3-(Trifluoromethyl)-1,2,4-triazolo[4,3-a]pyrazine

General procedure: (10 mmole) of compound 3 was dissolved in 5 volume of toluene and to this was added (20 mmole) of triethylamine at ambient temperature, and stirred for 1hour. Progress of the reaction was monitored by TLC. After completion of the reaction the reaction mixture was poured on 25g of ice water layers were separated and the organic layer was washed with2X 10ml of cold water dried over sodium sulphate and concentrated to give compound 4 in excellent yield.2) 6.0 g (55 mmol) of 2-hydrazinopyrazine was added250 mL of three-necked flask, Ice water cooled to 0 ° C, Under the magnetic stirring, 28.6 g was slowly added dropwise(136 mmol) of trifluoroacetic anhydride, Then rose to room temperature for 2 hours, Add 35 ml of diluted polyphosphoric acid(Diluted 10 grams of water per 100 grams of polyphosphoric acid)Heated to 80 ° C for 10 hours, After cooling to room temperature, To the residue was added 30 ml of ice water, Slowly drop the sodium hydroxide solution to adjust the pH value of 7-8, Ethyl acetate extraction, Combined organic layer, The organic phase is saturatedSodium chloride aqueous solution, Dried over anhydrous sodium sulfate, Condensed organic layer, To give 6.7 g of a pale yellow solid, Yield 65.1percent.A solution of 2-hydrazinopyrazine (1.10 g) in trifluoroacetic anhydride (10 mL) was stirred at room temperature for 4 h. To the mixture was added PPA (12 mL). The reaction mixture was heated at 80 °C for another 15 h. The reaction mixture was cooled to room temperature and filtered to afford the title compound as a white solid (0.94 g, 50.00 percent). The compound was characterized by the following spectroscopic data: MS (ESI, pos. ion) m/z: 189.0 (M+l); ' NMR (400 MHz, CDC1A solution of 2-hydrazinopyrazine (1.10 g) in trifluoroacetic anhydride (10 mL) was stirred at room temperature for 4 h. To the mixture was added PPA (12 mL). The reaction mixture was heated at 80° C. for another 15 h. The reaction mixture was cooled to room temperature and filtered to afford the title compound as a white solid (0.94 g, 50.00percent). The compound was characterized by the following spectroscopic data: MS (ESI, pos. ion) m/z: 189.0 (M+1); A mixture of 2-hydrazinopyrazine (820 mg, 7.45 mmol), prepared from 2-chloropyrazine and hydrazine using a procedure analogous to that described in the literature (P. J. Nelson and K. T. Potts, J. Org. Chem. 1962, 27, 3243, except that the crude product was extracted into 10percent methanol/dichloromethane and filtered, and the filtrate was concentrated and purified by flash chromatography on silica gel, eluting with 100percent ethyl acetate followed by 10percent methanol in dichloromethane), TFA (2.55 g, 22.4 mmol), and polyphosphoric acid (10 mL) was heated to 140° C. with stirring for 18 h. The solution was added to ice and neutralized by the addition of ammonium hydroxide. The aqueous solution was extracted with ethyl acetate (3×), washed with brine, and dried over anhydrous magnesium sulfate. Concentration followed by flash chromatography (silica gel, 1:1 hexane:ethyl acetate, then 100percent ethyl acetate) afforded the title compound as a solid (861 mg). General procedure: (10 mmole) of compound 3 was dissolved in 5 volume of toluene and to this was added (20 mmole) of triethylamine at ambient temperature, and stirred for 1hour. Progress of the reaction was monitored by TLC. After completion of the reaction the reaction mixture was poured on 25g of ice water layers were separated and the organic layer was washed with2X 10ml of cold water dried over sodium sulphate and concentrated to give compound 4 in excellent yield.2) 6.0 g (55 mmol) of 2-hydrazinopyrazine was added250 mL of three-necked flask, Ice water cooled to 0 ° C, Under the magnetic stirring, 28.6 g was slowly added dropwise(136 mmol) of trifluoroacetic anhydride, Then rose to room temperature for 2 hours, Add 35 ml of diluted polyphosphoric acid(Diluted 10 grams of water per 100 grams of polyphosphoric acid)Heated to 80 ° C for 10 hours, After cooling to room temperature, To the residue was added 30 ml of ice water, Slowly drop the sodium hydroxide solution to adjust the pH value of 7-8, Ethyl acetate extraction, Combined organic layer, The organic phase is saturatedSodium chloride aqueous solution, Dried over anhydrous sodium sulfate, Condensed organic layer, To give 6.7 g of a pale yellow solid, Yield 65.1percent.A solution of 2-hydrazinopyrazine (1.10 g) in trifluoroacetic anhydride (10 mL) was stirred at room temperature for 4 h. To the mixture was added PPA (12 mL). The reaction mixture was heated at 80 °C for another 15 h. The reaction mixture was cooled to room temperature and filtered to afford the title compound as a white solid (0.94 g, 50.00 percent). The compound was characterized by the following spectroscopic data: MS (ESI, pos. ion) m/z: 189.0 (M+l); ' NMR (400 MHz, CDC1A solution of 2-hydrazinopyrazine (1.10 g) in trifluoroacetic anhydride (10 mL) was stirred at room temperature for 4 h. To the mixture was added PPA (12 mL). The reaction mixture was heated at 80° C. for another 15 h. The reaction mixture was cooled to room temperature and filtered to afford the title compound as a white solid (0.94 g, 50.00percent). The compound was characterized by the following spectroscopic data: MS (ESI, pos. ion) m/z: 189.0 (M+1); A mixture of 2-hydrazinopyrazine (820 mg, 7.45 mmol), prepared from 2-chloropyrazine and hydrazine using a procedure analogous to that described in the literature (P. J. Nelson and K. T. Potts, J. Org. Chem. 1962, 27, 3243, except that the crude product was extracted into 10percent methanol/dichloromethane and filtered, and the filtrate was concentrated and purified by flash chromatography on silica gel, eluting with 100percent ethyl acetate followed by 10percent methanol in dichloromethane), TFA (2.55 g, 22.4 mmol), and polyphosphoric acid (10 mL) was heated to 140° C. with stirring for 18 h. The solution was added to ice and neutralized by the addition of ammonium hydroxide. The aqueous solution was extracted with ethyl acetate (3×), washed with brine, and dried over anhydrous magnesium sulfate. Concentration followed by flash chromatography (silica gel, 1:1 hexane:ethyl acetate, then 100percent ethyl acetate) afforded the title compound as a solid (861 mg).

Molecular Weight:188.11
XLogP3:1
Hydrogen Bond Acceptor Count:6
Exact Mass:188.03098060
Monoisotopic Mass:188.03098060
Topological Polar Surface Area:43.1
Heavy Atom Count:13
Complexity:195
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes