Method for preparing coumarin and derivatives thereof
AssigneeIndustrie Chimiche Caffaro, S.p.A.
InventorsStefano Alini, Livius Cotarca, Pietro Delogu
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Abstract
A process for producing coumarin and substituted coumarins starting from substituted hexahydrocoumarins or from substituted dihydrocoumarins. The process includes dehydrogenation in the presence of catalysts based on metals of Group VIII of the periodic table of the elements and in the presence of at least one easily reducible organic compound. The invention allows to achieve exceptionally high yields that do not require the recycling of the hexahydrocoumarin or of the dihydrocoumarin that are present at the end of the reaction, and also allows to achieve high selectivity and easy purification.
Claims20
Process for preparing a compound with formula (I):
- ##STR5## wherein each one of R1, R2, R3, and R4 is:
- hydrogen, alkyl, aryl alkyl, alkoxyl, halogen, or hydroxyl, by dehydrogenation of a compound with formula (II):
- ##STR6## or of a compound with formula (III):
- ##STR7## obtained by using catalysts based on metals of Group VIII of the periodic table of the elements, in the presence of at least one easily reducible organic compound.
Dependencies are inferred from the claim text.