Application of 31230-17-8, A common heterocyclic compound, 31230-17-8, name is 5-Methyl-1H-pyrazol-3-amine, molecular formula is C4H7N3, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
S-Ammo-S-methyl-pyrazole-l-carboxylic acid tert-butgammal esterNaH (95percent, 0.57g, 22.7mmol) was added slowly to a 00C solution of 3-Amino-5- methylpyrazole (2.Og, 20.6mmol) in THF (40ml). BoC2O (4.94g, 22.7mmol) was added after 30 min and the mixture was allowed to warm to room temperature. After stirring for 2 h at room temperature, the mixture was poured into a saturated aqueous solution of NaHCO3. The aqueous phase was extracted with CHCI3. The combined organic phases were dried over Na2SO4. Removal of the solvent in vacuum gave a crude mixture of the title compound and its 2-carboxylic acid tert.- butyl ester isomer, which were separated by chromatography on silica in ethyl acetate / heptane 2:1. Yield 2.4g, 59percent.1H-NMR: (400 MHz, D6-DMSO) 5.60 (IH, s), 5.27 (2H, s), 2.34 (3H, s), 1.51 (9H, s); MS (ESI+) = 198.26 (MH-H)+.
The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.
Reference:
Patent; F. HOFFMANN-LA ROCHE AG; WO2006/32518; (2006); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics