For many compounds, it is possible to establish alternative synthetic routes.The ones actually used depend on many factors, such as cost and availability of starting materials, the amount of energy needed to make the reaction proceed at a satisfactory rate, and the cost of separating and purifying the end products.Join Britannica's Publishing Partner Program and our community of experts to gain a global audience for your work! It is the process by which many substances important to daily life are obtained.
In industry, synthesis is used to make products in large quantity.chemical synthesis usually involves the breaking of existing bonds and the formation of new ones.
Synthesis of a complex molecule may involve a considerable number of individual reactions leading in sequence from available starting materials to the desired end product.
Moreover, knowledge of the reaction mechanism and the function of the chemical structure (or behaviour of the functional groups) helps to accurately determine the most-favoured pathway that leads to the desired reaction product.
A goal in planning a chemical synthesis is to find reactions that will affect only one part of the molecule, leaving other parts unchanged.
Despite the fact that it is the cheapest, safest and most non toxic solvent in the world, its presence is generally avoided through the dehydrative drying of substrates and solvents.
The use of water as a medium for organic reactions is therefore one of the latest challenges for modern organic chemists. Rao and co-workers report a new methodology for a high yielding (90-96%) chemoselective oxidation of sulphides to sulphoxides using β-cyclodextrin and N-bromosuccinimide (NBS), at room temperature, and under neutral conditions. Using a chemoenzymic oxidation methodology, Tong and co-workers successfully epoxidised water-soluble (81-93% yield) and lipophilic alkenes (60-99% yield). An asymmetric transfer hydrogenation of aromatic ketones using the Noyori-Ikariya Ru-Tsdpen catalyst (3) is now reported by Xiao and co-workers. Stavber and co-workers used Selectfluor (4), a commercial, stable and water-soluble fluorinating reagent, for the selective synthesis of a series of vicinal fluorohydrins 5 (from phenyl substituted alkenes, 84-86% yield), α-fluoroketones 6 (from ketones, 85-90% yield) and 7 (from 1,3-diketones or β-ketoesters, 87-91% yield) and fluorodienones 8 and 9 (from phenols, 74-78% yield) (Org.
The present Highlight presents a brief selection of different organic reactions run in an aqueous medium from the literature of the past two years. Chemoselectivity (no overoxidation to sulphones) is explained by the formation of reversible host-guest complexes between the sulphoxide and catalytic amounts of β-cyclodextrin (Tetrahedron Lett. Commercial Glucose Oxidase (GOx) is used to produce in situ hydrogen peroxide via the enzymic oxidation of glucose. The reaction proceeds with high yield (99%) and enantioselection (85-97% ee) using an aqueous solution of formic acid and Et Nano-palladium particles (ARP-Pd) supported on an amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin was found to effect the hydrogenation of styrene and cinnamic derivatives in high yield (81-99% yield).
An excellent review about stereoselective organic reactions in water have been recently published (Chem. The addition of catalytic amounts of sodium bicarbonate/manganese sulphate increases the rate and the yield of the process. Uozumi and co-workers found also that this catalytic system can be used in the hydrodechlorination of chloroarenes (81-99% yield), providing a recyclable, clean and safe protocol for the detoxification of aqueous pollutants (Org.
Chemists synthesize chemical compounds that occur in nature in order to gain a better understanding of their structures.
Synthesis also enables chemists to produce compounds that do not form naturally for research purposes.