Physical and Spectral Properties

Ionization constants of hydroxy- and mercaptopyridazines, ° of amino- and diaminopyridazines and their quaternization products,of methylsulfinylpyridazines, and of pyridazinium ylides have been recorded. The basicities of a series of pyridazines have been determined and correlated with substituent constants using the Hammett free-energy relationship. The magnetic susceptibility of pyridazine was measured, and the rate constant for the reaction of hydrogen atoms with pyridazine was determined. The experimental dipole moment, Kerr constant, and molar Cotton-Mouton constant, obtained at 298 K and 633 nm, are reported. The magnetic circular dichroism spectrum of pyridazine has been measured.  

Studies on the tautomerism of pyridazines with potential tautomeric groups have continued. On the basis of recorded ionization constants and UV spectra of 3,4,5-trimercaptopyridazine and its derivatives, it is concluded that the compound exists as 3,4-dimercaptopyridazine-5(2f/)-thione. Tautomerism of hydroxy- and mercaptopyridazines was investigated with the aid of the corresponding anhydro bases as reference compounds. They exist predominantly in the -one or -thione forms. Similarly, the 3-mercapto-pyridazine-6(l/f)-thione structure in aqueous solution has been redeter- 

Hochsch. Chem. Carl Schortemmer Leuna-Merseburg 10, 297 (1968). 

The synthesis of betaines of several aromatic azines and their benzologs by Katritzky et al. stimulated also investigations of the corresponding pyrida-zines. They were prepared by methylation of the corresponding pyridazinones with methyl toluene-p-sulfonate to 317 and subsequent conversion into betains (319). Contrary to other related betaines, compounds of the type 319 are unreactive toward a variety of dipolarophiles. The hydroxy form of the cation (317) was shown to (ncdominate over the oxo form (318). UV, IR, and NMR data have been used for structure examination of betaines (95) and some pyridazinones. NMR spectra established 

UV spectra of pyridazines and pyridazinones were recorded, and solvent effects on spectra were examined. jjjg absorption spectrum of the 

UV spectra of pyridazines and pyridazinones were recorded, and solvent effects on spectra were examined. 644-652 The absorption spectrum of the pyridazine radical was reported.653 Resonance fluorescence has been observed from pyridazine vapor.654 Electron transmission spectroscopy has 

The parent compound in the oxadiazole series has a boiling point of 87 V9 which falls within the normal range for two-carbon compounds of comparable molecular weights. The heats of vaporization of the first three homologs lie in the range 9.5-10 kcal/mole, comparable to ethanol.3 

The aliphatic derivatives of oxadiazole have an ethereal odor while the aromatic ones are more like aromatic esters in this respect.3 

Oxadiazole is soluble in water and organic solvents. Other homologs follow normal solubility rules.134 However, oxadiazole codistills with organic solvents, even ether this means that there is some van der Waals attraction with other molecules. It cannot be recovered in pure form from a solution by distillation (Section V, I). 

The boiling points or melting points of more than 400 oxadiazoles are recorded by Eloy3 with references. 

X-ray diffraction measurements have not been reported on oxadiazole so bond lengths, bond angles, and planar geometry have been 

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Vitamin K compounds ate yellow solids or viscous liquids. The natural form of vitamin is a single diastereoisomer with 2 (E), 7 (R), ll (R) stereochemistry. The predominant commercial form of vitamin is the racemate and a 2 (E)j (Z) mixture. Table 1 fists some physical and spectral properties of vitamin K. ... 

The compound is analyzed in aqueous phase by cold vapor-AA or ICP/AES method (See Mercury). It also may be derivatized with an olefin or benzene in alcohol to yield the corresponding mercuration product that may be identified from physical and spectral properties and elemental analysis. An ether or alcoholic solution of the compound may be analyzed by GC/MS. The characteristic masses should be 259, 257, 256, 202, and 200. 

In the discussion of structural and spectroscopic aspects of thiophenes to follow, the reader does well to bear in mind that in fact aromaticity is a hallmark of thiophenes that dominates their properties and governs their reactions. Moreover, thiophene stands as uniquely aromatic among the five-membered heterocycles. In concrete terms this means that not only does thiophene undergo the reactions and have the physical and spectral properties associated with the concept of aromaticity, but that this aromatic character is steadfastly maintained through all manners of transformations including fusion with other aromatic rings. This attachment of substituents or fusion with other rings spawns thousands of aromatic derivatives. 

