p-Toluenesulfonic acid → HCID 20191510, compound

Participants

Reaction Conditions

Reaction Steps

4-Carbethoxy-2,5-dimethyl-2-propyl-2,3-dihydrofuran was prepared by the acid-catalyzed rearrangement of ethyl-2-acetyl-4-methyl-2-heptenoate. The ethyl-2-acetyl-4-methyl-2-heptenoate was obtained by reacting 390 grams (3 moles) ethylacetoacetate with 300 grams (3 moles) 2-methylvaleradehyde in the presence of a small amount (10.2 grams; 0.12 mole) piperidine. For the rearrangement, 100 grams (0.47 mole) of the ethyl-2-acetyl-4-methyl-2-heptenoate was combined with 4.4 grams (0.023 mole) p-toluenesulfonic acid and 100 mls toluene. The mixture was heated at reflux (120° C.) for about 2 hours and worked up in accordance with the procedure of Example XXIV. Short path distillation of the crude product yielded 4-carbethoxy-2,5-dimethyl-2-propyl-2,3-dihydrofuran (B.P. 98°-100° C. at 2.5 mm Hg). The product had a pleasing cis-jasmine-like (jasmone, celery, jasmine absolute) odor. The structure ##STR25## was confirmed by infrared and nuclear magnetic resonance spectroscopy.

Provenance & Evidence