Aminoacetaldehyde dimethyl acetal → HCID 23462902, compound

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Reaction Steps

Following the procedures outlined in Examples 1 and 2, the 2-fluorohomoveratric acid is reacted with aminoacetaldehyde dimethylacetal to form N-(2,2-dimethoxyethyl)-3,4,-dimethoxy-2-fluorophenylacetamide which is ring closed with hydrochloric acid and glacial acetic acid to obtain 2,3-dihydro-7,8-dimethoxy-6-fluoro-2-oxo-1H-3-benzazepine. The dihydrobenzazepine is reduced first with hydrogen and palladium-on-carbon, then with diborane to give 7,8-dimethoxy-6-fluoro-2,3,4,5-tetrahydro-1H-3-benzazepine. The latter is treated with formaldehyde/formic acid to give the corresponding 3-methyl derivative which is demethylated with 48% hydrobromic acid. The resulting catechol is oxidized with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and the dione is treated with a methanolic solution of thiophenol to furnish the product 7,8-dihydroxy-9-fluoro-3-methyl-6-phenyl-thio-2,3,4,5-tetrahydro-1H-3-benzazepine.

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