p-Toluenesulfonic acid → 2,2-Dimethyl-2,3-dihydroperimidine

Participants

Reaction Steps

A solution of 1,8-naphthalene diamine (3.5 g, 22 mmol), distilled as in Example 1, acetone (25 ml) and p-toluene sulfonic acid (10 mg) was prepared and stirred at room temperature for 0.5 hour under a nitrogen atmosphere. The mixture was basified with concentrated sodium carbonate (2 ml) and concentrated to about 5 ml volume. The mixture was diluted with ether (150 ml), washed with water and brine, and dried over potassium carbonate. Concentration gave 3.35 g (77%) 2,3-dihydro-2,2-dimethyl perimidine as a pale pink solid. Recrystallization from hexane-ether gave crystals: mp 114°-115° C.; NMR (CDCl3) 7.07(m, 4H), 6.33(m, 2H), 4.06(bs, 2H), 1.42(s, 6H); IR (KBr) 3364, 3290, 1618, 1595 cm-1.

Provenance & Evidence