Chloroform → 2-(Naphthalen-1-yl)acetyl chloride

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Reaction Steps

1-Naphthylacetyl chloride is prepared according to the method described in Example 8 using 1-naphthylacetic acid (2.0 g, 10.8 mmol) to give a yellow oil which is dissolved in chloroform (10 mL). This solution is added to a solution of (±)-trans-[2-(4-morpholinyl)]cyclohexanethiol (2 g, 10 mmol) in chloroform (10 mL), and the mixture is stirred at room temperature for 8 hours under nitrogen. The solvent is removed and the residue is partitioned between 1M hydrochloric acid (100 mL) and ether (80 mL). The organic layer is separated and the aqueous is washed with more ether (2×60 mL). The aqueous mixture is basified to pH>12 by the addition of 50% sodium hydroxide solution, and extracted with ether (1×80 mL, 2×50 mL). These ether extracts of the basic aqueous solution are washed repeatedly with water to remove any unreacted aminothiol, dried over sodium sulfate, and the solvent is removed to leave the crude free thioester. This is converted to the hydrochloride salt by dissolving it in 1M hydrochloric acid (60 mL), adding sodium chloride (12 g), and extracting with chloroform (3×75 mL). The chloroform is removed in vacuo and the residue is recrystallised from ethyl acetate/methanol to yield the title compound.

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