The present invention is related to a novel intermediates and processes which are useful in the preparation of certain antihistaminic piperidine derivatives of the formula ##STR1## wherein W represents --C(.dbd.O)-- or --CH(OH)--; R.sub.1 represents hydrogen or hydroxy; R.sub.2 represents hydrogen; R.sub.1 and R.sub.2 taken together form a second bond between the carbon atoms bearing R.sub.1 and R.sub.2 ; n is an integer of from 1 to 5; m is an integer 0 or 1; R.sub.3 is --COOH or --COOalkyl wherein the alkyl moiety has from 1 to 6 carbon atoms and is straight or branched each of A is hydrogen or hydroxy; and pharmaceutically acceptable salts and individual optical isomers thereof, with the proviso that where R.sub.1 and R.sub.2 are taken to form a second bond between the carbon atoms R.sub.1 and R.sub.2 or where R.sub.1 represented hydroxy integer 0.