Tert-Butylamine → UV-328

Participants

Reaction Steps

To a 500 mL capacity stainless steel autoclave equipped with a stirrer, external heating jacket and internal heating and cooling coils are added 5.0 g (0.013 mole) of 2-nitro-2'-hydroxy-3',5'-di-tert-amylazobenzene, 0.25 g (dry weight) of (4% Pd/C+1% Pt/C) catalyst, 3.82 g (0.052 mole, 4 equivalent) of tert-butylamine, 5.16 g (0.039 mole, 3 equivalent) of aqueous hypophosphorous acid and 150 mL of methanol. The autoclave is purged with nitrogen gas and then hydrogen gas and then sealed and charged with hydrogen gas to a pressure of 53,000 Kg/m2. The reaction is stirred at room temperature and at 53,000 Kg/m2 pressure (recharging if necessary) for one hour. After one hour the temperature is raised to 50° C. and held at the same temperature and pressure for an additional 12 hours. Then the autoclave and its contents are cooled to 45°-47° C., removed and filtered through a Celite filter-aid pad to remove the catalyst. The catalyst and the residue on the filter pad are further washed with some ethyl acetate for complete recovery of the product. The organic solvents are removed on a rotary evaporator. The residue is diluted with about 500 mL of brine (saturated aqueous sodium chloride solution) and treated with hydrochloric acid dropwise until the Congo Red Indicator paper turns blue. The light brown insoluble material (the desired product) was filtered on a sintered glass funnel, washed with cold distilled water to remove any contaminated salt, and air-dried. This crude solid material was recrystallized from isopropanol/water to obtain 4.56 g of 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole as white solid (yield 99%; melting point 80°-81° C.) showing a retention time of 25.89 min. in HPLC analysis.

Provenance & Evidence