Carbon-carbon cyanoethylation of anisole and its derivatives: Synthesis of a potential intermediate for ring-C aromatic steroid

Cyanoethylations of o-cresyl methyl ether, anisole, α-naphthyl methyl ether, resorcinol dimethyl ether, and 1,7-dimethoxynaphthalene provided the desired products in reasonably good yields: synthetic applications are indicated.     

ON THE INDUCTION OF PROTECTIVE RESPONSES IN Salmonella typhimurium STRAIN TA1535/pSK1002 BY UVA (365 nm)

Exposure to UVA (365 nm) led to growth delay, loss of viability and inhibition of ³H-thymidine incorporation into the cells of Salmonella typhimurium strain TA1535 containing multiple copies of a plasmid pSK1002 carrying a umuC-'lacZ fusion gene. Ultraviolet-A induced umu gene expression, as monitored by the estimation of β-galactosidase, in a linear fluence-dependent manner. The induction of umu gene expression increased with the increase of postirradiation incubation period of the cells in the LB-ampicillin (LB A) medium at 37° C and leveled off from 2 h onward. The induction of gene expression depended on concomitant protein synthesis and represented the induction of the SOS response in the particular S. typhimurium cells used. The exposure to low fluences (sublethal) of UVA also led to the induction of an adaptive response in the same bacterial cells, which made them resistant to subsequent challenge by a much higher fluence of the same radiation. The adaptive response, as monitored by the assays of viability and β-galactosidase units, increased with the period of exposure to sublethal fluences of UVA, attained a maximum at the UVA exposure of 4.5 kj/m² (15 min) and thereafter gradually decreased with further increase of UVA exposure period. Modulation studies involving D₂O, LBA growth medium, different scavengers of free radicals and quenchers of activated oxygen species indicated the involvement of both hydroxyl free radicals and singlet oxygen in the UVA-induced umu gene expression.     

Synthesis, characterization and physicochemical studies of weakly interacting redox-responsive binuclear complexes incorporating ethylenediaminetetraacetatoruthanate(III)

Novel binuclear complexes of the type [{Ru(edtaH)}₂L] [edta- = ethylenediaminetetraacetate, L = pyrazine, 4,4′-bipyridyl, 3,3′-dimethyl-4,4′-bipyridyl, trans-1,2-bis(4-pyridyl)ethylene)] have been synthesized and characterized by physicochemical methods. All the complexes showed weak metal-metal interaction, depending on the nature of the bridging ligand, L. The electrochemical and magnetic susceptibility measurements are consistent with weak interactions between the ruthenium centres.     

Phase behavior of low molecular weight polyethylenes from homogeneous and heterogeneous solutions

The pseudophase diagrams of solutions of low molecular weight polyethylene (PE) (number‐average molecular weight < 1500 g/mol) in octamethyl cyclotetrasiloxane (OCTS) and isododecane (IS) were determined by direct observation of cloud points and optical microscopy. In addition, melting temperatures were also determined by differential scanning calorimetry. In the range of single liquid–solid transitions, the data conformed to the classical melting temperature composition relation as a result of the formation of extended crystallites. The melting data were used to determine the interaction parameter of the PE in OCTS (1.4 ± 0.1) and IS (0.22 ± 0.05). The structural and thermal properties of the gels formed by a competing liquid–liquid and liquid–solid phase separation, under nonequilibrium conditions, contrast with the properties of the crystals formed from a single liquid–solid transition. Coarsening within the liquid phases was evidenced by optical microscopy, and insights about the mechanism of the kinetics of the coarsening process are given. The temporal changes of the melting temperature of crystallites formed from the heterogeneous phase (OCTS) reveal dynamics within a nonequilibrium state. In contrast, the crystallites formed from a homogeneous solution (IS) showed negligible melting‐temperature changes with time. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 878–889, 2002     

Carbon-13 NMR spectra of some labdane diterpenoids

Carbon-13 signal assignments of the labdane diterpenoids phlogantholide-A, its diacetate and isophlogantholide-A are reported. The assignments of the ¹³C NMR signals of 14-deoxyandrographolide and its diacetate, made earlier, have now been confirmed by lanthanide shift studies on the former and also by ¹³C spectral studies on anhydroandrographolide diacetate and 14-deoxy-11,12-didehydroandrographolide diacetate.     

Various techniques for multiline operation of TEA CO2 lasers

The various techniques used for multiline operation of TEA CO₂ lasers are reviewed with particular reference to the multiline laser parameters of interest in laser applications.     

Spectrophotometric determination of lanthanum, thorium and iron(III) with chromotropic acid azo dyes of the pyridine series

Highly sensitive methods for the determination of lan thanum, thorium and iron(III) have been developed with the sodium salts of 2-(pyridyl-2-azo)chromotropic acid, 2-(pyridyl-3-azo)chromotropic acid and 2-(2-carboxypyridyl-3-azo)chromotropic acid. Optimum concentration ranges are of the order 1-20 ppm. The effect of diverse ions (cations and anions) including those of rare-earths are reported. The nature of the complexes has been investigated and values for the instability constants are given.     

Effect of hydrogen bonding on the acid character of some synthetic copolymers

A copolymer of p-hydroxybenzoic acid, formaldehyde, and p-bromoaniline was prepared in the presence of acid catalyst, and five fractions have been separated from it. Br content of each of the fractions was determined by chemical analysis, and on the basis of mole ratio of repeating units present in the copolymer chain, the total amounts of acidic and basic groups in a given weight of the copolymer were calculated. Nonaqueous titrations of all the fractions have been carried out in acidic and basic medium with suitable titrants. An excellent correlation was observed between the calculated and observed values of functional groups. The features of the titration curves were interpreted in terms of intramolecular hydrogen bonding and homoconjugation.     

Synthetic studies on alkaloids. Part 2. Stereospecific synthesis of 1β-methyl-13α-acetoxy-8,11-dioxotetracyclo[7:2:2:05,11:05,12]tridec-Δ6,7-ene; model reactions on the construction of aconitine skeleton

The title compound (2), an advanced relay towards the well-appreciated aconitine skeleton (1) of the C₁₉-norditerpene alkaloids, has been synthesised $\text{via}$ regiospecific intramolecular oxocarbenedo CH σ-bond insertion as the key step and this intermediate has the full potential for further elaboration to the intact skeleton.