AHIM ACIDS; 13'. INVESTIGATIONS ON THE SYNTHESIS OF DL-SERINE FRUH a-HALDACRYLIC ACID DERIVATIVES FRANZ EFFENBERGER* and CERHARD ZOLLER'

The alkoxide-catalyzed addition of alcohols 2 to a-chloroacrylonitrile (1) at -35°C gives rise to 3-alkoxy-2-chloropropancnitriles 3; at D-5°C with excess _2 alkyl 3-alkoxy-2-chloropropanicidates 3 are obtained. The yields of 3 or 4 decrease with increasing pK, values of the alcohols 2. In the basecatalyzed addition of phenols 5 to 1, a temperature-dependent addition equilibrium is set up in which the position of equilibrium is shifted in favour of the addition products 5 with increasing pK, values of 2. The 3-alkoxy-2-chloropropanoates i, which are readily accessible by hydrolysis of j. react smoothly with sodium aride in the presence of a phase transfer catalyst to furnish the 3-alkoxy-2-azidopropanoates 3. Starting from benryl 2-azido-3-benzyloxypropanoate (fi), the specific syntheses of OL-serine (!A). DL-serlne hydrochloride (N*HCl). DC-serine methyl ester hydrochloride (&-Ml). D-benzylDL-serine (g), and 0-benzyl-DL-serine benryl ester hydrochloride (llb*HCl) are possible by variation of the hydrogenation conditions.