Handbook of Data on Organic Compounds. Eds R. C. Weast and M. J. Astle. Boca Raton, Florida CRC Press. Data include physical and spectral properties and references. Chemical Abstracts Service registry number and Beilstein reference. 

The structure of compound X is of prime importance in understanding a mechanism involving a pentaalkylphosphorane, so that some of its reactions were studied in addition to its physical and spectral properties. Among these the reaction with methanol was very valuable because this process first yields a well-defined methoxy derivative XI and then leads to a complete degradation with formation of ethyltrimethoxysilane ... 

The physicochemical properties of oxazoles to 1972 have been comprehensively reviewed by Lakhan and Ternai (3) whose work constitutes a point of departure for this section. Mention is made here only of those properties relevant to the detection, isolation, structure elucidation, and behavior of the natural compounds. The oxazole moiety in nature is usually embedded in a variety of functionality, and the rather innocuous properties of the parent molecule do not dominate or influence the behavior of the oxazole alkaloids to the extent that these compounds can be collectively regarded as displaying any characteristic set of physicochemical properties. Table III lists the physical and spectral properties of the compounds covered in this chapter. 

Physical and Spectral Properties of Perfluoro Cyclic Phosphazenes... 

Physical and spectral properties of batrachotoxins are presented in Table I. Mass spectra have been presented and interpreted (3,13,14). The parent ion of batrachotoxin is virtually nondetectable by direct probe methods, and instead an apparent molecular ion of miz 399 is seen, probably because of pyrolytic elimination of the pyrrole carboxylate moiety. Batrachotoxin alkaloids do not chromatograph on capillary gas chromatographic columns, but a pyrolysis product has been detected at 280°C on the temperature-programmed, packed OV-1 columns used for analysis of other dendrobatid alkaloids (see Appendix). The pyrrole carboxylate moiety is responsible for major ions of C7H9N02 (m/z 139), C6H9N ... 

Physical and spectral properties of samandarine alkaloids are presented in Table II. Mass spectra of various samandarine alkaloids and derivatives have been presented 38-43). Fragments of C4H8NO (m/z 86) and C4H7NO+ (m/z 85) are typical of oxazolidine-containing samandarine alkaloids. Infrared spectra of various samandarine alkaloids have been published 33,34,43-46 and references therein). Proton magnetic resonance spectra for samandarone, samandenone, and cycloneosamandione have been presented 38,40,41). Samandarine, samandarone, and... 

Physical and Spectral Properties of Samandarine Alkaloids (33-36,38-47) Samandarine, C,9H3 N02... 

Other physical and spectral properties of the histrionicotoxins are presented in Table III. Proton and carbon-13 magnetic resonance assignments have been presented (57-59) and reviewed (5). For proton spectra, see Refs. 3,57-59 for carbon-13 assignments, see Ref. 55. The diagnostic infrared peaks for various histrionicotoxins in solution have been tabulated... 

Decahydroquinoline alkaloids, 206-212 biological activity, 211 occurrence, 211-212 physical and spectral properties, 208-211 structures, 206-211... 

Salutaridine, conversion of reticuline to, 164 Samandarines, 194-199 biological activity, 198 occurrence, 198-199 physical and spectral properties,... 

Ethyl trimethylsilylacetate is stable to the usual manipulations, and can be stored in glass containers for years without change of physical and spectral properties IR (liquid film) cm 1720, characteristic of a-silyl esters The reported physical constants are bp 16-lTC (40 mm),... 

In spite of the obvious structural differences, macrocycles 6.26 and 6.27 exhibit physical and spectral properties that are similar to those of the parent sapphyrins. For example, organic solutions of these macrocycles are green, while as solids they are metallic blue. The bishydrochloride salt of the alkyne-containing macrocycle (6.26b) in CH2CI2 displays a rather intense Soret-like absorbance band at 476 nm... 

Because of the contradictory literature reports, the physical and spectral properties of Af-salicylidene-l,2-diaminobenzene 46 were reinvestigated . In the solid state compound 46 exists as a phenol-imine tautomer, wherein the phenolic hydrogen atom is hydrogen-bonded to the imine nitrogen atom. 

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