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3- 2- pyrazinecarbonyl chloride

The most convenient synthesis of halogenopyrazines and -quinoxalines is by halogenation of pyrazinones and quinoxalinones with phosphoryl or other acid halides for example, 5-hydroxy-2-pyrazinecarboxylic acid, rather than 5(477)-pyrazinone-2-carboxylic acid, is chlorinated with phosphorus pentachloride/phosphoryl chloride to afford a 63% yield of 5-chloro-2-pyrazinecarbonyl chloride <1994SL814>. Sato and Narita provided an improved synthesis of various halogenopyrazines in which 2(l//)-pyrazinones were activated with chlorotrimethylsilane to give silyl ethers (Section 8.03.7.3). This procedure is most effective for synthesis of bromopyrazines whose overall yields are 62-81% <1999JHC783>. Bromopyrazine is directly prepared by treatment of 2-(l//)-pyrazinone with phosphoryl... [Pg.317]

Note Pyrazinecarbonyl chlorides are often used as reactive intermediates but they are not always characterized as such. [Pg.303]

Chloro-2-pyrazinecarboxyhc acid (28, R = Cl) gave 6-chloro-2-pyrazinecar-bonyl chloride (29, R = Cl) (SOCl2, PhH, reflux, 90 min 73%) 505 and 6-phenyl-2-pyrazinecarboxylic acid (28, R = Ph) gave 6-phenyl-2-pyrazinecarbonyl chloride (29, R = Ph) (neat SOCl2, reflux, 2 h uncharacterized product).1015... [Pg.304]

Methyl 2-pyrazinecarboxylate (90) gave A -methyl-2-pyrazinecarbohydrazide (89) without any of the. V-m ethyl isomer (91) [MeHNNH2, EtOH, reflux, 12 h 81% the isomer (91) can be made from 2-pyrazinecarbonyl chloride see Section 8.3.2] analogous esters behaved similarly to give, for example, 3-amino-/V -methyl-2-pyrazinecarbohydrazide (71%).1265... [Pg.313]

Chloro-2-pyrazinecarbonyl chloride (126) and 2-pyrazinamine gave 6-chloro-Ar-(pyrazin-2-yl)-2-pyrazinecarboxamide (127) (Et3N, PhH, 20°C, 30 min 85%).505... [Pg.318]

Pyrazinecarbonyl chloride gave 2-(aziridin-l-ylformyl)pyrazine (128) [HN(CH2)2, Et3N, PhH—PhMe, 0 - 20°C, 2 h 66% analogues likewise).8... [Pg.318]

Pyrazinecarbonyl chloride gave Af-methyl-2-pyrazinecarbohydrazide (133) [MeHNNH2, Et20, -35 20°C, slowly 36% the TV -methyl isomer (134)... [Pg.319]

Chloro-2-pyrazinecarbonyl chloride (140, R = Cl) and AKcyclopent- 1-en-1-yl)pyrrolidine gave 2-chloro-3-[2-(pyrrolidin-1 -yl)cyclopent-l-en-1 -ylcar-bonyl]pyrazine (141) (Et3N, CH2C12,--------40°C, N2, 2 h 63%).382... [Pg.320]

Pyrazinedicarbonyl dichloride (144) and cyclohexyl isocyanate gave 3-[a-chloro-a-(cyclohexylimino)acetyl]-2-pyrazinecarbonyl chloride (145) (PhH, 20°C, 1 h then 60°C, 45 min 54%).523 Also other examples.275 1091... [Pg.320]

Pyrazinecarbonyl chloride (146) with benzophenone oxime gave the ester-like... [Pg.321]

Pyrrol-l-yl)-2-pyrazinecarbonyl chloride gave the corresponding azide [sub-... [Pg.321]

Methylthio-2-imidazoline and 2-methylthio-l, 4,S,6-tetrahydropyrimidines react with 2-chioro-3-pyrazinecarbonyl chlorides to yield (46) which react with arylamines to give tricyclic linearly fused //-aiylpyrimidinones (47) [93CCC1133]. [Pg.253]

See other pages where 3- 2- pyrazinecarbonyl chloride is mentioned: [Pg.304]    [Pg.309]    [Pg.320]    [Pg.320]    [Pg.394]    [Pg.394]    [Pg.452]    [Pg.456]    [Pg.304]    [Pg.309]    [Pg.320]    [Pg.320]    [Pg.320]    [Pg.320]    [Pg.394]    [Pg.394]    [Pg.452]    [Pg.456]   
See also in sourсe #XX -- [ Pg.320 ]



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3- -2-pyrazinecarbonyl

3-Chloro-2-pyrazinecarbonyl chloride

6-Phenyl-2-pyrazinecarbonyl chloride

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