Enantiomers of an Indole Alkaloid Containing Unusual Dihydrothiopyran and 1,2,4-Thiadiazole Rings from the Root of Isatis indigotica

Abstract

A pair of enantiomers (1a and 1b) of an indole alkaloid containing dihydrothiopyran and 1,2,4-thiadiazole rings was isolated from an aqueous extract of the root of Isatis indigotica. The structures and absolute configurations of the enantiomers were determined by extensive spectroscopic analysis, especially 2D NMR, modified Mosher's method, and electronic CD (ECD). The proposed biosynthetic pathway and preliminary investigations of the biological activity of compounds 1a and 1b against influenza virus A/Hanfang/359/95 (H3N2) and HSV-1 are also discussed.

Simple indole alkaloids and those with a nonrearranged monoterpenoid unit

“…Then 127 was transformed into (+)-125 through oxidative lactonization and intramolecular cyclization as the key tactics (Scheme 35). 66,67 Snyder's synthesis of (+)-scholarisine A (125) via radical C-H arylation in 129 as the key features (Scheme 36). 68 Indole-3-acetonitrile-4-methoxy-2-C-b-D-glucopyranoside (130), isolated from the roots of the plant Isatis indigotica, was synthesized using the Sonogashira coupling reaction of ethynyl-b-C-glycoside 131 followed by Cu-mediated indole annulation, leading to indole-C-glycoside core 132 (Scheme 37).…”

“…12). 125 Seven new secondary metabolites, nakijinamines A (316), B Compound 323 displayed a moderate in vitro growth inhibitory activity on the ve cell lines (Fig. 14).…”

Chemistry, synthesis and progress report on biological activities of thiadiazole compounds - a review

“…The dipole moment of 1,3,4-thiadiazole in the gas phase by microwave technique and found a value of 3.28+-0.03 D. By use of geometry, the π-electron distribution and the bond moment, dipole moment of 3.0 D can be calculated, directed from the sulphur atom towards the center of the nitrogen-nitrogen bond [15][16][17] .…”

“…They have known to exhibit diverse biological activities such as in vitro inhibition of cyclooxygenase and 5-lipoxygenase activities 3 . New acylated 5-thio-beta-D-glucopyranosylimino-disusbstituted 1,3,4-thiadiazoles prepared by cycloaddition of the glycosyl isothiocyanate with the reactive intermediates 1-aza-2-azoniaallene hexachloro antimonates, and have been tested in vitro antiviral activity against HIV-1, HIV-2, human cytomegallovirus (HMCV) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] .…”

Two homosecoiridoids from the flower buds of Lonicera japonica

“…Chemical and pharmacological studies resulted in characterization of constituents with different structural features and biological activities [2][3][4][5][6][7][8]. As part of a programme to assess the chemical and biological diversity of traditional Chinese medicines [9][10][11], we conducted detailed chemical analysis of an aqueous extract of the flower buds of L. japonica, since the flower bud decoction is practically used. Our previous studies on the aqueous extract led to the isolation of homosecoiridoids having structural characters of the secoiridoid nucleus coupled with N-substituted nicotinic acid or pyridine units (lonijaposides A-W), phenylpyruvic acid derived moieties (loniphenyruviridosides A-D), and b-hydroxy amino acid units [12][13][14][15], as well as two N-(6-Oacyl-b-D-glucopyranosyl)-nicotinate (lonijaponinerosides A and B) [16].…”