反应详情

Following the procedure of Example XII, 4-carbomethoxy-2-ethyl-5-methyl-2,3-dihydrofuran was obtained by the reaction of 1,4-dichlorobutene-2 (500 grams) and methyl acetoacetate (500 grams). Five hundred grams potassium hydroxide and 30 grams tricaprylylmethylammonium chloride were also employed for the reaction which was carried out in sulfolane. One hundred thirty grams crude 4-carbomethoxy-5-methyl-2-vinyl-2,3-dihydrofuran obtained from the reaction was hydrogenated at 40 psig using 1 weight percent supported catalyst (5% Pd on carbon). Two distillations of the crude product afforded 4-carbomethoxy-2-ethyl-5-methyl-2,3-dihydrofuran in 99.4 percent purity (B.P. 124°-126° C. @ 37 mm Hg; nD25° 1.4708). The product had a very natural herbaceous odor making it suitable for lavender and chamomile formulations. The product also exhibited a very desirable safrole-like character which was not evident in the unhydrogenated precursor. The structure of the product ##STR19## was confirmed by infrared and nuclear magnetic resonance spectroscopic analysis.