1,721,017 research outputs found
A Mild and Chemoselective Reduction of Cyclic Iminium Salts
No full textN-Substituted cyclic iminium salts are conveniently reduced to the corresponding tertiary amines in good yields by reaction with tributylstannane in methanol at room temperature. A variety of functional groups (such as ketonic groups) present in the molecule are not affected under these conditions
A total synthesis of mycophenolic acid, some analogues and some biogenetic intermediates
No full textMycophenolic acid (28) has been obtained by a convergent synthesis starting from methyl 6-bromo-4-methylhex-4-enoate (13) and 5,7-dihydroxy-4-methylphthalide (24). For the total synthesis of 5,7-dihydroxy-4-methylphthalide, 1-carbethoxy-2,3-dimethylcyclohexa-4,6-dione (14) was aromatized and transformed into 4,6-dimethoxy-2,3-dimethylbenzamide. The photolysis of the corresponding N-chloroamide and subsequent hydrolysis gave 5,7-dimethoxy-4-methylphthalide which was hydrolysed to 5,7-dihydroxy-4-methylphthalide (24). The bromoester (13) was obtained starting from geraniol. Condensation between 13 and 24 with silver oxide in dioxane afforded the methyl ester of nor-O-methyl mycophenolic acid. Selective methylation and hydrolysis furnished mycophenolic acid. © 1972
Factors affecting cytochrome P-450 and horseradish peroxidase-catalyzed oxidative N-dealkylation of aromatic tertiary amines. A multivariate approach
No full textPartial least squares method was used as a multivariate approach intended to correlate kapp in the oxidation of N,N-dimethylanilines with peroxidase-hydrogen peroxide and υmax and KM in the oxidation of N,N-dialkylanilines with rat liver microsomes-NADPH-dioxygen with several parameters of the substrates. The variables used in these modeling studies were: σ = the electronic contribution of the nuclear substituent, π = the lipophilicity parameter of the substrate, MW = the molecular weight, IEΔ,degE = the mean information on magnitude of distance degree, χ = the Randic connectivity index (mean), NPSSA = non-polar saturated surface area, PSA = polar surface are
ANALYSIS, ANAEROBIC TREATMENT AND OZONATION OF WOOL SCOURING WASTE-WATER
No full textWool scouring effluents (WSE) were analyzed by high-resolution gas chromatography-mass spectrometry (HRGC-MS), and then exposed to anaerobic biological treatment using laboratory scale fixed-bed filters. This resulted in a nearly 50% reduction in chemical oxygen demand (COD). Ozonation of the effluent from the biological step led to an even further decrease in total organic carbon (TOC). The fatty acid content of the WSE was affected by both biological treatment and ozonation. Finally, steroids in the WSE underwent reduction reactions when exposed to the anaerobic biological treatment
Metal carbonyls catalysed reductive carbonylation of substituted nitrobenzenes in presence of alkenes as solvents
No full textSeveral nitrobenzene derivatives were submitted to reaction with carbon monoxide in alkene solvents in the presence of catalytic amounts of Ru3(CO)12. Ureas and amines were formed in this reaction, and the secondary amine derived from insertion of the nitrene intermediate at the allylic position of the alkene solvent was a secondary product. The influence of the electronic factor of the substituents on the urea vs. amine ratio is discussed
Pyrolysis gaschromatography mass spectrometry of polychlorophenols and polychlorophenates
No full textAnalysis and anaerobic degradation of wool scouring and olive oil mill wastewaters
No full textTwo types of fatty industrial wastewaters, wool scouring effluents (WSE)and olive oil mill effluents (OME) were analysed (lipids, phenols and COD), and were then treated anaerobically in laboratory-scale fixed bed filters. Approximately 50% of the organic compounds in both wastewaters was degraded at two days of hydraulic residence time. A higher biogas production was obtained when using OME rather than WSE. This experimental study confirmed that anaerobic digestion can be considered as a roughing treatment in a multi-step process for industrial fatty wastewater
- …
