Acetic Acid → 1-Tosyl-3,4-dihydro-1H-benzo[b]azepin-5(2H)-one

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Reaction Steps

A mixture of 5-hydroxy-1-(toluene-4-sulfonyl)-2,3-dihydro-1H-benzo[b]azepine-4-carboxylic acid methyl ester and 5-hydroxy-1-(toluene-4-sulfonyl)-2,3-dihydro-1H-benzo[b]azepine-4-carboxylic acid ethyl ester from Example E5.3 were heated at reflux in a mixture of ethanol (100 ml), acetic acid (300 ml), concentrated HCl (100 ml) and water (50 ml) for 18 h. The mixture was cooled to room temperature, diluted with water (800 ml) and extracted with chloroform. The combined organic ex-tracts were dried, filtered and reduced in vacuo. The residue was crystallised twice from methanol to yield the title compound (44 g, 60% over two steps).

Provenance & Evidence