Formaldehyde → Rifampicin

Participants

Reaction Steps

7 g. Rifamycin S are dissolved in 25 ml. dimethylformamide, then, while stirring, there are successively added 2.4 g. acetic acid, 0.6 g. paraformaldehyde and 0.85 g. 1,3,5-trimethyl-hexahydro-1,3,5-triazine. The mixture is then kept at 50° C. for 3 hours until the reaction is completed, with the formation of 3-methyl-1,3-oxazino (5,6-c) rifamycin (thin layer chromatography on silica gel 60 F254 - Merck: blue spot at Rf 0.19, eluent chloroform:methanol 9:1 v/v). 3.1 g. 1-amino-4-methylpiperazine are then added and the reaction is continued at 50° C. for about 1 hour until it is completed, as demonstrated by the disappearance of the blue spot in the TLC. After treatment in the usual way, a high yield (7.2 g.) of rifampicin is obtained. It can easily be purified by crystallisation from acetone.

Provenance & Evidence