Patent ID: 6090952
Filing Date: 2000-07-18
Classification: C07D

Abstract:
A process for the preparation of steroidal phytohormones possessing pathogenic disease resistance and anti-stress activity in plants as well as high plant growth promoting activity, from a compound having formula 1 of the drawings, having molecular formula C.sub.29 H.sub.50 O.sub.6 and represented by isomeric structural formulae (2R,3S,22R,23R)-2,3,22,23-tetrahydroxy-24-ethyl-.beta.-homo-7-oxa-5.alpha. -cholestan-6-one of the following formula ##STR2## and (2R,3S,22S,23 S)-2,3,22-23-tetrahydroxy-24-ethyl-.beta.-homo-7-oxa-5.alpha.-cholestan-6- one of the following formula ##STR3## comprising: a. treating the compound of formula 1 of the drawings with lithium bromide in acetonitrile in the presence of a cation exchange resin to yield compounds having molecular formula C.sub.33 H.sub.53 BrO.sub.7 and isomeric formulae 2 and 3 of the drawings;b. acetylating the compounds obtained in (a) to obtain corresponding bromotriacetates having molecular formula C.sub.35 H.sub.53 BrO.sub.8 ;c. subjecting the bromotriacetates obtained in (b) to solvolysis using acetic acid at elevated temperature to obtain respective hydroxytriacetates having molecular formula C.sub.35 H.sub.56 O.sub.9 and isomeric structural formulae 4 and 5 of the drawings;d. subjecting to acetylation the compounds of the molecular formula C.sub.35 H.sub.56 O.sub.9 obtained in (c) with acetic anhydride and pyridine in presence of a catalytic amount of 4-N,N-dimethyl aminopyridine to obtain tetraacetates having molecular formula C.sub.37 H.sub.58 O.sub.10 and isomeric structural formulae 6 and 7 of the drawings;e. subjecting the compounds having molecular formula C.sub.37 H.sub.58 O.sub.10 obtained in (d) to hydrolysis using potassium carbonate followed by acidification to yield compounds of molecular formula C.sub.29 H.sub.50 O.sub.6.