Structures of deoxypeganine salts

The structures of deoxypeganine (DOP) hydrochloride and oxalate were solved by x-ray structure analysis. An infinite chain along the crystallographic c axis was formed in the crystal structure of DOP oxalate. A molecular framework consisting of Cl anions and DOP cation protonated at N1 was found in the structure of unhydrated DOP hydrochloride. The molecular packing of the “host” (DOP cation) was pseudoisostructural in the studied ion-molecular crystals but differed from other known DOP salts. The “guest” molecules (acid anions) in the studied and known DOP salts formed different intermolecular contacts. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 280–283, May–June, 2006.     

Two enantiomerically pure cyclic arenesulfonamide hydrochloride salts

The crystal structures of N‐[(1R)‐1‐(1‐naphthyl)ethyl]‐3,4‐dihydro‐2H‐1,2‐benzothiazin‐4‐aminium 1,1‐dioxide chloride, C₂₀H₂₁N₂O₂S⁺·Cl⁻, (I), a six‐membered cyclic sulfonamide, and (1R)‐N‐[(5,5‐dioxo‐6,7‐dihydrodibenzo[d,f][1,2]thiazepin‐7‐yl)methyl]‐1‐(1‐naphthyl)ethanaminium chloride, C₂₆H₂₅N₂O₂S⁺·Cl⁻, (II), a seven‐membered cyclic sulfonamide, both representative of a novel family of agonists of the extracellular calcium sensing receptor (CaSR) of possible clinical importance, are reported. The known chirality of the naphthylethylamine precursor has enabled assignment of the absolute configuration of both compounds, which is crucial for the receptor recognition. The crystal structures, though different, reveal for these agonists a notable absence of intramolecular π–π stacking between their respective aromatic groups. This suggests a common structural feature that allows CaSR agonists to be distinguished from antagonists, since in the latter, such interactions have been shown to be important. The connectivities between molecules in the crystal structures are also different, but both involve hydrogen bonding mediated by chloride ions as a common dominant feature.     

Highly efficient oxidative amidation of aldehydes with amine hydrochloride salts

A mild and efficient copper-catalyzed oxidative amidation of aldehydes was developed using amine HCl salts and tert-butyl hydroperoxide as an oxidant.     

Methyl transfer in field desorption mass spectrometry of ammonioalkanecarboxylate hydrochloride salts

Intramolecular methyl transfer has been observed previously in pyrolysis electron impact mass spectra of complex ammonioalkanecarboxylates. We present here field desorption mass spectra results of more simple N,N,N-trimethylammoniocarboxylate hydrochloride salts and their N,N,N-perdeuterotrimethylammonium analogs in which we observe methyl transfer. We demonstrate that mechanisms for this and other fragmentation and rearrangement processes are dependent on anode heating current. Addition of the protonating agent p-toluenesulfonic acid suppresses most ions except the protonated molecular ion.     

Carbon-13 nuclear magnetic resonance spectroscopy of methyl-substituted piperidines and their hydrochloride salts

Carbon-13 chemical shifts and ¹J(CH) coupling constants of piperidine, 4-t-butylpiperidine, five C-methyl substituted piperidines and of the corresponding N-methyl compounds have been measured. These NMR parameters have also been determined for the fourteen corresponding hydrochlorides. The N-methyl-C-methyl piperidinium salts showed two stereoisomers on the positive nitrogen atom. The effect of protonation is discussed in relation to charge and steric effects and the methyl substituent effects are compared with those of methyl-substituted cyclohexanes. Deviations from the general tendencies in the series are correlated with changes in ring conformations around the highly crowded substituted carbons.     

Structures of sterically hindered p-hydroxystyrylpyridines and acid-base transformations of their quaternary salts

The structures of p-hydroxystyrylpyridines and a number of their new quaternary salts were studied by means of electronic absorption spectra. The reverse transformation of the salts to the corresponding quinonoid compounds was examined as a function of the pH of the medium, and the equilibrium constants were determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1087–1091, August, 1972.     

Structures and reactivities of benzo-1,2,3-dithiazolium salts and their selenium analogs

A number of benzo-1,2,3-dithiazolium chlorides (I) and their selenium analogs — benzo-1,2,3-thiaselenazolium, benzo-2,1,3-thiaselenazolium, and benzo-1,2,3-diselenazolium salts — were synthesized. The electronic structures and reactivities of the I cation and salts I–IV are discussed on the basis of a quantum-chemical calculation of cation I and the PMR spectra of salts I–IV. Successive substitution of the sulfur atoms in the I cation by selenium atoms, particularly in the 2 position, substantially increases the degree of transfer of positive charge to the condensed benzene ring. The trend of the nucleophilic reactivities of 6-methoxy derivatives of salts I–IV in the reaction with aromatic amines is the same as the trend of the degree of localization of the positive charge in the 6 position.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 912–916, July, 1978.     

A quantum-chemical investigation of deoxypeganine and its salts II. The photochemical oxidation of deoxypeganine hydrochloride

The stability of deoxypeganine hydrochloride under the action of light has been established. The kinetics of the oxidation of deoxypeganine hydrochloride in aqueous solution in the presence of deoxyvasicinone hydrochloride have been studied. The structures and electronic conformations of hypothetical models of the salt DOP HCl in the ground and excited states have been considered by the MO LCAO method in the AM1 approximation. The difference in the resistance of the molecules of the base deoxypeganine and its hydrochloride to photochemical oxidation is discussed on the basis of the results of experiments and calculations.Abbreviations HPLC high-performance liquid chromatography - MO LCAO molecular orbitals as linear combinations of atomic orbitals - AM1 Austin Model 1 - DOP HCl deoxypeganine hydrochloride - DOV HCl deoxyvasicinone hydrochloride Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 729–733, September–October, 1993.     

A quantum-chemical investigation of deoxypeganine and its salts II. The photochemical oxidation of deoxypeganine hydrochloride

The stability of deoxypeganine hydrochloride under the action of light has been established. The kinetics of the oxidation of deoxypeganine hydrochloride in aqueous solution in the presence of deoxyvasicinone hydrochloride have been studied. The structures and electronic conformations of hypothetical models of the salt DOP HCl in the ground and excited states have been considered by the MO LCAO method in the AM1 approximation. The difference in the resistance of the molecules of the base deoxypeganine and its hydrochloride to photochemical oxidation is discussed on the basis of the results of experiments and calculations.