Aromatic compositions
O Umted States Patent 1 1 1111 3,881,025  
 Flament 5] Apr. 29, 1975 [5 1 AROMATlC COMPOSITIONS 3,328,402 6/1967 Winter 260/250 3,380,456 4/1968 R be t 99/140 R [75] Inventor: Flame, Geneva swtzerland 3,529,064 9/1970 1:66;? 260/586 R x [73] Assignee: Firmenich S.A., Geneva, 3,559,656 2/1971 Heckman 260/586 R Switzerland 3,579,353 5 1971 Nakel 99/140 R 3,617,310 11/1971 Rizzi 99/140 R [22] Filed: Mar. 6, 1972 3,622,346 11/1971 Winter 99/140 R [21] A l N 232 279 3,681,088 8/1972 Katz 99/140 R FOREIGN PATENTS OR APPLlCATlONS [30] Foreign Application Priority Data ll56484 6/1969 United Kingdom Mar. 9, 1971 Switzerland 3396/71 Primary Examiner M0His O wolk Assistant Examiner-Sidney Marantz [52] US. Cl. 426/537; 131/17; 131/144; Ed  
  260/250 260/306]; 424/358 Att0rne Agent, or Firm Penme &amp; monds [51] Int. Cl. A231 1/26; A24b 15/00 [58] Field 61 Search 99/140 R; 260/250, 586; [57] ABSTRACT 131/17 144; 426 175 Process for flavoring foodstuffs, beverages, pharmaceuticals and tobacco products with particular cy- 5 References Ci clohexen-Z-ones alone or with particular pyrazines UNlTED STATES vPATENTS and/or with particular thiazolidines. 3,268,589 8/1966 Rowland 99/140 R 16 Claims. N0 Drawings AROMATIC COMPOSITIONS BACKGROUND OF THE INVENTION The invention relates to compositions and a process for improving, enhancing or modifying the flavouring properties of foodstuffs, feedstuffs, beverages, pharmaceutical preparation and tobacco products. The invention relates further to food products to which there are added compositions comprising at least one compound, pyrazine or a pyraizine derivative, of the formula I I R R wherein the substituents R R R, R and R may be the same or different and each represents a hydrogen atom, or a saturated or unsaturated, cyclic or acyclic, linear or branched hydrocarbon radical, and/or b. at least one compound of formula L k o wherein R represents a hydrogen atom, or a hydrocarbon radical as indicated sub(a), or an aromatic or araliphatic hydrocarbon radical.  
  Many of the compounds belonging to the classes described hereinabove are known, as are methods of their preparation. In respect to many pyrazine derivatives, for instance, their preparation, their nautral occcu&#39; rance and their use in the field of flavour industry have been described in seveal scientific publications and in the patent literaure. See, for example, U.S. Pat. No. 1,696,419; Helv. Chim. Acta, 47, 1581 (1964); Nature, 210, 1358 (1966); Helv. Chim. Acta, 48, 1809 (1965German Offen. 1,695,505; British Pat. Nos. 1,156,472 and 1,156,484; U.S. Pat. No. 3,459,556. However, none of the cited references disclosed the specific combination of said pyrazine or pyrazine derivatives with the compounds having formula 11 and or III.  
  The compounds of formula II, the cyclohexenone derivatives, constitute a well known class of chemical III compounds the synethesis of which has been thoroughly studied in the past and described in, e.g., J. Chem. Soc. 1944, 430; .l.Am.Chem. Soc. 71, 2028 (1949); J.Org.Chem., 21, 612 (1956). These references, however, do not show the addition of cyclohexenone derivatives to food products, nor do they suggest any possible application of said compounds for flavouring purposes.  
  Equally, the compounds of formula 111, many of which are described for the first time in our present application, have not been previously recognized as useful flavour additives.  
 DESCRIPTION OF THE INVENTION It has now been surprisingly found that by adding to foodor feedstuffs, beverages, pharamaceutical preparations and tobacco products, a composition comprising at least one compound of formula wherein the substituents R R R and R may be the same or different and either each represents a hydrogen atom, or a saturated or unsaturated, cyclic or acyclic, linear or branched hydrocarbon radical, or R together with R may constitute a benzene ring, or one of them represents an acyl radical and each of the other a radical of the same type as those mentioned above and a. at least one compound of formula wherein the substituents R R R, R and R may be the same or different and each represents a hydrogen atom, or a saturated or unsaturated, cyclic or acyclic, linear or branched hydrocarbon radical, and/or b. at least one compound of formula III ganoleptic characters of the ingredients taken separately. A synergistic effect was&#39;in fact observed.  
  Further, it has been found that many of the mentioned ingredients, specifically those belonging to the classes of compounds defined by general formulae II and III, posses useful flavouring properties even when taken separately It is a present object of the presnt invention to disclose a process for improving, enhancing or modifying the organoleptic properties of foodand feedstuffs, beverage, pharmaceutical preparation and tobacco, which comprises adding to said materials at least one of the compounds having formula II and/or at least one of the compounds having formula III.  
  Depending upon the nature of the other constitutents of the flavouring compositions, their proportion and, more specifically, upon the nature of the products to which the compounds or compositions of the present invention are added, said compounds or compositions develop or enhance flavour notes of various nature.  
  For instance, they can develop notes such as the roasted, burned or earthly ones, or simply they can impart to the products to which they are added a more defined taste of meat, cereals, hazel-nuts nuts or cocoa. Typically, they impart a roasted or burned note and, as a consequence, they find a particular utility for modifying or favourably enhancing the organoleptic character of certain flavouring compositions such as those possessing a nut, hazel-nut, pistachio, cocoa, coffee, caramel, roasted cereals, meat or spicy character.  
  Depending upon the desired effect, the mentioned compounds or compositions may be used in isolated form or in combination with various amounts of other flavouring ingredients, carriers or diluents.  
  The proportions of the compounds of formula I, I] or III, or composition thereof to be used in accordance with our present invention can vary within wide limits. For example, amounts as low as about 0.1 ppm (parts per million), based on the total weight of the flavoured material, have been found to be effective in many cases. Usually, however, depending on the nature of the product to be flavoured, it is desirable to add at least 1 to about 10 ppm of the flavouring ingredients.  
  In order to achieve special effects the hereinabove given upper limits can be raised to ppm or even higher.  
  In all cases, the ranges of proportions indicated may be varied depending upon the specific flavoring effect it is desired to achieve.  
  In the following description there is given a nonexhaustive list of the compounds belonging to the chemical groups defined by general formulae I, II and III. Immediately following the chemical name of each of the members of the selected group there is given the commercial source of a literature reference giving a method for its preparation, Commercially available products will be identified by the abbreviation 0a., and may be obtained, for example, from FLUKA AG., Buchs, S.G., Switzerland.  
  In those instances wherein new compounds are described a detailed method of preparation is given following the list of the group members. The new compounds will be identified by the abbreviation n.c.  
  The results of the organoleptic evaluation tests are set out in the examples following the detailed description of the groups of compounds.  
 A. Pyrazines In this first group there are included the compounds having the general formula I.  
 l. Pyruzines having saturated side chain(s) l. pyruzlne 0.11.  
  2. methylpyrazine ca C.  
  3. 2.3-dimethylpyrazine Berv 40, 4855 I907) 4. 2,5-dimethylpyrazine c.a. 5v 3,5-dimethylpyrazine c.a. 6. ethylpyrazine J. Org. Chem..26, 3379 1961) u 7. trimethylpyrzxzine .I.Am.Chem.Soc..72. 844 (I950) 8. Z-methyl-3-ethyI-pyrazine 9. 2-methyl-5-ethyl-py ne l0. Z-methyl-(z-ethyl-pyruzine l l, Z-n-propyl-pyrazine J.Org,Chem.,26. 3379 (I961) l2v Z-isopropyl-pyrazine J.Org.Chem..26. 3379 1961) 4 1 3. tetramethylpyruzine l4. 2,6-dimethyI-J-ethyl-pyraline I5. 2.5-dimethyl 3-ethyl-pyrazine l6. 2.3-dimethyl-5-ethyl-pyruzine n.cv l7. 2.3-diethyl-pyrazine l8. 2.5-diethylpyrn7.ine l9. 2.6-diethyl-pyrazine 20. Z-methyl-3-propyl-pyrazine 2 l. 2-methyl-S-propyl-pyruzine n.c. 22. 2-methyl-o-propyl-pyruzine J.Org.Chem..27. 1355 U962) 23. 2-methylJJsopropyl-pyrazine 24. 2-methyl-S-isopropyl-pyrazine 25. Z-methyl fv-isopropyl-pyruzine n.c 26. hutyl-pyruzine n.c. 27. isohutyl-pyrazine n.c. 28. [l&#39;-methyl-propyl l-pyruzine n.c. 29. tert. hutyl-pyruzine n.c C3  
 30. 2.3.6-lrimethyl-5-ethylpyrazine 3 l. Z-methyl-3-butyl-pyrazine 32. Z-methyl-S-hutyl-p n.c 33. 2-methyl-6-hutyl- I n.L 34. 2-methyl-3-isnhutyl-pyrazine 35. 2-methyl-5-isobutyl-pyruzine n.c. 36. 2-methyl-fiisobutyI-pyrazine n.c. 37. 2methyl-3-l l &#39;-melh \&#39;l-propylI-pyrnzine n.c.  
 The new compounds belonging to group A can be synthesized as following:  
  16. 2,3-Dimethyl--ethyl-pyrzine: This compound has been prepared by addition of an ethyl group in the position 5- of 2,3-dimethylpyrazine according to the procedure described by Klein et al. in J.Am.Chem.- Soc., 73, 2949 (1951).  
