Covalent amination of 1-alkyl- and 1-aryl-3-carbamoylpyridinium chlorides as “model” for enzymic activity of rabbit liver aldehyde oxidase

The site of animation for 1-alkyl-3-carbamoylpyridinium chlorides in liquid ammonia is dependent on the identity of the 1-alkyl substituent. For the methyl, ethyl and n-propyl derivatives exclusively 6-adducts are found. Adduct formation takes place at C-6 and C-4, when the 1-substituent is an i-propyl or t-butyl group. The adduct ratio for the latter compounds is determined by the size of the substituent. 1-Aryl derivatives exhibit amination at C-2 and C-6 and the adduct ratios are dependent on the temperature. When the aryl substituent is a 2,4,6-trimethylphenyl group the 4-adduct is detected as well. A comparison is made between the sites of oxidation of these compounds by rabbit liver aldehyde oxidase and the covalent amination pattern in liquid ammonia. It is shown that covalent animation as a “model” for the enzymic activity of aldehyde oxide1 is particularly valuable in cases where the enzyme reaction is controlled by steric factors.     

Recovering a frame from its sheaves of algebras

Let

be a frame, α an element of

and T a finitary algebraic theory. In this paper we compare the category

of sheaves of T-algebras on

with the category Sh(α↓,T) of sheaves of T-algebras on α↓ (where α↓ is the initial segment {β|β<α}). This comparison suggests the definition of formal initial segments of the category

. For a large class of theories to be called ‘integral’ (examples of which are sets, monoids, groups, rings, modules on a integral domain, boolean algebras,hellip;) the formal initial segments of

coincide with the usual initial segments of

: this means that we are able to recover

axiomatically from

.When

is the initial frame {0, 1}, the frame of formal initial segments of

is the frame of open subsets of a compact space Spec T, called the spectrum of the theory T. When T is the theory of modules on some ring R, we recover in this way various well known notions of spectra and their corresponding sheaf-representation of the ring.     

Structure determination of [C3H3N2]+ ions,formed from monosubstituted pyrazoles C3H3N2R,by collision-induced dissociation mass spectrometry

[C₃H₃N₂]⁺ ions have been generated under electron impact conditions from some monosubstituted pyrazoles C₃H₃N₂R. Collision-induced dissociation (CID) mass spectra of deuterium-labelled precursors suggest that the majority of the [C₃H₃N₂]⁺ ions formed from 1-nitro- and 4-bromo-pyrazole retain their cyclic structure, whereas the ions from 3(5)-bromopyrazole are mainly linear. This is confirmed by the relative values observed for the overall cross-sections for CID and for ion loss. An isotope effect of the order of 1.5–1.9 has been found for the collision-induced loss of H^˙ from [C₃H₃N₂]⁺, generated from 3(5)- and 4-bromopyrazole.     

Two-photon induced fluorescence and resonance-enhanced ionization of sulfur atoms

Two-photon induced fluorescence and resonance-enhanced photoionization have been observed in atomic sulfur originating from both the ³P_2,1,0 and the ¹D₂ states. Sulfur atoms are generated by the sequential multiphoton dissociation of CS₂ at probing wavelengths. The two-photon absorption process involves the 3 ³P_2,1,0 → 4 ³P_2,0,1 or the 3 ¹D₂ → 4 ¹F₃ transitions with resolution of the individual J″ → J′ transitions in most cases. Intensities of the 3³P_J″ → 4 ³P_J′ transitions have been compared with Hartree-Fock calculated transition probabilities from the analogous transitions in atomic oxygen. Photoionization is observed in a three-photon (two to resonance) ionization originating from the ³P_2,1,0 and the ¹D₂ states. Induced fluorescence is observed at 167 and 180 nm which is dipole-allowed radiation from the intermediate ³S⁰₁ and ¹D⁰₂ states, respectively.     

