Acylated Glycosides of Hydroxy Fatty Acid Methyl Esters Generated from the Crude Resin Glycoside (Pharbitin) of Seeds of Pharbitis nil by Treatment with Indium(III) Chloride in Methanol

Abstract

Treatment of the crude ether-insoluble resin glycoside (convolvulin) from seeds of Pharbitis nil (Pharbitis Semen), called pharbitin, with indium(III) chloride in methanol provided seven oligoglycosides of hydroxy fatty acid methyl esters partially acylated by 2-methyl-3-hydroxybutyric (nilic) and 2S-methylbutyric acids. Their structures were elucidated on the basis of NMR and MS data and chemical conversions.

Acylated Glycosidic Acid Methyl Esters Generated from the Convolvulin Fraction of Rhizoma Jalapae Braziliensis by Treatment with Indium(III) Chloride in Methanol

“…This fraction was therefore treated with indium(III) chloride in MeOH, as in the cases of the crude convolvulin fractions from Pharbitis Semen 11) and seeds of Quamolit pennata.…”

Three Acylated Glycosidic Acid Methyl Esters and Two Acylated Methyl Glycosides Generated from the Convolvulin Fraction of Seeds of <i>Quamoclit pennata</i> by Treatment with Indium(III) Chloride in Methanol

“…10) However, no pure convolvulin has thus far been isolated, and chemical studies had been confined only to characterization of the component organic acids and glycosidic acids afforded by alkaline hydrolysis of mixtures of convolvulins. [11][12][13][14][15] We recently reported the isolation and structural elucidation of seven acylated glycosidic acid methyl ester monomers that were generated by treatment of the crude convolvulin fraction (named pharbitin) from Pharbitis Semen using indium(III) chloride in methanol (MeOH), 16) which was reported by Mineno and Kansui 17) to be a catalyst for mild methyl esterification of carboxylic acids.Quamoclit pennata BOJER is a Convolvulaceae plant native to tropical regions of South America, and is primarily cultivated as an ornamental plant. We previously reported the isolation and structural elucidation of a glycosidic acid called quamoclinic acid A, which was obtained along with three organic acids, 2S-methylbutyric, n-decanoic, and n-dodecanoic acids, upon alkaline hydrolysis of the crude jalapin fraction of the plant seeds.…”

“…10) However, no pure convolvulin has thus far been isolated, and chemical studies had been confined only to characterization of the component organic acids and glycosidic acids afforded by alkaline hydrolysis of mixtures of convolvulins. [11][12][13][14][15] We recently reported the isolation and structural elucidation of seven acylated glycosidic acid methyl ester monomers that were generated by treatment of the crude convolvulin fraction (named pharbitin) from Pharbitis Semen using indium(III) chloride in methanol (MeOH), 16) which was reported by Mineno and Kansui 17) to be a catalyst for mild methyl esterification of carboxylic acids.…”

“…18,19) In the case of convolvulins from the seeds, we recently reported the structures of seven glycosidic acids, quamoclinic acids B, C, D, E, F, G, and H, and six organic acids, isobutyric, 2S-methylbutyric, (E)-2-methylbut-2-enoic (tiglic), 3R-hydroxy-2R-methylbutyric (2R,3R-nilic), 7S-hydroxydecanoic, and 7S-hydroxydodecanoic acids, which were obtained by alkaline hydrolysis of the crude convolvulin fraction of the seeds. 14,15) As part of an ongoing study of the resin glycosides from these seeds, this paper reports the isolation and structural elucidation of three acylated glycosidic acid methyl esters and two acylated methyl glycosides, which were generated by treatment of the crude convolvulin fraction with indium(III) chloride in MeOH.…”

Three New Resin Glycosides and a New Tetrahydropyran Derivative from the Seeds of <i>Quamoclit pennata</i>

“…In 1993, one of the present authors proposed that the terms, "jalapin" and "convolvulin," should be used not on the basis of solubility in ether, but rather to describe structural groups, namely, resin glycosides with intramolecular cyclic ester structures, and those without, respectively. 2,3) Quamoclit pennata BOJER is a Convolvulaceae plant native to tropical regions of South America and is cultivated primarily as an ornamental plant. In a previous paper, we reported the isolation and structural elucidation of a glycosidic acid called quamoclinic acid A, 11S-convolvulinolic acid 11-O-β-D-glucopyranosyl-(1 3)-O-[α-L-rhamnopyranosyl-(1 4)]-O-α-L-rhamnopyranosyl-(1 4)-O-α-L-rhamnopyranosyl-(1 2)-β-Dfucopyranoside, that was obtained along with three organic acids, 2S-methylbutyric, n-decanoic, and n-dodecanoic acids, upon alkaline hydrolysis of the crude jalapin fraction of the seeds of the plant.…”