacuo. The crude solid was suspended in boiling 95% ethanol (400 ml.), and chloroform was added until dissolution was achieved (70 ml.). About 50 ml. of the resulting solvent mixture was then boiled off before cooling to room temperature. This procedure afforded 624 mg. (60% yield) of the titled compound, m.p. >280° C. The NMR spectral analysis of a sample of this material indicated that a 1:1 mixture of the titled oxime isomers had been obtained. 1H NMR (DMSO d6, δ) (mixture of oxime isomers) 12.14 (s, 1H, OH), 11.12 (s, 1H, OH), 8.01 [d, 2H, J=7 Hz, 2-phenyl-H (ortho)], 7.89 (d, 2H, J=7 Hz, oxime-phenyl-H (ortho)], 7.2-7.7 (m, 17H, phenyl-H and pyrazole-H of one isomer), 6.76 (s, 1H, pyrazole-H), 6.12 (bs, 2H, (C(NOH)CH2), 5.72 (bs, 2H, C(NOH)CH2), 4.41 (s, 2H, NCH2), 4.30 (s, 2H, NCH2), 4.0 (m, 2H, cyclohexyl CH of both isomers), 1.1-1.9 (m, 20H, cyclohexyl CH2 of both isomers).

Provenance & Evidence