Phosphorus oxychloride → HCID 19809387, compound

Participants

Reaction Steps

The 6,7 dihydro-2-ethyl-8-methyl-3H-pyrimido[5,4-b][1,4]thiazine-4,7-dione of Example 115 (2.7g, 12.04 mmole) was suspended in approximately 150ml of phosphorus oxychloride and refluxed for about 20 hours. The solution was concentrated in vacuo and the excess phosphorus oxychloride was decomposed with the careful addition of ice and water. The aqueous solution was neutralized with the cautious addition of concentrated ammonium hydroxide, followed by the addition of sodium bicarbonate. The aqueous solution was extracted numerous times with chloroform; the extracts were combined, washed well with water, then brine, dried over magnesium sulfate, filtered and evaporated in vacuo to provide 2.4g (83%) of an off-white solid. The structural assignment was confirmed by infrared and nuclear magnetic resonance spectral analyses.

Provenance & Evidence