Unusual oxidative dehydration of vic-[alkyl(aryl)thio]-substituted aromatic (heteroaromatic) carboxamides

A new procedure was developed for the synthesis of nitriles of vic-[alkyl(aryl)sulfonyl] derivatives of benzoic, anthraquinonecarboxylic, and 4-isothiazolecarboxylic acids by the reactions of the corresponding vic-[alkyl(aryl)thio]-substituted aromatic (heteroaromatic) carboxamides with chlorine in organic solvents containing 20—65% of water. Oxidative dehydration of 1-(butylthio)anthraquinone-2-carboxamide afforded 1-butyl-6,11-dihydro-3H-1⁴-anthra[2,1-d]isothiazole-3,6,11-trione 1-oxide as a by-product. The structure of the latter was established by X-ray diffraction analysis. The reaction scheme involving the formation of S-chlorosulfonium chlorides followed by their hydrolysis was proposed.     

The smallest Hosoya index in (<Emphasis Type="Italic">n</Emphasis>, <Emphasis Type="Italic">n</Emphasis> + 1)-graphs

A (n, n + 1)-graph G is a connected simple graph with n vertices and n + 1 edges. In this paper, we determine the lower bound for the Hosoya index in (n, n + 1)-graphs in terms of the order n, and characterize the (n, n + 1)-graph with the smallest Hosoya index.     

Efficient one-pot syntheses of α-d-arabinofuranosyl tri- and tetrasaccharides present in cell wall polysaccharide of Mycobacterium tuberculosis

Two α-d-arabinofuranosyl oligosaccharides (2 and 3) found as constituent parts of the polysaccharide portion from the cell wall of Mycobacterium tuberculosis have been efficiently synthesized via a one-pot glycosylation procedure in which a key step is the chemoselective activation between d-arabinofuranosyl trichloroacetimidate donor 4 and partially protected aryl thioglycosides 5 or 7, respectively.     

Reductivetrans-1,3-dialkylation of isoquinoline on treatment with RLi and triallylborane

The preparative synthesis oftrans-1-alkyl(aryl)-3-allyl-1,2,3,4-tetrahydroisoquinolines based on the 1,2-addition of RLi to isoquinoline andtrans-allylboration is described. Dedicated to the memory of Academician M. E. Vol'pin timed to his 75th birthday. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1206–1209, June, 1998.     

ELECTRONIC AND LIGAND STRUCTURE DICTATED EFFECTS FOR TRIGONAL,TETRAGONAL AND RHOMBIC SYMMETRIES OF TRANSITION METAL CAGE COMPLEXES

Abstract

Spectroscopic and structural data of series of complexes with widely varied metal centers (d⁰ to d¹⁰) and an identical ligand sphere (figure) are presented. The structures comprise a range from near octahedral to near trigonal prismatic geometries and also involving additional small tetragonal perturbations. The complete series allows for an analysis of the various influences, viz. bonding and non-bonded interactions which dictate the compromise structure. Axial and rhombic distortions in solution and solid state of selected examples are discussed on the basis of electronic and EPR spectroscopy and trigonal distortions are analyzed on the basis of twist angles calculated from X-ray data.     

A small-angle neutron scattering study of the ethyl (n-octyl) phosphate micelles in water

Summary Mixed-double chain anionic surfactants, barium- and lithium-salts of ethyl(n-octyl) phosphate (EOP), which are asymmetric in the molecular shape, and a series of identical chain di-n-alkyl phosphate lithium salts have been synthezized. The limiting partial molar volume of a PO ₄ ^– group (23.43±0.41 cm³ mol^–1) for use in small-angle neutron scattering analysis was determined by density measurements of a series of identical chain di-n-alkyl phosphate lithium salts. For lithium EOP-D₂O system, a critical micellar concentration (2.3 wt%) was determined by³¹P NMR spectra. The micellar shape and size in the EOP-water binary system has been investigated by using small-angle neutron scattering (SANS) spectra. It has been found that the micelles of barium EOP in water have the shape of a prolate spheroid and aggregation numbers (n) equal to 48 at 23°C and 52 at 50°C. For the lithium EOP-micellar system, it has been found that the minimum micelle with an aggregation numbern=21 is spherical and micellar growth and variation from the spherical to the prolate shape might occur with an increase in concen tration above the CMC.     

The Merrifield–Simmons index in (<Emphasis Type="Italic">n</Emphasis>, <Emphasis Type="Italic">n</Emphasis> + 1)-graphs

A (n, n + 1)-graph G is a connected simple graph with n vertices and n + 1 edges. In this paper, we determine the upper bound for the Merrifield–Simmons index in (n, n + 1)–graphs in terms of the order n, and characterize the (n, n + 1)–graph with the largest Merrifield–Simmons index.     

The investigation of a series of n-hydroxybenzoic acids (n=p, m, o) on a new surface enhanced Raman scattering active substrate

Ag nanoparticles, organized on indium tin oxide (ITO) surface, can act as a new surface enhanced Raman scattering (SERS) active substrate as well as a dry electrode. Compared with the traditional SERS-active substrate, its notable advantage is that the microcosmic changes of the film can be reflected by the SERS spectrum during the investigation of the film's electrical and other macroscopic characteristics. To illuminate the above-mentioned property of this new substrate, a series of n-hydroxybenzoic acids (n-HBA; n=p, m and o) was tested as probe molecules by SERS technique. These SERS spectra indicate that the significant changes of frequencies as well as intensities, respectively, arise from the changes of the adsorption behavior along with the proportional variation of molecules and silver nanoparticles. Excellent SERS signals prove that the silver nanoparticles-coated ITO is a highly SERS-active substrate and can efficiently reflect the microcosmic property of the film, which suggest it has promising potential of being a new technique for further application in the field of thin-film research.     

A benign initiating system for cationic polymerization of isobutyl vinyl ether: Silver salt/aryl(alkyl) halide/lewis base

Aryl(alkyl) halides and silver salts were studied as environmentally benign initiating systems for cationic polymerization of isobutyl vinyl ether (IBVE). The reactivity of the benzyl cations could be effectively controlled by using dimethyl sulfide (Me₂S) as an additive, which was shown to be an effective Lewis base (LB), and diethyl ether as a reaction solvent. Detailed study of various benzyl cations and the order of addition of the reagents revealed that the reaction was controlled by the electronic and steric features of aryl(alkyl) halides, LBs, and IBVE, and a plausible reaction mechanism was presented. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2050–2058     

Excess volumes of decahydronaphthalene inn-alkanes at 10 and 25°C

The molar excess volumes of mixing decahydronaphthalene (decalin) with n-pentane, n-hexane, n-heptane, n-octane, n-dodecane and n-hexadecane have been measured over the whole composition range at two temperatures. These results together with the calculated molar excess volume temperature coefficients at equimolar composition have been compared with the results of other two-ring compounds (bicyclohexyl and tetralin) in the same n-alkanes.