Dimethylammonium tetrafluoroborate → Ethyl 2-dimethylamino-6-(4-biphenylyl)-5-methylthio-6-oxo-2,4-hexadienoate

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Reaction Steps

The procedure is as in Example 4 for the preparation of ethyl 6-phenyl-6-oxo-5-methylthio-2dimethylamino-2,4-hexadienoate, starting with N-(3-dimethylamino)-3-ethoxycarbonylpropenyldiene)-N-methylmethanaminium tetrafluoroborate (6 g), a 2M ethanolic solution of sodium ethylate (10.5 cc) and α-methylthio-4-phenylacetophenone (5.1 g) in ethanol (150 cc). After purification by chromatography on a silica column with a mixture of cyclohexane and ethyl acetate (50:50 by volume) as eluent, ethyl 2-dimethylamino-6-(4-biphenylyl)-5-methylthio-6-oxo-2,4-hexadienoate (2.8 g) is obtained in the form of an orange-coloured oil, and is used in the crude state in the subsequent syntheses.

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