5-hydroxy-1,3-dimethyl-1,3-diazinan-2-one

Conditions: temp:70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 1,3-dimethyl-5-triisopropylsilanyloxy-tetrahydro-pyrimidin-2-one (Step P8) (9.1 g, 28 mmol) in EtOH (70 mL) was added a 1M HCl (140 mL, 140 mmol) and the mixture was stirred for 3 h at 70° C. The mixture was concentrated, and the pH of the resulting aqueous phase was adjusted to 5 with a saturated aqueous NaHCO3 solution. The aqueous layer was saturated with NaCl and was extracted with CH2Cl2/isopropanol 3:1. The organic layer was dried (Na2SO4), filtered and concentrated to afford the title compound. ESI-MS: tR=0.33 min, [M+H]+ 145.1 (LC-MS 1). The mixture was concentrated was extracted with CH2Cl2/isopropanol 3:1 The organic layer was dried (Na2SO4) filtered concentrated