Process for the preparation of derivatives of 4-amino-3-hydroxypyrrole-2-carboxylic acid
申请人:——
公开号:US20040014984A1
公开(公告)日:2004-01-22
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)。