Design and applications of biomimetic anthraquinone dyes. III. Anthraquinone-immobilised C.I. reactive blue 2 analogues and their interaction with horse liver alcohol dehydrogenase and other adenine nucleotide-binding proteins

C.I. Reactive Blue 2 analogues were bonded onto an agarose support matrix by a novel method which entailed immobilisation by the anthraquinone ring 1-amino group as opposed to the usual triazine ring coupling methods. Dyes with spacer arms attached to the anthraquinone ring 1-amino group were synthesised by reacting methoxytriazine analogues of C.I. Reactive Blue 2 with chloroacetyl chloride and ethylenediamine. Unlike the blue parent dyes, all C.I. Reactive Blue 2 analogues with derivatised anthraquinone ring 1-amino groups were of a characteristic red colour. This change of chromaticity was entirely expected since the anthraquinone ring 1-amino group is an important component of the C.I. Reactive Blue 2 chromophore. Chromatographic studies indicated that, in comparison to adsorbents comprising triazine ring-immobilised dyes, adsorbents formed from C.I. Reactive Blue 2 analogues immobilised by the anthraquinone ring were better suited to the isolation of horse liver alcohol dehydrogenase and other adenine nucleotide-requiring enzymes. Similarities between C.I. Reactive Blue 2 analogues immobilised by the anthraquinone ring and N6-(6-aminohexyl)adenine nucleotide derivatives could be identified which may account for these observations. These studies confirm that highly effective affinity ligands based on synthetic textile dyes can be designed in a rational manner.     

Current measurement of nonaqueous solvents: Applicatons to capillry electrophoresis and electrochromatography

The solvents acetonitrile, methanol, N, N-dimethylformamide, dimethyl sulfoxide, formamide, and deionized water were investigated for their ability to support current flow without added electrolyte. Using open tubular capillary electrophoresis, currents were measured to be in the nanoampere (10^?9 A) range for all solvents but formamide (10^?6 A). Comparisons with flow data showed no clear relationship between current and electroosmotic flow. Packed capillary columns (3-μm ODS) were used for separations using both pure solvent and hydrophobic dyes showed mild retention in pure ACN. A 16 polynuclear aromatic hydrocarbon (PAH) standard soluton was separated in 80/20 ACN/H₂O with reduced plate heights (h) between 2.8 and 3.1 for retained species. A separation of nine androstenediones was achieved using a 70/30 MeOH/H₂O mobile phase.     

Synthesis of 2,4-dichlorophenyl methanesulfonate labeled with 14C and 35S

Radioactive 2,4-dichlorophenyl methanesulfonate labeled with ¹⁴C and ³⁵S has been synthesized because it was needed to facilitate the study of the metabolic fate of this interesting nematicide. It was prepared from the reaction between methanesulfonyl chloride and 2,4-dichlorophenol in the presence of a base. Three hundred milligrams of each ¹⁴C- and ³⁵S-2,4-dichlorophenyl methanesulfonate was obtained in a yield of 87% based on ¹⁴C-2,4-dichlorophenol or ³⁵S-methanesulfonyl chloride, respectively. The specific activity was 3.8 mCi/mmol for the compound labeled with ³⁵S and 2.5 mCi/mmol for the ¹⁴C material. Both tracers assayed over 99% after purification.     

Capillary supercritical fluid chromatography with ultraviolet multichannel detection of some pesticides and herbicides

The useful combination of capillary supercritical fluid chromatography with ultraviolet multichannel detection is demonstrated by the analysis of selected pesticides and herbicides. In this application the advantages of compound identification by ultraviolet spectrometry are appended to the separating capability of capillary supercritical fluid chromatography. A pseudo oncolumn detection approach is used. Compromises from the theoretically ideal conditions for both capillary SFC and the multichannel UV detector are made to achieve a practical interfacing of the chromatographic and spectrophotometric techniques. Detection limits are at the low nanogram levels.     

