Process for preparing 3-(1,2,3,4-tetrahydro-1- naphthyl)-4-hydroxycoumarin derivatives

Abstract From the Canadian patent

The invention provides a process for preparing a 4-hydroxycoumarin derivative having anti-coagulant properties useful as a rodenticide, of formula, (I) wherein R1 and R2 are independently selected from the group consisting of hydrogen, halogen, alkyl of up to 6 carbon atoms and alkoxy of up to 6 carbon atoms, and R3 represents a group selected from, (a) , where X represents a halogen atom or a group C1-12 alkyl C1-12, alkoxy, C3-8 cycloalkyl, CN, SO2R5 CF3, OCF3, COOR5 or COR5, where R5 is C1-6 alkyl n' is 0, 1 or 2 and Y is a fluorine or chlorine atom;, (b), where n' and Y are as defined above X is as defined above or is, hydrogen, n" is O or 1 and D is an oxygen atom or a group …