Pyrazine-2-Carboxylic Acid Hydrazide → tert-butyl 3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

HRID 576688Notes

Reaction equation

HRID 576688 reaction equation
C(O[C:4]1[CH2:5][N:6]([C:10]([O:12][C:13]([CH3:16])([CH3:15])[CH3:14])=[O:11])[CH2:7][CH2:8][N:9]=1)C.[N:17]1[CH:22]=[CH:21][N:20]=[CH:19][C:18]=1[C:23]([NH:25][NH2:26])=O>C(O)CCC>[N:17]1[CH:22]=[CH:21][N:20]=[CH:19][C:18]=1[C:23]1[N:9]2[CH2:8][CH2:7][N:6]([C:10]([O:12][C:13]([CH3:14])([CH3:15])[CH3:16])=[O:11])[CH2:5][C:4]2=[N:26][N:25]=1

Participants

4

Reactant 2

HCID 258796Pyrazine-2-Carboxylic Acid HydrazideHCID 67439401tert-butyl 3-ethoxy-5,6-dihydropyrazine-1(2H)-carboxylate

Product 1

HCID 90402528tert-butyl 3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylateYield 50%

Reagents, catalysts & solvents 1

HCID 2631-ButanolSolvent

Procedure

To a solution of tert-butyl 3-ethoxy-5,6-dihydropyrazine-1(2H)-carboxylate (1.14 g, 5 mmol) in 1-butanol (30 mL) was added pyrazine-2-carbohydrazide (685 mg, 5 mmol). The reaction mixture was heated at reflux for 16 h. After cooling to rt, the reaction mixture was concentrated and purified by chromatography (SiO2; 2.5% MeOH in DCM) to afford the desired product as a white solid (700 mg, 50% over 2 steps). MS (ESI): mass calcd. for C14H18N6O2, 302.2; m/z found, 303.2 [M+H]+. 1H NMR (500 MHz, CDCl3) d 9.57 (d, J=1.4 Hz, 1H), 8.62 (d, J=2.5 Hz, 1H), 8.59-8.54 (m, 1H), 4.94 (s, 2H), 4.63-4.50 (m, 2H), 3.89 (t, J=5.4 Hz, 2H), 1.51 (s, 9H).

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureat reflux for 16 h
  3. concentrationthe reaction mixture was concentrated
  4. custompurified by chromatography (SiO2; 2.5% MeOH in DCM)

Sources & evidence

ORD record
ord-47cf8348125d4cc58d071c89e9512495
Source dataset
uspto-grants-2015_05
Patent number
US09040534B2

Reaction notes

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