Subhra Banerjee

Bio: Subhra Banerjee is an academic researcher. The author has contributed to research in topic(s): Eria & Derivative (chemistry). The author has an hindex of 1, co-authored 1 publication(s) receiving 51 citation(s).

Structure of flavanthrin, the first dimeric 9,10-dihydrophenanthrene derivative from the orchid eria flava

Abstract: Flavanthrin, the first dimeric 9,10-dihydrophenanthrene derivative, was isolated from the orchid Eria flava which also yielded the previously reported 9,10-dihydrophenanthrene coelonin ( 2a ). The structure of flavanthrin was established as the 1.1'-dimer ( 1a ) of its congener coelonin from spectral and chemical evidence.

Natural phenanthrenes and their biological activity.

Abstract: The aim of this review is to survey the various naturally occurring phenanthrene compounds that have been isolated from different plants. Only one review has previously been published on this topic. Gorham (1989) reviewed the structures, biosynthesis, separations and spectroscopy of stilbenes and phenanthrenes. The present study furnishes an overview of the hydroxy or/and methoxy-substituted 9,10-dihydro/phenanthrenes, methylated, prenylated and other monomeric derivatives, dimeric and trimeric phenanthrenes and their biological activities. A fairly large number of phenanthrenes have been reported from higher plants, mainly in the Orchidaceae family, in the species Dendrobium, Bulbophyllum, Eria, Maxillaria, Bletilla, Coelogyna, Cymbidium, Ephemerantha and Epidendrum. A few phenanthrenes have been found in the Hepaticae class and Dioscoreaceae, Combretaceae and Betulaceae families. Their distribution correlates strongly with the taxonomic divisions. These plants have often been used in traditional medicine, and phenanthrenes have therefore been studied for their cytotoxicity, antimicrobial, spasmolytic, anti-inflammatory, antiplatelet aggregation, antiallergic activities and phytotoxicity. On the basis of 120 references, this review covers the phytochemistry and pharmacology of phenanthrenes, describing 252 compounds. This contribution stems from our work on the medicinal plant Tamus communis.

Bi-bicyclic and bi-tricyclic compounds from Dendrobium thyrsiflorum.

Abstract: One bi-bicyclic and two bi-tricyclic derivatives of coumarin–benzofuran, phenanthrene–phenanthrene and phenanthrene–phenanthraquinone, along with seven known compounds, were isolated from stems of Dendrobium thyrsiflorum Rchb.f. (Orchidaceae). On the basis of chemical, NMR (1H, 13C, HMQC, HMBC and NOESY) and mass spectrometry data, their structures were elucidated as denthyrsin [3-(5′,6′-dimethoxybenzofuran-2′-yl)-6,7-dimethoxy-2H-chromen-2-one; 1], denthyrsinol (4,5′-dimethoxy-[1,1′]biphenanthrenyl-2,5,4′,7′-tetraol; 2), and denthyrsinone (7,4′,7′-trihydroxy-2,2′,8′-trimethoxy-[5,1′]biphenanthrenyl-1,4-dione; 3). Compounds 1–3 and denthyrsinin (1,5,7-trimethoxyphenanthrene-2,6-diol; 4) showed significant cytotoxic activities against Hela (13.5, 9.3, 9.9 and 2.7 μM, respectively), K-562 (0.45, 1.6, 6.0 and 2.3 μM, respectively) and MCF-7 (18.1, not tested, 3.5 and 4.8 μM, respectively) cell lines.

Synthesis, resolution, and absolute stereochemistry of (-)-blestriarene C.

Abstract: A naturally occurring 1,1‘-biphenanthrene, blestriarene C (1), was prepared in 13 steps and 30% overall yield. The key steps are the ester-mediated nucleophilic aromatic substitution on 2,6-di-tert-butyl-4-methoxyphenyl 5-isopropoxy-2-methoxybenzoate (4) by 2-methoxy-4-methoxymethoxy-6-methylphenylmagnesium bromide (5) and a novel intramolecular cyclization of the resulting 4-isopropoxy-2‘-methoxy-4‘-methoxymethoxy-6‘-methylbiphenyl-2-carboxylic ester 14 to 7-isopropoxy-4-methoxy-2-(methoxymethoxy)phenanthren-9-ol (15). The racemic blestriarene C was optically resolved by chiral HPLC on a preparative scale to give several 10-mg yields of both the enantiomers in up to 95% ee. The absolute stereochemistry was determined to be Sa-(−) by the axial chirality recognition method, which was based on the stereospecific formation of a 12-membered cyclic diester containing two biaryl-o,o‘-diyl unites joined by ester −CO2− linkages. The validity of the method was confirmed by an X-ray crystallographic analysis and ab...

Phenanthrenes, 9,10-dihydrophenanthrenes, bibenzyls with their derivatives, and malate or tartrate benzyl ester glucosides from tubers of Cremastra appendiculata

Abstract: Eleven previously unknown compounds and 23 known compounds, including 20 phenanthrene or 9,10-dihydrophenanthrene derivatives, five bibenzyls, seven malate or tartrate benzyl ester glucosides, adenosine and gastrodin were isolated from tubers of Cremastra appendiculata. Among the obtained compounds, two are the first isolated dimers with one phenanthrene or bibenzyl unit connected to C-3 of 2,3,4,5-tetrahydro-phenanthro[2,1-b]furan moiety. In addition, 33 of these compounds were evaluated in vitro for their cytotoxic activity against two cancer cell lines. Among the compounds examined, one compound showed moderate cytotoxic activity, while five showed weak cytotoxic activity against the A549 cell line.