Hydrochloric Acid → HCID 21311874, compound

Participants

Reaction Steps

A solution of 1.82 g of 1-(4-methoxyphenyl)-3-(triphenylphosphoranylidene-hydrazono)-acetone in 12 ml of tetrahydrofuran is mixed with 0.84 g of pulverized sodium nitrite and the mixture is diluted with 5 ml of water. The resulting suspension is cooled to 0°-5°, treated dropwise over the course of 7 minutes with 8.8 ml of 2N hydrochloric acid and then kept for a further 30 minutes at 0°-5°. The aqueous phase is twice washed with methylene chloride; the combined organic solutions are washed with a saturated aqueous sodium chloride solution, dried over sodium sulphate and evaporated under reduced pressure. The oily residue is chromatographed on 40 g of acid-washed silica gel. A small quantity of a by-product is eluted with benzene and, using 1200 ml of a 95:5-mixture of benzene and ethyl acetate, the 4-methoxybenzylglyoxal is obtained in the form of the hydrate, which is an oily product; infra-red absorption spectrum (in methylene chloride): characteristic bands at 2.96μ, 5.79-5.84μ, 6.23μ and 6.63μ. The anhydrous product melts at 139°-140° after recrystallisation from a mixture of chloroform and hexane; ultra-violet absorption spectrum:λmax 333 mμ (in ethanol or hydrochloric acid/ethanol) and λmax 367 mμ (in potassium hydroxide/ethanol); ethanol); infra-red absorption spectrum (in methylene chloride): characteristic bands at 3.00μ, 5.97μ, 6.09μ, 6.24μ, 6.61μ and 7.15μ.

Provenance & Evidence