tert-Butyl 3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate synthesis

Yield:877402-43-2 100%

Reaction Conditions:

in dichloromethane at 20; for 4 h;

Steps:

Preparation of tert-Butyl 3-(Trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate.

A solution of 3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine (1.0 g, 5.2 mmol) in dichloromethane (20.0 mL) was treated with di-tert-butyl dicarbonate (1.36 g, 6.25 mmol). The mixture was stirred at room temperature for 4 h. After this time, the solution was concentrated to dryness to afford the crude product tert-butyl 3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate (1.52 g, 100%) as a white solid: ¹H NMR (300 MHz, CDCl₃) δ 4.90 (s, 2H), 4.16 (t, J = 5.4 Hz, 2H), 3.92 (t, J = 5.4 Hz, 2H), 1.50 (s, 9H); MS (ESI) m/z [M + H]⁺ calculated: 293.1, observed: 293

References:

Surman, Matthew D.;Chen, Ping;Avramovitch, Bianca;Haber, Kathy;Buckle, Ronald N.;Gazal, Sharon [Tetrahedron Letters,2022,vol. 106,art. no. 154058] Location in patent:supporting information