Triphenylphosphine → 1,2,3,4-Tetrahydro-3-methyl-2,4-dioxo5-trimethylsilylethynyl-quinazoline

Participants

Reaction Conditions

Reaction Steps

To a degassed solution of 5-bromo-3-methyl-2,4-dioxo-1,2,3,4-tetrahydro-quinazoline (1.0 g, 4.0 mmol) in 20 ml of DMF and 20 ml of triethylamine was added trimethylsilylacetylene (1.6 ml, 12 mmol), 50 mg of triphenylphosphine, 20 mg of palladium(II)acetate, and 1 mg of cuprous(I)iodide. The mixture was stirred under nitrogen, at 70° C. After 7 h additionally 0.4 ml of trimethylsilylacetylene was added and heating continued for 4 h. Then the mixture was evaporated in vacuo and the residue extracted with 100 ml of dichloromethane and 100 ml of water. The organic layer was washed twice with 100 ml of water, dried over anhydrous sodium sulfate, treated with charcoal, filtered through a pad of celite, and evaporated. The residue was triturated with ether/petroleum ether (1:1) and filtered off and dried giving 0.50 g (46%) of 1,2,3,4-tetrahydro-3-methyl-2,4-dioxo-5-trimethylsilylethynyl-quinazoline.

Provenance & Evidence