L. R. Mikhailova

Synthesis and high-resolution NMR spectra of A-nor-derivatives of 11-deoxyglycyrrhetic acid

Several skeletal and oxidative transformations of 11-deoxyglycyrrhetic acid were carried out to produce A-nor-derivatives. Signals for protons and C atoms in the PMR and 13C NMR spectra of the A-nor-derivatives were assigned using high-resolution 1H (400 MHz) and 13C (125 MHz) NMR spectroscopy.

Synthesis of new derivatives of 3β-hydroxy18βH-olean-9,12-dien-30-oic acid

Ring A was transformed and new A-homo-4-aza- and 3-cyano-3,4-seco-olean-4-ene derivatives of 3β-hydroxy18βH-olean-9,12-dien-30-oic acid were synthesized.

OZONOLYSIS OF 11-DESOXOGLYCYRRHETIC ACID AND ITS DERIVATIVES

Abstract12-Oxo derivatives of 11-desoxolycyrrhetic acid and its derivatives were produced by oxidative transformation using ozone. Olean-3,12-dion-30-oic acid was produced for the first time by exhaustive ozonolysis of 11-desoxoglycyrrhetic acid at −60°C.

Synthesis of 2,11-dioxo-norolean A(1)-12,18(19)-dien-30-oic acid

A new A-noroleanane triterpenoid with an altered pentacyclic skeleton of 2,11-dioxo-norolean A(1)-12,18(19)dien-30-oic acid based on 18,19-dehydroglycyrrhetic acid was synthesized.

Obtaining Glycyrrhizic Acid and Its Practically Useful Salts from a Commercial Licorice Root Extract

We describe an optimized method for obtaining glycyrrhizic acid (GA, 90.5 ± 1.5%), which is the main triterpene glycoside of licorice root (Glycyrrhiza glabra L., Gl. uralensis Fisher) extract, and its trisodium and monoammonium salts from a commercial licorice root extract containing 20.0 ± 1.5% GA.

Synthesis and NMR Spectra of New C-Modified Glycyrrhetic Acid Derivatives

New oxidative and skeletal transformations of olean-9(11),12(13)-dien-30-oic acid that were based on ozonolysis and UV irradiation produced the 9α,11α-epoxide and opened ring C.

Beckmann rearrangement of 11-deoxo-glycyrrhetic acid 3-ketoxime

A-Homo-4-aza-3-oxo- and 3-cyano-3,4-seco-olean-4,12-diene derivatives of 11-deoxo-glycyrrhetic acid were synthesized by first- and second-order Beckmann rearrangement of 3-hydroxyiminoolean-12-en-30-oic acid methyl ester.

New Stereoisomeric Glycyrrhetic Acid Derivatives and their Hypoglycemic Activity

New 1-hydroxy-1-en-3-one derivatives of 18β- and 18α-glycyrrhetic acids were synthesized via oxidation of the 3-ketotriterpenoids by atmospheric oxygen in the presence of an excess of t-BuOK. 2-Hydroxy-3,11-dioxo-18αH-olean-1,12-dien-30-oic acid exhibited pronounced hypoglycemic activity and decreased the blood glucose concentration by 42.7% compared with a control after 120 min at a dose of 50 mg/kg in a rat alloxan-induced diabetes model.

Ozonolysis of Methyl 3β-Hydroxyolean-9(11),12(13)-Dien-30-Oate

Ozonolysis of methyl 3β-hydroxyolean-9(11),12(13)-dien-30-oate at –60°C in CH2Cl2–MeOH followed by reduction of the ozonolysis products by dimethylsulfide formed methyl esters of 3β-hydroxy-18βH-olean-9(11),14(15)-dien-12β-methoxy-30-oic and -olean-9(11)-en-12-oxo-30-oic acids and stereoisomeric 12α, β-hydroxy derivatives of olean-9(11),14(15)-dien-12β-methoxy-30-oic acid. The structures of the oxidation products were established using CH-correlation NMR spectra.

Synthesis and Hypoglycemic Activity of 11-Deoxoglycyrrhetic Acid Derivatives

New 2-hydroxy-1-en-3-ones were prepared by oxidation of 11-deoxoglycyrrhetic acid 3-oxo-derivatives and its 30-methyl ester by atmospheric oxygen in the presence of t-BuOK. 2-Hydroxy-3-oxo-18βH-olean-1,12-dien-30-oic acid at a dose of 50 mg/kg reduced the blood glucose concentration in the alloxan-induced rat diabetes mellitus model by 34% compared with the control after 120 min.