反应详情

3,5-Bis(trimethylsilyloxy)-1,2,4-triazine (2.5 g) and 2-chlorotetrahydropyran (1.8 g) are dissolved in dimethylformamide (1 ml), and the mixture is stirred overnight at room temperature and concentrated in vacuo. The residue is column-chromatographed over silica gel using a mixture of acetone/n-hexane (1/3) as an eluent. The first major fraction gives 1.0 g (40%) of 2,4-bis(tetrahydro-2-pyranyl)-3,5-dioxo-2,3,4,5-tetrahydro-1,2,4-triazine (Compound No. 87) (yield, 1.0 g; 36%), the second gives 4-(tetrahydro-2-pyranyl)-3,5-dioxo-2,3,4,5-tetrahydro-1,2,4-triazine (Compound No. 88) (yield, 0.8 g; 40%) and the third gives 2-(tetrahydro-2-pyranyl)-3,5-dioxo-2,3,4,5-tetrahydro-1,2,4-triazine (Compound No. 100) (yield, 0.6 g; 30%). Compound Nos. 87 and 88 melt at 32° C. and 116° C., respectively.

1. concentrationconcentrated in vacuo
2. customThe residue is column-chromatographed over silica gel using
3. additiona mixture of acetone/n-hexane (1/3) as an eluent