Toluene → ethyl 1-cyclopropyl-5-methyl-1H-pyrazole-3-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 organic layers were combined and 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 (3.74 g, 19.26 mmol, 43% yield). tR: 3.84 min (HPLC 1); tR: 0.84 min (LC-MS 2); ESI-MS: 195 [M+H]+ (LC-MS 2); Rf=0.50 (hexane/EtOAc 1:1).

Provenance & Evidence