Oxazolones react most readily with compounds containing primary amino and hydroxyl, secondary amino and hydroxyl, and sulf-hydryl groups. Oxazolones probably react with the following groups in the protein molecule; free amino, phenolic, hydroxyl, sulfhydryl and guanidino. Methods are given for preparing the following compounds with d,l-benzoyl-[alpha]-alanine; isopropyl ester, m. 79-80[degree]; benzyl ester, m. 88-89[degree]; 1-menthyl ester, m. 104-5[degree]; phenyl ester, m. 131-2[degree]; [beta]-naphthyl ester, m. 164-5[degree]; thiophenol ester, m. 130-1[degree]; ethyl amide, m. 136-7[degree]; monomethylanilide, m. 119-20[degree]; piperidide, m. 114-15[degree]; and d,l-benzoyl-[alpha]-alanyl-l-proline, m. 228-230[degree], and d,l-benzoyl-alanyl-salicylic acid, m. 152-53[degree].