Abstract:
Isomeric formyl trimethylbicyclo[2.2.2]oct-7-enes, their use as perfumes, and a process for their preparation comprising a Diels-Alder reaction of acrolein with either 1,5,5-trimethylcyclohexa-1,3-diene, 3,5,5-trimethylcyclohexa-1,3-diene, 5,5-dimethyl-3-methylene-cyclohex-1-ene or mixtures thereof.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention: 
     This invention relates to isomeric formyl trimethylbicyclo[2.2.2]oct-7-enes, to their production, and to their use as perfumes. 
     2. Statement of Related Art: 
     Bicyclo[2.2.2]octenes are already known as perfumes from the literature. For example, bicyclooctenes substituted by an isopropyl group are described in Chem. Abstr. 76,4021z (1972). Substituted tetramethylbicyclo[2.2.2]octenes are disclosed in CH 611 517. 
     DESCRIPTION OF THE INVENTION 
     Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term &#34;about&#34;. 
     It has now been found that isomeric formyl trimethylbicyclo[2.2.2]oct-7-enes have surprising and valuable properties as perfumes. 
     Accordingly, the present invention relates to isomeric formyl trimethylbicyclo[2.2.2]oct-7-enes corresponding to the following general formulae ##STR1## 
     The present invention also relates to the use of these isomeric formyl trimethylbicyclo[2.2.2]oct-7-enes as perfumes, and to compositions containing them. 
     The odor of the isomer mixtures of the invention can be described as green and herb-like with a grass and hay note. The mixtures of the invention are also characterized by extremely high odor stability. 
     The isomeric formyl trimethylbicyclo[2.2.2]oct-7-enes of the invention are useful for the production of new, interesting perfume compositions where fresh, herb-like perfume notes are desired. Based on the composition as a whole, the content of the isomeric formyl trimethylbicyclo[2.2.2]oct-7enes is between 1 and 50% by weight and preferably between 1 and 25% by weight. These compositions can be used for the perfuming of commercial products, such as detergents and disinfectants, fabric treatment preparations, cosmetics of all kinds, such as toilet waters, creams, lotions, aerosols, toilet soaps, make-up and lipsticks and also in extract perfumery. The content of the perfume compositions of the invention in the perfumed products is between 2 and 20% by weight and preferably between 5 and 10% by weight. 
     The isomeric formyl trimethylbicyclo[2.2.2]oct-7-enes are prepared by a Diels-Alder reaction (see Wollweber in Houben-Weyl, Vol. V/1c, pages 977-1139 (1970)). To this end, 1,5,5-trimethylcyclohexa-1,3-diene, 3,5,5-trimethylcyclohexa-1,3-diene, 5,5-dimethyl-3-methylene-cyclohex-1-ene or mixtures containing one or more of these dienes are reacted with acrolein at a temperature in the range of from 20° to 220° C., optionally in the presence of catalysts The molar ratio of diene to acrolein is between 0.5:1 and 2:1 and preferably between 0.6:1 and 1.5:1. The catalysts include, for example, BF 3 , AlCl 3  and/or ZnCl 2 . The reaction is preferably carried out in an organic solvent, such as methylene chloride, dimethyl ether, and/or cyclohexane. On completion of the reaction, the isomeric product is isolated from the reaction mixture Preferably, the reaction product is washed with water, neutralized, for example with aqueous sodium hydrogen carbonate solution, aqueous sodium carbonate solution and/or potassium hydroxide, and then distilled. 
     The dienes to be used as educts for the preparation of the bicyclooctenes of the invention can be prepared by standard known methods of organic chemistry, for example by reduction of 3,5,5-trimethylcyclohex-2-en-1-one (isophorone) with, for example, lithium aluminum hydride to the corresponding alcohol 3,5,5-trimethylcyclohexen-1-ol. This alcohol is then reacted, for example, with potassium hydrogen sulfate to form dienes which can be used in accordance with the invention as educts for the production of isomeric formyl trimethylbicyclo[2.2.2]oct-7-enes. 
     The invention will be illustrated but not limited by the following examples. 
    
    
     EXAMPLES 
     1. Reduction of isophorone to 3,5,5-trimethylcyclohexen-1-ol 
     200 g isophorone (1.45 mol) in 500 ml absolute dimethyl ether were added dropwise with stirring to 13.77 g lithium aluminum hydride (0.3625 mol, suspended in 200 ml absolute dimethyl ether) in such a way that continuous refluxing occurred. The reaction mixture was thereafter refluxed for 1 hour. For working up, first ice water and then 10% sulfuric acid were carefully added with stirring after cooling, followed by separation in a separation funnel and extraction three times with ether. 
     After the organic phase had been washed with saturated sodium chloride solution, the organic phase was concentrated and distilled in a water jet vacuum (16 torr) at 60°-62° C. Yield: 170 g (84% of the theoretical) 
     2. Preparation of the diene mixture 
     170 g 3,5,5-trimethyl cyclohexen-1-ol obtained by reduction of isophorone in step 1 above, and 10 g potassium hydrogen sulfate were heated under nitrogen to the boiling temperature, the diene mixture distilling off. After drying with sodium sulfate, the diene mixture was directly used in the Diels Alder reaction in step 3 below 
     3. Preparation of 5(6)-formyl-1,3,3(3,3,7) -trimethyl-bicyclo[2.2.2]oct-7ene by Diels-Alder reaction 
     122 g (1 mol) of the diene mixture obtained in accordance with step 2 above containing 1,5,5-trimethylcyclohexa-1,3-diene,-3,5,5-trimethylcyclohexa-1,3-diene and 5,5-dimethyl-3-methylene-cyclohex-1-ene in a ratio by weight of 55:25:20, 84 g acrolein, and 6.11 g zinc chloride were dissolved in 200 ml methylene chloride and boiled under reflux for 4 hours For working up, the reaction product was washed with 100 ml water, neutralized with 100 ml of an aqueous saturated sodium hydrogen carbonate solution, and purified by distillation after removal of the solvent. 
     Isomeric 5(6)-1,3,3(3,3,7)-trimethylbicyclo[2.2.2]oct-7-ene boiling at 58° C. to 60° C./0.08 mbar was obtained in a yield of 115 g=65% of the theoretical. 
     COMPOSITION EXAMPLES 
     Fancy lavender 
     
         ______________________________________                  Parts by weight______________________________________5(6)-formyl-1,3,3(3,3,7)-trimethyl                    400bicyclo[2.2.2]oct-7-eneLavandin oil Gross       200Terpineol                100Linalyl acetate          100Linalool                 50Musk ketone              40Lavender oil, French     30Coumarin                 20Sandalwood oil (Haarmann &amp; Reimer)                    20Patchouli oil            20Camphor                  15Ambroxan (Henkel), 10% by weight in isopropyl                     5myristate                    1000Formulation for a foam bath/shampoo5(6)-formyl-1,3,3(3,3,7)-trimethyl                    200bicyclo[2.2.2]oct-7-enePine needle oil, Sibir.  100Isobornyl acetate        80α-Amyl cinnamaldehyde                    80Phenyl ethyl alcohol     70Lavandin oil Grosso      70p-Tert.-butyl cyclohexyl acetate                    60Nopyl acetate            50Orange oil sweet         50Cyclovertal (Henkel) 10% by weight in                    40dipropylene glycolCedryl acetate           40Galaxolide (IFF)         40Geraniol                 30Geranyl nitrile          30Styarallyl acetate       20Galbanum Resin synth. (RBD)                    20Phenyl acetaldehyde dimethyl acetal                    10Cylcohexyl salicylate (Henkel)                    10                    1000______________________________________