| 摘要 |
<p>The invention relates to a process for the preparation of chromenes of the general Formula V <IMAGE> V (wherein R1 and R2 are hydrogen, optionally halogeno substituted C1-6 alkyl or aryl; R3 and R7 stand for hydrogen, halogen or C1-6 alkyl; R4 represents C1-8 alkyl, aryl, aralkyl or a group containing a carbonyl group; R5 and R6 stand for C1-10 alkyl, aryl, amino, hydroxyalkyl, alkoxyalkenyl, alkylmercaptoalkyl, acyl, carboxy or an ester group or a halogen atom; n is 0 or 1) which comprises (a) for the preparation of compounds, in which R5 and R6 stand for different groups, reacting a compound of the general Formula I <IMAGE> (I) with an approximately equimolar, preferably 0.8-1.5 molar amount of a reactant of the general Formula R5-X-related to the amount of the compound of the general Formula I (wherein R5 has the same meaning as stated above X is halogen) and reacting the O-monosubstituted compound of the general Formula III <IMAGE> III (wherein R1-R6 and n are as stated above) obtained with a 1.1-1.5 molar amount of a compound of the general Formula III (wherein R6 and X are as stated above); or (b) for the preparation of compounds, in which R5 and R6 stand for the same group, reacting a chromanone of the general Formula I (wherein R1-R4 and m have the meaning as stated above) with a 2-3 molar amount of a compound of the general Formula R5-X-related to the amount of the compound of the general Formula I (wherein R5 and X are as stated above), preferably in the presence of a base, a catalyst and a solvent, and thereafter reducing the O-substituted chromanone derivative of the general Formula III thus obtained (wherein R1-R6 and n are as stated above) and dehydrating the chromanol derivative of the general Formula IV <IMAGE> IV thus obtained (wherein R1-R6 and n are as stated above) in acidic-aqueous medium. The compounds of the general Formula V are partly new and useful for the preparation of pesticides.</p> |
