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This work presents a novel nonaromatic ATPS formed by a piperazinium-based IL and an anionic surfactant, in which considerable size enhancement of aggregates takes place without the assistance of aromaticity in contrast to the other Structure-activity relationship study of position 4 in the urotensin-II receptor Trapella C, Regoli D, Tomatis R, Salvadori S.Pharmacology, University of Ferrara, 44100 Ferrara, Italy.In the present study we describe the synthesis and biological evaluation of 24 analogues of the urotensin II (U-II) fragment U-II(4-11) substituted in position 4 with coded and non-coded aromatic amino acids. All of the new analogues behaved as full U-II receptor (UT) agonists. Our results indicated that aromaticity is well tolerated, size, length and chirality of the side chain are not important, while substituents with a nitrogen atom are preferred. Thus Organic Synthesis of 6-butyl-n-hydroxynaphthimide trifluoromethanesulfonic acid of U-II(5-11) with small groups bearing nitrogen atoms could be instrumental in future studies for the identification of novel potent UT Radical-anionic cyclizations of enediynes: remarkable effects of benzannelation and remote substituents on cyclorearomatization reactions.
The reasons for large changes in the energetics of C1-C5 and C1-C6 (Bergman) cyclizations of enediynes upon one-electron reduction were studied by DFT and Coupled Cluster computations. Although both of these radical-anionic cyclizations are significantly accelerated relative to their thermal counterparts, the acceleration is especially large for benzannelated enediynes, whose reductive cyclizations are predicted to proceed readily under ambient conditions. Unlike their thermal analogues, the radical-anionic reactions can be efficiently controlled by remote substitution, and the effect of substituent electronegativity is opposite of the effect on the thermal cycloaromatization reactions. For both radical-anionic cyclizations, large effects of benzannelation and increased sensitivity to the properties of remote substituents result from crossing of out-of-plane and in-plane MOs in the vicinity of transition states. This crossing leads to restoration of the aromaticity decreased upon one-electron reduction of benzannelated enediynes. Increased interactions between nonbonding orbitals as well as formation of new aromatic rings (five membered for the C1-C5 cyclization and six membered for C1-C6 cyclizations) are the other sources of increased exothermicity for both radical-anionic cyclizations. The tradeoff between reduction potentials and cyclization efficiency as well as the possibilities of switching of enediyne cyclization modes (exo or C1-C5 vs endo or C1-C6)) under kinetic or thermodynamic control conditions are also outlined.
Treatment of pharmaceutical wastewater containing antibiotics by O3 and O3/H2O2 Ozonation of three different synthetic pharmaceutical formulation wastewater containing two human antibiotics and a veterinary antibiotic has been studied to enhance the their biodegradability. The effects of pH and initial chemical oxygen demand (COD) value as well as addition of hydrogen peroxide on ozonation process were investigated. Total organic carbon (TOC), COD, biochemical oxygen demand (BOD), and aromatic content (UV254) were the parameters followed to evaluate the performance of ozonation process. Comparison of the biodegradability of selected wastewaters containing different antibiotics confirmed that the variation of biodegradability was associated with the target compound. While BOD5/COD ratio of veterinary antibiotic formulation wastewater was increased from 077 to 08 with an applied ozone dosage of 26 g/l, this ratio for human antibiotic I and human antibiotic II was increased from 0 to 0 and 07 respectively. Moreover the results of this investigation showed that the ozonation process is capable of achieving high levels of COD and aromaticity removals at about their natural pH values.Measurements of personal exposure to nitrogen dioxide in four Mexican cities in Nitrogen dioxide is a ubiquitous pollutant in urban areas.
Indoor NO2 concentrations are influenced by penetration of outdoor concentrations and by indoor sources. The objectives of this study were to evaluate personal exposure to NO2, taking into account human time-activity patterns in four Mexican cities. Passive filter badges were used for indoor, outdoor, and personal NO2 measurements over 48 hr and indoor workplace measurements over 16 hr. Volunteers completed a questionnaire on exposure factors and a time-activity diary during the sample period. An unpaired t test, an analysis of variance (ANOVA), and a linear regression were performed to compare differences among cities and mean personal NO2 concentrations involving housing characteristics, as well as to determine which variables predicted the personal NO2 concentration. Sampling periods were in April, May, and June 1996 in Mexico City, Guadalajara, Cuernavaca, and Monterrey. All 122 volunteers in the study were working adults, with a mean age of 34 (SD +/- 78); 64% were female, and the majority worked in public offices and universities.
The highest NO2 concentrations were found in Mexico City (36 ppb for outdoor, 57 ppb for indoor, and 39 ppb for personal concentration) and the lowest in Monterrey (19 ppb for outdoor, 24 ppb for indoor, and 24 ppb for personal concentration).
