Ultra-violet absorption

Alkaloid A. This forms a chloride, [CjoHjaONjJ+Cl", HjO, isomeric with the chlorides of toxiferine, C-eurarine I and C-curarine III the picrate has m.p. 269° (dec.). The chloride differs from the isomerides named, in potency, colour reactions and ultra-violet absorption spectrum. The chloride in 2N-sulphuric acid gives a carmine-red colour with potassium dichromate. 

Pruckner and Witkop have compared the ultra-violet absorption spectra of a series of alkaloids and alkaloidal nuclei, with special reference to the effects produced by substitution on the harman group leading to yobjuine (p. 505) and its derivatives. 

Three new papers bearing on the structure of strychnine have become available too late for inclusion in this summary of recent work. Woodward, Brehm and Nelson have compared the ultra-violet absorption spectra of strychnine and Leuchs s strychnone (p.. 559) and used the results for a discussion of the relationship of the two alkaloids. Prelog and Kathriner have investigated the oxidation of strychnine, i/t-strychnine and brucine by permanganate in weakly acid solution and Bailey and Robinson from a study of the brucones have confirmed the conclusion of Woodward et al. that Leuchs s strychnone is a true indole derivative. Mention must also be made of a paper by Clemo and King on new reduction products of strychnine, of which a preliminary account has been published with a summary of the ensuing discussion. 

Craig, Michaelis, Graniek and Jacobs have reeently studied the ultra-violet absorption speetra of a series of items in this group of alkaloids. 

While the hydrolytic alkamines, aconine and delphonine, cannot be hydrogenated and have therefore been regarded as saturated, their ultra-violet absorption spectra as bases in solution and in common with those of heteratisine and tetrahydroatisine, show a strong absorption within the range 2,200 to 2,600 A, indicating unsaturation. With the bases in acid solution there is a reduction in intensity and a shift in the position of the absorption. It is assumed that these results arise from association of points of unsaturation with the nitrogen atom, A similar range of absorption is shown by iV-methylpyrrole, as base in solution, but in this case there is no shift in position on acidification. 

Hexahydrobenzoyloxodedelphonine acetate (VI) was dehydrogenated by selenium at 330° and gave as chief product a hydrocarbon, b.p. 90°/0-02 mm., whose composition, ultra-violet absorption spectrum and chemical properties, so far as examined, indicate that it may be a bicyclopentenobenzene and therefore in a different category from the phenanthrene hydrocarbons yielded by the atisine group of bases. 

Comparisons of the ultra-violet absorption spectra of the four hydrocarbons have been made with those of a series of condensed ring hydrocarbons and it is tentatively concluded that they may be derivatives of either epeiopentenophenanthrene or epeZopentenofluorene. All four hydrocarbons give a colour reaction in the Vanseheidt test. ... 

Tetrahydroalstonine gives with the Adamkiewicz test, as modified by Harvey et al., a colour similar to that given by yohimbine, which is taken to indicate the presence of a tetrahydro-/3-carboline ring system. Further, the ultra-violet absorption curves for yohimbine and tetrahydroalstonine... 

In view of the strychnine-like pharmacological action recorded for gelsemine, Janot and Berton have compared the ultra-violet absorption spectra of the two alkaloids, which proved to be remarkably similar. That of sempervirine was quite different and also unlike those of indole, quinoline and cinchonamine, with which it was also compared. 

The Ultra-violet Absorption of Some Degraded Deoxypentose Nucleic Acids," W. G. Overend, A. R. Peacocke, and M. Stacey, Trans. Faraday Soc., 50 (1954) 305. 

The reactants are then mixed in various proportions, and the sedimentation ratio (scompiex/smucin)—the ratio of the sedimentation coefficient of the complex to that of the pure mucin itself—is used as the measure for mucoad-hesion. The ultra-violet absorption optics on the XL-A or XL-1 ultracentrifuge have been used as the main optical detection system. Although the polysaccharide is generally invisible in the near UV ( 280 nm), at the concentrations normally employed the mucin—in uncomplexed and complexed form—is detectable. 

In table 2 are listed the various band systems with the origin (ve) of each, from which are derived the energy levels of table 1. In general, the value of ve is merely the frequency of the first line of the Q branch, but the error thus introduced is negligible. Richardson s recent conclusions are based entirely on the identification of the lower level of his A and B bands with Dieke and Hopfield s B level (215). The agreement is very striking. Thus the vibrational level intervals, as measured by Richardson are 1313.26, 1276.42 and 1247.67 cm.-1, while the same intervals, as measured by Dieke and Hopfield,6 from the ultra-violet absorption bands, are 1313, 1276 and 1247 cm.-1... 

On Johannes Wislicenus, see Lachman, The Spirit of Organic Chemistry, 67. E. C. C. Baly and C. H. Desch, "The Ultra-Violet Absorption Spectra of Certain Enol-Keto-Tautomerides, Pt. II," JCS 87 (1905) 766784. 

The ultra-violet absorption characteristics of a number of official pharmaceutical substances have been duly provided in Table 21.2. 

Jones, R. N. The Ultra-violet absorption Spectra of Aromatic Hydrocarbons. 

FlO. 4. Vacuum-ultra violet absorption spectrum of oxygen gas. The positions at which Rydberg series convergence limits occur are marked X—X. (We are indebted to Professor W. C. Price for this photograph.)... 

Cookson GH (1953) The ultra-violet absorption spectra of some pyrroles. J Chem... 

Ultra-violet absorption, 13, 132, 218 Umpolung, 211 Unsaturated acids afi-, from Perkin reaction, 227 j8y-, synthesis, 234... 

Nitramines dissolved in water, alcohol or dioxane, give a broad ultra-violet absorption band, the maximum of which lies between 225 and 240 fi. 

The ultra-violet absorption spectrum of nitroguanidine was first examined by Baly and Desch [34]. Figure 4 shows a curve plotted according to the investigations of R. N. Jones and Thorn [35]. In a neutral solution with an aqueous solvent the curve shows two maxima at about 210 and 265 p. The absorption curve is unaffected by the addition of hydrochloric acid but under the influence of 12V NaOH solution the two maxima are converted into one, at about 250 p. These changes may be caused by the tautomeric modifications of nitroguanidine. However, McKay,... 

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