  21. 2-Methyl-5-pyropyl-pyrazine: it has been prepared by alkylation of 2,5-dimethyl-pyrazine according to the synthetic method described by Levine and Behun, J.Org.Chem., 26, 3379 (1961).  
  25. 2-Methyl-6-isopropyl-pyrazine: it has been prepared by successively condensing propylene-diamine with isopropyl-glyoxal and catalytically dehydrogenating the obtained 2,3-dihydropyrazine according to the procedure described in Helv.Chem.Acta, 50 1754 (1967), and finally separating by means of vapour phase chromatography the isomeric mixture of 2-methyl-6-isopropyl-and 2-methyl-5-isopropy1- pyrazine.  
  26. Butyl-pyrazine: prepared by alkylating 2-methyl pyrazine according to the procedure described in J.Org.Chem., 26, 3379 (1961).  
  27. Isobutyl-pyrazine: prepared by alkylating 2- methyl-pyrazine according to the procedure described in .1.0rg.Chem., 26, 3379 (1961).  
  28. [1&#39;-Methyl-propyl]-pyrazine: prepared by alkylating ethyl-pyrazine according to the procedure described in J.Org.Chem., 26, 3379 (1961 29. tert.-Butyl-pyrazine: prepared by successively condensing ethylene-diamine with tert.-butyl-glyoxa1 and catalytically dehydrogenating the obtained 2,3- dihydro-pyrazine according to the method described in He1v.Chim.Acta, 50, 1754 (1967).  
  32. 2-Methy1-5-butyl-pyrazine: prepared by alkylating 2,5-dimethylpyrazine as described in J .Org.Chem., 26, 3379 (1961).  
  33. 2-Methyl-6-butyl-pyrazine: prepared by alkylating 2,6-dimethylpyrazine according to the procedure described in J.Org.Chem., 26, 3379 (1961).  
 35. 2-Methy1-5-isobutyl-pyrazine: prepared by alkylating 2,5-dimethyl-pyrazine according to the procedure described in J.Org.Chem., 26, 3379 1961 36. 2-Methyl-6-isobutyl-pyrazine: prepared by alkylating 2,6-dimethylpyrazine according to the procedure described in J.Org.Chem., 26, 3379 (1961).  
  37. 2-Methy1-3-[1&#39;-methyl-propyl]-pyrazine: prepared by successively condensing ethylene-diamine with 4-methyl-2,3-hexanedione and catalytically dehydrogenating the obtained 2,3-dihydro-pyrazine according to the method described in He1v.Chim.Acta, 50. 1754 (1967).  
  38. 2-Methyl-5-[1&#39;-methyl-propyl]-pyrazine: prepared by successively condensing methyl-3-oxopentanal with propylene-diamine and catalytically dehydrogenating the obtained 2,3-dihydro-pyrazine according to the method described in He1v.Chim.Acta, 50, 1754 (1967), and finally separating the isomeric mixture by means of vapour phase chromatography for obtaining 2-methyl-5- and 2-methyl-6-[1&#39;-methylpropyl]-pyrazine.  
  39. 2-Methyl-6-l-methyl-propy1]-pyrazine: prepared according to the same method as that described for the obtention of compound 38 hereinabove.  
  40. 2-Methyl-3-tert.-butyl-pyrazine: prepared by successively condensing 2,2-dimethyl-3,4-pentanedione with ethylene-diamine and catalytically dehydrogenating the obtained 2,3-dihydro-pyrazine according to the procedure described in Helv.Chim.Acta, 50, 1754 (1967).  
  41. 2-Methy1-5-tert.-butyl-pyrazine: prepared by successively condensing 3,3-dimethyl-2-oxo-butanal with propylene-diamine and catalytically dehydrogenating the obtained 2,3-dihydro-pyrazine according to the procedure described in He1v.Chim.Acta. 50, 1754 (1967), and finally separating the isomeric mixture of 9 Z-methyl-S- and 2-methyl-6 tert.-butyl-pyrazine by means of vapour phase chromatography.  
  42. 2-Methyl-6-tert.-butyl-pyrazine: prepared according to thesame method as that described hereinabove for 2-methyl-5-tert.-butyl-pyrazine.  
  43. 2-Ethyl-3-propyl-pyrazine: prepared by successively condensing ethylene-diamine with 3,4- heptanedione and catalytically dehydrogenating the obtained 2,3-dihydro-pyrazine according to the procedure described in Helv.Chim.Acta, 50, 1754 (1967).  
  44. 2-Ethyl-5-propyl-pyrazine: prepared by alkylating 2,5-diethy1pyrazine according to the method described by Levine and Behun, J.Org.Chem., 26, 3379 (1961). and finally separating by means of vapour phase chromatography the obtained isomeric mixture.  
