Ring-Opened Azlactone Photoiniferters for Radical Polymerization

Dithiocarbamic-5-oxo-4,5-dihydro-oxazole derivatives have been prepared that are useful in controlled free radical polymerization reactions. When these azlactone photoiniferters were used in the polymerization of styrene or methyl methacrylate, the Mr, as a function of reaction time was constant. 

Preparation of 2-(2-Chloro-Acetylamino)-2-Methyl Propionic Acid 

A reaction vessel containing 2-aminoisobutyric acid (1.61 mol), sodium hydroxide (1.61 mol), and 800 ml of water was cooled to 5°C and treated with chloroacetyl 

A mixture consisting of the Step 1 product (0.100 mol), triethylamine (0.110 mol), and 100 ml of acetone was cooled in an ice bath and then treated with ethyl chloroformate (0.110 mol) over a period of 10 minutes. The reaction mixture was warmed to ambient temperature and stirred for 2 hours. The mixture was filtered and the filtrate concentrated. The residue was treated with 200 ml of hexane, re-filtered, and re-concentrated. It was distilled, and the product was isolated as a colorless oil in 82% yield, BP = 59-60°C at 7 mmHg. 

Preparation of Diethyl-Dithiocarbamic Acid 4,4-Dimethyl-5-Oxo-4,5-Dihydro-Oxazol-2-Ylmethyl Ester 

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Title Ring-Opened Azlactone Photoiniferters for Radical Polymerization... 

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