Dimethylformamide → 5-Chloro-1-methyl-1H-pyrazole-4-carbaldehyde

Temperature

80 °C

N,N-Dimethyl formamide (2980 mg, 40.8 mmol) was added to 1-methyl-1H-pyrazol-5-ol (1000 mg, 10.19 mmol). Phosphorus oxychloride (7.46 ml, 81.5 mmol) was then added dropwise over 10 minutes. The reaction was then heated to 80° C. for 6 hours. The reaction was concentrated in vacuo and crude material neutralised with saturated aqueous NaHCO3 solution. The product was then extracted with ethyl acetate (2×25 ml), the combined organics were washed with brine (20 ml) dried over Na2SO4, filtered and concentrated in vacuo to give the title product as a brown oil which formed a crystalline solid upon standing (1130 mg, 77% yield). 1H NMR (400 MHz, CD3OD) 3.84-3.87 (3H s) 7.95-7.97 (1H d) 9.76-9.78 (1H d).

1. concentrationThe reaction was concentrated in vacuo and crude material
2. extractionThe product was then extracted with ethyl acetate (2×25 ml)
3. washthe combined organics were washed with brine (20 ml)
4. dry with materialdried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated in vacuo

ORD record

ord-f5401a0733474179b0f8e1331381a2e5

Source dataset

uspto-grants-2011_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07964732B2