Hydroxamic acid esters isocyanates

An alkyl isocyanate annulates an ester-hydroxamic acid in high yield without the need for external heat. 

Carbamyl chloride, N,N-dimethyl-. See Dimethylcarbamyl chloride Carbamyl hydroxamate. See Hydroxyurea Carbanil. See Phenyl isocyanate Carbanilaldehyde. See N-Phenylformamide Carbanilic acid, m-chloro-, 1-methyl-2-propynyl ester. See Chlorbufam d-(-)-Carbanilic acid (1-ethylcarbamoyl) ethyl ester. See Carbetamide Carbanilic acid, m-hydroxy-, methyl ester, m-methyl carbanilate. See Phenmedipham Carbanilic acid isopropyl ester. See Propham Carbanilide. See N,N -Diphenylurea Carbani Ii de, 4,4 -dichIoro-3-(trifluoromethyl)-. See Cloflucarban... 

The common methods for the S5mthesis of p-lactams are cycloaddition reactions such as the Staudinger s ketene-imine cycloadditions, ester enolate-imine cycloadditions, alkyne-nitrone cycloadditions (Kinugasa reaction), alkene-isocyanate cycloadditions, and Torii s cyclocarbonylation of allyl halides with imines. Several cyclizahon reactions of p-amino esters, p-amino acids, p-hydroxamate esters, and a-diazocarbonyls have been developed for the formation of p-lactam ring. N,N-Disubstituted a-haloamides cyclize by C3-C4 bond formation leading to the formation of P-lactam ring. 

---