Yield:21323-71-7 86%

Reaction Conditions:

with acetic acid;sodium nitrite in water at 0 - 20; for 2 h;

Steps:

B.1 7-chloro-3-methyl-1,2,3-triazolo[4,5-d]pyrimidine (86 % yield; starting compound 4)

A solution of sodium nitrite (1.2eq.) in water (30mL) was added dropwise to a cold (0-5 °C) stirred solution of the appropriate 5-amino-4-chloro-6-aminoderivative pyrimidine (14 mmol, 1 eq.) in acetic acid (25 mL) and water (90 mL). The mixture was stirred for 2 h between 0 °C and room temperature. Ethylacetate was then added and the mixture was washed using NaHCO3 solution until pH neutral. The combined organic layers were washed with water and brine, dried (Na2SO4) and evaporated to afford the title compound.

References:

EP1598354,2005,A1 Location in patent:Page/Page column 91