p-Toluenesulfonic acid monohydrate → p-Toluenesulfonic acid

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Reaction Steps

A suspension of 2-thioxo-benz[cd]indole-1(2H)-acetic acid (1.0 g, 4.11 mmol, described in Example 6) aminoethanol (0.5 g, 0.49 mL, 8.22 mmol) and p-toluenesulfonic acid hydrate (1.88 g, 9.86 mmol) in benzene (50 mL) was refluxed for 48 hr with stirring in a Soxhlet apparatus containing a thimble filled with 3A molecular sieves. The mixture was evaporated to dryness, and the residue was triturated with cold water (50 mL). The precipitate was collected by filtration, washed with diethyl ether (50 mL), and crystallized from water to give the 4-methylphenylsulfonic acid salt of the title compound (1.0 g): Anal. Calcd for C15H14N2O2S.C7H8O3S: C, 57.63% H, 4.84% N, 6.11% and Found: C, 57.58% H, 4.94% N, 6.23%; IR (mineral oil) 2900, 1740, 1375, and 11700 cm-1 ; UV max (methanol) 342 (ε3400), 310 (6700), 304 (6740), 267 (27,900), 259 (21,580), and 218 nm (26,210); NMR (DMSO-d6)ε 2.25 (s, 3H), 3.12 (t, 2H), 4.32 (t, 2H), 5.3 (s, 2H), 7.7 (m, 10H), and 7.9 (s, 3H).

Provenance & Evidence