Synthesis, bioactivities, and X-ray structure analysis of 2-cyano-5-methylpyrazolo[1,5-a]pyrimidine

Abstract

The title compound crystallizes in the monoclinic space group P21/c with unit cell parameters a = 3.8380(12), b = 11.994(4), and c = 16.245(5) A, β = 90.743(5)◦, V = 747.7(4) A3, and Z = 4. The final reliability index is 0.0409 for 1088 observed reflections. All the non-hydrogen atoms in the title compound are almost coplanar, the largest deviation from the mean plane being 0.030(2) A for atom C5. The crystal cohesion is accentuated by C---H· · ·N hydrogen bond. The X-ray crystallography analysis indicates that the methyl group is at the 5-position of the compound 4 rather than at the 7-position of the isomer 4-1. The preliminary biological test shows that the title compound has moderate herbicidal activity.