Matrix reactions of Zn,Cd and Mg atoms with NO2. Infrared spectra of M+NO2− species

Matrix reactions of Mg, Zn and Cd atoms and NO₂ have been performed. Infrared absorptions in the 1220 cm^?1 range show isotopic shifts appropriate for M⁺NO₂^? species. Bands near 950 cm^?1 in the zinc experiments are attributed to a different ion-pair structural isomer.     

Photochemical activation of the carboxyl group via n-acyl-2-thionothiazolidines

Photolysis of N-acyl derivatives of 2-thionothiazolidine in the presence of ethanol affords ethyl esters; a mechanism involving γ-hydrogen abstraction by sulfur is postulated.     

Computer-aided Modelling of Decision-support Systems

Information systems have become increasingly complex over recent years, underscoring the challenge of designing systems which will provide the different functions in an organization with the information necessary for effective decision-making. With rapidly developing computer technology, it is natural that information systems evolve in a manner which is greatly dependent on computing hardware and software. Yet, there has been little development in the techniques of systems analysis and design to handle new and less well-understood functions which are of increasing interest.This paper demonstrates an application of structural modelling concepts to decision-support system synthesis. With the aid of the computer, structural modelling serves as an effective tool for: (1) partitioning a system into a set of subsystems; (2) specifying subsystems sufficiently to permit separate testing before total system tests; (3) eliminating redundant control information flow; and (4) facilitating decision-maker and system-analyst coordination and participation in the design process.     

Argon matrix absorption spectra of ClO, BrO, and IO and emission spectra of IO

Absorption spectra of ClO, BrO, and IO and the emission spectrum of IO have been observed from argon matrix samples prepared by microwave discharging the reagent mixture before condensation. Vibronic progressions were observed for each system. The spectroscopic scopic constants T_e, ω′_e, ω_ex′_e, ω″_e, and ω_ex″_e were evaluated from the absorption and emission data for comparison with gas-phase constants. Very good agreement is found for ClO. The argon matrix observations dictate a revision of the gas-phase vibronic assignments for BrO. The ground-state vibrational fundamental and T_e for argon matrix isolated IO are similar to the gas-phase values, but a lower excited-state spacing is found in the matrix.     

A parallel synthesis demonstration library of tri-substituted indazoles containing new antimutagenic/antioxidant hits related to benzydamine

A solution phase strategy for the multiple parallel synthesis of a demonstration library of indazoles is described by which regio-selectivity problems inherent to previous syntheses of this nucleus are largely overcome. Synthesis of selected components proceeded satisfactorily indicating that a fully realized library of indazole analogs could readily be produced using this methodology. Simple modifications of the basic nucleophilic aromatic substitution route unambiguously produce a range of N-1 substitutions (alkyl, aryl and aralkyl) in 50-75% yields. Next a range of substituents was introduced at the C-3 position in 50-80% yields by O-alkylation. Careful choice of reagents and reaction conditions were required to prevent by-product formation due to competing alkylation at N-2 (trace to 15% yields). When present, these contaminants were readily removed by chromofiltration. A third diversity site was sketched in at C-5 in 75-90% yield by reductive alkylation or acylation. Screening of some of the demonstration library members in vitro revealed highly active antioxidants suggesting that producing a full library would be worthwhile.