Acetamidofurans, acetamidopyrones, and acetamidoacetaldehyde from pyrolysis of chitin and n-acetylglucosamine

Pyrolysis of N-acetylglucosamine in vacuo gives a tar from which 3-acetamidofuran, 3-acetamido-5-acetyl-furan and acetamidoacetaldehyde can be isolated in 5%, 2% and 3% yield respectively. Capillary column pyrolysis—gas chromatography—mass spectrometry analysis of N-acetylglucosamine indicated the presence of four other nitrogen-containing compounds, in addition to acetamide. These compounds have been tentatively assigned structures from their mass spectra, and are 3-acetamido-5-methylfuran, acetamido-substituted 2- and 4-pyrones and hydroxydihydropyran-4-one. The mass spectra of tha above-mentioned acetamidofurans have been fully interpreted, and their fragmentations are discussed. It is suggested that both acetamidofurans are unique chitin and N-acetylglucosamine pyrolysis products, and better indicators than acetamide for the presence of chitin in biological or geochemical samples.