ChemInform Abstract: Synthesis of Thiogibberellins: X-Ray Molecular and Crystal Structure of 19,10-Thio-3-epigibberellin A1.

ChemInform Abstract

1. The 7-thiogibberellin analogues (II) are prepared by sulfhydrolysis of the sym. anhydrides (I). Photolysis of (IIa), (IIc) leads, under intramolecular functionalization, to the thiolactones (III). 2. The known acid (IVa) is converted to the thiocarboxylic acid (IVb) which gives the thiolactone (V) by intramolecular photoaddition or upon treatment with H₂S-pyridine. Deacetylation of (V) with NaOMe leads via a simultaneous retro-aldol reaction to the 3α-hydroxylated thiolactone ester (VIa) which is demethylated to give 19,10-thio-3-epi-GA1 (VIb). The crystal structure of (VIa) is investigated (space group C2; Z=4). - The thiogibberellins synthesized are required for studies on structure-biological activity relationships (in part yields given in mg).