2-Mono- and 2,5-bis[bis[(4-dimethylamino)phenyl]hydroxymethyl]-substituted furans,thiophenes and N-methylpyrroles: New color-formers for carbonless imaging

2-Mono- and 2,5-bis[bis[(4-dimethylamino)phenyl]hydroxymethyl]substituted furan, thiophene and N-methylpyrrole were synthesized by mono- and dilithiation of furan, thiophene and N-methylpyrrole, respectively, and subsequent reaction with Michler's ketone. The title compounds develop black or dark-blue colors in acidic media.     

Molecular mechanics (MM3) calculations on conjugated hydrocarbons

The MM3 molecular mechanics program has been extended to conjugated systems. A VESCF method is applied to the pi-system to calculate bond orders, from which various stretching and torsional parameters are obtained. The procedure gives somewhat better results than the analogous MM2 calculations. It has been applied to a study of 81 compounds of aromatic and other conjugated hydrocarbons, as well as 45 alkenes and unconjugated polyenes. The structures calculated are generally in good agreement with experiment, and the heats of formation of these compounds can be calculated with a rms value of 0.62 kcal/mol, which may be compared with the average experimental error of 0.61 kcal/mol. In addition, vibrational frequencies for five representative conjugated model structures are calculated, with an rms value of 46 cm^?1, and from these, other properties such as entropy can be calculated.     

A study of the perovskite solid solution series LaxSr1−xRuO3 and LaxCa1−xRuO3 by ruthenium-99 Mössbauer spectroscopy

The magnetic, electronic, and structural properties of the solid solutions La_xSr_1−xRuO₃ and La_xCa_1−xRuO₃ have been studied by ⁹⁹Ru Mössbauer spectroscopy and other techniques. The La_xCa_1−xRuO₃ phases are reported for the first time and have been shown by powder X-ray diffraction measurements to be orthorhombically distorted perovskites. Electrical resistivity measurements on compacted powders show that all the phases are metallic with p 10⁻³, ohm-cm. Progressive substitution of Sr²⁺ by La³⁺ in ferromagnetic SrRuO₃ leads to a rapid collapse of the magnetic hyper-fine splitting at 4.2°K. For x = 0.25 some ruthenium ions still experience a magnetic field but for 0.4 x 0.75 only single, narrow resonance lines are observed, consistent both with the complete removal of the ferromagnetism and with the presence of an averaged ruthenium oxidation state in each phase, i.e., La_x³⁺Sr_1−x²⁺Ru^(4−x)+O₃ rather than La_x³⁺Sr_1−x²⁺Ru_x³⁺Ru_1−x⁴⁺O₃. LaRuO₃ and CaRuO₃ both give essentially single-line spectra at 4.2°K, indicating that the ruthenium ions in these oxides are not involved in long-range antiferromagnetic order but are paramagnetic. The solid solutions La_xCa_1−xRuO₃ (0 < x 0.6) give sharp symmetrical singlets with chemical isomer shifts (relative to the Ru metal) which move progressively from the value characteristic of Ru⁴⁺ (−0.303 mm sec⁻¹) toward the value for Ru³⁺ (−0.557 mm sec⁻¹), consistent with the presence of intermediate ruthenium oxidation states in these phases also.     

Benzacridines VI.. Functional derivatives of 5,6-dimethylbenz[c]acridine

5,5-Dimethyl-5,6-dihydrobenz[c]acridone has been synthesized by three different routes: a, from a condensation of anthranilic acid with 4,4-dimethyl-1-tetraIone; b, by a catalytic hydrogenation of 2-(o-nitrobenzal)-4,4-dimethyl-1-tetralone oxide followed by an acid catalyzed cleavage of the oxide ring and closure of the nitrogen heterocyclic ring; c, a multi-step process starting with 7-carboxy-5,5-dimethyl-5,6-dihydrobenz[c]acridine. Several new functional derivatives of both 5,5-dimethyl-5,6-dihydrobenz[c]acridine and of 5,6-dimethylbenz[c]acridine were also produced for biological study by others.     

The mass spectra of small-ring heterocycles. IV

Both the high and low resolution mass spectra of fourteen isomeric trans- and cis-aroylaziridines are presented. In contrast to earlier low resolution mass spectral work on these compounds [1], a new fragmentation pathway for the loss of hydroxyl is presented. Also, the simple fission of the N-alkylnitrogen bond is described. Detailed fragmentation mechanisms are presented and discussed for the major ions found in the mass spectra.     

Edulisones A and B, two epimeric benzo[b]oxepine derivatives from the bark of Aglaia edulis

Two benzo[b]oxepine derivatives, edulisones A (1) and B (2), were isolated from the bark of Aglaia edulis, collected in Indonesia. The relative stereochemistry of 1 was determined by single-crystal X-ray diffraction analysis. Treatment of compounds 1 and 2 with lithium hydroxide produced the same hydrolysis products, 1a and 1b, as a result of cleavage of the pyrrolidine ring to an alkylated amide mixture in each case, which demonstrated that these substances are epimeric at their 2-aminopyrrolidine moiety.     

Termination and side-reactions of polystyryllithium with beta-bromostyrene

Low molecular weight polystyryllithium was synthesised and terminated with a two-fold molar excess of beta-bromostyrene to produce an end-functionalised polymer. 1,3-Diphenylallyl-terminated polystyrene and other reaction products were analysed by FT-Raman spectroscopy. By comparison with model compounds, it can be deduced that beta-bromostyrene with a predominantly trans configuration gave rise to primarily cis conformational unsaturation at the polystyrene chain-end. It was also demonstrated that a polystyrene 'dimer' and 1,4-diphenylbutadiene were produced via side-reactions which are considered to result from metal-halogen exchange in the reagents.     

Bands of groups with universal properties

For a nonempty setX, a bandB, and a mapping :XB, we construct a band of groups, here called a cryptogroup,F(X,,B) which exhibits some remarkable properties. The first of these is a universal property relative to the classCG of all cryptogroups. In fact,CG is a variety with the operations of multiplication and inversion. For a varietyV of bands, we find a varietyV ⁰ of cryptogroups such that wheneverB is a band free inV ⁰ on the setX with embedding :XB, F(X,,B) is free inV ⁰. IfB is a normal band given as a strong semilattice of rectangular bands, we construct an isomorphic copy ofF(X,, B) which is a strong semilattice of completely simple semigroups. The objectsX, , B) admit the structure of a category, which is then related to the category of cryptogroups and their homomorphisms.This research was supported, in part by, NSERC Grant A4044.     

A force field for allenes and for nonlinear acetylenes within the MM2 approximation

Geometries and heats of formation for allenes may now be calculated with an extended version of MM2. The torsional barriers about bonds in an acetylenic unit are much more complicated than originally thought, if the unit is nonlinear. Ab initio calculations have been used to show just what these torsional barriers are, and the MM2 force field has been adapted to this information.