Realization of a Gravity-Capillary Wave Surface Using Sub-Nyquist Spectral Samples

A method for numerical realization of a full gravity-capillary wave surface that is specified by a wave-spectral model and a dispersive relationship of the surface wave is developed on the basis of the angular spectral representation of a random water surface. A significant aspect of the method is that it requires a smaller number of spectral samples than that required by the Whitteker-Shannon sampling theorem for the complete generation of a full gravity-capillary wave surface, without resulting in any appreciable errors in auto-correlation functions for the surface displacement or surface slopes. The method enables the unified treatment of gravity and capillary waves in numerical studies of higher order characteristics of the thermal radiation emitted from, and the light scattered by, the wave surface.     

Annotation: Drying conditions for potassium dichromate

The optimum conditions for drying primary-standard or SRM grade potassium dichromate have been further examined, and it has been established that if organic impurities are present in the material the drying temperature should not exceed 200. At higher temperatures the organic matter is decomposed oxidatively by the dichromate, with a resultant error when the dichromate is used for standardization purposes.     

Ring opening reaction of N-substituted dihydropyrimidines with metal hydride complexes

N-Substituted dihydropyrimidines, 1, 3 , and 4 , easily afforded N,N′-disubstituted 2,4-diaminopentanes 2 in good yield by the ring opening reaction with sodium borohydride. The reaction with lithium aluminum hydride was also examined.     

Novel synthesis of 2,4-diphenylquinolines

2,4-Diphenylquinolines (3) were quantitatively prepared by heating of 3-aryl-4,6-diphenyl-2-oxo-1,3-diazabicyclo[2,2,0]hex-5-enes (2), which were obtained by photochemical electrocyclization of 1-aryl-4,6-diphenyl-2(1H)-pyrimidin-2-ones (1), in benzene at reflux temperature.     

Photochemistry of N-aryl-2(1H)-pyrimidin-2-ones

Irradiation of N-aryl-2(1H)-pyrimidin-2-ones ($\text{3a}$-$\text{c}$) in a mixed benzene-alcohol solution afforded the products initiated by Type I cleavage, 1-(3-alkoxycarbonylamino-2-propene)-N-arylimines ($\text{4a}$-$\text{c}$, $\text{5}$, and $\text{6}$) in 45–51% yields.     

The photochemical reactions of N,N-dialkyl α,β-unsaturated amides

Upon benzene-sensitized irradiation N,N-dibenzyl α,β-unsaturated amides 1a-1c cyclized to the corresponding 2-azetidinones 2a-2c in good yields via intramolecular hydrogen abstraction by the β-C atom. Under the same conditions N,N-diisopropyl amides 1e and 1f were found to undergo a novel photoreaction to give N-isopropyl saturated amides via the abstraction. Irradiation of N,N-diethyl and dimethyl amides gave neither 2-azetidinones nor N-monosubstituted amides.     

Coulometric investigation of the conditions for drying bauxites for chemical analysis

In order to dry a bauxite sample to constant weight for the determination of alumina content, the following procedure is recommended. The sample should be placed in a small flat weighing bottle and heated at 105-110 degrees for 5 hr in a dried atmosphere, then cooled in a desiccator containing magnesium perchlorate. After weighing, it should be reheated at 105-110 degrees for 40-60 min then cooled and weighed under the same conditions to ensure it has attained constant weight.     

Purification of potassium dichromate and its assay by precise coulometric titration

Potassium dichromate was purified and crystallized by a zone-melting technique, and the purity of the crystal obtained was determined by precise coulometric titration. The dichromate obtained by zone melting was not a single crystal but lumpy material (aggregate of small crystals). The purity of the dichromate obtained by six zone passages in the upward or downward direction was 99.990 (s=0.015%). The water adsorbed on the surfaces of the lumpy crystals which were stored in a desiccator for 3.5 h was about 0.002%. The zone-melting technique is satisfactory for the purification of potassium dichromate and the purified crystals are suitable for use as a primary standard in titrimetric analysis.     

Synthesis of 1,2-benzoquinones by the oxidation of 1,4-benzodioxins by peroxide derivatives

The oxidation reaction of 1,4-benzodioxin 1 by m-chloroperbenzoic acid (m-CPBA) and t-butyl hydroperoxide (t-BHP) are reported. 1,2-Benzoquinone 2 was given in moderate yields by the m-CPBA oxidation of 1,4-benzodioxin 1 , while 1,2-benzoquinone 2 was predominantly formed by t-BHP oxidation.     

Adapting the DeepSARM approach for dual-target ligand design

The structure–activity relationship (SAR) matrix (SARM) methodology and data structure was originally developed to extract structurally related compound series from data sets of any composition, organize these series in matrices reminiscent of R-group tables, and visualize SAR patterns. The SARM approach combines the identification of structural relationships between series of active compounds with analog design, which is facilitated by systematically exploring combinations of core structures and substituents that have not been synthesized. The SARM methodology was extended through the introduction of DeepSARM, which added deep learning and generative modeling to target-based analog design by taking compound information from related targets into account to further increase structural novelty. Herein, we present the foundations of the SARM methodology and discuss how DeepSARM modeling can be adapted for the design of compounds with dual-target activity. Generating dual-target compounds represents an equally attractive and challenging task for polypharmacology-oriented drug discovery. The DeepSARM-based approach is illustrated using a computational proof-of-concept application focusing on the design of candidate inhibitors for two prominent anti-cancer targets.