Chemical Synthesis

(redirected from Synthesis Reaction)

chemical synthesis

[′kem·i·kəl ′sin·thə·səs]
(chemistry)
The formation of one chemical compound from another.

Synthesis, Chemical

 

the planned production of complex compounds from simpler compounds based on a knowledge of the reactants’ chemical structure and reactivity. Chemical synthesis usually implies a sequence of several chemical processes (steps).

In the early period in the development of chemistry, chemical synthesis was carried out mainly for inorganic compounds and was fortuitous in nature. The synthetic production of complex substances became possible only after knowledge had been gained on the composition and properties of the substances, knowledge derived from the development of organic and physi-cochemical analysis. Of cardinal importance were the first syntheses of organic compounds, namely, oxalic acid and urea, by F. Wôhler in 1824 and 1828. Attempts to synthesize analogues of complex natural compounds in the mid-19th century, when a unified theory on the structure of organic compounds did not exist, indicated only the possibility, in principle, of synthesizing such compounds as fats (P. E. M. Berthelot) and carbohydrates (A. M. Butlerov). Indigo, camphor, and other relatively simple compounds were subsequently synthesized in accordance with a theory, as were more complex molecules, such as certain carbohydrates, amino acids, and peptides.

In the 1920’s, the work of R. Robinson on the preparation of a series of complex molecules by paths that imitated those governing the formation of the molecules in nature proved to be of seminal importance to the methodology of chemical synthesis. A rapid development of chemical synthesis began in the late 1930’s, first in the area of steroids, alkaloids, and vitamins and then in the area of isoprenoids, antibiotics, polysaccharides, peptides, and nucleic acids. R. B. Woodward made significant contributions to the development of fine organic synthesis in the 1940’s through 1960’s, carrying out the synthesis of a series of important natural compounds, including quinine, cortisone, chlorophyll, tetracycline, and vitamin B,2. An example of the great advance in chemical synthesis is seen in the first complete synthesis of the gene of the alanine transfer-ribonucleic acid of yeast, which was carried out in 1970 by H. G. Khorana and his colleagues.

The development of organic synthesis is proceeding in a number of directions. One of these involves the production of industrially important products (polymers, synthetic fuels, dyes), another the preparation of various physiologically active substances for medicine, agriculture, food processing, and perfumery. A third branch is concerned with establishing the structure of complex natural compounds and obtaining molecules with unusual structures for testing and refining theories of organic chemistry. A fourth branch seeks to expand the number of reactions and methods that can be used in chemical synthesis. Included in this category is the use of catalysts and high energies and the broader use of microorganisms and purified enzymes under rigidly controlled conditions. In the 1970’s, computers have been used for optimizing the results of multi-step chemical syntheses.

The development and perfection of certain methods used in synthesis has permitted the preparation of many important chemical products on an industrial scale. In inorganic chemistry, these products include nitric acid, ammonia, sulfuric acid, sodium carbonate, and various coordination compounds. There is also large-scale production of the organic substances used in various branches of the chemical industry, as well as of the products of fine organic synthesis (hormones, vitamins).

REFERENCES

Reutov, O. A. Organicheskii sintez, 3rd ed. Moscow, 1954.
Perspektivy razvitiia organicheskoi khimii. Edited by A. Todd. Moscow, 1959. (Translated from English and German.)
Cram, D., and G. Hammond. Organicheskaia khimiia. Moscow, 1964. (Translated from English.)

S. A. POGODIN and E. P. SEREBRIAKOV

References in periodicals archive ?
The synthesis reaction of the chitosan methacrylate is shown in Fig.
This plot enables the experimenter to study and gain better understanding of the evolution of the NP synthesis reaction. It is possible to use the surface plot to identify significant changes in the maximum absorbance, SPR peak, and FWHM that occur during the synthesis process.
Therefore, different reaction conditions will significantly impact on the synthesis reaction. Meanwhile, the effects of Si/C ratio and holding time on the fabrication of the in situ SiC/Al composites have not been involved in previous work.
Raw Oxide content,% component Si[O.sub.2] [Al.sub.2][O.sub.3] [Fe.sub.2][O.sub.3] Chalk 2,68 0,61 0,22 Glandular 14,1 3,35 39,8 waste Sulfate 0,39 0,39 2,84 waste Raw Oxide content,% component CaO MgO S[O.sub.3] [R.sub.2]O Other * Chalk 53,74 0,26 0,01 0,15 -- Glandular 10,5 1,52 14,2 -- 16,32 waste Sulfate 28,90 2,25 36,70 -- 11,18 waste * [Cr.sub.2][O.sub.3], Ti[O.sub.2], Mn[O.sub.2], [V.sub.2][O.sub.5] Table 2: The values of the Gibbs energy for the synthesis reaction of the mineral [C.sub.2]F at different temperatures.
This may explain the continuity of the synthesis reaction for samples "a" and "b" but not for sample "c" where the initiation step successfully generated the CMS* radical which, in its turn, initiates an oxidation reaction resulting in the generation of new aldehydic end groups capable of reducing [Ag.sup.+] to [Ag.sup.0].
Mechanisms of action of these functions discussed in detail include the synthesis reaction, regulatory, mechanical sensor for shear flow, permeability, and getting agonist-related signals and releasing necessary biomolecules.
Although we did manage to improve the efficiency of the cDNA synthesis reaction, the fact that variation in cDNA synthesis remained under the optimized conditions shows the importance of analyzing cDNA synthesis in individual samples.
In composite materials, the grain size may not be the same for all constituent phases depending on the mechanism of the synthesis reaction and the tendency of each material to coarsen during sintering.
There are two potential effects of this procedure on the synthesis reaction: (a) reduction of the induction period preceding the detection of crystalline product and (b) promotion of a dominant crystalline phase; thus, overall synthesis time can be shortened and product purity improved (Cundy et al, 1998).
Product innovations unveiled at the event included: an advanced electronic pipette; chemical synthesis reaction equipment; an enhanced flow chemistry system; a new entry level spectrophotometer and a space-saving, energy-efficient thermal cycler to support PCR research.