GB1330360A - Cardiac steroid talomethylosides - Google Patents

Abstract

1330360 Steroid talomethylosides DR KARL THOMAE GmbH 2 Nov 1971 [2 Nov 1970 25 Sept 1971] 50939/71 Heading C2U The invention comprises compounds of formula wherein R 1 and R 2 are each H or C 2-4 alkanoyl, or together represent a -C(A)(B)- group in which A is H or Me and B is Me or Ph, or A, B and the intervening carbon atom together form a 6- or 7-membered cycloaliphatic ring; R 3 is H, C 2-4 alkanoyl or the acyl radical of a heterocyclic carboxylic acid; R 4 is CH 3 , CHO or CH 2 OH; R 5 is a 20(22)-cardenolide or 20, 22-bufadienolide lactone ring; R 6 is H and R 7 is H or OH or R 6 and R 7 together represent an additional 4,5- bond; with the provisos that (i) when R 5 is a cardenolide lactone ring and R 4 is CHO or CH 2 OH, then at least one of R 1 , R 2 and R 3 is other than H; and (ii) when R 5 is a bufadienolide lactone ring, then R 7 is other than H. Compounds I are prepared (a) by reduction of the 4<SP>1</SP>-oxo group in compounds of Formula II or (b) by reacting a compound of Formula III with a compound of Formula IV wherein R 4 <SP>1</SP> is CH 3 or CHO, Hal is Cl or Br and Ac is acyl. Method (a) (which may also be used for the preparation of compounds I which violate proviso (i) above) may be effected with a complex metal hydride and may result in partial or complete reduction of any 19-oxo group to hydroxy. Method (b) may be effected in the presence of Ag 2 O, Ag 2 CO 3 , Hg(CN) 2 , pyridine or 2,6-lutidine, and, when the groups Ac are other than as defined for R 1 , R 2 and R 3 , they must be removed. The products of methods (a) and (b) are convertible into other compounds of Formula I by esterification, acetalization, ketalization, hydrolysis of ester, acetal and ketal groups, and reduction of 19-oxo to hydroxy. Compounds II wherein R 1 and R 2 together represent a -C(A)(B)- group as defined above, are prepared by oxidation of the corresponding acetalized or ketalized α-L-rhamnosides. Compounds I are said to be cardioactive, and may be made up with carriers into pharmaceutical compositions for oral, rectal or parenteral administration.