Synthesis, Crystal Structure and Plant Growth Regulatory Activity of 1-(3-Amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one

The title compound 1-(3-amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one (3) was synthesized by Hofmann-alkylation reaction of 1- chloro-3,3-dimethyl- butan-2-one (1) and 1H-[1,2,4] triazol-3-ylamine (2) with equal amount of K2CO3 as acid acceptor. The structure of compound 3 was characterized by H-1 NMR, C-13 NMR, HRMS and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P2(1)/n with a = 5.7227(8), b = 27.924(4), c = 6.2282(7) angstrom, beta = 101.892(11)degrees, V = 973.9(2) angstrom(3), Z = 4, T = 180.00(10) K, mu(MoKa) = 0.087 mm(-1), Dc = 1.243 g/cm(3), 3832 reflections measured (3.648 <=theta <= 26.022 degrees), 1916 unique reflections (R-int = 0.0359, R-sigma = 0.0572) used in all calculations. The final R = 0.0557 (I > 2 sigma(I)) and wR = 0.1276 (all data). Bioassay showed that 3 displayed excellent activity as plant growth regulator with inducing lateral root formation and enhancing primary root elongation at 0.27 mmol/L (50 ppm) in soybeen (He Feng-50). Good water solubility was found with 50 mg in 1 mL of water. Therefore, application of 3 in agriculture is more environmentally friendly due to cosolvent- free condition, and results in improved abiotic-stress tolerance by affecting the root growth. And furthermore, it can be used as a precursor to investigate the function of regulating plant root growth.