Application of 930-36-9, These common heterocyclic compound, 930-36-9, name is 1-Methylpyrazole, 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.
Example 1. Synthesis of 2-methyl-2H-pyrazole-3-carbaldehyde In a dry 50 ml Vial is placed a solution of 1.642 g (20 mmol) N-Methylpyrazole in 30 ml dry THF. The mixture is cooled to -20 C and while stirring 8 ml (20 mmol, 2.5M in hexane) n-BuLi-solution is slowly added. The reaction mixture is stirred for 2.5 h at -20 C. With vigorous stirring 4.7 ml (4.39g, 60 mmol) dry DMF is slowly added at -20 C and the mixture kept at this temperature for 1 h. The reaction mixture is then poured into 100 ml of a 1 M acetic acid / sodium acetate buffer (pH: 4.5), 50 ml MTBE is added and the organic layer is separated, washed with 50 ml sat. Na2CO3-solution to remove excess acetic acid (extraction with ethyl acetate leads to DMF in the final product). The organic layer is separated, dried with MgSO4 and the solvent is removed by om a rotary evaporator. The crude product is purified by vacuum distillation (bp: 67 C, 21 mbar). 3 preparations which were distilled together yielded 5.969g (54 mmol, 90%) of the title compound. 1H-NMR (300 MHz, CDCl3): 4.18 (s, 3H, CH3-N), 6.91 (d, 1H, 3J=2.0 Hz, CH=C-N), 7.53 (d, 1H, 3J=2.0 Hz, CH=N), 9.87 (s, 1H, CH=O) ppm. 13C-NMR (100 MHz, CDCl3): 39.31 (CH3-N), 114.78 (CH=C-N), 138.54 (CH=N), 138.98 (CH=C-N), 179.83 (CH=O) ppm.
Statistics shows that 1-Methylpyrazole is playing an increasingly important role. we look forward to future research findings about 930-36-9.