Synthesen auf dem Vitamin‐B₁₂‐Gebiet. 4. Mitteilung Partialsynthese von Vitamin B₁₂

Abstract

Abstract A partial synthesis of vitamin B 12 is described, starting from factor V 1a , a monocarboxylic acid. The necessary phosphoric acid diester containing the nucleotide and 1‐amino‐2‐propanol is obtained from the 2′,3′‐cyclic phosphate of 1‐α‐ D ‐ribofuranosyl‐5,6‐dimethyl‐benzimidazole. Condensation of factor V 1a with the ‘side chain’ is effected via a mixed anhydride. Unnatural analogues of vitamin B 12 , one with L ‐1‐amino‐2‐propanol in place of the D ‐isomer, and one with the phosphoric acid group attached to the 2′‐hydroxy group of ribose, have been obtained.