2-Nitrobenzaldehyde → HCID 21442894, compound

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Reaction Steps

15.1 g of o-nitrobenzaldehyde, 16.8 g of 3-aminocrotonic acid piperidide and 13.6 g of methylsulphonylacetone are stirred in 100 ml of hexamethylphosphoric acid triamide for 10 hours under nitrogen at a bath temperature of 115° C. The mixture is cooled and dissolved in 600 ml of ethyl acetate and the solution is washed with a mixture of 600 ml of water, 90 ml of methanol and 90 ml of sodium chloride solution. The organic phase is separated off and the aqueous phase, in which a dark brown product precipitates, is filtered. The crystalline product is dried by azeotropic distillation on a rotary evaporator and treated twice in methanol/chloroform with animal charcoal. The filtrate is evaporated and the residue is recrystallised from isopropanol. 2,6-Dimethyl- 3-piperidinocarbonyl-4-(2-nitrophenyl)-5-methylsulphonyl-1,4-dihydropyridine, which is thus obtained, melts at 275°-276° C.

Provenance & Evidence