3- pyrazine l-oxide

Azido-pyrazin-l-oxid reagiert in einer verwandten Reaktion bereits beim Kochen in Benzol in 83% Ausbeute zu 2-Cyan-l-hydroxy-imidazol4 28. [Pg.91]

Zu erwahnen sind schlicBlich die photochemische Umlagerung von 2,4-Dimethyl- bzw. 2,4-Diphenyl-pyrazin-l-oxid, die zu 2,4(5 )-Dimethyl- (15%) bzw. 2,4(5)-Diphenyl-imidazol (29%) fiihrt429, und die ebenfalls photochemische Herstellung von Imidazolen aus 2,3-Dihydro-pyr-azinen (s.Bd. IV/5b, S. 1107-1108). [Pg.91]

Malonsaure (Arnino-brom-methy-len) -methylester-nitril E1S/2, 1653 [ROOC-CH(CN)2 + HBr] Pyrazin-l-oxid 2-Bromo-5-methoxy-E9b/2. 319 (H -. Br)... [Pg.195]

Pyrazin-l-oxid 2-Amino-3-cyan-5-(hydroxyimino-methyl)- E9b/2, 283 [HO —N = CH—CO—... [Pg.255]

Hydroxy-trimethyl- E9b/2, 268f. (Butandion + H2N-CHR-CO-NH2) Pyrazin-l-oxid 2(or 3)-Propyl-E9b/2, 306 (N-Oxidat.) Pyrimidine... [Pg.388]

Dimethyl-3-ethyl-2-hydroxy-E9b/2, 268f, (Gloxal + H2N-CHR-CO-NH2) 2-Hydroxy-3-isopropyl-5-methyl-E9b/2, 268f. (H3C-CO-CHO + H2N-CHR-CO-NH2) 2-Hydroxy-5(or6)-methyl-3-propyl-E9b/2, 268 f. (H3C-CO-CHO -I- H2N-CHR-CO-NH2) Pyrazin-1,4-bis-oxid 2,5-Diethyl-E9b/2, 309 (N-Oxidat.) Pyrazin-l-oxid... [Pg.510]

Pyrazin 2,5-Diethoxy- E9b/2, 295 ( — H2 -> Hetaren) Pyrazin-l,4-bis-oxid Tetramethyl-E9b/2, 305 (N-Bis-oxidation) Pyrazin-l-oxid 3,6-Diethyl-2-hydroxy- E9b/2, 312 (4-Oxid-Red.)... [Pg.510]

Pyrazin-l-oxid 2-Chloro-6-methyl-3-phenyl- E9b/2, 307 (N-Oxidat.) IH-Pyrazol... [Pg.846]

E19a, 984 (R-Br + Allyl-CO) Pyrazin-l-oxid 2-Hydroxy-6-methyl-... [Pg.855]

Prnpan 2-Dimethylamino-2-(4-nitro-phenyl)- El9a, 499 (Cl -> NR2) Pyrazin-l-oxid, 3,5(or3,6)-Diisopro-pyl-2-formyl- E9b/2, 322 (H -> CHO)... [Pg.912]

Pyrazin 3-Hydroxy-5-isopropyl-2-(2-methyl-propyl)- E9b/2, 264 (R -CO-CH2-NH-CHR2-COOR/NH3) Pyrazin-l-oxid 2-Hydroxy-3 (or6)-isopropy l-6(or 3)-(2-methy 1)-propyl)-E9b/2, 312(4-Oxid-Red.) Pyrazol 4-(3-Methyl-butanoyl)-1,3,5-trimethyl- VII/2a, 103 Undecan 2-Diazo-l-oxo-E14b, 1167 (R-CHO + R-S02-N3)... [Pg.924]

Pyrazin-l-oxid 3,6-Bis-[2-methyl-propyl]-2-chloro- E9b/2, 307/309 (N-Oxidat.)... [Pg.1056]

Chloro-l-methylpyrazinium ion with liquid ammonia reacted by addition at the 2-position to give 2-amino-3-chloro-l-methyl-1,2-dihydropyrazine (24) (609). The hexafluoroantimonate salt of perfluoropyrazine has been prepared and F n.m.r. measurements used to determine the relative order of its base strength with other perfluoroheterocycles (914). Hydrogen-deuterium exchange rates of Hj and Hg in 3-chloro(and other substituted)pyrazine l-oxide(s) have been correlated with a-constants, and the logs of the H2 exchange rates have been shown to be linearly related to the pK values (745). The pK value of 3-chloropyrazine 1-oxide is - 1.05 (745). [Pg.120]

The standard Sonogashira reaction conditions were not successful for the coupling reaction of 3-chloropyrazine 1-oxide 122 and 1-hexyne [65]. In contrast, treatment of 122 and 1-hexyne with Pd(Ph3P)4 and KOAc produced 3-(l-hexynyl)pyrazine-l-oxide (123), together with the codimeric product, ( )-enyne 124 [65]. Presumably, the codimerization product 124 resulted from the cis addition of 1-hexyne to adduct 123. [Pg.452]

Pyrazine-l-oxide [2433-84-9] M 96.1, m 113-114°, pKe <0. Recrystallise the oxide from C6H6. It is soluble in hot petroleum ether (b 60-68°, see pyrazine-l,4-dioxide above). Dry it in vacuo. It has Vmav at 1305cm. [Koelsch Gumprecht J Org Chem 23 1605 7958.]... [Pg.476]

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