Rotundatin, a new 9,10-dihydrophenanthrene derivative was isolated from the orchid, Dendrobium rotundatum, which also afforded the known stilbenoids 2,7-dihydroxy-3,4,6-trimethoxyphenanthrene, 2,7-dihydroxy-3,4,6-trimethoxy-9,10-dihydrophenanthrene, nudol, moscatin and batatasin-III. Rotundatin was shown to be 2,5,9-trihydroxy-4-methoxy-9,10-dihydrophenanthrene from spectral and chemical evidence. © 1992.

P L MAJUMDER

(NEE RAY) S PAL

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Rotundatin, a new 9,10-didydrophenanthrene derivative from Dendrobium rotundatum

Phytochemistry

Agrostophyllol and isoagrostophyllol, two novel diastereomeric 9,10- dihydrophenanthropyran derivatives isolated from the orchid Agrostophyllum callosum, were shown to have the structures 2,7-dihydroxy-6-methoxy-9,10- dihydro-5H-phenanthro[4,5-bcd]pyran-5(ax)ol (1l) and 2,7-dihydroxy-6-methoxy- 9,10-dihydro-5H-phenanthro[4,5-bcd]pyran-5(equat)ol (1n), respectively, from spectral and chemical evidence. 1l and 1n were shown to be the racemic mixtures of 1l' and 1l'', and 1n' and 1n'', respectively.

Tetrahedron

Agrostophyllol and isoagrostophyllol, two novel diastereomeric 9,10- dihydrophenanthropyran derivatives from the orchid Agrostophyllum callosum

Thunalbene, a new stilbene derivative, was isolated from the orchid Thunia alba which also afforded six known stilbenoids: batatasin-III, lusianthridin, 3,7-dihydroxy-2,4-dimethoxyphenanthrene, 3,7-dihydroxy-2,4,8- trimethoxyphenanthrene, cirrhopetalanthrin and flavanthrin. The structure of thunalbene, the first stilbene derivative isolated so far from an Orchidaceae plant, was established as 3,3'-dihydroxy-5-methoxystilbene from spectral and chemical evidence.

Thunalbene, a stilbene derivative from the orchid Thunia alba

Cirrhopetalanthridin and cirrhopetalidinin, two new stilbenoids isolated from the orchid Cirrhopetalum andersonii, were shown to be 4,7-dihydroxy-2,3-methylenedioxy-9,10-dihydrophenanthrene and 3,2'-dihydroxy-5'-methoxy-4,5-methylenedioxy bibenzyl, respectively, from spectral and chemical evidence.

2 STILBENOIDS FROM THE ORCHID CIRRHOPETALUM-ANDERSONII

An amorphous phenanthrene, named nudol has been isolated from Eulophia nuda, Eria carinata and E. stricta. It was identified as 2,7-dihydroxy-3,4-dimethoxyphenanthrene. Synthesis of nudol and its dimethyl ether is described. © 1985.

Nudol, a phenanthrene of the orchids Eulophia nuda, Eria carinata and Eria stricta

Bulbophyllanthrin, a novel phenanthrene derivative from the orchid Bulbophyllum leopardium, was shown to have the structure 1a mainly on the basis of spectral evidence including 13C and 2D NMR spectra. © 1985.

Bulbophyllanthrin, a phenanthrene of the orchid Bulbophyllum leopardium

Coelogin and coeloginin, two novel 9,10-dihydrophenanthrene derivatives of the high altitude Himalayan orchid Coelogyne cristata, have been shown to have the phenanthro[4,5-bcd]pyran structures (1a) and (1b), respectively, from spectral and chemical evidence.

Journal	Phytochemistry
Publisher	-
ISSN	0031-9422