The microbial transformation of ()-isolongifolen-4-one (4) by a number of fungi by means of a standard two-stage fermentation technique afforded (7R)-12-hydroxyisolongifolen-4-one (5), (7S)-13-hydroxyisolongifolen-4-one (6), (11R)-11-hydroxyisolongifolen-4-one (7), (10R)-10-hydroxyisolongifolen-4-one (8), and (9R)-9-hydroxyisolongifolen-4-one (9) (Scheme). All five metabolites were found to be new, and metabolites 6 and 9 showed potent tyrosinase inhibitory activity ( Table 1). The metabolites and their derivatives were characterized on the basis of spectroscopic and single-crystal X-ray-diffraction techniques.

The structure of a chromic acid oxidation product of the norditerpenoid alkaloid lycoctonine (1) was established as hydroxylycoctonal (3) by spectrometric analyses and X-ray crystallography of its reduction product, hydroxylycoctonine (5); the structure of lycoxonine, a chromic acid oxidation product of the lactam, lycoctonam (7), was similarly confirmed as N-ethyl-4,7,8-trihydroxy-1α,6β,14α,16β-tetramethoxy-19-oxoaconitane (8). Reduction of lycoxonine with lithium aluminium hydride gave the 1,14-di-O-methyl ether (12) of the bisnorditerpenoid alkaloid delbine (9).

The title compound, [Sn(CH3)3(C16H12ClO3)]n, forms polymeric chains incorporating both O atoms of the propenoate ligand. The coordination geometry around the Sn atom is distorted trigonal bipyramidal. The three methyl C atoms occupy the equatorial positions with almost identical Sn—C distances [2.115 (3)–2.120 (3) Å] and O atoms from two symmetry‐related ligands are in the axial positions with significantly different Sn—O distances [2.150 (2) and 2.430 (2) Å].