The reaction of 4-(p-nitrobenzyl)pyridine with some electrophiles

The nucleophile 4-(p-nitrobenzyl)pyridine was allowed to react with four carcinogenic alkylating agents, chloromethyl methyl ether, bis(chloromethyl) ether, glycol sulfate and propane sultone, one carcinogenic acylating agent, N,N-dimethylcarbamyl chloride, and one noncarcinogenic electrophile, perchlorocyclobutenone. The structures of the major products formed, which are substituted pyridinium salts or 1,4-dihydropyridines, were determined.     

Activation analysis of geological material using ruthenium as a multiisotopic comparator

The isotopes⁹⁷Ru,¹⁰³Ru and¹⁰⁵Ru, produced by reactor irradiation of elemental ruthenium, were applied as triple comparators in the activation analysis of rock FU-41, a basanitoid from Fuerteventura, Canary Island. The concentrations of the following elements were determined: Sm, Sc, Fe, Co, Na, La, Hf, Eu, Th and Cr. The aim of this work was the experimental control of the error theory of the multiple comparator method as well as the experimental check of the accuracy. Presented at the 3rd Symposium on the Recent Developments in Neutron Activation Analysis, Cambridge (U.K.), 2–4 July 1973.     

Sequential injection spectrophotometric determination of phenylephrine hydrochloride in pharmaceutical preparations

A fully automated sequential injection spectrophotometric method for the determination of phenylephrine hydrochloride in pharmaceutical preparations is reported. The method is based on the condensation reaction of the analyte with 4-aminoantipyrine in the presence of potassium ferricyanide. The absorbance of the condensation product was monitored at 503 nm. A linear relationship between the relative peak height and concentration was obtained in the range 0.5-17.5 mg l⁻¹. The detection limit (as 3σ value) was 0.09 mg l⁻¹ and repeatability was 0.8 and 0.6% at 2.5 and 5 mg l⁻¹, respectively. Results obtained by this method agreed very well with those obtained by the AOAC official method.     

Oxidation of polypropylene in benzene solution

The oxidation of both amorphous and crystalline polypropylene in benzene solution was studied at 100–130°C. tert-Butyl peroxide was used as an initiator. The kinetic behavior of the amorphous and crystalline forms differs slightly; the oxidation rate of the amorphous type is slower for a given polymer and initiator concentration. The oxidation rate of solutions of the crystalline form can be simply described by the expression: R₀ = 1.87 × 10¹³ exp {?29,000/RT} [t-Bu₂O₂]^0.58[polypropylene]^0.73, mole/l.-min. Product analyses of the oxidized solutions are incomplete, but the results do show that only ～40% of the absorbed oxygen is present as hydroperoxide. Further, much of the hydroperoxide is present in low molecular weight polar fragments which are acetone-soluble. These results show that oxidized polypropylene cannot be regarded simply as “polypropylene hydroperoxide” with repeating hydroperoxide groups attached to the polymer chain in 1,3,5… (tertiary) positions.     

Benzo- and indoloquinolizine derivatives. III. Synthesis and structural assignments of 4b,5,6,7,8,8a,10,11-octahydro-15bH-tribenzo-[a,c,h]quinolizine (4b,5,6,7,8,8a,10,11–octahydro-15bH-isoquino[2,1-f] phenanthridine)

Starting from either trans-2-phenylcyclohexylamine or the cis isomer, two epimers of 4b,5,6,7,8,8a,10,11-Octahydro-15bH-tribenzo[a,c,h]quinolizine have been synthesized. The four possible diastereoisomers of this compound were obtained by reduction of the enamine 5,6,7,8,10,11-hexahydro-15bH-tribenzo[a,c,h]quinolizine. Configuration and conformation are discussed by use of ir, 67.88 MHz cmr and 270 MHz pmr spectroscopy.     

Organo group VB chemistry: Part IV: on the NQR spectra of tertiary aryl group VB compounds (35Cl, 75As, 121Sb, 209Bi)

The NQR spectra for the nuclei ³⁵Cl, ⁷⁵As, ¹²¹Sb/¹²³Sb and ²⁰⁹Bi at 300°K in the series of compounds (4-XC₆H₄)₃M and (3-XC₆H₄)₃M (M = P, As, Sb, Bi; X = H, F, Cl) are measured. Hammet sigma constants are calculated. The bonding in these molecules is discussed.