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Synthesis of 2,2-difluoro-1-keto-5-tosylbenzazepine

IP.com Disclosure Number: IPCOM000019408D
Publication Date: 2003-Sep-12

Publishing Venue

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Abstract

A procedure for the preparation of the title compound was developed. This is shown schematically below. The keto benzazepine,1 was treated with lithium hexamethyldisilazane in THF to generate the lithium enolate. This was reacted with trimethyl silyl chloride to furnish the silyl enol ether, 2. After distillation of the solvents, and excess chloride, the enol ether was reacted with the SelectfluorTM Reagent , (1-chloromethyl-4-fluoro)-1,4-diazabicyclo(2.2.2)ooctane bis(tetrafluoroborate) in acetonitrile to produce the monofluoro compouind, 3. The sequence of enolization, silylether formation and fluorination with Selectfluor was applied to the monofluoro ketone in order to obtain the difluoro compound,4.