Amadori compound, occurrence

Tobacco leaf has a complicated chemical composition including a variety of polymers and small molecules. The small molecules from tobacco belong to numerous classes of compounds such as hydrocarbons, terpenes, alcohols, phenols, acids, aldehydes, ketones, quinones, esters, nitriles, sulfur compounds, carbohydrates, amino acids, alkaloids, sterols, isoprenoids [48], Amadori compounds, etc. Some of these compounds were studied by pyrolysis techniques. One example of pyrolytic study is that of cuticular wax of tobacco leaf (green and aged), which was studied by Py-GC/MS [49]. By pyrolysis, some portion of cuticular wax may remain undecomposed. The undecomposed waxes consist of eicosyl tetradecanoate, docosyl octadecanoate, etc. The molecules detected in the wax pyrolysates include hydrocarbons (Cz to C34 with a maximum of occurrence of iso-Czi, normal C31 and anti-iso-C32), alcohols (docosanol, eicosanol), acids (hexadecanoic, hexadecenoic, octadecanoic, etc ). The cuticular wax also contains terpenoids such as a- and p-8,13-duvatriene-1,3-diols. By pyrolysis, some of these compounds are not decomposed and others generate closely related products such as seco-cembranoids (5-isopropyl-8,12-dimethyl-3E,8E,12E,14-pentadecatrien-2-one, 3,7,13-trimethyl-10-isopropyl-2,6,11,13-tetradecatrien-1al) and manols. By pyrolysis, c/s-abienol, (12-Z)- -12,14-dien-8a-ol, generates mainly frans-neo-abienol. 

Heyns and Stumme260 have provided further evidence as to the widespread occurrence of this type of rearrangement for compounds in which the a-hy-droxy carbonyl group is either terminal or non-terminal, and a detailed electronic mechanism for this rearrangement has been put forward.264 Confirmatory evidence for the formation of products of the Amadori type... 

Further work on chemical structure and reactivity might well include an examination of the possibility of occurrence of an Amadori rearrangement in the case of the glycosyl ureides. In addition, studies of the tautomerism of glycosyl ureides under various conditions of pH and of the neighboring-group effect would be of value in the interpretation of many of the seemingly unorthodox chemical reactions of these compounds. 

Owing to the presence of active methylene compounds and ammonia, the conditions of these reactions are favorable for the occurrence of an Amadori rearrangement, and, on this basis, the structures proposed by Voto6ek and Valentin have been questioned.The products could be derived either from glycosylamines or from the 1-amino-l-deoxyketoses that result from their Amadori rearrangement. 

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