National Research Council of Canada

Prabhat Ayra

Graham W Burton

Novel bile acids according to the general formula ##STR1## wherein R.sub.1 represents a hydroxyl group, R.sub.2 and R.sub.3 both represent a hydrogen or a hydroxyl group, or R.sub.2 represents a hydroxyl group or a .beta. hydroxyl group and R.sub.3 represents a hydrogen or R.sub.3 represents a hydroxyl group and R.sub.2 represents a hydrogen, and R.sub.4 represents a (CH.sub.2).sub.n R.sub.5 wherein n is from 1 to 6, and R.sub.5 represents --0--PO(OH).sub.2, --CH(OH)COOH, a nitrogen containing saturated heterocyclic ring group, NR.sub.6 R.sub.7, wherein R.sub.6 and R.sub.7 are the same or different and each represent hydrogen or a C.sub.1 -C.sub.10 alkyl group or CO--R.sub.8 wherein R.sub.8 represents an amino acid moiety, R-phenylglycine, 12-aminododecanoic acid or 4-aminohippuric acid are synthesized from cholic, deoxycholic, chenodeoxycholic, ursodeoxycholic and lithocholic acids and iodo-derivatives thereof by known processes and/or by novel processes according to the present invention. The novel processes of the present invention are (1) a free radical Michael-type chain lengthening approach and using a free radical mediator such as new tris(trimethylsilyl)silane (TTMSS); and (2) a malonate ester chain lengthening approach. The bile acids with systematic modifications in their structures can play an important role in understanding their mechanistic actions in biology and chemistry.

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Gatineau, Canada

Prabhat Ayra