Cyanogenesis of Adenia volkensii Harms and Tetrapathaea tetrandra Cheeseman (Passifloraceae) Revisited: Tetraphyllin B and Volkenin. Optical Rotatory Power of Cyclopentenoid Cyanohydrin Glucosides.

Abstract

The cyclopentenoid cyanophydrin glucosides tetraphyllin B and volkenin, (1S,4S)-and (1R,4R)-1-(.beta.-D-glucopyranosyloxy)-4-hydroxy-2-cyclopentene-1-carbonitrile, were isolated from Adenia volkensii Harms and Tetrapathaea tetrandra Cheeseman (Passifloraceae). Enzymatic hydrolysis of the gluosides yielded enantiomeric 1,4-dihydroxy-2-cyclopentene-1-carbonitriles along with the enantiomeric 4-hydroxy-2-cyclopenten-1-ones, establishing the relative stereochemistry of C1 and C4. Molecular rotations of alkyl .beta.-D-glucopyranosides and simple allylically substitued cyclopentenes have been surveyed. The sign and the magnitude of the optical rotations of cyclopentenoid cyanohydrin glucosides at 589 nm were demonstrated to be suitable for immediate determinations of the stereochemistry of the allylic hydroxy group. Tetraphyllin B and volkenin are easily converted into the corresponding amides. (1S,4S)- and (1R,4R)-1-(.beta.-D-glucopyranosyloxy)-4-hydroxy-2-cyclopentene-1-carboxamides; the reaction probably involves assistance by the allylic hydroxy group. The (1S,4S) amide was synthesized from tetraphyllin B by alkaline hydrolysis, esterification of the resulting carboxylic acid, and ammonolysis. On standing in methanol, the carboxylic acid undergoes spontaneous lactonication involving the hydroxy group at C2 of the glucose moiety.