Process of producing 2-cyano-4-oxo-4H-benzopyran compounds

Details Process of producing 2-cyano-4-oxo-4H-benzopyran compounds Process of producing 2-cyano-4-oxo-4H-benzopyran compounds

1994-07-11

1997-08-19

Trinh, Ba K.

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

549402, 549404, 549405, 549407, 558311, 558312, 558382, 564134, C07D31124

Patent

active

056590512

ABSTRACT:
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.

REFERENCES:
patent: 3839339 (1974-10-01), Ellis et al.
Ellis et al, "Journal of Medicinal Chemistry", 1972, vol. 15, No. 8, pp. 865-867.
Ciattini et al, "Synthesis", 1983, pp. 311-312.
Journal of Med. Chem., vol. 31, No. 1, 1988, pp. 84-90, Hisao Nakai et al. "New Potent Antagonists of Leukotriene C.sub.4 and D.sub.4 1. Synthesis and Structure-Activity Relationship.".
Campagna et al, "Tetrahedron Letters", No. 21, pp. 1813-1816, 1977.

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