Toluene → ethyl 1-cyclopropyl-3-methyl-1H-pyrazole-5-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of cyclopropylhydrazine (Step 17.2) (4.90 g, 45.1 mmol) in toluene (30 mL) and EtOH (30 mL) was added ethyl 2,4-dioxavalerate (6.34 mL, 45.1 mmol). The reaction mixture was stirred for 1 hr at 100° C., quenched with a saturated aq. NaHCO3 solution, and extracted with EtOAc. The combined organic layers were washed with a saturated aq. NaHCO3 solution, dried over Na2SO4 and evaporated. The crude material was purified by silica gel column chromatography (hexane/EtOAc 2.5-30%) to afford the title product (3.01 g, 15.50 mmol, 34% yield). tR: 4.70 min (HPLC 1); tR: 1.01 min (LC-MS 2); ESI-MS: 195 [M+H]+ (LC-MS 2); Rf=0.33 (hexane/EtOAc 9:1).

Provenance & Evidence