| abstract |
METHOD FOR THE PREPARATION OF CHROMENES AND SIMILAR. IT INCLUDES: A) REACTING A COMPOUND OF FORMULA (II) WITH A REACTANT OF FORMULA (R5-X) OR (R6-X), IN THE PRESENCE OF A BASE SUCH AS SODIUM HYDROXIDE OR POTASSIUM HYDROXIDE AND A CATALYST SUCH AS A SALT OF QUATERNARY AMMONIUM OR PHOSPHINIUM AND A SOLVENT SUCH AS WATER OR CHLOROFORM, TO MAKE A COMPOUND OF FORMULA (III); B) REDUCE TO (III) TO GIVE A CHROMANOL DERIVATIVE OF FORMULA (IV); AND C) DEHYDRATE (IV) IN AN ACID-AQUEOUS MEDIUM, TO OBTAIN A COMPOUND OF FORMULA (I). BEING: R1 AND R2, H OR C 1 TO 6 ALKYL; R3 AND R7, H, HAL OR C 1 TO 6 ALKYL; R4 ALKYL OF C 1 TO 8, ARYL AND OTHERS; R5 AND R6 ALKYL OF C 1 TO 10, ARYL, AMINO AND OTHERS; AND N 0 OR 1. THEY ARE USED AS PESTICIDES. |