2,5 -Diisopropyl-3 -phenylpyrazine

Chloro-3,6-diisopropylpyrazine (121) gave 2,5-diisopropyl-3-phenylpyrazine (122) [PhjB (made in situ from BF3.Et2O, PhBr, Mg, EcO), K2CO3, Me2NCHO, reflux. A, 12 h 47% (with 32% substrate recovery)] the same substrate (121) gave 2-ethyl-3,6-diisopropylpyrazine (123) ( 136, likewise 89%) and analogues were made somewhat similarly ... 

Hydrolysis. 2-Methoxy-3-methyl-5-phenylpyrazine (16) gave 3-methyl-5-phenyl-2(l//)-pyrazinone (17) (6 M HC1, reflux, 3 h 97%) 1307 other products like 3,6-diisopropyl-2( I //(-pyrazinonc (18, R = Pr ) (97%)1311 and 3,6-diphenyl-2(l/7)-pyrazinone (18, R = Ph) (84%)82 were made similarly. Hydriodic acid may also be used.1307... 

The following alkoxypyrazines have been prepared from the corresponding dichloropyrazines and alkoxide ions 2,3-dimethoxy-5,6-dimethyl(and diphenyl) (797) 2,3-dibenzyloxy (sodium benzyl oxide in benzyl alcohol at reflux for 24 hours (883)] [but 23-dichloropyrazine with sodium hydride and benzyl alcohol in xylene gave l,4-dibenzyl-2,3-dioxo-l,2,3,4-tetrahydropyrazine)(988)] 2-chloro-5-methoxy (838) 2,5-diethoxy-3,6-dimethyl (872) 2methanolic sodium methoxide refluxed for 2 h) 2,5-dimethoxy-3-phenyl (817) 2-chloro-5-methoxy(and ethoxy)-3,6-diphenyl (817) 2,5-dimethoxy-3,6-dimethyl (and diisopropyl) (844) 2,5-dimethoxy-3-isopropyl-6-methyl (methanolic potassium methoxide at reflux for 6 days) (844) 2(5)-s-butyl-3-chloro-6-ethoxy-5(2)-isobutyl (93) 2-chloro-6-methoxy (838, 883) 2,6-dimethoxy (reflux for 8h) (832) 2,6-diethoxy (reflux for 14 h) (883) 2-benzyloxy-6-chloro (1 equiv. of sodium hydride and benzyl alcohol in benzene at reflux) (832) 2,6-dibenzyloxy (5 equiv. of sodium benzyloxide in benzene at reflux gave 70%) (832) and 3,5-dimethoxy-2-methyl (535). 

---