A variety of vinylogous iminium salt derivatives have been examined as useful precursors for the regiocontrolled synthesis of heterocyclic appended pyrazoles. The reaction conditions for such processes have been optimized and the regiochemical preferences have been determined. Such reaction sequences represent methodologies which may have useful applications for the preparation of biologically interesting substances.

The synthesis of heterocyclic appended vinylogous iminium salts is described along with their conversion to heterocyclic appended pyrimidines, triazolopyrimidines, and pyrroles.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The reaction of unsymmetrical vinylogous iminum salts and related analogs with β-aminocrotononitrile to yield 2,3,6-trisubstituted pyridines with regioselective control is described.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The synthesis of two, vinylogous iminium salts, which contain an appended thiophene group, are described along with their conversion to thiophene substituted pyrimidines and pyrroles.

A three step synthesis of a novel 2-(1-benzotriazolyl)-vinamidinium salt is described along with its direct conversion to a series of unusual 5-(1-benzotriazolyl)pyrimidines, 4-(1-benzotriazolyl)-pyrazoles, and 4-(1-benzotriazolyl)pyrroles.

During the last 15 years, over 400 patients with adenocarcinoma of the rectum have undergone a course of endocavitary irradiation for cure or palliation of Dukes' A and B disease. This treatment method makes use of an unconventional fractionation scheme, by which the tumour receives 10,000-12,000 cGy in approximately four fractions over a period of about 60 days. The treatments are separated by an interval of 2 or 3 weeks. This method of definitive irradiation allows suitable patients to avoid abdominoperineal resection and its drawbacks. Hospitalization is avoided and the patients maintain a normal daily life. Approximately 15-20 per cent of all rectal cancer patients may be expected to fulfil the criteria for selection, which are sufficiently strict that the local control (95 per cent) and 5-year survival rates (94 per cent) can exceed those of surgery for comparable disease.

The paper describes the use of metric techniques in an electronic support measures (ESM) data processing scheme developed at Smith Associates Consulting System Engineers Limited for the UK Ministry of Defence (Procurement Executive). The ESM data processing scheme takes in digital pulse data describing the radar pulses illuminating an ESM receiver. The output from the scheme is a continuously updated emitter table, which lists the emitters present in the environment and specifies the deduced parameters of these emitters. Metric techniques play an important role at two distinct stages of the scheme: firstly in direction-of-arrival (DOA) RF pulse filtering, and secondly in emitter table updating. In DOA RF filtering, the pulses are processed using two-dimensional cluster analysis. The method ensures that pulses from a single emitter are not separated into different batches, but that pulses from distinct emitters are separated, unless their parameters overlap in both DOA and RF. The same result cannot in general, be achieved using one-dimensional filtering. The scheme uses a computationally efficient method, in which the metric technique is applied to groups of pulses following sequential one-dimensional filterings in DOA and then RF. In emitter table updating, a metric technique is used to ensure that the pulses from an emitter already on the emitter table are correctly associated with that emitter table entry, and are not added as a new emitter seen for the first time. This overcomes the problem that, for some emitters, some of the parameters can change discontinuously when the emitter changes mode. The metric technique ensures that, provided some of the parameters remain approximately constant, the correct association is made.

A study is made of the spontaneous percolation occurring when particles fall under gravity through a fixed bed of larger particles. A variety of different circumstances arise in practical applications in for example powder mixing but there are two limiting cases which are still both important. The first is when small particles cascade almost elastically through an ensemble of layer particles. It is shown that the percolation velocity is proportional to (1 – α ) 1/4 , where α is the coefficient of restitution.The diffusion tensor is calculated from which Péclet numbers are derived. These results are compared with computer experiments with reasonable agreement. The second case is of almost inelastic interactions when the percolating particle slithers and drops into the next encounter in the fixed bed. The distributions of landing angles (the angles which the percolating particles make on the spherical obstacle on landing) and the Péclet numbers are deduced and differ substantially from random models. It is shown that there is low radial diffusion and the Péclet number is high.

The problem of the surface fluctuations in a settled granular material is posed. A simple model is given which describes the process by which a particle settles and comes to rest on the existing surface of the packing and from this a set of Langevin equations for the Fourier modes of the surface are derived. These equations imply that the Fourier amplitudes behave like the velocities of a set of independent Brownian particles. We show that this results in logarithmically divergent surface fluctuations if the flux of particles onto the surface is random, the divergence being removed by a more accurate description of the settling material, for example by having the granules fall through a sieve.