8-O,n- and 8,21-di-o-acyl-3-piperazinyl-rifamycin S derivs. - with hypolipaemic activity, prepd. by acylation of non-acylated cpds. with a tri:alkyl-acetic acid deriv. e.g. pivaloyl chloride

摘要

8-O,N- or 8,21-diacyl- 3-(4-(2,6-dimethylbenzyl) -1-piperazinyl) rifamycin S derivs. of formula (I) and their salts are new: (where R is lower alkyl; R1 is tri(lower alkyl) methyl-carbonyl; and one of R2 and R3 is tri(lower alkyl)methyl-carbonyl and the other is H). 8,21-Di-O-pivaloyl- 3-(4-(2,4,6-trimethylbenzyl) -1-piperazinyl) rifamycin S (Ia) and 8-O,N-dipivaloyl-3 -(4-(2,4,6-trimethylbenzyl) -1-piperazinyl) rifamycin S (Ib) are specifically claimed. (I) are obtd. by reaction of corresponding non-acylated cpds. of formula (II) with an acylating agent capable of introducing a tri-(lower alkyl)methyl carbonyl gp. into the 8-position and into the 21-posn. or onto the ring amide N-atom, a resulting isomer mixt. being sepd. if desired.