Lawesson's reagent → 2-Methyl-4-(trimethylsilanylmethyl-thiocarbamoyl)-benzoic acid methyl ester

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Reaction Steps

To a solution of 2-methyl-N-trimethylsilanylmethyl-terephthalamic acid methyl ester (Example I7) (1.83 g) in toluene (50 ml) was added 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide (Lawesson reagent) (2.65 g). The reaction mixture was stirred at ambient temperature for 30 minutes and then at 110° C. for 1.5 hours. The reaction mixture was concentrated and the residue purified by chromatography on silica gel (eluent: ethyl acetate/heptanes 1:5) to give 2-methyl-4-(trimethylsilanylmethyl-thiocarbamoyl)-benzoic acid methyl ester (1.85 g). 1H-NMR (400 MHz, CDCl3): 7.75-7.20 (m, 3H), 3.70 (s, 3H), 3.35 (m, 2H), 2.45 (s, 3H), 0.00 (s, 9H) ppm.

Provenance & Evidence