Methanol → 5-Methyl-2-(prop-1-en-2-yl)hex-4-enoic acid

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Reaction Steps

In a nitrogen atmosphere, a mixture of the 125 mmol of sodium hydride, obtained from 5.00 g of a 60% suspension in mineral oil by removal of mineral oil with n-hexane washing, and 30 ml of toluene was heated to reflux with stirring, and subjected to dropwise addition of 20.0 g of 2-methyl-3-buten-2-yl senecioate having a purity of 96.9% over one hour. After reflux was continued for 22 hours, the reaction mixture was cooled to room temperature, and 10 ml of methanol and 40 ml of water were added dropwise thereto. The organic phase was extracted with water and then discarded. The aqueous phases were combined and then made acidic with 20% hydrochloric acid, followed by extraction with diethyl ether. The diethyl ether solution was subjected to typical work-up including washing, drying and concentration to obtain 20.0 g of the crude product having a purity of 3.6% on basis of stoichiometric amount. The content of each isomer in the crude product was analyzed using capillary GC analysis and GC-MS under the similar conditions as in Example 1. The results are shown in Table 2.

Provenance & Evidence