Three new cholinesterase-inhibiting cis-clerodane diterpenoids from Otostegia limbata

Three new tricyclic cis-clerodane type diterpenoids trivially named as limbatolide A (1), limbatolide B (2) and limbatolide C (3) have been isolated from the roots of Otostegia limbata along with two known compounds; oleanic acid and beta-sitosterol. The structure elucidation of the new compounds was based primarily on two-dimensional (2D) NMR techniques. Compounds 1-3 displayed inhibitory potential in a concentration-dependent manner against acetylcholinesterase (AChE; EC 3.1.1.7) and butyrylcholinesterase (BChE; EC 3.1.1.8) enzymes, respectively.     

A Convenient Synthesis of β-Amino Acid

We have reported the reductive cleavage of azlactones¹ and phenylhydrazones² of carbonyl compounds in the presence of a suitable catalyst. In this paper a general method involving a one step synthesis of β-amino acid^3,4, in good yield, through catalytic reduction of oximes of α-β-unsaturated acid is reported. This method involves the reaction of α, β-unsaturated acid with hydroxylamine hydrochloride in the presence of sodium acetate. Markovnikov's rule is followed in the synthesis of oximes of α, β-unsaturated acids.     

Two New Disulfated Triterpenoids from Zygophyllum fabago

From the aerial parts of Zygophyllum fabago, two new monosodium salts of sulfated derivatives of ursolic acid, along with two known quinovic acid glycosides were isolated. The structures of the new compounds were determined as (3β,4α)‐3,23,30‐trihydroxyurs‐20‐en‐28‐al 3,23‐di(sulfate) sodium salt (1 : 1) ( 1 ) and of (3β,4α)‐3,23,28‐trihydroxyurs‐20‐en‐30‐yl β‐D ‐glucopyranoside 3,23‐di(sulfate) sodium salt (1 : 1) ( 2 ) with the molecular formula C₃₀H₄₇NaO₁₀S₂ and C₃₆H₅₉NaO₁₅S₂, respectively. The structures of the known compounds were 3‐O‐(2‐O‐sulfo‐β‐D ‐quinovopyranosyl)quinovic acid 28‐β‐D ‐glucopyranosyl ester ( 3 ) and 3‐O‐(β‐D ‐glucopyranosyl)quinovic acid 28‐β‐D ‐glucopyranosyl ester ( 4 ) (quinovic acid=(3β)‐3‐hydroxyurs‐12‐ene‐27,28‐dioic acid). The structures of all these compounds were determined by using 1D‐ and 2D‐NMR spectroscopic techniques.     

Tetrathiafulvalene hydrazone: efficient synthon for the synthesis of novel bidentate redox active ligands

The synthesis and the ability of TTF-hydrazone to act as a versatile precursor for the design of electroactive ligands are reported together with the chelating ability of these ligands through their M(CO)₄ complexes, (M = Mo, W).     

New terpenoids from Stachys parviflora Benth

Two new triterpenoidal saponins were isolated from the n-butanolic extract of Stachys parviflora (Lamiaceae). Their structures were elucidated on the basis of spectral data as stachyssaponin A; 3beta, 15alpha, 19alpha, 21beta, 22alpha-pentahydroxyolean-12-ene-28-oic acid 3-O-{alpha-L-rhamnopyranosyl-(1 --> 3)-beta-D-glucopyranoside}-22-O-{alpha-L-arabinofuranosyl-(1 --> 3)-beta-D-glucopyranoside} (1) and stachyssaponin B; 2beta, 3beta, 15alpha, 21beta-tetrahydroxyolean-12-ene-28-oic acid 2-O-[alpha-L-arabinofuranoside]-3, 21-bis-O-[beta-D-glucopyranoside] (2).     

Two new rare-class tetracyclic diterpenoids from Otostegia limbata

Two new tetracyclic diterpenoids trivially named as limbatenolide D (1) and limbatenolide E (2) have been isolated from Otostegia limbata. The structure elucidation of the compounds was based primarily on two-dimensional (2D) NMR techniques and on comparison with the literature data.     

Complete (1)H and (13)C NMR assignments of two new trans-clerodane diterpenoids from Otostegia limbata

Two new tricyclic trans-clerodane diterpenoids trivially named as ballotenic acid A (1) and ballodiolic acid A (2) have been isolated from ethyl acetate fraction of Otostegia limbata. The structure assignments are based on (1)H and (13)C NMR spectra, 2D NMR (HMQC, HMBC, COSY, NOESY and NOE) techniques and comparison with the literature data.     

Standardization of Biomarkers Gallic Acid and Berberine in Polyherbal Formulation Entoban Capsules by High-Performance Thin-Layer Chromatography—Densitometry

JPC – Journal of Planar Chromatography – Modern TLC - The technological improvement in the structural elucidation of natural compounds has made it probable to generate appropriate...     

Two New Octulosonic Acid Derivatives and a New Cyclohexanecarboxylic Acid Derivative from Erigeron bonariensis L.

The AcOEt‐soluble part of a MeOH extract from the whole plant of Erigeron bonariensis yielded two new rare‐class octulosonic acid derivatives, rel‐methyl (1R,2S,3S,5R)‐3‐(trans‐caffeoyloxy)‐7‐[(trans‐caffeoyloxy)methyl]‐2‐hydroxy‐6,8‐dioxabicyclo[3.2.1]octane‐5‐carboxylate ( 1 ) and 5,8‐di[O‐trans‐caffeoyl]‐3‐deoxy‐β‐D ‐gluco‐oct‐2‐ulopyranosonosyl 4,8‐di[O‐trans‐caffeoyl]‐3‐deoxy‐β‐D ‐gluco‐oct‐2‐ulopyranosidonic acid ( 2 ) along with a cyclohexanecarboxylic acid derivative, (1α,3β,4β,5β)‐1,4‐di‐3,5‐dihydroxy‐bis(trans‐caffeoyloxy)cyclohexanecarboxylic acid ( 3 ). The structures of these compounds were elucidated through ESI‐MS, and 1D‐ and 2D‐NMR spectroscopic techniques including ¹H‐ and ¹³C‐NMR, HMQC or HSQC, and HMBC experiments.     

A new eudesmane sesquiterpene from Pluchea arguta

A new eudesmane sesquiterpene, pluchargen A (3-beta-[3'-chloro-2'-hydroxy-2'-methyl butyroyl]-cuauhtemone), was isolated from the whole plant of Pluchea arguta, and the structure was elucidated on the basis of 1- and 2-D NMR spectroscopic studies.