  45. 2-Ethyl--propyl-pyrazine: prepared by alkylating 2-methyl-6-ethy1-pyrazine according to the procedure described in .l.Or g.Chem., 26, 3379 (1961).  
  46. 2-Ethyl-3-isopropyl-pyrazine: prepared by successively condensing ethylene-diamine with 2-methyl- 3,4-hexadione and catalytically dehydrogenating the obtained 2,3-dihydro-pyrazine according to the procedure described in Helv.Chim.Acta, 50, 1754 (1967).  
  47. 2-Ethyl-5-isopropyl-pyrazine: prepared by alkylating 2,5-diethyl-pyrazine according to the procedure described in J.Org.Chem., 26, 3379 (1961), and finally separating the various obtained isomers by means of vapour phase chromatography.  
  48. 2-Ethyl-6-isopropyl-pyrazine: prepared by alkylating 2,6-diethyl-pyrazine according to the procedure descried in .1.0rg.Chem., 26, 3379 (1961 49. 2,6-Dimethyl-3-isopropyl-pyrazine: prepared by successively condensing propylene-diamine with 4-methyl-2,3-pentanedione and catalytically dehydro genating the obtained 2,3-dihydropyrazine according to the procedure described in Helv. Chim. Acta, 50, 1754 (1967). and finally separating the isomeric mixture of 2,6-dimethyl-3-isopropyland 2,5-dimethyl-3- isopropyl-pyrazine by means of vapour phase chromatography.  
 (10.2); 54 (7.0); 43 (12.1); 42 (26.6); 41 (16.3); 40 10.3); 39 (30.5); 27 (9.5). 50. 2,5-Dimethy1-3- isopropyl-pyrazine: prepared according to the same method as that described for the obtention of 2,6-dimethyl-3-isopropy1-pyrazine.  
  51. 2,3-Dimethy1-5-isopropyl-pyrazine: prepared by successively condensing 2,3-diamino-butane with&#39;isopropyl-glyoxal and catalytically dehydrogenating the obtained 2,3-dihydro-pyrazine according to the procedure described in He1v.Chim.Acta, 50, 1754 (1967).  
  2,6-Dimethyl-3-propyl-pyrazine: prepared by adding a propyl group in the position 3- of 2,6-dimethylpyrazine according to the proocedure described in .l.Am.Chem.Soc., 73, 2949 (1951).  
  56. 2,5-Dimethyl-3-propy1-pyrazine: prepared according to the procedure described in J.Am.Chem.- Soc., 73, 2949 (1951) by adding a propyl group in the position 3- of 2,5-dimethy1-pyrazine.  
  57. 2,3-Dimethyl-5-propy1-pyrazine: prepared by adding a propyl group in the position 5- of 2,3- dimethyl-pyrazine according to the same procedure as indicated for compound 56.  
  58. Amyl-pyrazine: prepared by alkylating methylpyrazine according to the synthetic method described in .l.Org.Chem., 26, 3379 (1961).  
  59. lsoamyl-pyrazine: prepared by alkylating methylpyrazine according to the procedure described in J.Org.Chem., 26, 3379, (1961).  
  60.- [2&#39;-Methyl-butyl]-pyrazine: prepared by alkylating methyl-pyrazine according to the method described in .l.Org.Chem.,26, 3379 (1961).  
  61. [1&#39;-Methy1-butyl]-pyrazine: prepared by successively condensing ethylene-diamine with trimethyl-Z- oxo-hexanal and catalytically dehydrogenating the obtained 2,3- dihydro-pyrazine according to the method described in l-lelv. Chim. Acta, 50, 1754 (1967).  
  62. [1&#39;,2-Dimethy1-propyll-pyrazine: prepared by successively condensing ethylene-diamine with 3,4-dimethyl-2-oxo-pentanal and catalytically dehydrogenating the obtained 2,3-dihydro-pyrazine according to the method described for compound 61.  
 63. [1&#39;-Ethy1-propy1]-pyrazine: prepared according to the same procedure as that indicated for compound B. Cyclohexen-2-ones In this group there are included the compounds belonging to the general formula 11. Typical examples of the compounds of class B are:  
 Z-methyl-cyclohexen-2-one 3-methy1-cyclohexen-2-one 4-methyLcyclohexen-Z-one 5-methyl-cyclohexen-2-one 6-methyl-cyclohexen-Z-one ,6-dimethyl-cyclohexen-Z-one .4-dimethyl-cycl0hexen-2-0ne .5-dimethyl-cyclohexene-2-one .6-dimethyl-cyclohexen-2-one .6-d imethyl-cyclohexen-Z-one .3-dim ethyl-cyclohexen-Z-one ,4-dimethyl-cyclohexen-Z-one .5-dimethyl-cyclohexen-lone .5-dimethyl-cyclohexen-Z-one 5 .6-dimethyl-cyclohexen-Z-one Z-ethyl-cyclohexen-Z-one 3-ethyl-cyclohexen-2-one 4-ethyl-cyclohexen-2-one S-ethyl-cyclohexen-Z-one 6-ethyl-cycl0hexen-2-onc c.a. Ann.. 379. 17 (1911) 0.11. .1.Chem.Soc.. 1960 3563 J.Chem.Soc.. 1946. 595 .1.Am.Chem.Soc.. 78. 4604 (1956) J.Chem.Soc.. 1944. 430 C0mpt.Rend.. 205. 680 (1937) .1.Chem.Soc., 1960. 3563 .1.Chem.Soc.. 1944. 430 J.Chem.Soc.. 1944, 430 J.Org.Chem.. 4. 266 (1939) CA. 61. 585c J.Chem.Soc.. 1944. 430  
 C.A.. 64. 194361&#34; .|.Org.Chem.. 21. 612 (1956) Ann.. 360. 49 (1908) .I.Am.Chem.Soc.. 71. 2028 (1949) C.A.. 64. 11099 b prepared according to the method described in .1.Chcm.Soc.. 1944. 4.11).  
 62 hereinabove starting from ethylene diamine and 3-ethyl-2-oxo-pentanal.  
 64. [2,2&#39;-Dimethyl-propyl]-pyrazine: prepared in accordance with the method described for compound 63 starting from ethylenediamine and 4,4-dimethyl-2- oxo-pentanal.  
 5-Ethy1-cyclohexen-2-one Ethyl-cyclohexen-Z-one MS: 124 (7.1); 96 (46.0); (6.6); 68 55 Among the compounds C. Thiazolidines belonging to the present group (compounds of formula III) we can mention the following:  
 65. [1,1 Dimethyl-propyl]-pyrazine: prepared by alkylating pyrazine with 2-bromo-(2-methyl)-butyllithium according to the procedure described in .1 .Am.- Chem.Soc., 73, 2949 (1951).  
 h.p. 65-70/l 8 Torr h.p. 634/l 2 Torr 76-7/ 10 Torr n.c.. h.p. 723/l2 Torr 87-8/12 Torr h.p. 934/12 Torr h.p. 778/1() Torr h.p. l06-7/12 Torr h.p. 1()4-6/l0 Torr h.p. 1023/12 Torr 1234/12 Torr The boiling points indicated in the hereinabove list are given in degrees centigrade.  
  The compounds mentioned above have been pre- 65 pared according to a synthetic method analogous to that indicated hereinbelow for the preparation of 2- propyl-thiazolidine:  
  102 g of n-butyraldehyde (1.42 Mole) were added under stirring to 91 g (1.18 Mole) of cisteamine in 190 ml of water. The reaction was slightly exothermic and the temperature of the reaction mixture raised to approximately 60 C. The reaction mixture was kept under stirring for five more hours and extracted then with 2 portions of 500 ml of ether. After the usual treatment of separation, washing with water and drying over sodium sulfate, the organic extracts were evaporated to dryness and the obtained residue was distilled under reduced pressure to give 2-propyl-thiazolidine, b.p. 758/l0 Torr; 126 g; yield 82 A portion of the obtained product was subjected to a fractional distillation, b.p. 767/1O Torr.  
  The invention is better illustrated by the following examples:  
 EXAMPLE 1 A base flavouring composition has been prepared by admixing the following ingredients (parts by weight):  
 Z-methyl-pyrazine 2,5-dimethyl-pyrazine 8. 2-methyl-6-ethyl-pyrazine l 2-methyl-3-ethyl-pyrazine 2 3 ,S-dirnethyl-Z-ethyl-pyrazine l 2.5-dimethyl-3-ethyl-pyrazine 2 propylene glycol I. S-methyl-Z-cyclohexen-l-one 5 ppm 2. o-methyl-l-cyclohexen-l-one 5 ppm 3. 3.6-dimethyl-Z-cyclohexen-l-one 5 ppm 4. 4.6-dimethyl-2-cyclohexen-1-one 5 ppm The flavoured solutions thus obtained were subjected to an organoleptic evaluation by a group of trained tasters, who have defined the taste of the solutions as follows:  
 1. Green hazelnuts 2. Meat character 3. Burned, roasted meat character, slightly earthy 4. Analogous to that indicated sub 3.  
