1-Hydroxybenzotriazole → racemic tetrahydro-furan-3-carboxylic acid 4-[4-(1,5-dimethyl-1H-pyrazol-4-ylmethyl)-3,4,5,6-tetrahydro-2H-[1,2']bipyrazinyl-3'-yl]-benzylamide

Participants

Reaction Steps

Dissolve racemic tetrahydro-furan-3-carboxylic acid (0.067 g, 0.58 mmol) in methylene chloride (5 mL). Add benzotriazol-1-yloxy-tripyrrolidinophosphonium hexafluorophosphate (PyBOP) (0.453 g, 0.87 mmol). Add 1-hydroxybenzotriazole (0.118 g, 0.87 mmol). Add 4-[4-(1,5-dimethyl-1H-pyrazol-4-ylmethyl)-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl-3′-yl]-benzylamine (0.24 g, 0.63 mmol) dissolved in methylene chloride (5 mL). Stir at rt for 5 min. Add diisopropylethylamine (0.113 g, 0.87 mmol). Stir at rt for 4 hr. Purify by normal phase chromatography (4% 7 N ammonia-methonal/ethyl acetate) to give racemic tetrahydro-furan-3-carboxylic acid 4-[4-(1,5-dimethyl-1H-pyrazol-4-ylmethyl)-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl-3′-yl]-benzylamide (0.107 g, 39%). MS (ES): m/z=476.3[M+H]. Dissolve this racemate (0.107 g, 0.23 mmol) in acetonitrile (1 mL) and water (4 mL). Add aq. 1 N HCl (1 eq., 0.23 mmol, 0.23 mL). Freeze the solution to −78° C. in a dry-ice/acetone bath. Place the solution in the lyophilizer for 48 hr. to give the title compound (0.110 g, 94%). MS (ES): m/z=476.3 [M+H].

Provenance & Evidence