p-Toluenesulfonic acid → 2,3-Dihydroperimidine

Participants

Reaction Steps

A solution of the above aldehyde (1.17 g, 4 mmol), distilled 1,8-diamino naphthalene (0.63 g, 4 mmol), p-toluenesulfonic acid (10 mg), and tetrahydrofuran (6 mL) was stirred for 0.5 h at room temperature. The mixture was basified with 1 mL saturated sodium carbonate, diluted with THF-ether (1:1) and washed with water. The extract was concentrated and the residual solid was recrystallized from THF-ether (1:1, 30 mL) to give the 2,3-dihydroperimidine (1.50 g, 87%): mp 165-167° C.; 1H NMR (CDCl3) 7.59(s, 4H), 7.45 and 6.9(2d, 4H), 7.1(m, 4H), 6.4(d, 2H), 4.7(bs, 2H), 4.45(t, 1H), 4.0(t, 2H), 2.0-1.5(m, 8H); IR 3385, 3360, 2225, 1601 cm-1.

Provenance & Evidence