to 60 u00b0 c over the course of 60 min to 112 1 g 1 mol of 4 6 dihydroxypyrimidine and 460 g 3 mol of poc1 3 and the mixture was then heated at from 95 u00b0 to 100 u00b0 c for 3 h subsequently 416 5 g 2 mol of pc1 5 were added at from 50 u00b0 to 60 u00b0 c over the course of 90 min and the mixture was allowed to react for a further 60 min poc1 3 was then distilled off at 200 hpa on a 20 cm packed column 355 g of 1 chlorobutane were added at 65 u00b0 c to the resulting mixture of 4 6 dichloropyrimidine and n n dimethylcylcohexylamine hydrochloride and the mixture was heated at reflux for 60 min it was then filtered at room temperature the hydrochloride was washed three times with 100 ml 88 4 g of 1 chlorobutane moist yield 210 8 g after the product was dried at 100 u00b0 c and at atmospheric pressure 163 7 g 100 of hydrochloride and 32 g of 1 chlorobutane were obtained the 1 chlorobutane was removed from the extracts by distillation at atmospheric pressure on a 20 cm packed column yield 580 8 g 93 7 40 g of diphenyl carbonate as distillation auxiliary were added to the crude 4 6.