| abstract |
PROCEDURE FOR PREPARING DIHYDROPYRIDINES. IT INCLUDES: A) REACTION A LOWER ALKYL 3-KETOSTER OF FORMULA (III) AND (IV) WITH A FORMULA ALDEHYDE (V); B) AN / ADIR A SELECTED REACTIONANT OF AMMONIUM HYDROXIDE AND GASEOUS AMMONIA THROUGH THE REACTION PRODUCT OF STAGE (A), IN THE PRESENCE OF A SUITABLE INERT SOLVENT, TO GIVE A HYDROXIPIPERIDINE; AND C) DEHYDRATE HYDROXIPIPERIDINE WITH A DEHYDRATION AGENT TO GIVE A DIHYDROPYRIDINE OF FORMULA (I) AND (II), WHERE R IS PHENYL, ALKYL, CYCLOALKYL C 3 TO 6 AND OTHERS; EACH R1 IS SELECTED INDEPENDENTLY FROM RADICALS LOWER ALKYL FROM C 1 TO 4; AND R2 AND R3 ARE THE SAME FLOWERED METHYL RADICALS, IN A SINGLE REACTION MIXTURE. THEY ARE USED AS HERBICIDES. |