(4-Chlorophenyl)hydrazine → HCID 178515181, compound

Participants

Reaction Steps

A mixture of 0.6 g of ethyl 4-chloro-5,7-dihydrothieno[3,4-b]pyridine-3-carboxylate, p-chlorophenylhydrazine(0.35 g) and 10 ml of n-butanol is heated at reflux for 24 hours, then evaporated to dryness. To the residue is added additional p-chlorophenylhydrazine (0.35 g) and 10 ml of N-methyl-2-pyrrolidone, and the mixture is heated at 150° for 18 hours, then evaporated to dryness. The residue is treated with 20 ml of 2N NaOH and 40 ml of ether. Alkaline layer is separated and pH adjusted to 6.5 depositing solid which is dissolved in methanol; the solution is decolorized with charcoal and concentrated to deposit crystals. Recrystalization from methanol affords 2-(p-chlorophenyl)-2,3,6,8-tetrahydrothieno[3,4-b]pyrazolo[3,4-d]pyridin-3(5H)-one, mp>330°; IR(cm-1)1600, 1570, 1470, 1000, 931, 835, 830 and 762; (the compound of formula IA wherein R1 =p-chlorophenyl, R2 and R3 =H and A represents ##STR27## The starting material is prepared as follows:

Provenance & Evidence