Step 3. Preparation of methyl 2-chloroquinazoline-7-carboxylate
To methyl 2-oxo-1,2-dihydroquinazoline-7-carboxylate (1.0 eq.) was added phosphorous trichloride (POCl3, 3.0 eq.), the reaction mixture was heated to 100 °C and the reaction was stirred at this temperature for 20 minutes. Upon completion of the reaction, the mixture was cooled to room temperature and the reaction was quenched by slowly pouring into ice water. The precipitated solid product was collected by filtration and washed with cold water. The resulting solid was dried overnight under high vacuum to afford methyl 2-chloroquinazoline-7-carboxylate in 60% yield. The product was confirmed by electrospray mass spectrometry (ES/MS), m/z 223 (MH+).
