2-a]pyrazine synthesis

Yield:1276056-84-8 80%

Reaction Conditions:

with N-Bromosuccinimide in acetonitrile at 0; for 1.5 h;

Steps:

3.1.1. 3-Bromo-6-methylimidazo[1,2-a]pyrazine (13)

NBS (26 mg, 0.15 mmol) was added to a solution of 6-methylimidazo[1,2-a]pyrazine (11) (20 mg, 0.15 mmol) in anhydrous acetonitrile at 0 °C. The ice bath was removed and after 1.5 h the reaction was concentrated under reduced pressure. The residue was purified by preparative TLC eluting with petroleum ether/EtOAc (1:2) to give 3-bromo-6-methylimidazo[1,2-a]pyrazine (13) (25 mg, 80%) as a yellow solid. mp 80-83 °C; IR (KBr): 3430, 2923, 1618, 1502, 1436, 1320, 923 cm^-1; ¹H NMR (400 MHz, CDCl₃): δ=8.99 (s, 1H), 7.88 (s, 1H), 7.74 (s, 1H), 2.55 (s, 3H); ¹³C NMR (100 MHz, CDCl₃): δ=142.7, 140.4, 139.5, 135.6, 113.6, 100.0, 20.9; HRMS-ESI: calcd for C₇H₇BrN₃ (M+H)⁺: 211.9823 and 213.9803; found: 211.9818 and 213.9794.

References:

Harris, Anthony R.;Nason, Deane M.;Collantes, Elizabeth M.;Xu, Wenjian;Chi, Yushi;Wang, Zhihan;Zhang, Bingzhi;Zhang, Qingjian;Gray, David L.;Davoren, Jennifer E. [Tetrahedron,2011,vol. 67,# 47,p. 9063 - 9066] Location in patent:experimental part