j. Cosmet. Sci., 50, 99-104 (March/April 1999) Synthesis of new fragrances from 2-methylfuran. Part II JANUSZ NOWICKI and J6ZEF G6RA, Institute of Heavy Organic Synthesis, "Blachownid," Energetykgw 9, 47-225 Kqdzierzyn-Kooele, Poland, and Institute of General Food Chemistry, Technical University of Lgdoe, Stefanowskiego 4/10, 90-924 Lgdoe, Poland. Accepted for publication March 31, 1999. Synopsis The synthesis of new furan acetals from 2-methylfuran are described. Odor and physicochemical character- istics of all new compounds are also presented. INTRODUCTION Acetals make a very important group of fragrance synthetic compounds. They offer high resistance to alkalies alkaline media induce no changes in acetals even at elevated temperatures. Compared to aldehydes, acetals also reveal much higher resistance to oxidizers. Special stability can be expected from cyclic acetals that are derived from aldehydes and corresponding glycols. The fragrance properties of such products are usually much different from those of initial aldehydes. There are many reports available in the literature on cyclic acetals with very interesting fragrance performances that are obtained from aliphatic aldehydes (1,2) and terpene aldehydes (3,4). The investigations that had been carried out for a few years on the ways of obtaining new furane derivatives with fragrance activity yielded furan aidehyde 1 (Figure 1): R R 1 Figure 1. These aldehydes were intermediates in the synthesis of a range of new fragrances (5). Since they themselves were not offering any attractive fragrance characteristics, attempts were made to convert them into new cyclic acetals. 99

100 JOURNAL OF COSMETIC SCIENCE RESULTS AND DISCUSSION New acetals were produced in the reaction of aidehyde 1 with selected derivatives of ethylene glycols (Figure 2): /•CHO R 1 2a' R=H R1,R2=H 2b: R=H Ri=H , R2=CH 3 2c: R=H R•=H, R2=C2H 5 + Ho7•R• HO - R2 2a-f 2d: R=CH3 R•,R2=H 2e ß R=CH3 R•=H, R2=CH 3 2f: R=CH3 R•=H, R2=C2H 5 Figure 2. and 1,3-propylene glycol (Figure 3): R1 /•C HOSR2 HO + R HO'--/ R3 1 3a' R=H R•, R2, R3=H 3b ß R=H R2=CH3 R2, R3=H 3c: R=H: R•=H R2, R3=CH 3 3a-f R3 3d: R=CH3 R•, R2, R3=H 3e: R=CH3 R•=CH3 R 2, R3=H 3f' R=CH3: R2=H R 2, R3=CH 3 Figure 3. The acetylation reactions were carried out in the presence of an acidic catalyst. Since furane compounds were sensitive to mineral acids, FeSO 4 was employed this turned out to be an efficient and mildly acting acetylation catalyst. Very interesting fragrance properties were also offered by new cyclic furane acetals: dioxane and dioxolane deriva- tives. They are presented in Table I. EXPERIMENTAL Purity of the obtained new compounds reached 98% and their structures were confirmed by IR and 1H-NMR spectra. IR spectra were obtained in a Perkin-Elmer spectrometer Model SP-1000. Gas chromatographic analyses were performed in a Perkin-Elmer chro- matograph Model 900 (column 1.8 m, LAC 2R, 15% on chromosorb WAW 60/80 mesh, temperature 80-195øC, argon as a carrier gas). •H-NMR spectra were obtained in a Hitachi-Perkin-Elmer spectrometer R24A (80 MHz, CC14, TMS).