Use of 5-methyl-hept-2-en-4-one as a fragrance and/or flavor
This is a division of application Ser. No. 679,180, filed Dec. 7, 1984, U.S. Pat. No. 4,563,365. 
    
    
     The invention relates to the use of 5-methyl-hept-2-en-4-one as a fragrance and/or flavor and to fragrance compositions and/or flavoring compositions containing this substance. 
     Within the framework of the investigation under which ketols can be obtained by partial hydrogenation of 1,3-diketones, 5-methyl-hept-2-en-4-one has been described as an intermediate in the preparation of the saturated ketone which was used for determination of the ketol structure (J. Am. Chem. Soc. 61, 3303 (1939)). 
     Tetrahedron Letters 23, 335 (1982) describes a reaction mixture which consists of 4 parts of 5-methyl-hept-1-en-4-one and 1 part of 5-methyl-hept-2-en-4-one. 
     No data on the properties of 5-methyl-hept-2-en-4-one are known. 
     It has been found that 5-methyl-hept-2-en-4-one may be used as a fragrance and/or flavor. 
     Moreover, fragrance compositions and/or flavoring compositions containing 5-methyl-hept-2-en-4-one have been found. 
     5-Methyl-hept-2-en-4-one, to be used according to the invention, is a valuable fragrance and/or flavor which in higher concentration has a nutty note, in particular a note reminiscent of hazelnut, in greater dilution exhibits an enhancer action and, in fragrance compositions, imparts greater naturalness, being usable in amounts of 0.01 to 10% by weight, based on the total composition. 
     5-Methyl-hept-2-en-4-one to be used according to the invention can be obtained for example by reacting 2-butylmagnesium bromide (prepared, for example, from 2-bromobutane and magnesium filings) with crotonaldehyde in ether solution. 5-Methyl-hept-2-en-4-ol is obtained as an intermediate and is oxidized with a mixture of sodium dichromate and sulphuric acid to give 5-methyl-hept-2-en-4-one. The 5-methyl-hept-2-en-4-one is obtained as a mixture of the cis- and trans-isomers, with the latter predominating. The isomer mixture can be separated into the cis-isomer and trans-isomer by simple methods of separation, such as, for example, fractional distillation by a packed column or slotted tube column or preparative gas chromatography. However, it has been found that the use of the individual isomers offers no advantages over the use of the mixture. 
     The fragrance to be used according to the invention is employed in combination with other fragrances, known per se (Arctander, Perfume and Flavor Chemicals, Montclair, N.J. (USA), 1969) and etheral oils (Arctander, Perfume and Flavor Materials to Natural Origin., Elisabeth, N.J. (USA), 1960) and leads to perfume bases and fragrance compositions having highly expressive notes, which are outstandingly suitable for perfuming finished products in the aerosol, detergent and industrial chemicals sector, but especially for the fine perfumery or cosmetic sector, for example for detergents, hair conditioners, foam baths, bath salt, dishwasher detergents, washing powders, soaps, antiperspirants, powders, creams, shaving lotion, aftershave lotions, air fresheners, toilet cleaners, room sprays, antiperspirant sprays, deodorant sprays, body sprays, insecticide sprays and sun lotions. 
     The perfume compositions and perfumed products are prepared in a customary manner, for example by mixing the components. 
     Moreover, the 5-methyl-hept-2-en-4-one to be used according to the invention is a valuable flavor distinguished by a surprisingly low taste threshold. Thus, in 3% strength sucrose solution the perception threshold is at about 5×10 -6  ppm and the recognition threshold at about 30×10 -6  ppm. 
     At the perception threshold 5-methyl-hept-2-en-4-one produces a taste which can be described as &#34;soft, buttery, full sensation in the mouth&#34; while at and above the recognition threshold the description of the taste is &#34;nutty, hazelnut, soft, buttery, full sensation in the mouth&#34;. In addition to its specific characterization in the hazelnut direction in appropriate flavoring compositions, it has, in all non-nut types of compositions, a particularly rounding effect, and provides more naturalness through its buttery soft basic fullness. 
     The flavoring compositions prepared using 5-methyl-hept-2-en-4-one can be employed in the entire foodstuff and beverage field, in mouth care and in animal feeds. In particular, they are suitable for icings, fruit pastilles, hard caramels, toffee compositions, chocolate compositions, nougat compositions, fat compositions, margarine, edible oil, cake flours, biscuit compositions, patisserie, extruded products, dairy products, sour milk products, drinks, ices, chewing gum, mouth-care agents, tobacco products, ready-cooked meals, meat and sausage products, soups, sauces, preserved vegetables, spirits, vegetable and microbial proteins and all types of industrially produced animal feeds. 
     The 5-methyl-hept-2-en-4-one according to the invention is employed in amounts of 5×10 -6  ppm to 100 ppm, preferably 3×10 -5  ppm to 10 ppm, based on the ready-to-consume foodstuff. 
    
