Hydrochloric Acid → HCID 14745571, compound

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Reaction Steps

2-Phenylazophenyltellurium trichloride (Preparation A) (10.4 g, 0.025 mole) was suspended in ethanol (100 ml) in a flask equipped with a nitrogen gas inlet, magnetic stirrer, reflux condenser, and powder addition funnel. While stirring, under a nitrogen atmosphere, at room temperature, sodium borohydride (3.8 g, 0.10 mole) was added in increments at a rate sufficient to maintain a vigorous exothermic reaction. Stirring of the reaction mixture at room temperature was continued for 30 minutes after the addition was complete, maintaining the nitrogen atmosphere. A thermometer was inserted while still maintaining a nitrogen atmosphere and propionic anhydride (3.9 g, 0.03 mole) was added dropwise. The reaction temperature rose from 25° C. to 30° C. Upon completion of the addition, stirring was continued until the temperature returned to 25° C. Concentrated hydrochloric acid (25 ml) was added dropwise to the reaction mixture, resulting in formation of a black solid. The temperature rose to around 50° C. Stirring was continued until the temperature returned to 25° C. The black solid was removed by filtration, and washed with ethanol, and discarded. The filtrate was concentrated in a rotary evaporator, diluted with about an equal volume of water, filtered through a Celite® pad, and neutralized to a pH of about 7 with sodium bicarbonate. Extraction with diethyl ether and removal of the ether from the extracts left a red, oily semisolid, which was purified by being dissolved in dichloromethane and being applied to a thick layer silica gel chromatography plate. An ultraviolet absorbing substance separated as a pale yellow oil. This was determined to be pure by thin layer chromatography. The infrared and nuclear magnetic resonance spectra were in agreement with that expected for the structural formula.

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