Carbohydrate chemistry carboxylic acid

Another interesting variant of Claisen rearrangement has been introduced by Ireland [149], and used by his group in carbohydrate chemistry. The starting compound is again an allylic alcohol that is esterified by a suitable carboxylic acid. This ester is enolized in basic medium, and quenching of the intermediate enolate at low temperature gives a ketene silyl... 

Some of the key reactions in carbohydrate chemistry involve oxidation of aldoses to carboxylic acids. You will encounter some of these if you work Exercise 20-1. There is a simple nomenclature system for these acids. In abbreviated notation, the products of oxidation at Cl, C6, or both are called ... 

Since we are interested in the sulfur-carbon chemistry of diagenesis, the relevant geochemical processes are limited to those occurring within the very narrow temperature span of approximately 0 to 60 °C. The reactions must occur under hydrous conditions although in media having at least some capacity to accommodate lipophilic source molecules as a result of the presence of substances such as low grade carbohydrates and small carboxylic acids or their salts. If the sulfur source is a form of reduced sulfur from active microbial reduction of sulfate, the pH will range from near neutral... 

Radicals from Carboxylic Acids. Carboxy radicals appear to be involved in three venerable reactions in preparative carbohydrate chemistry, the Ruff degradation, the Hunsdiecker reaction and the Kolbe electrolysis. 

Much of the chemistry of that group of compounds referred to as carbohydrates (compounds of carbon corresponding to, approximately, C(H20) ) is a function of the numerous hydroxyl groups that adorn their structures. However, despite the view that they be considered as polyhydroxy derivatives of carbon (polyols), their rich chemistry must include reference to reactions of the carbonyl group (aldehydes, ketones, and carboxylic acids). Therefore, elaboration of the chemistry of carbohydrates is postponed to Chapter 11. 

The design of fluorescent sensors is of major importance because of the high demand in analytical chemistry, clinical biochemistry, medicine, the environment, etc. Numerous chemical and biochemical analytes can be detected by fluorescence methods cations (H+, Li+, Na+, K+, Ca2+, Mg2+, Zn2+, Pb2+, Al3+, Cd2+, etc.), anions (halide ions, citrates, carboxylates, phosphates, ATP, etc.), neutral molecules (sugars, e.g. glucose, etc.) and gases (O2, CO2, NO, etc.). There is already a wide choice of fluorescent molecular sensors for particular applications and many of them are commercially available. However, there is still a need for sensors with improved selectivity and minimum perturbation of the microenvironment to be probed. Moreover, there is the potential for progress in the development of fluorescent sensors for biochemical analytes (amino acids, coenzymes, carbohydrates, nucleosides, nucleotides, etc.). 

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