532-54-7 → 2-Amino-3-benzyl-5-phenylpyrazine

HRID 1184319Notes

Reaction equation

[CH:1]1[CH:6]=[CH:5][C:4]([C:7](/[CH:9]=[N:10]/O)=O)=[CH:3][CH:2]=1.Cl.[NH2:13][CH:14]([CH2:17][C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)[C:15]#[N:16]>Cl[Ti](Cl)(Cl)Cl.N1C=CC=CC=1>[NH2:16][C:15]1[C:14]([CH2:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)=[N:13][C:7]([C:4]2[CH:5]=[CH:6][CH:1]=[CH:2][CH:3]=2)=[CH:9][N:10]=1

Participants

Conditions

Temperature: -20 °C

Procedure

A round bottomed flask was charged with 5 g (33.5 mmol) of 2-isonitrosoacetophenone, 6.7 g (36.8 mmol) of 2-amino-3-phenylpropanenitrile hydrochloride and 100 mL of dry pyridine. The mixture was cooled to −20° C. and 4.6 mL (40.0 mmol) of TiCl4 was added dropwise. The reaction was kept at −20° C. for 30 min and heated to 80° C. for 2.5 hrs. The solvent was evaporated, and the residue taken up in 1 L of DCM. This solution was washed with saturated NaHCO3 and brine. All volatiles were evaporated, and the residue redissolved in ethanol (400 mL). Raney Ni (2.0 g, aqueous suspension) was added, and the reaction allowed to stir for 5 days under 1 atm of hydrogen. The mixture was passed through celite, and volatiles removed. The residue was chromatographed on silica gel (heptanes/DCM) to give 2.5 g (29%) of 2-amino-3-benzyl-5-phenylpyrazine.

Workup

temperatureheated to 80° C. for 2.5 hrs
customThe solvent was evaporated
washThis solution was washed with saturated NaHCO3 and brine
customAll volatiles were evaporated
dissolutionthe residue redissolved in ethanol (400 mL)
additionRaney Ni (2.0 g, aqueous suspension) was added
customremoved
customThe residue was chromatographed on silica gel (heptanes/DCM)

Sources & evidence

ORD record: ord-a2225c74ca80452eb6487a3da5035b71
Source dataset: uspto-grants-2014_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08669103B2

Reaction notes

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