 EXAMPLE 2 A base flavouring composition was prepared by admixing the following ingredients (parts by weight):  
 Z-methyl-pyrazine 5 2.5 -dimethyl-pyrazine 8 2-methyl-6-ethyl-pyrazine l 2-methyl-3-ethyl-pyrazine 2 3.5-dimethyl-2-ethyl-pyrazine l 2,5-dimethyl-3-ethyl-pyrazine 2 propylene-glycol The above indicated base composition was added in the proportion of 0.01 to a solution at 0.5 (weight- /volume) of sodium chloride in water (solution A) and to a solution of l (volume/volume) of a commercially available vegetal proteins hydrolysate in water (solution B). The solutions thus obtained were respectively divided into four parts of equal volume. These fractions were then flavoured by adding the following ingredients (parts by weight based on the total weight of the solution):  
 1. 2-n-propyl-thiazolidine 5 ppm 2. 2-isopropyl-thiazolidine 5 ppm 3. Z-n-butyl-thiazolidine 5 ppm 4. Z-isobutyl-thiazolidine 5 ppm The flavour solutions thus obtained were subjected to an organoleptic evaluation by a group of trained tasters, who have defined the taste of the solutions as follows:  
 1. Meat, nut, coffee character 2. Sulfury note, meaty after-taste 3. Cereal character, meaty or hazelnut after-taste 4. Chocolate, cocoa, note.  
 EXAMPLE 3 A base flavouring composition prepared by admixing the same ingredients as those indicated in Examples 1 and 2, was added to a solution of 0.5 (weight- /volume) of sodium chloride in water (solution A) and to a solution of l (volume/volume) of a commercially available vegetal proteins hydrolysate in water (solution B).  
  1.1. By adding to above indicated solution A 5 ppm of 2-n-propyl-thiazolidine and 2.5 ppm of 3,6-dimethyl- 2-cyclohexen-l-one there is obtained a solution which shows a taste reminiscent of fried potatoes and vaguely of meat.  
  1.2. By adding to solution B 5 ppm, based on the total weight of the solution to be flavoured, of 2-n-propylthiazolidine and 2.5 ppm of 3,6-dimethyl-2- chclohexen-l-one there is obtained a solution possessing a taste reminiscent of roast beef.  
  1.3. By adding to solution B 5 ppm of 2-n-propylthiazolidine and 2.5ppm of 4,6-dimethyl-2-cyclohexenl-one there is obtained a solution possessing a taste of meat presenting a burned note as well.  
  2.1. By adding to solution A 5 ppm of 2-n-butylthiazolidine and 2.5 ppm of 3,6-dimethyl-2- cyclohexen-l-one there is obtained a solution having a taste reminiscent of fried potatoes. When the same ingredients were added to solution B, there is obtained a solution possessing the taste of beef meat.  
  2.2. An analogous effect has been obtained by adding to solution B 5 ppm of 2-n-butyl-thiazolidine and 2.5 ppm of 4,6-dimethyl-2-cyclohexen-l-one.  
  3.1. By adding to solution B 5 ppm of 2-isopropylthiazolidine and 1.5 ppm of 3,6-dimethyl-2- cyclohexenl-one there is obtained a solution possessing a meaty taste.  
  3.2. By adding to solution B 5 ppm of 2-isopropylthiazolidine and 2.5 ppm of 3,6-dimethyl-2- cyclohexen-l-one there is obtained a solution having a very interesting note of roast beef.  
  3.3. The same effect as that observed in paragraph 3.2. is obtained by adding to solution B 5 ppm of 2-isopropyl-thiazolidine and 2.5 ppm of 4,6-dimethyl-2- cyclohnexen- 1 -one.  
 EXAMPLE 4 A base flavouring composition was prepared by admixing the following ingredients (parts by weight):  
 Z-methyl-pyrazine 2,5-dimethyl-pyrazine 2 ,G-dimethyl-pyrazine 2-methyl-6-ethyl-pyrazine 2-methyl-B-ethyl-pyrazine 3 ,5-dimethyl-Z-ethyl-pyrazine 2,5-dimethyl-3-ethyl-pyrazine 2,6-dimethyl-3.S-diethyl-pyrazine propylene glycol The base composition indicated above was added in the proportion of 0.01 to a solution at 15 of sucrose in water. By adding to the solution thus obtained ppm of vanillin, 1 ppm of a-methylbutyraldehyde and 5 ppm of 2-isobutyl-thiazolidine there is obtained a solution having a very interesting burned chocolate taste and possessing as well a nutty after-taste.  
 EXAMPLE 5 A base flavouring composition was prepared by admixing the following ingredients (parts by weight):  
 dimethyl sulphide 0.03 2-methyl-3-ethyl-pyrazine 0. l 5 Z-acetyl-pyrazine 0.20 2-ethyl-6-methyl-pyrazine 0.20 indole 0.20 2.5-dimethyl-B-ethyl-pyrazine 0.30 2,3.5-trimethyl-pyrazine 0.50 2,5-dimethyl-pyrazine 0.50 capric acid 1.00 caprylic acid 2.00 n-butyric acid 2.00 caproic acid 3.50 vegetable oil 89.42  
  The above indicated base composition was added in the proportion of 0.01 to a solution of g of commercially available gravy mix in 600 ml of water. This solution represents the control solution. Said solution was then divided into four parts of equal volume and these fractions were then flavoured by adding the following ingredients in the amount indicated (parts by weight based on the total weight of the solution):  
 1. 2-n-propyl-thiazolidine 5 ppm 2. 2-isopr0pyl-thiazolidine 5 ppm 3. 2-n-butyl-thiazolidine 5 ppm The flavoured solutions thus obtained were subjected to an organoleptic evaluation by a group of trained tasters who defined their taste as follows:  
