4-{[4-Hydroxy-4-(trifluoromethyl)(1,3-thiazolin-2-yl)]amino}-5-methylthiothiophene-2-carboxamidine → 4-{[4-Hydroxy-4-(trifluoromethyl)(1,3-thiazolin-2-yl)]amino}-5-methylthiothiophene-2-carboxamidine

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Reaction Steps

4-{[4-Hydroxy-4-(trifluoromethyl)(1,3-thiazolin-2-yl)]amino}-5-methylthiothiophene-2-carboxamidine: Using a procedure similar to Example 154, step (b), 40 mg (0.11 mmol) of methyl 4-{[4-hydroxy-4-(trifluoromethyl)(1,3-thiazolin-2-yl)]amino}-5-methylthiothiophene-2-carboxylate was allowed to react with 8 equiv (0.89 mmol) of the AlMe3/NH4Cl reagent and purified by preparative thin layer chromatography 20%-MeOH—CHCl3-sat'd. NH3, 500 μm SiO2 plate) to afford 11 mg (28%) of 4-{[4-hydroxy-4-(trifluoromethyl)(1,3-thiazolin-2-yl)]amino}-5-methylthiothiophene-2-carboxamidine as a ca. 1:1 mixture of cyclized aminal and open imine tautomers. 1H NMR (DMSO-d6, 300 MHz) δ 2.73 (s, 3H tautomer), 2.89 (s, 3H tautomer), 3.36 (d, 2H, J=6.5 Hz), 3.62 (d, 2H, J=7.2 Hz), 7.95 (s, 1H), 8.36 (bs, 2H), 9.79 (bs, 1H). Mass spectrum (ESI, m/z): Calcd. for C10H11F3N4OS3, 357.01 (M+H), found 357.2.

Provenance & Evidence