Potassium Carbonate → 4-Butyl-6,7-dichloro-2,3-dihydro-pyrazino(2,3-b)(1,4)oxazine

Participants

Reaction Steps

A mixture of tetrachloropyrazine (21.8 g, 0.1 mol), n-butylaminoethanol (11.7 g, 0.1 mol), and potassium carbonate (28 g, 0.2 mol) were heated to 80° in 225 ml of dioxane and 50 ml of water for 24 hours. After extraction with CH2Cl2 and concentration with rotary evaporation, 30 g of an oil characterized by nmr as the N-substituted product was obtained. An attempt to distill 5 g of this material led to decomposition. The rest of the material was dissolved in 200 ml of benzene and refluxed for 2 hours with crushed KOH (10 g, 85% assay, 0.15 mol). The mixture was partitioned between water and CH2Cl2. The organic layer was dried (MgSO4) and rotary evaporated to give a crude oil. This was distilled two times on a Kugelrohr apparatus (b.p. about 130° at 0.5 mm Hg) to give 12.5 g (48% yield) of the title product.

Provenance & Evidence