Pyrazinecarbonitriles can be decyanated by hydrogenation with platinum on carbon in the presence of activated carbon under acidic conditions. Pyrazine carbonitrile-N-oxides undergo a stepwise reduction to the deoxy-pyrazinecarbonitriles followed by decyanation to give pyrazines in good yields. (C) 2002 Published by Elsevier Science Ltd.
A process for the preparation of substituted 2-aminopyrazines
申请人:ELI LILLY AND COMPANY
公开号:EP0018144A1
公开(公告)日:1980-10-29
A process for the preparation of substituted 2-aminopyrazines is described, of the formula
wherein
R1 is hydrogen or C1-C4 alkyl;
R2 is hydrogen, halo, C,-C3 alkyl, or trifluoromethyl;
n is 0, 1, or 2, with the proviso that when n=2, only one ortho position may be substituted; and
R3 is C1-C4 alkyl, which comprises cyclizing a hydroxyimino-substituted aminoacetonitrile of the following formula
wherein R1, R2, R3, and n have the same values as set forth hereinbefore, with an acid selected from the group consist ing of polyphosphoric acid, about 85% phosphoric acid and a mixture of phosphoric acid with phosphorus pent oxide.
Aminomethylphenolic pyrazines, their preparation and use
申请人:ICI AMERICAS INC.
公开号:EP0293170A1
公开(公告)日:1988-11-30
The invention discloses novel pyrazine amide derivatives of the formula III (set out below) which are useful as eukalemic diuretics. Also disclosed are pharmaceutical compositions containing the novel amides and processes for the manufacture of said amides.
本发明公开了新型吡嗪酰胺式 III 衍生物(如下文所述),可用作真核利尿剂。本发明还公开了含有上述新型酰胺的药物组合物以及上述酰胺的生产工艺。
Efficient synthesis of substituted 2-aminopyrazines: FeCl3-promoted condensation of hydroxyiminoketones with aminoacetonitriles
作者:Takahiro Itoh、Kenji Maeda、Toshihiro Wada、Koji Tomimoto、Toshiaki Mase
DOI:10.1016/s0040-4039(02)02375-4
日期:2002.12
FeCl3. promoted condensation of hydroxyiminoketones with aminoacetonitriles followed by catalytic hydrogenation afforded the desired pyrazines in moderate-good yields. This protocol provides an efficient and practical synthesis of substituted 2-aminopyrazines. (C) 2002 Elsevier Science Ltd. All rights reserved.