N,N,N',N'-Tetramethylazodicarboxamide → Benzoxazines

Participants

Reaction Steps

To 6.5 g (27 mmol) of the phenolic diamide in 200 mL of anhydrous CH2Cl2 was added 6.5 g CuSO4, 2.3 g (10 mmol) camphor sulfonic acid, 36 g (400 mmol) trioxane, and 10 drops H2SO4 with rapid stirring. The resulting suspension was heated to reflux under argon atmosphere and refluxed for 72 hr. The reaction mixture as concentrated to 100 mL by simple distillation at which point no starting material was seen by TLC (EtOAc). The reaction mixture was diluted to 400 mL with CH2Cl2, and then filtered through celite. The filtrate was washed with 100 mL of 1 N NaOH, dried over Na2SO4, and concentrated in vacuo yielding 6.0 g crude benzoxazine intermediate. The crude benzoxazine was chromatographed on 200 g of silica gel (EtOAc) yielding 4.0 g (59%) of intermediate with one spot to TLC and the following property: FTIR 3327, 1664, 1641, 1552, 1428, 1329.

Provenance & Evidence