3,3,3-Trifluoropropyne → HCID 66523230, compound

Participants

Reaction Conditions

Reaction Steps

5-[(Benzyloxy)carbonyl]-4,5,6,7-tetrahydro[1,2,3]oxadiazolo[3,4-a]pyrazin-8-ium-3-olate (C58, prepared from 4-[(benzyloxy)carbonyl]piperazine-2-carboxylic acid using the general procedure described by T. S. Mansour et al., 2006, PCT Intl. Appl. WO 2006/130588) (65 g, 0.24 mol) was dissolved in o-xylene (250 mL) and cooled to −78° C. in a bomb reactor. 3,3,3-Trifluoroprop-1-yne (25 g, 0.27 mol) was injected into the reaction mixture, and the bomb was heated to 270° C. for 24 hours. After cooling to room temperature, the reaction was concentrated in vacuo, and the residue was purified by silica gel chromatography to provide C60 as white crystals. Yield: 7.5 g, 23 mmol, 10%. [The major regioisomer, benzyl 2-(trifluoromethyl)-6,7-dihydropyrazolo[1,5-a]pyrazine-5(4H)-carboxylate (C59), was also isolated, in 61% yield.]

Provenance & Evidence