    
     PREPARATION 
     Example 1 
     2-Butylmagnesium bromide is prepared from 24.32 g of magnesium filings and 137 g of 2-bromobutane in 100 ml of ether. 56 g of crotonaldehyde dissolved in 60 ml of ether are added dropwise to the solution at 0° to 10° C. The mixture is then boiled for 2 hours under reflux temperature. Thereafter it is cooled, the batch decomposed with ice water/hydrochloric acid and the product extracted, neutralized and distilled. 56 g of 5-methyl-hept-2-en-4-ol of boiling point 70° C./18 mb are obtained. To 52 g of this alcohol there is slowly added a mixture of 40.34 g of sodium dichromate and 54.1 g of sulphuric acid, while cooling with ice. After a further hour&#39;s reaction at room temperature, the batch is extracted with ether, the organic phase is washed until neutral, the solvent stripped off and the crude product distilled. Redistillation using a slotted tube column gives 17.2 g of 5-methyl-hept-2-en-4-one of boiling point 72° C./20 mb. 
     USE 
     Example 2 
     A perfume composition having an orange note is prepared by mixing the following components: 
     
         ______________________________________                                    
white orange oil 650                                                      
linalyl acetate  325                                                      
styrolyl acetate 20                                                       
95% strength nootkatone                                                   
                 5                                                        
                 1000     parts by weight                                 
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     On addition of 1 part by weight of 5-methyl-hept-2-en-4-one the composition acquires a very natural, mandarin-peel and orange-peel note. 
     EXAMPLE 3 
     A flavoring composition A with apple flavor is prepared by mixing the following constituents: 
     
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acetaldehyde   10                                                         
n-butyl acetate                                                           
               50                                                         
trans-hex-2-enal                                                          
               30                                                         
ethyl acetate  30                                                         
hexyl acetate  20                                                         
n-butyric acid 10                                                         
propylene glycol                                                          
               850                                                        
               1000      parts by weight                                  
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     A flavoring composition B is prepared by adding 0.002% of 5-methyl-hept-2-en-4-one to A. 
     A and B are added in a dose of 7.5 ppm to a solution of 5% of sucrose and 0.05% of citric acid in water and subjected to a flavor test. Composition B is unanimously preferred to composition A. The flavor of composition B is described as being fuller, more natural, juicier and more typical of ripe apples. 
     EXAMPLE 4 
     A flavoring composition C with vanilla flavor is prepared by mixing the following constituents: 
     
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vanillin       50                                                         
ethylvanillin  10                                                         
heliptropin    2                                                          
diacetyl       2                                                          
propylene glycol                                                          
               936                                                        
               1000      parts by weight                                  
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     A flavoring composition D is prepared by adding 0.004% of 5-methyl-hept-2-en-4-one to C. 
     C and D are added in a dose of 37.5 ppm to a solution of 5% of sucrose in water and subjected to a flavor test. Composition D is clearly preferred to composition C. The flavor of composition D is described as fuller, softer and more natural. 
     EXAMPLE 5 
     A flavoring composition E with walnut flavor is prepared by mixing the following constituents: 
     
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vanillin         10                                                       
methylcyclopentenolone                                                    
                 30                                                       
resorcinol dimethyl ether                                                 
                 10                                                       
maltol           5                                                        
propylene glycol 945                                                      
                 1000      parts by weight                                
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     A flavoring composition F is prepared by adding 0.003% to 5-methyl-hept-2-en-4-one to E. 
     F and E are added in a dose of 75 ppm to a solution of 5% of sucrose in water and subjected to a flavor test. Composition F is clearly preferred to composition E. The flavor of composition F is described as fuller, softer and more typical of walnut. 
     EXAMPLE 6 
     A flavoring composition G with hazelnut flavor is prepared by mixing the following constituents: 
     
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vanillin         30                                                       
benzaldehyde     10                                                       
furfurol         5                                                        
2-ethyl-3,5(3,6)-                                                         
                 5                                                        
dimethylpyraz1ne                                                          
2-methyl-3-ethyl-                                                         
                 5                                                        
pyrazine                                                                  
resorcinol dimethyl ether                                                 
                 50                                                       
propylene glycol 895                                                      
                 1000      parts by weight                                
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     A flavoring composition H is prepared by adding 0.05% of 5-methyl-hept-2-en-4-one to G. 
     G and H in a dose of 15 ppm are added to a solution of 5% of sucrose in water and subjected to a flavor test. Composition H is clearly preferred to composition G. The flavor of composition H is described as fuller, more natural and substantially more typical of hazelnut. 
     EXAMPLE 7 
     A flavoring composition I with mushroom flavor is prepared by mixing the following constituents: 
     
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oct-1-en-3-ol  40                                                         
hexanol        5                                                          
propylene glycol                                                          
               955                                                        
               1000      parts by weight                                  
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     A flavoring composition J is prepared by adding 0.01% of 5-methyl-hept-2-en-4-one to I. 
     I and J are added in a dose of 7.5 ppm to a solution of 0.5% of sodium chloride in water and subjected to a flavor test. Composition J is clearly preferred to composition I. The flavor of composition J is described as fuller, substantially more natural and more typical in mushroom character. 
     It will be appreciated that the instant specification and examples are set forth by way of illustration and not limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention.