Epimerisation of 3-vinyl-piperidine cpds. - by heating in protonic solvent

摘要

Epimerisation of 3-vinylpiperidines of formula (I) is carried out by heating a soln. of the 3R (or 3S) epimer, partially or totally in salt form, at 50 degrees C in a protonic solvent, opt. in the presence of HCHO, and isolating the resulting 3S (or 3R) epimer. (where R is H or a substituent). The products (e.g. cinchona alkaloid analogues) are useful as intermediates for pharmaceuticals, e.g. for antiarrhythmic and antimalarial agents (see FR2012152 and US3753992 and 3857846).