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AssigneeThe Procter & Gamble Company
InventorsKenneth Edward Yelm, Gregory Mark Bunke, John Christian Haught
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The present invention provides synthetic routes for preparing various isomers of cyclohexane-based coolants, such as menthyl esters and menthanecarboxamide derivatives, in particular those substituted at the amide nitrogen, for example with an aromatic ring or aryl moiety. Such structures have high cooling potency and long lasting sensory effect, which make them useful in a wide variety of consumer products. One synthetic route involves a copper catalyzed coupling of a primary menthanecarboxamide with an aryl halide, such reaction working best in the presence of potassium phosphate and water. Using this synthetic route, specific isomers can be prepared including the menthanecarboxamide isomer having the same configuration as l-menthol and new isomers such as a neoisomer having opposite stereochemistry at the carboxamide (C-1) position. The neoisomer unexpectedly has potent and long lasting cooling effect. Preparation schemes for neoisomers of other menthyl derivatives which are useful as coolants, including esters, ethers, carboxy esters and other N-substituted carboxamides are also provided.
A process for preparing N-substituted menthanecarboxamide of general formula
A process for preparing specific isomers of menthane derivatives comprising
A process for preparing neo-menthane-based derivatives having coolant properties comprising derivatizing a neo-menthane carboxylic acid, a neo-menthane acid chloride or a neo-menthane carboxamide.
A process for preparing intermediates useful for preparation of neo-menthyl derivatives having 1S,2S,5R configuration comprising subjecting neo-menthyl acetate to hydrolysis conditions comprising a base to obtain neo-menthol, wherein neo-menthyl acetate is prepared from l-menthol having 1R,2S,5R configuration by
A process for preparing neo-menthyl derivatives having 1S,2S,5R configuration comprising derivatizing neo-menthol.
A process according to claim 19 comprising a reaction between neo-menthol and a derivatizing agent selected from a carboxylic acid, carboxylic acid anhydride, dicarboxylic acid anhydride or carboxylic acid chloride to obtain a neo-menthyl ester having coolant properties.
Neoisomers having 1S,2S,5R configuration of menthane derivatives selected from menthyl esters, menthyl ethers, menthane carboxy esters or menthane carboxamides having coolant properties.
A product for application to the mouth, throat or skin comprising an amount of a neo-menthane derivative selected from a neo-menthyl ester, neo-menthyl ether, neo-menthane carboxy ester or neo-menthane carboxamide, effective to give a cooling sensation to the mouth, throat or skin.
A method of providing a cooling effect to the mouth, throat or skin by applying thereto a product comprising a neo-menthyl ester, neo-menthyl ether, neo-menthane carboxamide or neo-menthane carboxy ester compound.
Dependencies are inferred from the claim text.