Hydrochloric Acid → 4-Methyl-6-hydroxy-2,4-hexadien-1-al

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Reaction Steps

Trans 3-methyl-3-penten-1-in-5-ol is reacted with orthoformic acid ethyl ester. The resulting 1,1-diethoxy-4-methyl-4-hexen-2-in-6-ol is partially hydrogenated by means of a deactivated palladium catalyst, followed by treatment with hydrochloric acid to form 4-methyl-6-hydroxy-2,4-hexadien-1-al. Reaction with α-carbethoxy-ethylene-triphenyl-phosphoran yields 2,6-dimethyl-8-hydroxy-2,4,6-octatrien-1-oic acid ethyl ester, which can be oxidized by means of manganous oxide to 2,6-dimethyl-8-oxo-2,4,6-octatrien-1-oic acid ethyl ester.

Provenance & Evidence