Triethylamine → Tyramine hydrochloride

Participants

Reaction Steps

The product of Example 1, 5.5 mg. (0.014 millimoles) is dissolved in about 2.5 ml. of dimethylformamide and 1.4 ml. of 1 N sodium hydroxide (0.014 millimoles) and 0.2 ml. of triethylamine (0.014 millimoles) are added. The reaction flask is cooled in an ice bath and 0.2 ml. (0.015 millimoles) of isobutyl chloroformate is added. The mixture is stirred gently for 20 min. to allow formation of the mixed anhydride. A solution of 2.4 mg. (0.014 millimoles) of tyramine hydrochloride in dimethylformamide is prepared, neutralized with 1.4 ml. of 1 N sodium hydroxide, and added to the reaction mixture. The reaction mixture is allowed to warm to room temperature with stirring for 60 min. The progress of the amidification reaction is measured by thin-layer chromatography using the solvent system chloroform:methanol:acetic acid (40:10:0.5) in which the starting materials remain near the origin and the product of Formula V migrates with Rf 0.6. After completion of the reaction, the mixture is dried on a rotary evaporator and the residue is resuspended in a small amount of dimethylformamide. Water is added, and the mixture is neutralized with 0.5 M sodium carbonate and the product extracted into ether. The ether phase is dried, the residue dissolved in methanol, and the product purified by thin-layer chromatography using the above solvent system. The major band which appears at Rf 0.6 is eluted from the silica gel with ethanol, concentrated and rechromatographed. The resulting material is used without further purification or characterization for iodination as described below.

Provenance & Evidence