4.4- dimethyl-2-substituted-5 -oxazolones

Ring opening of 2-aryl-5(477)-oxazolones 230, obtained from A-acylglycines, with A,A-dimethyl-2-aminoethanol provides choline esters of A-substituted amino... 

The simplest amino acid in the series, dimethylglycine or 2-aminoisobutyric acid (Aib), has been widely studied and 4,4-dimethyl-2-substituted-5(4//)-oxazolones have been used to incorporate Aib into model small peptides and into hnear oligopeptides in order to perform structural smdies. Dipropylglycine (Dpg) has been incorporated into model peptides using 4,4-dipropyl-2-(trifluoromethyl)-... 

Reaction of hippuric acid and A, A -dimethylacetamide in the presence of phosphorous oxychloride affords 4-[l-(dimethylamino)ethylidene]-2-phenyl-5(4//)-oxazolone 424 " ° that is converted to 4-benzoylaminopyrazolones 425 via ring opening and cyclization with hydrazines (Scheme 7.139). " ° 4-(A, Af-Dimethyl-aminomethylene)-2-substituted-5(477)-oxazolones react similarly. 

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