N-difluoroMenthyl-4-nitropyrazole synthesis
- Product Name:N-difluoroMenthyl-4-nitropyrazole
- CAS Number:956477-64-8
- Molecular formula:C4H3F2N3O2
- Molecular Weight:163.08
Yield: 97%
Reaction Conditions:
Stage #1:4-nitro-1H-pyrazole with caesium carbonate in N,N-dimethyl-formamide at 120; for 0.0833333 h;
Stage #2:sodium chlorodifluoroacetate in N,N-dimethyl-formamide for 0.5 h;
Steps:
30A 3 OA. Preparation of 1 -(difluoromethyl)-4-nitro- 1H-pyrazole
Cs2CO3 (14.41 g, 44.2 mmol) was suspended in a solution of 4-nitro-1H-pyrazole(5.00 g, 44.2 mmol) and DMF (40 mL). After heating to 120 °C for 5 mm, solid sodium2-chloro-2,2-difluoroacetate (13.48 g, 88 mmol) was added in 10 equal portions over 20 mm. The reaction was complete after 10 mm of additional heating. The mixture wasadded to a separatory funnel containing 100 mL water and extracted with Et20 (2 x 50 mL). The combined organic layers were concentrated. Purification by normal-phasechromatography eluting with a gradient of hexanes/EtOAc yielded 1 -(difluoromethyl)-4- nitro-1H-pyrazole (6.99 g, 42.9 mmol, 97% yield) as a clear, colorless oil. ‘H NMR(500MHz, CDC13) ö 8.58 (s, 1H), 8.22 (s, 1H), 7.39-7.05 (t,J= 60Hz, 1H).
References:
BRISTOL-MYERS SQUIBB COMPANY;CORTE, James R.;DE LUCCA, Indawati;FANG, Tianan;YANG, Wu;WANG, Yufeng;DILGER, Andrew K.;PABBISETTY, Kumar Balashanmuga;EWING, William R.;ZHU, Yeheng;WEXLER, Ruth R.;PINTO, Donald J. P.;ORWAT, Michael J.;SMITH, Leon M. II WO2015/116886, 2015, A1 Location in patent:Page/Page column 200
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