76504-82-0Relevant articles and documents
The Chemistry of Fungi. Part 76. The Synthesis and Transformations of Three Steroisomeric 2-(2,6-Dimethoxybenzoyl)-3-methoxycarbonyl-7-oxabicycloheptanes
Borthwick, Alan D.,Curry, David J.,Poynton, Alan,Whalley, W. Basil,Hooper, John W.
, p. 2435 - 2444 (2007/10/02)
Condensation of 1-lithio-2,6-dimethoxybenzene with the anhydride (10) of 7-oxabicycloheptane-2β,3β-dicarboxylic acid and subsequent esterification of the product gave 2β-(2,6-dimethoxybenzoyl)-3β-methoxycarbonyl-7-oxabicycloheptane (8; R1=H, R2=Me).The isomeric 2α-(2,6-dimethoxybenzoyl)-3α-methoxycarbonyl-7-oxabicycloheptane (11; R=Me) was prepared similarly using the anhydride (9) from 7-oxabicycloheptane-2α,3α-dicarboxylic acid.Epimerisation of (11; R=Me) or of (8; R1=H, R2=Me) gave 2α-(2,6-dimethoxybenzoyl)-3β-methoxycarbonyl -7-oxabicycloheptane (12).Treatment with boron trichloride of (11; R=Me) gave 1α-chloro-4β-hydroxy-2α-(2-hydroxy-6-methoxybenzoyl)-3α-methoxycarbonylcyclohexane (13; R=H) and 1,7α-dihydroxy-8β-methoxycarbonyl-5aα,5,6,7,8,8aα-hexahydroxanthone (23; R=H); similarly (8; R1=H, R2=Me) gave 4β-hydroxy-2β-(2-hydroxy-6-methoxybenzoyl)cyclohexane-1β,3β-carbolactone (24; R=H) and 1,7α-dihydroxy-8α-methoxycarbonyl-5aα,5,6,7,8,8aα-hexahydroxanthone (25; R=H).The third isomer (12) formed 4α-chloro-1β-hydroxy-2α-(2-hydroxy-6-methoxybenzoyl)-3β-methoxycarbonylcyclohexane (31; R=H) together with 1,7α-dihydroxy-8α-methoxycarbonyl-5aα,5,6,7,8,8aα-hexahydroxanthone (32; R=H).Hydrogenolysis of (1; R1=R2=Me) or treatment of (11; R=Me) with acid yielded 2-(2,6-dimethoxybenzoyl)-4β-hydroxy-3α-methoxycarbonylcyclohexene (15; R=H); the corresponding acetate (15; R=Ac) was hydroxylated to form 4β-acetoxy-2α-(2,6-dimethoxybenzoyl)-1β,2β-dihydroxy-3α-methoxycarbonylcyclohexane (18) as the major product.The steroisomeric cyclohexene (34; R=H) was similarly obtained.Bromination of the ketone (11; R=Me) gave the α-bromoketone (33): similarly the α-bromoketone (8; R1=Br, R2=Me) was obtained from (8; R1=H, R2=Me).Dehydrobromination of each of these bromoketones formed 2-(2,6-dimethoxybenzoyl)-3-methoxycarbonyl-7-oxabicyclohept-2-ene (1, R1=R2=Me).Various further transformations of these products are described.
