Chemical studies on tuberactinomycin. XV. Total synthesis of tuberactinomycin O

Tuberactinomycin O, one of the four congeners of the antituberculous peptide tuberactinomycin, was totally synthesized. The beta-ureidodehydroalanine moiety was constructed from beta,beta-diethoxyalanine with excess urea in acidic medium after a cyclization reaction of a pentapeptide was finished. Cyclization was carried out by means of the 1-succinimidyl ester method. To the cyclic pentapeptide, beta-lysine was introduced as the branched moiety and then deprotected to afford tuberactinomycin O which was completely identified with the natural form of the antibiotic.