Chloroform → 2-(2-Naphthyl)acetyl chloride

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Reaction Steps

2-Naphthylacetyl chloride is prepared according to the method described in Example 8 using 2-naphthylacetic acid (2.47 g, 13.3 mmol) to give a yellow solid which is dissolved in chloroform (15 mL). This solution is added to a solution of (±)-trans-[2-(4-methyl-1-piperazinyl)]cyclohexanol (2.5 g, 12.6 mmol) in chloroform (10 mL), and the mixture is refluxed for 11 hours under nitrogen. The solvent is removed in vacuo, and the residue is partitioned between 1M hydrochloric acid (100 mL) and ether (60 mL). The ether layer is separated and the aqueous is washed with more ether (2×30 mL), and then basified by the addition of 50% sodium hydroxide solution. This is then extracted with ether (4×30 mL), and the combined ether extracts are washed repeatedly with water to remove any unreacted aminoalcohol. The ether containing the product is then dried over sodium sulfate, and the solvent is removed to leave the crude free ester. The free ester is dissolved in ether/dichloromethane (35 mL, 4:3) and converted to the dihydrochloride salt by treatment with an excess of HCl in the same solvent. The resulting solid is washed with ether and recrystallised from hot methanol to yield the title compound.

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