2 trichloroethyl chloroformate 6 5 ml dissolved in 1 1 1 trichloroethane 20 ml was added dropwise the mixture was refluxed for another 2 hours sodium carbonate 2 g was added and reflux continued for 0 5 hours after cooling the mixture was filtered through silica gel eluted with dichloromethane yield 10 g of crude carbamate derivative to a solution of the carbamate 6 g in 90 aqueous acetic acid 110 ml was added finely powdered zn 12 g in small portions at 45 u00b0 c during 1 hour the mixture was heated for another hour at 50 u00b0 c zn salts were filtered off and most of the acetic acid evaporated in vacuo the remaining oil was dissolved in water 200 ml and ethyl acetate 200 ml the ph of the aqueous phase was adjusted gt 9 by adding diluted aqueous ammonia the organic phase was finally worked up as previously yielding 3 5 g of crude title product 17a as an oil which was used without further purification to prepare compound 10h to a solution of 1 6 aminoindan 1 ylmethyl 4 hydroxy 4 3 trifluoromethyl 4 chlorophenyl piperidine 2j 6 7 g and triethylamine 4 ml in dichloromethane 100 ml was added dropwise at 0 5 u00b0 c a solution of chloroacetylchloride 2 6 ml in dichloromethane 50 ml the mixture was stirred overnight at room temperature water was added and ph.