in 1 0m hydrazine hydrate in ethanol 14 4 ml 14 4 mmol was stirred at room temperature under argon after stirring at room temperature for 8 hours ethanol 10 ml was added to allow for greater ease of stirring after a total of 32 hours the mixture was diluted with an equal volume of ethyl acetate filtered and the filtrate was evaporated to dryness the residue was taken up in toluene filtered and again evaporated to dryness purification of the crude product by flash chromatography on silica gel whatmann lps 1 eluting with methanol methylene chloride 5 100 gave 1 64 g of crude product crystallization from ethyl ether hexane gave 1 51 g of pure title compound as a white crystalline solid m p 110 u00b0 111 5 u00b0 tlc methanol methylene chloride 1 9 r f 0 31 u03b1 d 257 7 u00b0 c 0 51 chloroform sodium nitrite 10 3 g 280 mmol was added to a solution of d phenylalanine 30 0 g 181 mmol and potassium bromide 73 5 g in sulfuric acid 2 5n 365 ml over a period of one hour while maintaining the temperature of the reaction mixture at 0 u00b0 c the mixture was stirred for an additional hour at 0 u00b0 c and then for one hour at room temperature the reaction solution was extracted with ether the ether was back extracted with water and the ether layer was dried over sodium sulfate ether was.