Fungal metabolites. Part VII. Stereochemistry of gibberellic acid: X-ray analysis of methyl bromogibberellate

Abstract

Methyl bromogibberellate crystallises in the orthorhombic system, space group P2₁2₁2₁, with four molecules of C₂₀H₂₃BrO₆ in a unit cell of dimensions a= 10·74, b= 10·70, c= 16·64 Å. The crystal structure was elucidated by the heavy-atom method and Fourier and least-squares methods were employed in the refinement of the atomic parameters. The analysis defines the absolute stereochemistry of gibberellic acid.