Gibberellins A60, A61, and A62 : partial syntheses and natural occurrence

Abstract

ent-1α,10,13-Trihydroxy-20-norgibberell-16-ene-7,19-dioic acid 19,10-lactone (gibberellin A₆₀) and ent-1α,10-dihydroxy-20-norgibberell-16-ene-7,19-dioic acid 19,10-lactone (gibberellin A₆₁) have been prepared from gibberellin A₃ and gibberellin A₇, respectively, and shown to be identical with two gibberellins previously detected by g.l.c.–mass spectrometry in developing grains of Triticum aestivum. ent-1α,10-Dihydroxy-20-norgibberella-2,16-diene-7,19-dioic acid 19,10-lactone (gibberellin A₆₂) has also been prepared from gibberellin A₇ and shown to be present in the grain of T. aestivum. Gibberellins A₆₁ and A₆₂ have also been detected in immature seed of Pyrus malus. Attempts to prepare a fourth putative gibberellin, detected in T. aestivum, were not successful.