Quinone Derivatives by Chemical Transformations of 16-Hydroxycarnosol from Salvia Species

Abstract

The known diterpenes 12,16-epoxycarnosol (2), isotanshinone II (6), and (؉)-neocryptotanshinone (8) were obtained by partial synthesis from 16-hydroxycarnosol (1), a C-16 hydroxylated abietatriene diterpene isolated in relative abundance from the aerial part of Salvia mellifera GREENE. The physical and spectroscopic data of these semisynthetic diterpenes were identical to those given for the natural ones in the literature. These abietane diterpenes have very interesting biological activities and the semisynthetic approach described here represents an alternative to obtain them from other major diterpenes isolated from Salvia species. Additionally, seven new semisynthetic diterpene analogues, 11,14-dioxo-12,16-epoxy-8,12-abietadien-20,7b b-olide (3), 11,14-dioxo-12,16-epoxy-8,12,15(16)-abietatrien-20,7b b-olide (4), 15,16-didehydro-12,16-epoxycarnosol (5), 1-oxoisotanshinone II (7), 16-hydroxycolumbaridione (9), 12,16-diacetoxycolumbaridione (10), and 14-methoxy-12,16-epoxycarnosol (13), were obtained from 1. The structures of the new compounds were established based on their spectroscopic data.

Oxidation of 2-Hydroxynevirapine, a Phenolic Metabolite of the Anti-HIV Drug Nevirapine: Evidence for an Unusual Pyridine Ring Contraction

“…As part of a program aimed at evaluating the possible contribution of quinoid derivatives of phenolic NVP metabolites to the toxic responses elicited by the parent drug, we investigated the oxidation of 2-hydroxy-NVP with dipotassium nitrosodisulfonate (Frémy’s salt). This reagent is frequently employed in the generation of quinones from phenolic derivatives [23,24], mimicking the one-electron oxidation involved in enzyme-mediated metabolic oxidations [25,26].…”

Natural products possessing protein tyrosine phosphatase 1B (PTP1B) inhibitory activity found in the last decades

“…Bioassay-guided fractionation and purification of the MeOH extract of the dried root of the plant Salvia miltiorrhiza called 'Dan-Shen' in China, produced three related abietanetype diterpene metabolites, namely isotanshinone IIA 228, dihydroisotanshinone I 229, and isocryptotanshinone 230 [147] . [148] , which were also obtained by partial synthesis from 16-hydroxycarnosol [149] . Lipidyl pseudopteranes A 231 and D 232 were isolated from the soft coral Pseudopterogorgia acerosa collected from the Bahamas [150] .…”

Chemical Composition and Antigerminative Activity of the Essential Oils from Five Salvia Species

“…S. mellifera is a dominant species in much of the California coastal scrub sage and bordering chaparral. Several studies reported the chemical composition of this species [ 22 , 23 , 24 ] and the biological activity of its volatile terpenes [ 8 ]. In northernmost Baja California as the coastal sage scrub becomes increasingly xeric , S. mellifera is replaced by S. munzii [ 22 ].…”