1H, 13C and 15N NMR spectral assignments of adenosine derivatives with different amino substituents at C6-position

The complete (1)H, (13)C and (15)N NMR signals assignment of adenosine derivatives differently substituted at C(6)-position was achieved using one- and two-dimensional experiments (gs-COSY, gs-NOESY, gs-HSQC and gs-HMBC).

Purines. LXII. Both enantiomers of N6-(1,3-dimethyl-2-butenyl)adenine and their 9-beta-D-ribofuranosides: synthesis and cytokinin activity

Both enantiomers [(1'R)-6 and (1'S)-6] of N6-(1,3-dimethyl-2-butenyl)adenine and their 9-beta-D-ribofuranosides [(1"R)-16 and (1"S)-16] have been synthesized for the first time from both enantiomers of alanine (15) in nine steps. These aglycones and nucleosides, together with N6-(3-methyl-2-butenyl)adenine (5) and its 9-beta-D-ribofuranoside (18) as well as 9-beta-D-ribofuranosyl-cis-zeatin (20) and 9-(2-deoxy-beta-D-ribofuranosyl)-cis-zeatin (19), were tested for cytokinin activity in the tobacco callus bioassay. The order of their activity was 5 > (1'R)-6 > (1"R)-16 approximately 18 > (1'S)-6 > (1"S)-16 > 20 > 19. The bioassay results are compared with those obtained previously for the derivatives modified analogously in the N6-substituent in the cis- and trans-zeatin series.