A New Synthesis of 8-Methoxypsoralene
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Authors
Brautigan, David L.
Issue Date
1972
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
The present work was undertaken to develop a high-yield synthesis
of 8-methoxypsoralene. The synthesis begins with pyrogallol (XIII),
which is methylated with dimethyl sultate to form 1,2,3-trimethoxy-
benzene (XIV). This is brominated to form 1,5-dibromo-2, 3,4-trimethoxybenzene
(XV), which is converted to 5-bromo-2,3,4-trimethoxybenzaldehyde
(XVI) with n-butyllithium and dimethylformamide. The methoxy group
ortho to the formyl group is then cleaved with boron trichloride,
forming 5-bromo-3,4-dimethoxysalicylaldehyde (XVII). Treatment with
methyl bromoacetate and potassium carbonate gives methyl (4'-bromo-
2',3'-dimethoxy-6'.tormylphenoxy)acetate (XVIII) which is hydrolyzed
with base to give 4'-bromo-2',3'-dimethoxy-6'.formylphenoxyacetic acid
(XIX). Cyclization to 5-bromo-6,7-dimethoxybenzofUran (XX) is done
with acetic anhydride, acetic acid, and sodium acetate. Treatment
with n-butyllithium and dimetbylformam1de gives 6.7-dimethoxy-5-to~1-
QenzoiUran (XXI), and cleavage with boron trichloride gives 5-tormyl-
6-byd~XY-7-methoxybenzo£Uran (XXII). The final cyclization to
8-methoxypsoralene (XXIII) is an iodine catalyzed Perkin condensation.
Description
v, 31 p.
Citation
Publisher
Kalamazoo College
License
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