New Clerodane Derivatives fromTeucrium scordium

Abstract

A reinvestigation of the aerial parts of TEUCRIUM SCORDIUM afforded in addition to several known diterpenes five new clerodane derivatives, all closely related to teucrin. The structures and the stereochemistry were elucidated by high resolution (1)H-NMR spectroscopy.

Neoclerodane Diterpenoids from Teucrium montbretii Subsp. libanoticum and Their Absolute Configuration

“…11 The latter has been correlated in turn with teulepicin (18) and tafricanin A ( 19), 23 whose neoclerodane absolute configuration is known. 12 Hence, in the present paper, the absolute configurations were determined for 20-epi-3,20-di-O-deacetylteupyreinidin (3), 3,20-di-Odeacetylteupyreinidin (8), 12-epi-montanin G (2), and tafricanin B (20), the latter being in turn correlated with 4R,18-epoxytafricanin B (13). 12 Previously known compounds were identified by conventional methods.…”

“…20- epi -3,20-Di- O -deacetylteupyreinidin ( 3 ) could be an artifact formed during the extraction or the chromatography through a CHO-9α intermediate, even if there are no prior examples in the literature of the isolation of two C-20 epimers from the same plant. ,− …”

“…prior examples in the literature of the isolation of two C-20 epimers from the same plant. 16,[19][20][21] Oxidation of the mixture of 20-epi-3,20-di-O-deacetylteupyreinidin (3) and 3,20-di-O-deacetylteupyreinidin (8), repeated in a concentrated solution of CH 2 Cl 2 using only 1 equiv of pyridinium dichromate, was more selective; besides a small amount of 4R,18-epoxytafricanin B (13), 12-epimontanin G (2) was isolated as the main product.…”

Diterpenoid Constituents of Teucrium scordium L. Subsp. scordioides (Shreb.) Maire Et Petitmengin

“…In compound 4, these signals were reported at δ C 68.6 (CH-2)/δ H 4.44 dddd (J 1α(ax), 2β(ax) = 10.4, J 1β(eq), 2β(ax) = 3.7, J 2β(ax), 3α(ax) = 9.5, J 2β(ax), 3β(eq) = 6.5) for the axial proton H-2β. (4). The small value of the coupling constants for H-2 in 1 required the proton to be in the equatorial position, in this case, α-oriented.…”

“…The diterpenoid composition of Teucrium scordium subsp. scordium had been thoroughly studied in the period of 1981-1985 by different collectives [1][2][3][4] . Ten known clerodane diterpenes in addition to 11 new derivatives were isolated.…”