2-Chloroethyl methyl sulfide → 4-Amino-5-chloro-2-[2-(methylthio)ethoxy]benzoic acid

Participants

Reaction Conditions

Reaction Steps

A cooled (5° C.) suspension of 60% sodium hydride oil dispersion (0.52 g, 13 mmole) in anhydrous dimethylformamide (15 ml) under nitrogen was treated in portions with 4-amino-5-chloro-2-hydroxybenzoic acid (0.94 g, 5 mmoles) stirred for 15 minutes at 25° C., treated with (2-chloroethyl)methyl sulfide (1.66 g, 15 mmoles), and heated to 100°±5° C. for 18 hours. The solution was cooled, concentrated in vacuo to remove most of the dimethylformamide and water (25 ml) was added. The aqueous solution was extracted with ether (2×25 ml), and the combined extracts were dried (MgSO4), concentrated in vacuo, taken up in 50% aqueous ethanol (50 ml), treated with potassium hydroxide (5.0 g), and refluxed for one hour. The mixture was concentrated to remove most of the ethanol, diluted with water to 75 ml total volume, extracted with ether (2×35 ml), and acidified to pH 3 with concentrated HCl. The resultant precipitate was filtered, washed with water, air dried, and recrystallized from ethyl acetate to yield 0.75 g (57%) of fine voluminous white needles, mp 137.5°-139.5° C.

Provenance & Evidence