 1. Possessed a more defined meaty character than the control solution, particularly in the fatty and charred note.  
 2. Strong burnt. charred character 3. Analogous to 2, but with stronger beef fat note.  
 EXAMPLE 6 A base flavouring composition was prepared by admixing the following ingredients (parts by weight):  
 dimethyl sulphide 0.03 2-methyl-3-ethyl-pyrazine Z-acetyl-pyrazine Continued 2-ethyl-6-methyl&#39;pyrazine 0.20 indole 0.20 2.5-dimethyl-3-ethyl-pyrazine 0.30 2.3.5-trimethyl-pyrazine 0.50 2.5-dimethyl pyrazine 0.50 capric acid 1.00 caprylic acid 2.00 n-butyric acid 2.00 caproic acid 3.50 vegetable oil 89.42 10000 The above indicated base composition was added in the proportion of 0.01 to a solution of 25 g of commercially available gravy mix in 600 ml of water. The solution thus obtained was divided into two parts of equal volume and these fractions were then flavoured by adding the following ingredients in the amount indicated (parts by weight based on the total weight of the solution):  
 5 ppm 1. 6-methyl-2-cyclohexenone 5 ppm 2. 4,5-dimethyl-2 cyclohexenone l. Z-isopropyl-thiazolidine 2.5 ppm 4.6-dimethyl-2-cyclohexenone 5.0 ppm 2. 2-n-butyl-thiazolidine 5.0 ppm 4,6-dimethyl-Z-cyclohexenone 5.0 ppm In the opinion of the panel the solutions flavoured with l. and 2. were fuller and rounder in flavour with enhanced roasted meaty note when compared to the control solution.  
 EXAMPLE 7 A flavour base composition of the chocolate type was prepared by admixing the following ingredients (parts by weight):  
 acetic acid 0.50 isobutyraldehyde 0.50 Z-methylbutyric acid 1.00 isovaleraldehyde l .50 caproic acid 1.50 Z-methylbutanal 1.50 furfuryl alcohol 2.00 vanillin |0.00 propylene glycol 81.50  
 A: Chocolate milk drinks A commercial chocolate instant milk drink powder containing cocoa powder. milk powder and sugar was used as a base. g of said base were dissolved in 600 ml of cold water. The solution was then divided into three fractions of equal volume. One of these fractions was used as a control solution whereas the two others were separately flavoured by 1. adding 0.005 of the base solution as indicated above and 0.005 (based on the total weight of the flavoured solution) of the pyrazinic base flavouring composition indicted in Example 4, and  
 2. adding 0.005 of the base solution as indicated above, 0.005 of the pyrazinic base flavouring composition indicated in Example 4 and L5 ppm of 2-isobutyl-thiazolidine.  
  It was the opinion of the evaluation panel that the addition of 2-isobutyl-thiazolidine promoted an enhancement to the chocolate note of the solution. Said solution possessed as well a more rounded flavour.  
 B: Chocolate bars A low grade commercial chocolate converture was used as material to be flavoured. The same flavouring compositions as those indicated for carrying out the aromatization of the chocolate milk drinks of the paragraph A hereinabove were used. Also in this case the panelists found that the chocolate bars flavoured with the flavouring composition prepared according to 2. of paragraph A possessed a better defined chocolate character and a fuller and rounder flavour note than the base unflavoured material.  
 I claim:  
  1. A process for improving, enhancing or modifying the organoleptic properties of foodstuffs, feedstuffs, beverages, pharmaceutical preparations and tobacco products which comprises adding thereto a small but effective amount of a flavouring composition comprising at least one compound having the formula wherein the substituents R R R, R and R each represent a hydrogen atom, an aliphatic hyrocarbon radical, or a cyclic hydrocarbon radical; and at least one compound of formula III wherein R represents a hydrogen atom, an aliphatic hydrocarbon radical, a cyclic hydrocarbon radical, or an aromatic or araliphatic hydrocarbon radical.  
  2. A process for improving, enhancing or modifying the oranoleptic properties of foodstuffs, feedstuffs, beverages, pharmaceutical preparations and tobacco products which comprises adding thereto a small but effective amount of at least one compound having the formula II, as set forth in claim 1, and at least one compound of formula III, as set forth in claim 1.  
  3. A process for improving, enhancing or modifying the organoleptic properties of foodstuffs, feedstuffs, beverages, pharmaceutical preparations and tobacco products wich comprises adding thereto a small but effective amount of a flavouring composition comprising at least one compound having the formula I, as set forth in claim 1, and at least one compound of formula H, as set forth in claim 1.  