PhINSes mediated aziridination of 11-pregnane derivatives: synthesis of an 11,12-aziridino analogue of neuroactive steroids

Reaction of 11-pregnene-3,20-dione (6) or 3-α-acetoxy-11-pregnen-20-one (12) with trimethylsilylethanesulfonyl (‘Ses’) iminoiodinane 5 in the presence of copper (I) triflate gave the corresponding α,α-11,12-aziridino steroids 7 and 13 in 53 and 45% yields, respectively. The Ses group of each compound was removed using the TASF reagent and the resulting free aziridine NH was methylated to afford the 11α,12α-N-methyl aziridinosteroids 9 and 15, respectively. The latter is a conformationally constrained analogue of the endogenous neurosteroid pregnanolone (1).     

Over 20 years of reaction access systems from MDL: a novel reaction substructure search algorithm

From REACCS, to MDL ISIS/Host Reaction Gateway, and most recently to MDL Relational Chemistry Server, a new product based on Oracle data cartridge technology, MDL's reaction database management and retrieval systems have undergone great changes. The evolution of the system architecture is briefly discussed. The evolution of MDL reaction substructure search (RSS) algorithms is detailed. This article mainly describes a novel RSS algorithm. This algorithm is based on a depth-first search approach and is able to fully and prospectively use reaction specific information, such as reacting center and atom-atom mapping (AAM) information. The new algorithm has been used in the recently released MDL Relational Chemistry Server and allows the user to precisely find reaction instances in databases while minimizing unrelated hits. Finally, the existing and new RSS algorithms are compared with several examples.     

Positional isomerization of quinine and quinidine via rhodium on alumina catalysis: practical one-step synthesis of Δ-isoquinine and Δ-isoquinidine

The synthesis of Δ^3,10-isoquinine (5Z,5E) and Δ^3,10-isoquinidine (6Z,6E) was achieved in one-step through positional isomerization of the terminal alkene in the parent cinchona alkaloids using catalytic amounts of 5% Rh/Al₂O₃ and excess hydrochloric acid in refluxing 50% aqueous EtOH. The products were obtained in good yields as a mixture of E and Z geometric isomers and fully characterized using spectroscopic methods.     

On the algebras of symmetries (groups of collineations) of designs from finite Desarguesian planes with applications in statistics

Decomposition into a direct sum of irreducible representations of the representation of the full collineation group of a finite Desarguesian plane, as a group of matrices permuting the flags of the plane and the simple components of the corresponding commutant algebra, have been worked out here for the projective plane PG(2, 2) and the affine plane EG(2, 3). The dimension and the components of the covariance matrix of the observations from a design derived from such a plane, which commutes with such a permutation representation of the full collineation group of the plane, are thus determined. This paper is in the spirit of earlier works by, James (1957), Mann (1960), 6., 7., McLaren (1963), and Sysoev and Shaikan (1976). A. T. James, Ann. Math. Statist.28 (1957), 993–1002, H. B. Mann, Ann. Math. Statist.31 (1960), 1–15, E. J. Hannan, Research Report (Part. (I)), Summer Research Institute, Australian Math. Soc. and Methuen's Monographs on Applied Probability and Statistics, Supplementary Review Series in Applied Probability, Vol. 3, A. D. McLaren, Proc. Cambridge Philos. Soc.59 (1963), 431–450, and L. P. Sysoev and M. E. Shaikin, Avtomat. i Telemekh.5 (1976), 64–73.     

The validity of computational models in organization science: From model realism to purpose of the model

Computational models are widely applied to address fundamental and practical issues in organization science. Yet, computational modeling in organization science continues to raise questions of validity. In this paper, we argue that computational validity is a balance of three elements: the question or purpose, the experimental design, and the computational model. Simple models which address the question are preferred. Non-simple, imbalanced computational models are not only inefficient but can lead to poor answers. The validity approach is compared with well-known validity criteria in social science. Finally we apply the approach to a number of computational modeling studies in organization science, beginning with Cyert's. They were pioneering and are examples of well designed computational models.In Honor of Richard M. Cyert Carnegie-Mellon University Pittsburgh, PA...even though the assumptions of a model may not literally be exact and complete representation of reality, if they are realistic enough for the purposes of our analysis, we may be able to draw conclusions which can be shown to apply to the world.An earlier version was issued as a Stanford University CIFE working paper, April 1994, and presented at the Conference in Honor of Richard M. Cyert, Pittsburgh, September 1993.