Patent ID: 6455708
Filing Date: 2002-09-24
Classification: C07D

Abstract:
A process for producing 4-substituted benzopyran derivatives represented by formula (G-VI) where R1 and R2 which may be the same or different represent a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxy group, an optionally substituted lower alkoxycarbonyl group, an optionally substituted lower alkylsulfonyl group, an optionally substituted arylsulfonyl group, a halogen atom, a nitro group, a cyano group or NYaYb where Ya and Yb which may be the same or different and each represents a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted lower alkoxycarbonyl group, an acyl group, an optionally substituted lower alkylsulfonyl group or an optionally substituted arylsulfonyl group or, when taken together with the nitrogen atom to which they are bound, may form a 3- to 8-membered ring or, when taken together, represent a substituent &boxH;N&boxH;Oâ€”N&boxH;; R3 and R4 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group or, when taken together with the carbon atom to which they are bound, represent a polymethylene group or a substituent forming a heterocycle, provided that R3 and R4 are not both a hydrogen atom; R5 and R6 which may be the same or different represent a hydrogen atom or an optionally substituted lower alkyl group by scheme (2), comprising the following steps(2):(2-1)â†’(2-2)â†’(2-3)â†’(2-4)â†’(2-5)â†’(1-5); (2-1) reaching a compound of formula (II) â€ƒwere X and Y which may be the same or different represent a leaving group selected from a halogen atom, an optionally substituted lower alkylsulfonyloxy group or an arylsulfonyloxy group; R1 and R2 have the same meanings as defined above with acetylene of formula (VII) â€ƒwhere R3 and R4 have the same meanings as defined above to give a compound of formula (VIII) â€ƒwhere Y, R1, R2, R3 and R4 have the same meanings as defined above; (2-2) reacting the resulting compound of formula (VIII) with a reducing agent to give a compound of formula (IX) â€ƒwhere Y, R1, R2, R3 and R4 have the same meanings as defined above; (2-3) reacting the resulting compound of formula (X) with a base to give a benzopyran derivative of formula (X) â€ƒwhere R1, R2, R3 and R4 have the same meanings as defined above; (2-4) reacting the resulting compound of formula (X) with a halogenating agent to give a 3,4-dihalobenzopyran derivative of formula (XI) â€ƒwhere R1, R2, R3, R4 and Hal have the same meanings as defined above; (2-5) reacting the resulting compound of formula (XI) with a base to give a 4-halobenzopyran derivative of formula (I) â€ƒwhere R1, R2, R3, R4 and Hal have the same meanings as defined above; to give a 4-substituted benzopyran derivative of formula (G-VT) set forth above.