  4. A process for improving, enhancing or modifying the organoleptic properties of foodstuffs, feedstuffs, beverages, pharmaceutical preparations and tobacco products which comprises adding thereto a small but effective amount of a flavouring composition comprising at least one compound having the formula II, as set forth in claim 1.  
  5. Flavouring composition which comprises at least one compound of formula II, as set forth in claim 1, and at least one compound of formula II, as set forth in claim 1.  
  6. A foodstuff having added thereto a small but flavour-modifying quantity of the composition as set forth in claim 4.  
  7. A foodstuff according to claim 6 having added thereto betweeen about 0.l and about 10 ppm by weight of the flavouring composition.  
  8. Flavouring composition which comprises at least one compound having the formula I, as set forth in claim 1, and at least one compound of formula ll, as set forth in claim 1.  
  9. A foodstuff having added thereto a small but flavour-modifying quantity of the composition as set forth in claim 8.  
  10. A foodstuff according to claim 9 having added thereto between about 0.1 and about 10 ppm by weight of the flavouring composition.  
  11. Flavouring composition which comprises at least one compound of formula II, as set forth in claim 1.  
  12. A foodstuff having added thereto a small but flavour-modifying quantity of the composition as set forth in claim 1.  
  13. A foodstuff according to claim 12 having added thereto between about 0.1 and about 10 ppm by weight of flavouring composition.  
  14. Flavouring composition which comprises at least one compound having the formula I, as set forth in claim 1, at least one compound of formula [1, as set forth in claim 1, and at least one compound of formula III, as set forth in claim 1.  
  15. A foodstuff having added thereto a small but flavour-modifying quantity of the composition as set forth in claim 14.  
  16. A foodstuff according to claim 15 having added thereto between about 0.1 and about 10 ppm by weight of the flavouring composition.  
 UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION Q PATENT NO. 3,881,025  
 DATED April 29, 1.975  
 lN\/ ENTOR(S) Ivon Flament It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:  
 1. In Column 1, line 57 &#34;seveal&#34; should be -several-.  
 2w In Column 1, line 62 (1965&#34; should be (l965)-.  
 &#39;30 In Column 2, line 59 &#34;reprsents a represents atom&#34; should be represents a hydrogen atom.  
 4.. In Column 2, line 66 &#34;diffeent&#34; should be -different.  
  5. In Column 2, line 67 &#34;different by the sum&#34; should be Q expe&#39;cted by the sum-.  
 6., In Column 4, line 7 &#34;at least 1&#34; should be at least about 1- 7. In Column 4, line 19 &#34;source of&#34; should be source or--.  
 us. In Column 4, in Formula I &#34;30. 2,3,6-trimethyl-5-ethylpyrazine&#34; should be 30. 2,3,6-trimethyl-5-ethyl- 9., In Column 8, line 42 &#34;Z-Methyl-6-l&#39;methyl -propyl]pyrazine:  
 should be 2-Methyl-6- [l&#39;-methylpropyl]pyrazine:-.  
 10. In Column 10, line 2 &#34;50. 2,5-Dimethyl3&#34; should have started as a new paragraph.  
 11., In Column 10, line 18 &#34;2,6-Dimethyl-3-propyl-pyrazine: prepared by adding&#34; should be 55. 2,6-Dimethyl-3-propyl- I Q pyrazine: prepared by adding--.  
 12. In Column 10, line 20 &#34;proocedure&#34; should be procedure&#39;.  
 UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION DATED April 29, 1975 lNv ENTOR(S) Ivon Flament It is certified that error appears in the ab0ve-identified patent and that said Letters Patent are hereby corrected as shown below:  
 In Column 11, line 4 &#34;79 (7.0). 7.0) 53&#34; should be In Column 11, line 62 &#34;39 (11.5) b 27 (4.6) should be In Column 12, line 45 &#34;hiazoli-dine&#34; should be thiazoli-dine In Column 13, line 32 &#34;sodium in water&#34; should be sodium chloride in water--.  
 In Column 14, line 40 &#34;chclohexen-l-one&#34; should be --cyclohexen-l-one.  
 In Column 14, line 68 &#34;cyclohnexen-l-one.&#34; should be cyclohexen-lone.-.  
 In Column 17, line 12 &#34;converture&#34; should be coverture.  
 In Column 18, line 5, claim 2, &#34;oranoleptic properties&#34; should be organoleptic properties.  
 In Column 18, line 14, claim 3, &#34;wich&#34; should be which-.  
 In Column 18, line 28, claim 5, &#34;formula II&#34; should be formula III.  
 Signed and Scaled this {SEAL} second Day of December1975 Arrest:  
 RUTH C. MASON Arresting Officer C. MARSHALL DAN&#34; Commissioner of Patents and Tmdemllh