Nucleosides, XXXVI. Synthesis of 3′‐Homocitrullylamino‐ and 3′‐Lysylamino‐3′‐deoxyadenosine and Their Relation to Cordyceps militaris Derived Products

Syntheses of N 6 ‐desmethylpuromycin ( 6 ), of 3′‐ L ‐homocitrullylamino‐3′‐deoxyadenosine ( 3 ) and its L ‐lysyl analog 4 are reported, based on a preparatively efficient procedure for the preparation of 3′‐amino‐3′‐deoxyadenosine ( 2 ) from D ‐xylose, and on attachment of the corresponding amino acid components via the N ‐benzyloxycarbonyl‐blocked N ‐hydroxysuccinimidyl and p ‐nitrophenyl derivatives Z,Z‐Lys‐OSU ( 18 ), Z‐Phe(OMe)‐OSU ( 20 ) and Z‐ h Cit‐ONP ( 23 ), each characterized in crystalline form. – Synthetic 3 was identical with the product isolated previously from Cordyceps militaris , thus now unequivocally establishing its structure. – In biological evaluation, 3 and 4 exhibited inhibition of poly (U) directed polyphenylalanine synthesis analogous to that of puromycin ( 5 ), yet lower by factors of 20 and 40, respectively, whilst that of 6 was identical with 5 qualitatively and quantitatively; hence, the N 6 ‐methyl groups in 5 are not essential for termination of ribosomal peptide chain elongation.