申请人:Sumitomo Chemical Company, Limited
公开号:US05659051A1
公开(公告)日:1997-08-19
There is disclosed a process of producing a 2-cyano-4-oxo-4H-benzopyran compound of the general formula (2): ##STR1## wherein R.sup.1 and R.sup.2 are independently hydrogen, halogen, hydroxy, C.sub.1 -C.sub.5 alkyl, C.sub.1 -C.sub.5 alkoxy, nitro or a group of the RCONH wherein R is C.sub.1 -C.sub.20 alkyl, phenyl, phenyl-substituted (C.sub.1 -C.sub.20) alkyl, phenyl (C.sub.1 -C.sub.20)alkoxyphenyl or (C.sub.1 -C.sub.20) alkoxyphenyl. This production process is characterized in that a carboxamide of the general formula (1): ##STR2## wherein R.sup.1 and R.sup.2 are each as defined above, is reacted with a dehydrating agent in the presence of a pyridine compound of the general formula (4): ##STR3## wherein A.sup.1 and A.sup.2 are independently hydrogen or C.sub.1 -C.sub.5 alkyl. If the final product cannot be obtained as crystals having good filtration properties by ordinary treatments, a novel technique as disclosed herein can provide such crystals by dissolving the reaction product in an organic solvent insoluble or slightly soluble in water; pouring the resultant solution into water; and removing the organic solvent by distillation with stirring to effect the crystallization of the final product.
本发明公开了一种生产一般式(2)的2-氰基-4-氧代-4H-苯并吡喃化合物的方法:其中R.sup.1和R.sup.2独立地为氢、卤素、羟基、C.sub.1-C.sub.5烷基、C.sub.1-C.sub.5氧烷基、硝基或RCONH的基团,其中R为C.sub.1-C.sub.20烷基、苯基、苯取代的(C.sub.1-C.sub.20)烷基、苯基(C.sub.1-C.sub.20)氧基苯基或(C.sub.1-C.sub.20)氧基苯基。该生产过程的特征在于,一般式(1)的羧酰胺:其中R.sup.1和R.sup.2如上所定义,与脱水剂在吡啶化合物的存在下反应,该吡啶化合物的一般式(4):其中A.sup.1和A.sup.2独立地为氢或C.sub.1-C.sub.5烷基。如果最终产品不能通过常规处理获得具有良好过滤性能的晶体,本文所公开的新技术可以通过将反应产物溶解在有机溶剂中,该有机溶剂不溶或微溶于水中;将所得溶液倒入水中;并通过搅拌蒸馏去除有机溶剂以促使最终产品结晶来提供这样的晶体。