Biosynthetic studies on the botcinolide skeleton: new hydroxylated lactones from Botrytis cinerea.
[reaction: see text] The biosynthetic origin of the botcinolide skeleton was investigated by means of feeding 13C- and 2H-labeled precursors to Botrytis cinerea. Three new compounds, two homobotcinolide derivatives, 3-O-acetylhomobotcinolide (5) and 8-methylhomobotcinolide (6), and a new 11-membered lactone (7), were isolated. Their structures were elucidated on the basis of spectroscopic data, including one-bond and long-range 1H-13C correlations. The relative stereochemistries were determined by combined analyses of NOE data and 1H-1H coupling constants. According to the results of feeding experiments with 13C- and 2H-labeled acetate and l-S-methylmethionine, 5 is an acetate-derived polyketide whose methyl groups originate from l-S-methylmethionine. This is a rare example of the incorporation of a methyl from methionine into a supposed C3 starter unit of the polyketide synthesis.
Reino
José L
JL
Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Cádiz, Apdo 40, 11510 Puerto Real, Cádiz, Spain.
Durán-Patrón
Rosa M
RM
Daoubi
Mourad
M
Collado
Isidro G
IG
Hernández-Galán
Rosario
R
D000085:Acetates; D020171:Botrytis / Q000737:chemistry* / Q000254:growth & development; D006900:Hydroxylation; D007783:Lactones / Q000737:chemistry* / Q000302:isolation & purification; D008715:Methionine; D008958:Models, Molecular; D008968:Molecular Conformation
D000085:Acetates; D007783:Lactones; D008715:Methionine