http://www.revistadechimie.ro REV.CHIM.(Bucharest)♦68♦No. 1 ♦2017 180 Convenient Synthesis of (Z)-7- and (E)-9-dodecene-1-yl Acetate, Components of Some Lepidoptera Insect Sex Pheromone ADRIANA MARIA ANDREICA, LUCIA GANSCA, IRINA CIOTLAUS, IOAN OPREAN Babes Bolyai University Raluca Ripan Institute for Research in Chemistry, Natural Products Laboratory, 30 Fantanele Str., 400294, Cluj Napoca, Romania Were developed new and practical synthesis of (Z)-7-dodecene-1-yl acetate and (E)-9-dodecene-1-yl acetate. The routes involve, as the key step, the use of the mercury derivative of the terminal-alkyne ω-functionalised as intermediate. The synthesis of (Z)-7-dodecene-1-yl acetate was based on a C 6 +C 2 =C 8 and C 8 +C 4 =C 12 coupling scheme, starting from 1,6-hexane-diol. The first coupling reaction took place between 1-tert- butoxy-6-bromo-hexane and lithium acetylide-ethylendiamine complex obtaining 1-tert-butoxy-oct-7-yne, which is transformed in di[tert-butoxy-oct-7-yne]mercury. The mercury derivative was directly lithiated and then alkylated with 1-bromobutane obtaining 1-tert-butoxy-dodec-7-yne. After acetylation and reduction with lithium aluminium hydride of 7-dodecyne-1-yl acetate gave (Z)-7-dodecene-1-yl acetate with 96 % purity. The synthesis of (E)-9-dodecene-1-yl acetate was based on a C 8 +C 2 =C 10 and C 10 +C 2 =C 12 coupling scheme, starting from 1,8-octane-diol. The first coupling reaction took place between 1-tert-butoxy-8- bromo-octane and lithium acetylide-ethylendiamine complex obtaining 1-tert-butoxy-dec-9-yne, which is transformed in di[tert-butoxy-dec-9-yne]mercury. The mercury derivative was directly lithiated and then alkylated with 1-bromoethane obtaining 1-tert-butoxy-dodec-9-yne. After reduction with lithium aluminium hydride of 1-tert-butoxy-(E)-9-dodecene and acetylation was obtained (E)-9-dodecene-1-yl acetate with 97 % purity. Keywords: (Z)-7-dodecene-1-yl acetate, (E)-9-dodecene-1-yl acetate, Lepidoptera, sex pheromone * email: adriana.andreica@gmail.com (Z)-7-dodecene-1-yl acetate and (E)-9-dodecene-1-yl acetate are components of lots of Lepidoptera insect sex pheromones [1]. Some important economic pest insects are: Trichoplusia ni (cabbage looper) and Sparganothis Pilleriana (vine leaf roller). The synthesis of (Z)-7-dodecene-1-yl acetate [2-5], (E)- 9-dodecene-1-yl acetate [ 6, 7] and (Z)-and(E)-8-dodecene- 1-yl-acetate [8] are well known in the literature.Also, the synthesis of (11Z, 13Z)-hexadodecadien-1-yl was studied in [9]. Experimental part GS-MS analysis were performed on a GS-MS spectrometer Agilent 7890A GC& 5975 GS/MS Serie MSD. 1 H-NMR (300 MHz) and 13 C-NMR (75 MHz) spectra were recorded at rt in CDCl 3 on a Bruker 300 MHz spectrometer, using TMS line as reference. A Perkin Elmer Spectrometer Model 700 was used for IR spectra. 6-Bromo-hexane-1-ol (4) To a solution 59 g (0.5 mole) of 1,6-hexane-diol solved in 300 mL benzene was added 86 mL hydrobromic acid 47%. The reaction mixture was refluxed for 2.5 h. The organic layer was separated and washed with brine, saturated NaHCO 3 solution and dried over anhydrous MgSO 4 . After distillation of the solvent, 44.1g of 6-bromo- hexane-1-ol (4) were obtained. Yield: 75%, GC purity: 99%. Mass spectrum (m/z. %): 162(1.47), 135(12.74), 133(13.72), 108(3.92), 109( 4.41), 96(1.96), 94(1.96), 84(3.92), 83(57.84), 82(16.17), 81(4.9), 80(< 1), 79(1.96), 69(15.68), 68(2.45), 67(13.72), 57(6.86), 56(8.82), 55(100), 54(11.76), 53(8.82), 51(1.96), 50(< 1), 45(2.94), 44(4.41), 43(19.6), 42(28.43), 41(80.39), 40(7.35), 39(41.17), 38(2.94), 31(50.98), 29(27.45), 28(9.8). 1-tert-Butoxy-6-bromo-hexane (5) To a solution 33.1 g (182 mmoles) of 4-bromo-hexane- 1-ol (4) and 154 mL tert-butyl-methyl-ether was added dropwise 9.3 mL concentrated sulfuric acid under cooling. The reaction mixture was maintained at 40°C. The reaction was checked by TLC on silica gel G (benzene:ether 2:1, detection with H 2 SO 4 d= 1.25). The reaction mixture was diluted with water. After removal of the tert-butyl-methyl- ether under reduced pressure, the mixture was extracted with ethyl ether (3x50 mL). The combined ethereal extracts were washed with saturated NaHCO 3 solution up to basic and dried over Na 2 SO 4 . After the removal of the solvent, 28.5 g of 1-tert-butoxy-4-bromo-hexane (5) were obtained. Yield: 84%, GC purity: 97%. Mass spectrum (m/z. %): 221(13.72), 181(< 1), 163(13.23), 135(< 1), 121(< 1), 107(< 1), 83(44.12), 67(< 1), 57(100), 41(51.47), 29(24.51). 1-tert-Butoxy-oct-7-yne (6) All operations were performed in an inert gas atmosphere and under stirring. To a stirred and cooled (0°) suspension of 5.35 g (58 mmoles) lithium acetylide-ethylendiamine complex in 29 mL anhydrous dimethyl sulfoxide was slowly added (60 min) 6.87 g (28 mmoles) compound 5 . The reaction mixture was stirred at room temperature for 6h, then it was poured into ice water and extracted with hexane. The combined hexane extracts were washed with water, brine and dried over MgSO 4 . After removal of the solvent, 4.3 g of 1-tert-butoxy-oct-7-yne (6) were obtained. Yield: 76 %, GC purity: 94 %. Mass spectrum (m/z, %): 168(< 1), 167(22.55), 149(< 1), 137(< 1), 126(< 1), 110(< 1), 109(13.72), 93(< 1), 81(16.67), 67(52.94), 57(100), 43(20.59), 41(53.92), 29(19.61).