Elucidative programming

CASE (computer-assisted structure elucidation) programs. ... 

DeHaseth, J.A. Mir, K.A., A Minicomputer Based Structure Elucidation Program , paper 217, 1985. Pittsburgh Conference Exposition on Analytical Chemistry and Applied Snectroscopy,... 

ACD/Labs Structure Elucidator v7.0. In 42 min of computer time, the program output 296 structures that were sorted on the basis of the match between predicted shifts for each structure and the observed shift data. On this basis, the structure of quindoline, 6, was first in the output list with a deviation d=336 ppm. The next structure in the output list had a deviation of 5.26 ppm. Applications of the Structure Elucidator program to hundreds of examples have shown that only in rare cases does the actual structure have d>5 ppm. 

The Computerized Information System of Organic Chemistry-Structure Elucidation Subsystem (CISOC-SES) is another structural elucidation program to generate candidate structures given NMR information. The algorithms in this system emphasize the use of long-range distance constraints by chemists. 

Kossiakoff A, Rice FO (1943) Thermal decomposition of hydrocarbons, resonance stabilization and isomerization of free radieals. J Am Chem Soc 65 590-594 Kowalewski I, Vandenbroucke M, Hue AY, Taylor MJ, Faulon JL (1996) Prehminary results on molecular modeling of asphaltenes using structure elucidation programs in conjunction with molecular simulation programs. Energy Fuels, 10 97-107... 

Exchange of structure data between automatic structure elucidation programs (perhaps based on spectroscopic analysis) and chemical structure databases. 

Although reaction rate expressions and reaction stoichiometry are the experimental data most often used as a basis for the postulation of reaction mechanisms, there are many other experimental techniques that can contribute to the elucidation of these molecular processes. The conscientious investigator of reaction mechanisms will draw on a wide variety of experimental and theoretical methods in his or her research program in an attempt to obtain information about the elementary reactions taking... 

The authors work demonstrated that even samples as small as 2.5 mg could be studied yielding data with s/n > 5 1. They further demonstrated for samples with aromatic rings that 60 Hz optimization of the experiment was beneficial and that correlations to aliphatic carbons with smaller LJcc couplings did not experience a serious adverse impact due to the larger optimization but the reverse was not true. Correlations to aromatic carbons were not amenable to optimization biased toward aliphatic carbons (e.g. 40 Hz). Correlations observed in the 1,1-ADEQUATE spectrum of retrorsine (22) are shown on the structure. Complete 1,1-ADEQUATE correlations were not shown for delcosine (23) but the authors noted that the key correlations shown on the structure that were observed in the 1,1-ADEQUATE data were not observed in the H2BC spectrum acquired. The impact of the availability of the 1,1-ADEQUATE data on the Structure Elucidator CASE program is discussed in Section 7. 

Monitoring programs should focus not only on parent compounds but also on metabolites (i.e., conjugates). Moreover, attention should be paid on elucidating the transformation products generated after wastewater treatment and on evaluating their toxicity. 

The interpretation becomes complicated if several reactions take place simultaneously. Since the measured current gives only the sum of the rate of all charge-transfer reactions, the elucidation of the reaction mechanism and the measurement of several rate constants becomes an art. A number of tricks can be used, such as complicated potential or current programs, auxiliary electrodes, etc., which work for special cases. 

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