Hydrochloric Acid → 4,4-Dimethyl-7-(3-methyloctan-2-yl)-1,4-dihydro-3H-thieno[3,4-c][1]benzopyran-9-ol

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Reaction Conditions

Reaction Steps

A suspension of 6.0 g. (0.017 mole) of the pyrone of Example 26, part B, in 150 ml. of benzene was added to a Grignard reagent prepared by adding bromomethane to 8.47 g. (0.36 mole) of magnesium turnings in 100 ml. of ether. The mixture was heated at 45°C for 24 hours and then decomposed by the addition of dilute hydrochloric acid. The organic layer was separated, washed with water, dried over sodium sulfate and evaporated to give a gummy residue. This material, as the triol, was dissolved in benzene and refluxed for 3 hours with a few crystals of p-toluenesulfonic acid. The benzene solution was washed, dried and evaporated to give a dark gum which was chromatographed using Florisil (60-100 mesh) and graded ether/petroleum ether solvent mixtures. 2.6 g. (42%) of colorless gum was obtained. The material was shown to be pure by TLC (20% ether/petroleum ether) and exhibited λmaxEtOH 284 mμ (logε 4.157). The IR and NMR spectra were in agreement with the proposed structure.

Provenance & Evidence