Yield:-

Reaction Conditions:

with sodium hydrogencarbonate in N,N-dimethyl-formamide at 40; for 5 h;

Steps:

17.17a

A mixture of 4-(4-chlorophenylsulfanyl)thiophene-3-carboxylic acid (1.0 g), sodium hydrogen carbonate (1.6 g), iodomethane (2.3 ml_) and N, N- dimethylformamide (10 ml_) was stirred was stirred at 4O⁰C for 5 hours. The mixture was cooled to room temperature, diluted with water (100 ml_) and the aqueous phase extracted with ethyl acetate. The combined organic extract was dried over magnesium sulfate and concentrated under reduced pressure to afford the title compound as a yellow oil (1.0 g).¹H NMR (DMSO-d₆): δ 3.77 (d, J = 0.6 Hz, 3H), 6.96 (dd, J = 0.6, 3.4 Hz, 1 H), 7.41-7.52 (m, 4H), 8.49 (dd, J = 0.6, 3.4 Hz, 1 H).

References:

WO2009/77728,2009,A1 Location in patent:Page/Page column 38