Sulfuric Acid → 5-Methyl-2-hepten-4-one (natural)

2-Butylmagnesium bromide is prepared from 24.32 g of magnesium filings and 137 g of 2-bromobutane in 100 ml of ether. 56 g of crotonaldehyde dissolved in 60 ml of ether are added dropwise to the solution at 0° to 10° C. The mixture is then boiled for 2 hours under reflux temperature. Thereafter it is cooled, the batch decomposed with ice water/hydrochloric acid and the product extracted, neutralized and distilled. 56 g of 5-methyl-hept-2-en-4-ol of boiling point 70° C./18 mb are obtained. To 52 g of this alcohol there is slowly added a mixture of 40.34 g of sodium dichromate and 54.1 g of sulphuric acid, while cooling with ice. After a further hour's reaction at room temperature, the batch is extracted with ether, the organic phase is washed until neutral, the solvent stripped off and the crude product distilled. Redistillation using a slotted tube column gives 17.2 g of 5-methyl-hept-2-en-4-one of boiling point 72° C./20 mb.

1. temperaturewhile cooling with ice
2. customAfter a further hour's reaction at room temperature
3. extractionthe batch is extracted with ether
4. washthe organic phase is washed until neutral, the solvent
5. distillationthe crude product distilled
6. distillationRedistillation

ORDレコード

ord-b736b6dc20184394b7860d2648656a47

出典データセット

uspto-grants-1987_03

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US04654168