Hydrochloric Acid → 6-[4-(3,6-Dihydro-4-phenyl-1(2H)-pyridinyl)-1-butynyl]-3-pyridinamine

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Reaction Steps

A solution of 1,2,3,6-tetrahydro-1-[4-(5-nitro-2-pyridinyl)-3-butynyl]-4-phenylpyridine (Example 9) (2.0 g, 0.006 mol), reduced iron (3.1 g), and 0.10 mL of concentrated hydrochloric acid in 30 mL of 95% ethanol and 10 mL of water is heated at 80° C. with vigorous stirring for 30 minutes. The hot solution is filtered through diatomaceous earth (Celite), and the filter cake is washed with 300 mL of hot ethanol. The solvent is removed under reduced pressure, and the residue is partitioned between 50 mL of dichloromethane and 50 mL of saturated aqueous sodium bicarbonate. The aqueous layer is extracted with dichloromethane and the combined organic layers are washed with water and dried (sodium sulfate), and the solvent is removed in vacuo. The residue is chromatographed (silica gel, 2% methanol/98% dichloromethane) to give the title compound, containing 0.3 mol of water; mp 135.5°-137° C.

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