Phosgene → 6-Methyl-2H-thieno[2,3-d][1,3]oxazine-2,4(1H)-dione

Participants

Reaction Conditions

Reaction Steps

step 2—A suspension of 60b (4.0 g, 25.5 mmol) and dioxane (65 mL) was cooled to 5° C. Phosgene (22.5 mL of a 20% solution in toluene, 45.9 mmol) was added dropwise through a septum. The flask was equipped with a condenser and the mixture was refluxed for 4 h. After cooling the solvents were evaporated in vacuo to afford 5.0 g (100%) of 6-methyl-1H-thieno[2,3-d][1,3]oxazine-2,4-dione (61a) which was used without purification: ms [M−H]=182.

Provenance & Evidence