Abstract
1-Cyano-isothiochromane (1a) can be alkylated in position 1, using the carbanion that is formed from sodium amide, sodium hydride, or n-butyllithium. With methyl iodide or ethyl iodide 1c and 1d are formed; with α-halogenated ether or thioether, 1e and 1f; with propargyl bromide, 1h; with bromo acetophenone, li; and with ethyl chloroacetate, 1k. Similarly, acylation with benzoyl chloride leads to 11, and with 2,4-dinitrofluorobenzene to 1m. The alkylation products of 1a can be oxidized with peracids to the sulfones 2 and with LiAlH4 reduced to 1-aminomethyl-isothiochroman (3): Acid hydrolysis of 1 gave isothiochromane-1-carboxylic acids, 4, whereas when 1 is treated with hydrogen peroxide in alkaline medium the S-dioxide and the S-oxide acid amides, 5 and 6 respectively, are formed.