Saswati Chattopadhyay

Bio: Saswati Chattopadhyay is an academic researcher. The author has contributed to research in topics: Agrostophyllum & Pyran. The author has an hindex of 1, co-authored 2 publications receiving 3 citations.

Agrostophyllanthrol and Isoagrostophyllanthrol, Two Novel Diastereomeric Phenanthropyran Derivatives (I) from the Orchid Agrostophyllum khasiyanum.

Abstract: Agrostophyllanthrol and isoagrostophyllanthrol, two novel diastereomeric phenanthropyran derivatives were isolated from the orchid Agrostophyllum khasiyanum which earlier afforded eleven stilbenoids, viz. the two dimeric phenanthrene derivatives agrostonin [2,2',7,7'-tetrahydroxy-4,4',6,6'-tetrainethoxy-1,1'-biphenanthryl] and agrostonidin [2,2',6,6'-tetrahydroxy-4,4',7,7'-tetramethoxy-1,1'-biphenanthryl], eight phenanthropyran derivatives imbricatin [2,7-dihydroxy-6-methoxy-9,10-dihydro-5H-phenanthro[4,5-bcd]pyran], agrostophyllidin [7-hydroxy-2,6-dimethoxy-9,10-dihydro-5H-phenanthro[4,5-bcd]pyran], agrostophylloxidin [7-hydroxy-2,5,6-trimethoxy-5H-phenanthro[4,5-bcd]pyran], flaccidinin [2,6-dihydroxy-7-methoxy-5H-phenanthro[4,5-bcd]pyran-5-one], isoflaccidinin [2,7-dihydroxy-6-methoxy-5H-phenanthro[4,5-bcd]pyran-5-one], agrostophyllin [7-hydroxy-2,6-dimethoxy-5H-phenanthro[4,5-bcd]pyran], agrostophyllone [7-hydroxy-2,6-dimethoxy-5H-phenanthro[4,5-bcd]pyran-5-one], agrostophylloxin [2,6,7-trimethoxy-5H-pheaanthro[4,5-bcd]pyran-5-one] and the bibenzyl derivative moscatalin [4,4'-dihydroxy-3,3',5-trimethoxybibenzyl]. The structures of agrostophyllanthrol and isoagrostophyllanthrol were established as 7-hydroxy-2,6-dimethoxy-5H-phenanthro[4,5-bcd]pyran-5(equat)ol and 7-hydroxy-2,6-dimethoxy-5H-phenanthro[4,5-bcd]pyran-5(ax)ol, respectively from various spectral and chemical evidence. Agrostophyllanthrol and isoagrostophyllanthrol, thus, represent two novel examples of otherwise conformational isomers becoming highly stable diastereomers due to unusual steric hindrance to conformational flipping.

Five New Biphenanthrenes from Cremastra appendiculata

Abstract: Five new biphenanthrenes, cremaphenanthrenes A–E (1–5), along with six known ones, were isolated from the ethanolic extract of the tubers of Cremastra appendiculata (D. Don) Makino (Orchidaceae). Their structures were elucidated on the basis of extensive spectroscopic analyses. All the compounds obtained were tested in vitro for cytotoxic activities against colon (HCT-116), cervix (Hela), and breast (MDA-MB-231) cancer cell lines. They all showed moderate or weak cytotoxicities to the above cancer cell lines.

Agrostophyllanthrol and Isoagrostophyllanthrol, Two Novel Diastereomeric Phenanthropyran Derivatives (I) from the Orchid Agrostophyllum khasiyanum.

Abstract: Agrostophyllanthrol and isoagrostophyllanthrol, two novel diastereomeric phenanthropyran derivatives were isolated from the orchid Agrostophyllum khasiyanum which earlier afforded eleven stilbenoids, viz. the two dimeric phenanthrene derivatives agrostonin [2,2',7,7'-tetrahydroxy-4,4',6,6'-tetrainethoxy-1,1'-biphenanthryl] and agrostonidin [2,2',6,6'-tetrahydroxy-4,4',7,7'-tetramethoxy-1,1'-biphenanthryl], eight phenanthropyran derivatives imbricatin [2,7-dihydroxy-6-methoxy-9,10-dihydro-5H-phenanthro[4,5-bcd]pyran], agrostophyllidin [7-hydroxy-2,6-dimethoxy-9,10-dihydro-5H-phenanthro[4,5-bcd]pyran], agrostophylloxidin [7-hydroxy-2,5,6-trimethoxy-5H-phenanthro[4,5-bcd]pyran], flaccidinin [2,6-dihydroxy-7-methoxy-5H-phenanthro[4,5-bcd]pyran-5-one], isoflaccidinin [2,7-dihydroxy-6-methoxy-5H-phenanthro[4,5-bcd]pyran-5-one], agrostophyllin [7-hydroxy-2,6-dimethoxy-5H-phenanthro[4,5-bcd]pyran], agrostophyllone [7-hydroxy-2,6-dimethoxy-5H-phenanthro[4,5-bcd]pyran-5-one], agrostophylloxin [2,6,7-trimethoxy-5H-pheaanthro[4,5-bcd]pyran-5-one] and the bibenzyl derivative moscatalin [4,4'-dihydroxy-3,3',5-trimethoxybibenzyl]. The structures of agrostophyllanthrol and isoagrostophyllanthrol were established as 7-hydroxy-2,6-dimethoxy-5H-phenanthro[4,5-bcd]pyran-5(equat)ol and 7-hydroxy-2,6-dimethoxy-5H-phenanthro[4,5-bcd]pyran-5(ax)ol, respectively from various spectral and chemical evidence. Agrostophyllanthrol and isoagrostophyllanthrol, thus, represent two novel examples of otherwise conformational isomers becoming highly stable diastereomers due to unusual steric hindrance to conformational flipping.