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Constitution, stereochemistry and conformational behaviour of the photoreaction product of 7‐deacetoxy‐7‐oxokhivorin
Author(s) -
Okogun Joseph I.,
Duddeck Helmut,
Habermehl Gerhard,
Krebs Hans C.,
Tóth Gábor,
Simon András
Publication year - 1998
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/(sici)1097-458x(199805)36:5<371::aid-omr279>3.0.co;2-5
Subject(s) - chemistry , stereochemistry , ring (chemistry) , epoxide , limonoid , photodissociation , constitution , photochemistry , organic chemistry , political science , law , catalysis
By means of 2D NMR experiments (COSY, HMQC, HMBC, ROESY), the constitution of the photoreaction product 3‐deoxo‐1α,3 α‐diacetoxy‐1,2,3,3,8,30‐hexahydro‐18β H ‐andirobin (2), obtained by photolysis of 7‐deacetoxy‐7‐oxokhivorin (1) in methanol, was shown to be a ring B seco‐limonoid with the 14,15‐epoxide intact. The configuration of C‐8 is R . Ring C adopts a twist‐boat conformation. No conformational preferences for the rotation of ring A in 2 with respect to rings C/D and for the side‐chain C‐6/C‐7 could be detected. Nearly all 1 H and all 13 C resonances were assigned unambiguously. © 1998 John Wiley & Sons, Ltd.