| 摘要 |
<p>1,173,451. Pyrazine derivatives. MERCK & CO. Inc. 7 June, 1967 [25 Aug., 1966], No. 26213/67. Heading C2C. Novel alkyl N-amidino- and guanidino-3,5- diamino-6-halopyrazinimidates of the general formula wherein n is 0 or 1; X is a chlorine or bromine atom; R is a C 1-5 alkyl group; R<SP>1</SP> and R<SP>2</SP> are each a hydrogen atom or a C 1-6 alkyl, C 3-5 alkenyl or C 4-8 cycloalkylalkyl group; R<SP>3</SP> is a hydrogen atom, a C 1-5 alkyl, C 1-5 hydroxyalkyl or pyridyl-C 1-2 alkyl group or a phenyl-C 1-2 , alkyl group that is optionally substituted by one or more halogen atoms or C 1-2 alkyl or C 1-2 alkoxy groups in the phenyl moiety; R<SP>4</SP> is a hydrogen atom, a C 1-5 alkyl group or a phenyl- C 1-2 alkyl group that is optionally substituted by one or more halogen atoms or C 1-2 alkyl or C 1-2 alkoxy groups in the phenyl moiety; and R<SP>5</SP> is a hydrogen atom or, when n is 0, a C 1-5 alkyl group; or R<SP>4</SP> and R<SP>6</SP> together form an ethylene or trimethylene group; or R<SP>3</SP> and R<SP>4</SP> together form a -(CH 2 ) x - group, where x is 4, 5, 6 or 7, are prepared (a) by heating together an orthopyrazinoate and a guanidine derivative of the respective general formulµ in the presence of an anhydride of a C 2-6 alkanoic acid; or (b) when n is 0 and R<SP>5</SP> is a hydrogen atom, by reaction of a hydrochloric or hydrobromic acid addition salt of a pyrazinimidate of the general formula with cyanamide or a cyanogen halide in the presence of an anhydrous alcohol while slowly adding a base, followed by reaction of the resulting N-cyano-pyrizinimidate of the general formula with an amine of the general formula NHR<SP>3</SP>R<SP>4</SP>. Orthopyrazinimidates of the second general formula above are prepared by heating a hydrochloric or hydrobromic acid addition salt of a pyrazinimidate of the fourth general formula above and a C 1-5 alkanol. The said acid addition salts of pyrazinimidates of the fourth general formula above are prepared by reaction of an alkyl 3,5-diamino-6-halopyrazinoate of the general formula with ammonia, treatment of the resulting pyrazinamide of the general formula with phosphoryl chloride or thionyl chloride in the presence of dimethylformamide, followed by a strong mineral or organic acid, and reaction of the resulting pyrazinonitrile of the general formula with a C 1-5 alkanol, under anhydrous conditions in the presence of hydrogen chloride or bromide gas. The alkyl N-amidino- and guanidino-3,5- diamino-6-halopyrazinimidates of the first general formula above may be hydrolysed with a strong mineral acid to produce 3,5-diamino-6- halo - pyrazinoyl- and pyrazinoamido - guanidines of the general formula</p> |
