Patent GB-1156480-A (GB)
Title: Furan Flavouring Agents
Inventor: WINTER M
IPC: A23L27/20
Filed: 1966-05-02
Abstract: 1,156,480. Furan derivatives. R. FIRMENICH, G. FIRMENICH, R. E. FIRMENICH, and F. H. FIRMENICH, [trading as FIRMENICH & CIE.]. 2 May, 1966 [30 April, 1965; 18 April, 1966], No. 2381/69. Divided out of 1,156,472. Heading C2C. [Also in Division A2] 2-Isopropenyl-benzofuran.-According to the method described in J.A.C.S. 73, 754 (1951), 2-acetyl-benzofuran is reacted with methylmagnesium bromide to form 2-(2-hydroxyisopropyl)-benzofuran which is converted to its acetate. Pyrolysis of the acetate yields 2-isopropenyl-benzofuran of b.p. 81-83‹ C./0À001 mm. Hg. 7-Ethyl-benzofuran is prepared by the method described in J. Chem. Soc. 1920, 1534, but using o-ethylphenol instead of o-cresol. The MS. of the product thus obtained shows the following ion peaks with the relative intensities given within brackets: 131 (100%), 146 (38%) and 77 (10%). 2,7 - Dimethyl - benzofuran.-7 - Methylbenzofuran is subjected to a WILSMEYER reaction to form 7-methyl-benzofuran-2-aldehyde which is converted into 2,7-dimethylbenzofuran by a WOLFF-KISHNER reaction by the method described in Bull. Soc. Chim. France 29, 1875 (1952). The product thus obtained has the following peaks in its MS: 146 (100%), 145 (92%) and 131 (32%). 5 - Methyl - furfuryl furfuryl ether was prepared by the procedure described by J. E. Zanetti in J. Am. Chem. Soc. 49, 1066 (1927) for the difurfuryl ether, starting with 5-methylfurfuryl bromide (Compt. Rend. 222, 1441 (1946)) instead of furfuryl bromide of Zanetti. The product was isolated by ether extraction of the crude mixture after having diluted with water. For purification the ether extract was distilled twice-b.p. 68-70‹ C. at 0À01 mm./Hg vacuum. The product was a viscous colourless liquid, darkening rapidly on contact with air. 7 - Methyl - benzofuran - 2 - aldehyde was prepared by formylating 7-methyl-benzofuran according to the same method as used for the preparation of benzofuran-2-aldehyde. The product thus obtained has the following ion peaks in its mass spectrum: 160 (100%), 159 (62%) and 131 (33%). (5-Methyl-furfuryl) methyl ketone was prepared according to the procedure described by Hass et al. in J. Org. Chem. 15, 8 (1950) by condensing 6-methyl-furfuryl-aldehyde with nitroethane. The product has a b.p. of 75‹ C./ 10 mm. Hg. (5-Methyl-furfuryl) ethyl ketone was prepared by the same method as used for the preceding compound, except that 1-nitropropane was used instead of nitroethane. The product has a b.p. of 97-100‹ C./15 mm. Hg. 1-(5-Methylfuryl)-3-pentanone was prepared by the method described in Ber. 76, 192 (1943). It has a b.p. of 101-102‹ C./11 mm. Hg. The following five compounds can be obtained by reacting the corresponding acid chlorides with furfuryl alcohol, for example by the method described in Houben-Weyl, fourth edition, volume 8, page 543 (1952), and are found to have the following boiling points: Furfuryl isovalerate, b.p. 97-98‹ C./11 mm. Hg. Furfuryl crotonate, b.p. 96-98‹ C./11 mm. Hg. Furfuryl-α-methylbutyrate, b.p. 96‹ C./11 mm. Hg. Furfuryl - #,#<SP>1</SP> - dimethylacrylate, b.p. 113- 115‹ C./11 mm. Hg. Furfuryl valerate, b.p. 100-104‹ C./11 mm. Hg. Furfurylthioacetone was prepared in the same manner as methylthioacetone according to the method described in J.A.C.S. 76, 114 (1954) by condensing 0À122 mole of chloroacetone with 0À11 mole of sodium furfurylmercaptide. After the usual separation and purification of the reaction product there were obtained by distillation 13À9 g. of pure furfurylthioacetone distilling at 115-177‹ C./10 Torr. n D <SP>22À8</SP> = 1À5250; d 4 <SP>23</SP> = 1À150. Difurfurylmercaptal of α-methylbutanal.-This compound was prepared by the same method as furfuryl methyl ether, using 0À11 mole of furfurylmercaptan instead of methanthiol. 6À4g. of difurfurylmercaptal were obtained; b.p. 130‹ C./0À1 Torr; n D <SP>22À8</SP> = 1À5500; d 4 <SP>23</SP> = 1À126.