5-AMINO-1-PHENYLPYRAZOLE

Uses

5-Amino-1-phenylpyrazole is a reagent that is used in the synthesis of sulfaphenazole(S689020) derivatives as inhibitors and tools for comparing active sites of human liver cytochromes P 450 2C subfamily.

Synthesis

General procedure for the synthesis of 5-amino-1-phenylpyrazole-4-carboxylic acid from ethyl 5-amino-1-phenylpyrazole-4-carboxylate: Step 1: Synthesis of 1-phenyl-1H-pyrazol-5-amine (F1) 5-Amino-4-ethoxy-1-phenylpyrazole (1 eq.) was dissolved in 36% hydrochloric acid solution (30 eq.) and the reaction mixture was stirred under reflux conditions overnight. After completion of the reaction, the mixture was cooled to room temperature, slowly poured into ice water and the pH was adjusted to basic with ammonia. The mixture was extracted with dichloromethane (3 times) and the organic phases were combined. The organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to remove the solvent to give a light yellow oily product in 94% yield. Mass spectrometry (electrospray positive ionization mode): the theoretical molecular weight of C9H9N3 was 159, and the measured value was 160 (M+H)+.

References

[1] Patent: WO2010/23480, 2010, A1. Location in patent: Page/Page column 48
[2] Bioorganic and Medicinal Chemistry, 2016, vol. 24, # 18, p. 4492 - 4498
[3] Journal of the Brazilian Chemical Society, 2018, vol. 29, # 1, p. 159 - 167
[4] Patent: US2858309, 1957,
[5] Helvetica Chimica Acta, 1958, vol. 41, p. 306,309