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SYNTHESIS OF $alpha$-DL-ALANINE-2-C$sup 1$$sup 4$ (in German)

Journal Article · · Pharmazie (West Germany)
OSTI ID:4030925

BS>A multistep synthesis of alanine-2-/sup 14/C in 32 to 47% overall yield based on starting Na acetate-/sup 14/C is described. High yields are obtained by the use of high vacuum techniques, and the apparatus is illustrated. Na acetate-1-/sup 14/C is acidified with HCl to yield acetic acid-l-/sup 14/C in 99% yield. This is converted to acetyl chloride in 97.0% yield by the use of phthaloyl chloride at 80 deg C. The acetyl chloride-1-/sup 14/C is reduced with 2N LiAlH/sub 4/ in diethylene glycol-diethyl ether at 0 deg C, giving ethanol-1-/ sup 14/C in 88% yield. The alcohol is next converted into ethyl iodide-1-/sup 14/ C with HI at 110--130 deg C; the yield is 71% based on Na acetate, The ethyl iodide is converted to the Grignard reagent and carbonated to yield (as the isolated product) sodium propionate-2-/sup 14/C in 81% yield (based on ethyl iodide, or 58% based on Na acetate). The salt is converted into the free acid in the fashion described for acetic acid, and this is treated with red P and Br/sup 2/ to yield alpha -bromopropionic acid-2-/sup 14/C in 52% yield (based on Na acetate). Treatment of this with ammonium carbonate-- aqueous ammonia at temperatures not over 60 deg C yields alpha -DL-alanine-2-/sup 14/C in 79% yield (based on bromoacid; 41% based on Na acetate) after purification on a Wofatit F column and sublimation. No further impurities could be detected by paper chromatography. Alanine labelled in the one or three position may be prepared in an analogous fashion. (BBB)

Research Organization:
Zentralinstitut fur Kernphysik, Rossendorf, Ger.
NSA Number:
NSA-18-020033
OSTI ID:
4030925
Journal Information:
Pharmazie (West Germany), Journal Name: Pharmazie (West Germany) Vol. Vol: 18; ISSN PHARA
Country of Publication:
Country unknown/Code not available
Language:
German