p-Toluenesulfonic acid monohydrate → HCID 15549484, compound

Participants

Reaction Steps

Method A. A mixture of 6 (2.85 g, 13.6 mmol) and p-toluenesulfonic acid monohydrate (1.3 g, 6.84 mmol) in 80 mL of acetone/water (1:1, v/v) was refluxed for 6 h. After cooling, the reaction mixture was extracted with CH2Cl2 (3×100 mL). The combined organic extracts were dried (MgSO4) and concentrated under reduced pressure. The resulting solid was recrystallized from acetone/CH2Cl2 to afford 7 (1.81 g, 80%) as a colorless solid: mp 88-90° C.; 1H NMR (CDCl3) d 2.77 (t, 2H, J=5.8), 3.66 (q, 2H, J=5.8), 6.16 (m, 1H), 6.38 (br, 1H), 6.50 (m, 1H), 6.87 (m, 1H), 9.69 (br, 1H), 9.78 (bs, 1H); 13C NMR (CD3COCD3) d 33.7 (e), 44.6 (e), 109.6 (o), 110.0 (o), 122.1 (o), 127.1 (e), 162.0 (e), 201.9 (o); IR (nujol) 1715, 1622, 1565, 1409, 1328 cm−1; MS m/z (relative intensity) 167 (M++1, 100), 138 (15) , 123 (28), 94 (50); Anal. Calcd for C8H10N2O2: C, 57.82; H, 6.07; N, 16.86; Found: C, 57.68; H, 5.17; N, 16.79. Method B. To a stirred solution of oxalyl chloride (0.12 mL, 1.31 mmol) in 3 mL of CH2Cl2 at −78° C. was added DMSO (0.21 mL, 2.9 mmol) in 0.6 mL of CH2Cl2 under argon. After 2 min, a solution of 5 (0.2 g, 1.19 mmol) in 40 mL of CH2Cl2 was added to the mixture and allowed to stir for 15 min. Next, triethylamine (830 mL, 5.92 mmol) was added and the reaction mixture was allowed to warm to room temperature. After 15 min, the mixture was poured into 10 mL of water and the organic layer was separated and washed successively with 10% citric acid (20 mL), saturated NaHCO3 (20 mL), and saturated NaCl (20 mL). The organic layer was dried (MgSO4) and concentrated under reduced pressure. The resulting residue was purified by flash column chromatography (CH2Cl2/MeOH 19:1) to afford 7 (0.14 g, 70%) as a colorless solid.

Provenance & Evidence