Immobilized enzyme electrode for the determination of salicylate in blood serum

This determination of salicylate in blood serum is based on application of an immobilized enzyme electrode. Salicylate hydroxylase (E.C.1.14.13.1) is chemically immobilized onto a pig intestine mounted on an oxygen electrode. The signals are monitored amperometrically and the resulting output voltage is read using a simple adapter. The experimental parameters and possible interferences are discussed. Samples containing 1.0 × 10^?5?1.87 × 10^?3 M (1.6–300 μg ml^?1) salicylate were assayed with relative standard deviations between 1.3% and 6% and recoveries between 98.7 and 103%. Results obtained by the proposed method and by the established clinical method for randomly spiked pooled serum samples correlated well (r = 0.99).     

Synthesis of (pyridinyl)-1,2,4-triazolo[4,3-a]pyridines

Methods for the synthesis of (pyridinyl)-1,2,4-triazolo[4,3-a]pyridines were developed. The principal route to the required intermediate 2-chloropyridines was based on rearrangements of mono N-oxides of 2,2′-bipyridine, 2,3′-bipyridine, 3,3′-bipyridine, 2,4′-bipyridine and 4,4′-bipyridine with phosphorus oxychloride. Reaction of 3,3′-bipyridine 1-oxide or 2,2′-bipyridine 1-oxide with phosphorus oxychloride gave mixtures of chloro isomers. Reaction with acetic anhydride, 3,3′-bipyridine 1-oxide and 2,2′-bipyridine 1-oxide gave exclusively [3,3′-bipyridine]-2(1H)-one and [2,2′-bipyridine]-6(1H)-one, respectively. 1,2,4-Triazolo[4,3-a]pyridines with pyridinyl groups at the 5,6,7 and 8 positions were synthesized.     

Angular momentum decoupling approximations in the quantum dynamics of reactive systems

Two methods for implementing angular momentum decoupling approximations in quantum mechanical reactive scattering examined. Applications of both reactive and nonreactive H + H₂ collisions indicate that for the most intense individual reactive transitions and for all degeneracy-averaged ones, these decoupling methods (especially the “proper” decoupling method) yield results in good agreement with those of fully-coupled calculations. However, for the less intense reactive transitions and all individual nonreactive transitions, very large errors can result from use of these approximate methods.     

Excess volumes for n-alkanols + n-alkanes I. Binary mixtures of methanol,ethanol, n-propanol,and n-butanol + n-heptane

Excess volumes V^E measured at 298.15 K in a successive-dilution dilatometer are reported for binary mixtures of the n-alkanols C₁ to C₄ + n-heptane. For ethanol +, and n-butanol + n-heptane, the measurements were extended to high dilutions of alkanol. V^E is positive for all of the mixtures but decreases rapidly in magnitude for increasing chain length of the n-alkanol. The results were used to estimate the excess partial molar volumes of the components.     

Symmetry allowed π4s+π2s additions silacyclopentadienes

π⁴s+π²s cycloaddition of hexaphenylsilacyclopentadiene with ethyl acrylate gives rise to a bicyclosilaheptene derivative. High resolution NMR studies have shown that the ester group in this adduct is in the endo position and that the ester methylene protons are magnetically inequivalent. Similar cycloadditions of hexaphenylsilacyclopentadiene, 1,1-dimethyl-2,3,4,5-tetraphenylsilacyclopentadiene, 1-methyl-1,2,3,4,5-pentaphenylsilacyclopentadiene, and 1-methyl-1-vinyl-2,3,4,5-tetra-phenylsilacyclopentadiene with dienophiles like acrylonitrile, maleic anhydride and dibenzoylacetylene have been carried out. The stereochemistry of these adducts has been deduced on the basis of NMR studies. Mass spectral fragmentation studies of some of the silabicycloheptenes have been carried out.     

Reactions of dimethyl acetylenedicarboxylate—VI : Reaction with aldehyde and ketone phenylhydrazones

Benzaldehyde phenylhydrazone with dimethyl acetylenedicarboxylate gives dimethyl 1,3-diphenylpyrazoline-4,5-dicarboxylate, dimethyl 1,3-diphenylpyrazole-4,5-dicarboxylate and trimethyl 1-phenylpyrazole-3,4,5-tricarboxylate; p-chlorobenzaldehyde phenylhydrazone gives trimethyl 1-phenyl-3,4,5-tricarboxylate and 1,2-(bis-phenylazo)-1,2-di-p-chlorophenylethane. Under similar conditions, p-tolualdehyde phenylhydrazone gives only trimethyl 1-phenylpyrazole-3,4,5- tricarboxylate. Acetophenone phenylhydrazone with dimethyl acetylenedicarboxylate gives dimethyl 1,3-diphenylpyrazole-4,5-dicarboxylate. Benzophenone phenylhydrazone, on the other hand, gives a mixture of dimethyl 1,3-diphenylpyrazoline-4,5-dicarboxylate and dimethyl 1,3-diphenylpyrazole-4,5- dicarboxylate. Benzyl methyl ketone and dimethyl acetylenedicarboxylate gives an enamine maleate, which is the Michael addition product.