Structurally Related to Carbohydrates

Generally, it may be observed that the first bands of the alcohols and ethers fall approximately in the same position, and the small differences in position are not related to structure. From the spectra, there is evidence of predissociation, but the evidence is less marked for the ethers than for compounds which contain the hydroxyl group. The transitions originate from the non-bonding electrons of the oxygen atom, and may be of the N Q or N R type in the first band. Since the second bands of the alcohols fall below 1660 A., they may be complicated by transitions involving bonding electrons. 

From a study of the absoiption spectra and reaction products, it has been postulated - that the photochemical decomposition of alcohols is 

The region of 2000-1667 A. corresponds to an absorption energy of 143-189 Kcal., suflBcient to break any bond in the molecule, or to break two bonds, provided that the energy is properly distributed. If transfer of energy is neglected, probable primary reactions are as follows. 

The same principal products were detected in the photolysis of an alcohol and its corresponding ether. For example, ethanol and ethyl ether gave ethylene (process a), acetaldehyde (process b), and formaldehyde (process b). In an attempt to find out whether the formaldehyde and 

The photosensitized oxidation of alcohols has been extensively studied, because the fading and tendering of dyes absorbed on cellulosic fibers are believed to proceed by way of such processes. It is possible, also, that the initial step in the photosynthetic reaction is an oxidation-reduction involving metastable, excited chlorophyll. 

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Inositols provide a good starting-point for studying the binding of such metal ions as Gd " " and Mn " to carbohydrates, because each is unique, they are structurally related to carbohydrates, and they do not contain other functional groups (carboxyl, amino) which may also interact with metal... 

The main compounds yielded by flash pyrolysis are transformation or degradation products of biogenic precursors. Next to the amino acid glycine I most of the identified compounds are structurally related to carbohydrates, amino acids and condensed molecules of both components resulting from Maillard reactions. Examples include furfural 2, methylfurfural 3 and pyrrol-2-carboxaldehyde 4 (see Fig. 3). 

Several dozens of aldolases have been identified so far in nature [23,24], and many of these enzymes are commercially available at a scale sufficient for preparative applications. Enzyme catalysis is more attractive for the synthesis and modification of biologically relevant classes of organic compounds that are typically complex, multifunctional, and water soluble. Typical examples are those structurally related to amino acids [5-10] or carbohydrates [25-28], which are difficult to prepare and to handle by conventional methods of chemical synthesis and mandate the laborious manipulation of protective groups. 

Another important metal-containing enzyme, chlorophyll (structure 16.24), is structurally related to myoglobin and is responsible for photosynthesis, the conversion of water and carbon dioxide, with the aid of solar energy, to carbohydrates. 

Many glycosidase inhibitors are structurally related to natural substrates, closely resembling carbohydrates. However, several exceptions to this generalization are known. These include such diverse structures as the diterpene andrographolide and its analogues (38, Scheme 12),134 3,21-di-O-acetylcichoridiol (39, a triterpenoid),135 acridone alkaloids, and oriciacridone (40).136... 

The majority of more recent structures relate to the sialyl Lewis X blood group carbohydrate receptor function for the selectin family of eukaryote lectins that mediate leucocyte-endothelial cell interaction during the initial stages of extravasation ( neutrophil rolling ) (20). These structures are the sialyl Le , Le, and Le sequences and several 6 sulfo GlcNAc and 3 sulfo Gal derivatives found in both protein and sphingolipid glycoconjugates (21-24). 

Anorectic drugs act mainly on the satiety centre in the hypothalamus (1). They also have metabohc effects involving fat and carbohydrate metaboUsm. Most of them are structurally related to amfetamine and increase physical activity. Their therapeutic effect tends to abate after some months, and part of this reduction in effect may be due to chemical alterations in the brain. Fenfluramine commonly produces drowsiness in normal doses, but has stimulaut effects in overdosage. Dexamfetamine, phenmetrazine, and benzfetamine all tend to cause euphoria, with a risk of addiction. Euphoria occasionally occurs with amfepramone (diethylpropion), phentermine, and chlorphentermine, but to a much lesser extent. Some adverse effects are due to sympathetic stimulation and gastrointestinal irritation these may necessitate withdrawal but are never serious. There are interactions with monoamine oxidase inhibitors and antihypertensive drugs. 

Conalbumin comprises 3-16% of the egg-white from various species of birds. It is structurally related to plasma serotransferrin, the polypeptide chain being coded by the same structural gene [27], but the carbohydrate moiety being different (see section 3.1.3). Because of the close relationship of these two proteins, the name ouotransferrin is now used in place of conalbumin. 

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