2-monobromomethyl 1,4-dihydropyridines is selectively synthesized by bromination of the parent compound by 1.1 equivalents of pyridinium bromide perbromide in dichloromethane/pyridine at -20 °C. The same reagent in dichloromethane at 0 °C produce the 2,6-bis(bromomethyl) 1,4-dihydropyridines.

The antioxidant activity of the crude n-hexane, dichloromethane, and methanol extracts from 25 species belonging to the Asteraceae, Euphorbiaceae, Rubiaceae, and Solanaceae families collected at natural reserves from the Eje Cafetero Ecorregión Colombia, were evaluated by using the spectrophotometric 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging method. The strongest antioxidant ...

Problem statement: Persea cordata previously demonstrated antispasmodic action against two neurotransmitters. It is important confirm such action against other neurotransmitters. Approach: Present study described the antispasmodic activity of polar (EtOAc; n-BuOH) and non polar (nhexane; dichloromethane) fractions from the bark of Persea cordata, against guinea pig ileum contracted by 5-hydroxy...

In this study elements of validation of headspace GC method of determination of residual methanol, n-pentane, ethanol, tert-butylamine, 2propanol, acetonitrile, dichloromethane and toluene in pharmaceutical substance are presented. Validation of the method included: selectivity, system precision, method precision, accuracy (recovery), limits of detection and quantitation (in substance), robustn...

The influence of chemical cleaning agents on the bond strength between resin cement and glass-fiber posts was investigated. The treatments included 10% hydrofluoric acid, 35% phosphoric acid, 50% hydrogen peroxide, acetone, dichloromethane, ethanol, isopropanol, and tetrahydrofuran. Flat glass-fiber epoxy substrates were exposed to the cleaners for 60 s. Resin cement cylinders were formed on th...

A novel flavonoidic compound, 3,5-dihydroxy-4’,7-dimethoxyflavone, has been isolated from the rhizomes of Zingiber phillipseae. The dichloromethane extract of this species was shown to be non-toxic with LC50 for acute and toxic levels at 9,732 ppm and 562 ppm, respectively. The extract showed higher antioxidant activity than the standard (butylated hydroxytoluene, BHT) but lower than dichlorome...

The synthesis of alpha-aminonitriles and their fluorinated analogs has been carried out in high yield and purity by the Strecker reaction from the corresponding ketones and amines with trimethylsilyl cyanide using gallium triflate in dichloromethane. Monofluoro-, difluro-, or trifluoromethyl groups can be incorporated into the alpha-aminonitrile product by varying the nature of the fluorinated ...

The smoke of Peganum harmala seeds is traditionally used in Iran as a disinfectant agent. The aim of this study was to determine the antimicrobial activity of two smoke condensates from Peganum harmala seeds. Furthermore the composition of smoke preparations was studied using gas chromatography and mass spectroscopy analysis. The most prevalent compound detected in a dichloromethane extract was...