Novel processes and intermediates are provided for the synthesis of derivatives of 4-amino-3-hydroxypyrrole-2-carboxylic acids that are useful as monomers for polyamides capable of binding dsDNA. According to one preferred reaction scheme, an alkyl alkoxymethylene nitroacetate (Formula VIII) is prepared by reaction of a trialkyl orthoformate or orthoacetate with a nitroacetate ester in the presence of a carboxylic anhydride. The compound of Formula VIII is condensed with an N-substituted glycine to yield an N-substituted (2-nitro-2-alkoxycarbonyl)vinyl glycinate ester (Formula VII). Ring closure in the presence of an alkali metal alkoxide yields a 4-nitro-3-hydroxypyrrole-2-carboxylic ester (Formula V). After blocking of the 3-hydroxy group to produce a further intermediate (Formula IV), the 4-nitro group is reduced to a 4-amino group (Formula III), and the 4-amino group is then blocked by reaction with a dicarbonate diester to produce the fully blocked intermediate (Formula II). Saponification of the 2-carboxylic acid ester yields a monomer having a free 2-carboxylic ester moiety (Formula I).
提供了一种新的合成4-
氨基-3-羟基
吡咯-2-羧酸衍
生物的方法和中间体,这些衍
生物可用作能够结合dsDNA的聚酰胺单体。根据一种首选的反应方案,通过三烷基正
甲酸酯或正
乙酸酯与硝基
乙酸酯在
羧酸酐存在下反应制备烷基烷氧亚甲基硝基
乙酸酯(式VIII)。将式VIII的化合物与N-取代甘
氨酸缩合,得到N-取代(2-硝基-2-烷氧羰基)
乙烯基甘氨酸酯(式VII)。在碱
金属醇化物存在下环合,得到4-硝基-3-羟基
吡咯-2-羧酸酯(式V)。通过阻断3-羟基的产生进一步得到中间体(式IV),将4-硝基还原为4-
氨基(式III),然后通过与二
碳酸二酯反应阻断4-
氨基,得到完全阻断的中间体(式II)。2-
羧酸酯皂化后得到具有自由2-
羧酸酯基团的单体(式I)。