Angular heterocycles. Utilization of arylaminonaphthoquinones in the synthesis of benzophenothiazines

Substituted 6-ethoxyanilino-5H-benzo[a]phenothiazin-5-ones (3a-f) were synthesized by the cyclocondensation of 2-chloro-3-ethoxyanilino-1,4-naphthoquinones with zinc mercaptides of 2-aminothiophenol in pyridine. The nmr, ir and mass spectral data are presented and discussed.     

Thermal transformations in systems based on zeolites Y,X, and A containing zinc and sodium nitrates

Thermal transformations in systems formed by interaction of Zn and Na nitrates with Y, X, and A zeolites were studied by TG—DTA technique. Temperature regions of existence of adsorbed water, water of crystallization, and decomposition of NO₃ ^– anion were determined. These intervals depend on the composition, structure, method of preparation, and pre-treatment conditions of zeolite systems. The extent of NO₃ ^– decomposition depends not only on the zinc and sodium content but also on the presence of ammonia involved in NO₃ ^– reduction. The zeolite matrix strongly stabilizes the occluded NO₃ ^– anions. A portion of zinc oxide formed by zinc nitrate decomposition is probably localized inside the zeolite cavities as the [Zn—O—(ZnO) _n —Zn]²⁺ particles. The latter compensate charges of the isolated [AlO₄]^– tetrahedra.     

Synthesis and spectral studies of 2-mercapto-benzimidazole derivatives. II

This communication describes synthesis and spectral data of new 2-mercaptobenzimidazole derivatives.     

Heat transfer enhancement for boundary layer flow over a wedge by the use of electric fields

The effect of an electric field is investigated for heat transfer properties in a laminar, incompressible, non-isothermal boundary layer gas flow over a wedge. The governing boundary layer equations are reduced to an ordinary differential equation system using similarity transformations. The reduced equations are solved numerically for different values of electric and flow field parameters characterizing the ratio of electric force to fluid inertia force, Joule heating and ion kinetic work. For specific electric field function forms, leading to similarity solutions, velocity boundary layers are observed to become thinner and heat transfer properties are shown to be enhanced near the wall. The level of enhancement is controlled by the electric body force with additional effects of Joule heating and ion kinetic work on the bulk flow. The effects of low and high Prandtl numbers are also demonstrated. Heat transfer enhancement is observed to increase with increasing Prandtl number.     

Angular heterocycles. A convenient synthesis of 6-N-(acetylanilino)-5H-benzo[a]phenothiazin-5-one, 6-N-(acetylanilino)-5H-benzo[a]phenoxazin-5-ones and their derivatives

The reaction of 2-N-(acetylanilino)-3-chloro-1,4-naphthoquinone ( 2 ) with bifunctional aromatic amines afforded angular heterocycles 6 and 7 . Reductive acetylation of 7 provided o-acyl 9 and O,N-diacyl 10 derivatives depending upon the reaction conditions. The ir, uv, pmr and mass spectral data are also presented.     

Spectrophotometric multicomponent analysis of a mixture of chlorhexidine hydrochloride and lidocaine hydrochloride in pharmaceutical formulation using derivative spectrophotometry and partial least-squares multivariate calibration

Two spectrophotometric methods were applied to the simultaneous assay of chlorhexidine hydrochloride (CHL) and lidocaine hydrochloride (LIH) in pharmaceutical formulations. Using derivative spectrophotometry, CHL was determined by measurement of its first derivative signal at 290 nm (peak to zero amplitude) in the concentration range 5–9 μg/mL, and LIH was analysed by measurement of its second derivative signals at 272 and 276 nm (peak to peak amplitude) in the concentration range 160–480 μg/mL. With the partial least-squares (PLS-2), the experimental calibration matrix was constructed using 9 samples. The concentration ranges considered were 5–7 μg/mL for CHL and 220, 240, 260 μg/mL for LIH. The absorbances were recorded between 240 and 310 nm at every 5 nm.     

Speech synthesis by linear interpolation of spectral parameters between dyad boundaries.

A recent study [Olive and Spickenagel, J. Acoust. Soc. Am. 59, 993-996 (1976)] has shown that area parameters derived from linear prediction analysis can be linearly interpolated between dyad boundaries with very little distortion in the resultant synthesized speech. The success of area parameter interpolation raises a question: can other acoustic parameters, such as the power spectrum of the speech waveform, be similarly interpolated? The spectrum is of special interest because speech can be synthesized in real time from spectral parameters on a programmable digital filter. To study this question a speech analysis-synthesis system using spectral parameters (samples of power spectra at different frequencies) was simulated. These parameters were determined from the speech signal at every dyad boundary, and interpolated for intermediate values. Dyad boundaries (representing the limits of transition regions between phonemes) were determined manually. Informal listening tests comparing synthetic speech with and without linear interpolation showed slight degradation in the interpolated speech. This degradation is significantly reduced by using an additional point within the dyad boundaries for interpolation.