Ammonium Chloride → HCID 131713995, compound

Participants

Reaction Steps

The hemiacetal obtained in Example 6, dl-5-hydroxy-2,2-dimethyl-8-(1,1-dimethylheptyl)-3,3a,4,5-tetrahydro-2H-pyrano[4,3,2-de]benzopyran, (491 mg, 1.42 mmole) was dissolved in 10 ml of diethyl ether and cooled in an ice bath for 15 minutes. From a syringe 1.58 ml of 2.9M methylmagnesium iodide was added slowly with stirring. The reaction mixture was allowed to warm to room temperature and stirred for three hours. Ammonium chloride crystals (ca. 100 mg) was added to consume the unreacted Grignard reagent and the mixture stirred for 20 minutes. Ethyl acetate, 75 ml, and water, 50 ml, were added, the mixture stirred for a few minutes, and the layers separated. The aqueous layer was extracted with 50 ml of ethyl acetate and the combined organic layers washed with 50 ml each of water, brine and water again. The organic layer was dried over anhydrous magnesium sulfate and solvent evaporated in vacuo to provide 525 mg of crude oil. The oil was chromatographed on a pair of 2 mm thickness silica gel plates employing an ethyl acetate/pentane (1:3 by volume) solvent system. The region with Rf 0.09-0.21 was extracted with 200 ml of ethyl acetate for 2-3 hours to afford 300 mg of product (58.3%).

Provenance & Evidence