Substituted cyanonaphthalene process
AssigneeEthyl Corporation
InventorVenkataraman Ramachandran
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Abstract
6-Alkoxy-5-halo-1-cyanonaphthalenes, useful as pharmaceutical intermediates, are prepared by (1) reacting a 6-alkoxytetralone with cyanide ion and a Lewis acid in a nitroalkane or nitroarene solvent to form a 6-alkoxy-1-cyano-3,4-dihydronaphthalene, (2) intimately mixing the resultant solution with an aqueous base selected from alkali metal, alkaline earth metal, and tetraalkylammonium hydroxides, alkoxides, carbonates, and bicarbonates to aromatize the 6-alkoxy-1-cyano-3,4-dihydronaphthalene, and (3) halogenating the resultant 6-alkoxy-1-cyanonaphthalene while still in the nitroalkane or nitroarene solvent.
Claims18
A process which comprises (1) cyanating a 6-alkoxy-tetralone which has 1-20 carbons in the alkoxy group by reacting it with hydrogen cyanide, a tri- or tetraalkylammonium cyanide, or a metal cyanide and a Lewis acid in a nitroalkane or nitroarene solvent at about 60.degree.-120.degree. C. so as to form a 6-alkoxy-1-cyano-3,4-dihydronaphthalene, (2) intimately mixing the resultant solution with an aqueous base selected from alkali metal and tetralkylammonium hydroxides and alkoxides at about 15.degree.-100.degree. C. so as to aromatize the 6-alkoxy-1-cyano-3,4-dihydronaphthalene, and (3) halogenating the resultant 6-alkoxy-1-cyanonaphthalene while still in the nitroalkane or nitroarene solvent so as to form a 6-alkoxy-5-halo-1-cyanonaphthalene.
A process which comprises (1) cyanating 6-methoxy-tetralone by reacting it with hydrogen cyanide and aluminum chloride in nitrobenzene at about 60.degree.-120.degree. C. so as to form 6-methoxy-1-cyano-3,4-dihydronaphthalene, (2) intimately mixing the resultant solution with an aqueous solution of sodium hydroxide or potassium hydroxide in the presence of a phase transfer agent at about 15.degree.-100.degree. C. as as to aromatize the 6-methoxy-1-cyano-3,4-dihydronaphthalene, and (3) brominating the resultant 6-methoxy-1-cyanonaphthalene while still in nitrobenzene so as to form 6-methoxy-5-bromo-1-cyanonaphthalene.
A process which comprises (1) cyanating 6-methoxy-tetralone by reacting it with sodium cyanide and aluminum chloride in the presence of a phase transfer agent, an activating amount of water and/or concentrated HCl, and nitrobenzene at about 60.degree.-120.degree. C. so as to form 6-methoxy-1-cyano-3,4-dihydronaphthalene, (2) intimately mixing the resultant solution with an aqueous solution of sodium hydroxide or potassium hydroxide at about 15.degree.-100.degree. C. so as to aromatize the 6-methoxy-1-cyano-3,4-dihydronaphthalene, and (3) brominating the resultant 6-methoxy-1-cyanonaphthalene while still in nitrobenzene so as to form 6-methoxy-5-bromo-1-cyanonaphthalene.
Dependencies are inferred from the claim text.