Chemical investigation

Other Syntheses. Acryhc acid and other unsaturated compounds can also be made by a number of classical elimination reactions. Acrylates have been obtained from the thermal dehydration of hydracryhc acid (3-hydroxypropanoic acid [503-66-2]) (84), from the dehydrohalogenation of 3-halopropionic acid derivatives (85), and from the reduction of dihalopropionates (2). These studies, together with the related characterization and chemical investigations, contributed significantly to the development of commercial organic chemistry. 

The extensive hydrolysis of protactinium in its V oxidation state makes the chemical investigation of protactinium extremely difficult. Ions of protactinium(V) must be held in solution as complexes, eg, with fluoride ion, to prevent hydrolysis. 

D. A. Young, Recent Physico-Chemical Investigations on Silver Ac de, NAVORD 5746, Washiagton, D.C., 1958. 

Whereas oxaziridine and diaziridine were partial subjects of comprehensive theoretical studies on cyclic compounds (73MI50800), diazirine and some of its simple derivatives were the special target of quantum chemical investigations. Since diazirine, the lowest molecular weight heterocycle, has only five atoms and is of high symmetry, there was a chance for ab initio calculations, which followed some semiempirical studies. 

Diazirine, fluoromethoxy-nitrogen extrusion, 7, 224 Diazirine, methylvinyl-rearrangement, 7, 221 Diazirines addition reactions to Grignard compounds, 7, 2 0 as carbene precursors, 7, 236 IR spectra, 7, 203 microwave spectrum, 7, 199 molecular spectra, 7, 202-204 nitrogen extrusion, 7, 223 NMR, 7, 202 photoconversion to diazoalkanes, 7, 234 photoisomerization, 7, 221 photolysis, 7, 225-227 quantum chemical investigations, 7, 197 reactions... 

Finally, the phenomenon of shock-induced polarization represents perhaps the most distinctive phenomenon exhibited by shock-compressed matter. The phenomenon has no counterpart under other environments. The delineation of the details of the phenomenon provides an unusual insight into shock-deformation processes in shock-loading fronts. Description of the phenomenon appears to require overt attention to a catastrophic description of shock-compressed matter. In the author s opinion, a study of shock-induced polarization represents perhaps the most intriguing phenomenon observed in the field. In polymers, the author has characterized the effect as an electrical-to-chemical investigation [82G02]. 

Shock-induced solid state chemistry represents the most complex fundamental problem ever encountered in shock-compression science. All the mechanical and physical complications of other work are present, yet the additional chemical complications are added. Indeed, all mechanical, physical, and chemical aspects of the problem are intimately intertwined. Chemical investigations promise to provide a description of shock compression that differs considerably from that to which we have become accustomed. Nevertheless, a full description of the process requires contributions from a number... 

These results indicate that in these new ester mydriatics, the structural factors, which influence the development of this type of pharmacological action are similar to those made evident by the chemical investigations of Jowett and Pyman and the pharmacological work of Marshall, Dale, Laidlaw and Cushny on the tropeines. The nature of the basic component is obviously important since mydriasis is produced by simple bases such as ephedrine. As regards the nature of the esterifying acid, Jowett and Pyman drew the following conclusions — ... 

NMR and visible spectra have established that a number of S-N anions are present in such solutions.The primary reduction products are polysulfides Sx, which dissociate to polysulfur radical anions, especially the deep blue 83 ion (/Imax 620nm). In a IM solution the major S-N anion detected by NMR spectroscopy is cycZo-[S7N] with smaller amounts of the [SSNSS] ion and a trace of [SSNS]. The formation of the acyclic anion 5.23 from the decomposition of cyclo-Sjl is well established from chemical investigations (Section 5.4.3). The acyclic anions 5.22 and 5.23 have been detected by their characteristic visible and Raman spectra. It has also been suggested that a Raman band at 858 cm and a visible absorption band at 390 nm may be attributed to the [SaN] anion formed by cleavage of a S-S bond in [SSNS]. ° However, this anion cannot be obtained as a stable species when [SsN] is treated with one equivalent of PPhs. 

A Chemical Investigation of Two Cases of Glycogen Storage Disease, S. A. Barker, M. Stacey, and M. A. L. Al-Farisi, Clin. Chim. Acta, 8 (1963) 311-314. 

The setting chemistry of resole resins is complex, and experimentally difficult to study, mainly because the cured product, being insoluble, is not amenable to ready chemical investigation. Part of the information on these materials has come from studies of model systems such as mononuclear methylphenols, which give soluble products. These products present fewer difficulties in chemical analysis. 

