u00b0 c after a certain time say about 12 to about 36 suitably about 24 hours the conversion was determined by hplc then volatile acid where present such as acetic acid tca or tfa was removed by evaporation and recovered by condensation the reaction mixture was diluted with water and catalyst is filtered off the ph of the filtrate was adjusted to over 13 the isolation of pao of general formula 2 was carried out by recrystallization or distillation direct derivatization was carried out in the reaction mixture this was cooled at 4 u00b0 c and a suitable derivatizing agent for example benzyl chloroformate was added dropwise whereby the n blocked phenylalaninol was precipitated after filtration white crystals were obtained by recrystallization in water methanol 1 1 the following examples are illustrative embodiments of this invention however these examples are for illustrative purposes only and should not be construed as limitations upon the invention 1 ml of concentrated sulfuric acid was slowly added to 15 ml of water and 75 mg of 5 pd c and 1 g of l 2 amino 1 phenyl 1 3 propanediol l appd added thereto the reactions were carried out under 35 psi hydrogen pressure at 55 u00b0 c after 24 hours the reaction was terminated by filtration to remove the catalyst the ph of the filtrate was adjusted to ca 3 by adding 50 aqueous naoh and diluted with water 10 ml and methanol 10 ml the conversion was determined by hplc.