Chemistry, like other sciences, progresses through the use of models. Models are the means by which we attempt to understand nature. In this book, we are primarily concerned with models of complex systems, those systems whose behaviors result from the many interactions of a large number of ingredients. In this context, two powerful approaches have been developed in recent years for chemical investigations molecular dynamics and Monte Carlo calculations [4-7]. Both techniques have been made possible by the development of extremely powerful, modern, high-speed computers. 

Phillipson, J. S. 1982. Chemical investigations of herbarium material for alkaloids. Phytochemistry 21 2441-2456. 

In order to identify chemically the so-caUed monascidin A discussed by some Chinese scientists in their papers as a component suitable for the preservation of food, it was isolated and chemical investigations using mass spectrometry and NMR were undertaken. Monascidin A was characterized as citrinin which is known to be a mycotoxin responsible for nephropathies. Thus, in order to avoid the production of this toxin, various strains were screened in order to see whether all were toxino-genic and it was shown that among the species of Monascus available in pubhc collections, non-toxinogenic strains were obtainable. 

Bode HB, A Zeeck, K Pluckhahn, D Jendrossek (2000) Physiological and chemical investigations into microbial degradation of synthetic poly(cw-l,4-isoprene). Appl Environ Microbiol 66 3680-3685. 

Substrate concentrations that are environmentally realistic are much lower than those often used in purely chemical investigations. 

Co (I I) complex formation is the essential part of copper wet analysis. The latter involves several chemical unit operations. In a concrete example, eight such operations were combined - two-phase formation, mixing, chelating reaction, solvent extraction, phase separation, three-phase formation, decomposition of co-existing metal chelates and removal of these chelates and reagents [28]. Accordingly, Co (I I) complex formation serves as a test reaction to perform multiple unit operations on one chip, i.e. as a chemical investigation to validate the Lab-on-a-Chip concept. 

Uzumasa, Y. (1965) Chemical investigation of hot springs in Japan. Tsukijishokan, 189 pp., (in Japanese). 

McMahon, M. T., deDios, A. D, Godbout, N., Salzmann, R., Laws, D. D., Le, H., Havlin, R. H., Oldfield, E., 1998, An Experimental and Quantum Chemical Investigation of CO Binding to Heme Proteins and Model Systems A Unified Model Based on 13C, 170 and 57Fe Nuclear Magnetic Resonance and 57Fe Mossbauer and Infrared Spectroscopies , J. Am. Chem. Soc., 120, 4784. 

The CH Clj extract (4.7 g) was mainly composed of the more polar constituents found in the PE extract. The MeOH extract (12.lg) remains to be chemically investigated. 

Beer PD, Bayly SR (2005) Anion Sensing by Metal-Based Receptors. 255 125-162 Bertini L, Bruschi M, de Gioia L, Fantucci P, Greco C, Zampella G (2007) Quantum Chemical Investigations of Reaction Paths of Metalloenzymes and Biomimetic Models - The Hydrogenase Example. 268 1-46 Bier FF, see Heise C (2005) 261 1-25... 

Dihydroepistephamiersine 6-acetate (7) was isolated from Stephania abyssinica as a homogeneous oil. The UV spectrum showed an absorption maximum at 286 nm, and the IR spectrum exhibited a band corresponding to an aliphatic ester carbonyl group at 1725 cm-1 (20). The H-NMR data are summarized in Table II. In chemical investigations, hydrolysis of 7 with barium methoxide gave an alcohol identical with 6-dihydroepistephamiersine (17), which on further treatment with mineral acid gave the known alkaloid, stephasunoline (17). Thus structure 7 was proposed for 6-dihydroepistephamiersine 6-acetate (20). 

Shukla MK, Leszczynski J (2002) Phototautomerism in uracil a quantum chemical investigation. J Phys Chem A 106 8642... 

Fleig T, Knecht S, Hattig C (2007) Quantum-chemical investigation of the structures and electronic spectra of the nucleic acid bases at the coupled cluster CC2 level. J Phys Chem A 111 5482-5491... 

Tomic K, Jorg T, Marian CM (2005) Quantum chemical investigation of the electronic spectra of the keto, enol, and keto-imine tautomers of cytosine. J Phys Chem A 109 8410-8418... 

Marian CM (2007) The guanine tautomer puzzle quantum chemical investigation of ground and... 

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