Search results for "Dichloromethane"
showing 10 items of 682 documents
Chemoselective reactions of N1-methyl-2-hydroxy-3-methylamino-3-phenylpropanamide with electrophiles. Synthesis of chiral hexahydro-4-pyrimidinones a…
2002
Abstract The reactivity of (2S,3S)-N1-methyl-2-hydroxy-3-methylamino-3-phenylpropanamide 1 , containing three nucleophilic centres has been studied against dihaloalkanes and aldehydes. Hexahydro-4-pyrimidinones or oxazolidines were obtained chemoselectively. Experimental results were explained by ‘ab initio’ calculations.
Polyfurfuryl alcohol composite as adsorbent of polychlorinated biphenyls and pyrethroid insecticides
2007
Abstract Composites from furfuryl alcohol and silica gel were prepared in dichloromethane using trifluoroacetic acid as catalyst and characterized by means of thermogravimetric analysis, transmission electron microscopy and nitrogen adsorption–desorption isotherms. The polymer content in the composites ranged between 19.5% and 32.9%. The capability to adsorb polychlorinated biphenyls and pyrethroid insecticides was tested for composite samples containing different percentages of polymer. Pyrethroids are retained almost totally by composites containing around 24–33% of polymer, while recovery of PCBs close to 80% is obtained with all the composites. No selectivity between compounds of the sa…
ChemInform Abstract: E,Z-Stereodivergent Synthesis of N-Tosyl α,β-Dehydroamino Esters via a Mukaiyama-Michael Addition
2016
The stereodivergent synthesis of N-tosyl α,β-dehydroamino esters via a Mukaiyama–Michael addition is reported. The reaction of silylketene acetals with N-tosylimines derived from β,γ-unsaturated α-keto esters in dichloromethane provided the corresponding (Z)-α,β-dehydroamino esters while the (E)-isomers were obtained when the reaction was carried out in the presence of 10 mol% copper(II) triflate.
Synthesis of 1,3-Oxazolidines and 1,3-Dioxolanes by Reaction of (2R, 3R)-3-Methylamino-3-phenyl-1,2-propanediol with Electrophiles
2003
Abstract The chemoselective reaction of (2R, 3R)-3-methylamino-3-phenyl-1,2-propanediol 1 with dimethoxypropane and dichloromethane under different conditions are reported as useful preparative procedures, for the synthesis 1,3-oxazolidines and 1,3-dioxolanes.
Generation of Stereocenters Around a C3-Symmetric Cyclotriveratrylene Crown
2012
The oxidation of racemic methylthio-substituted C3-symmetric cyclotriveratrylene (CTV) 2 produces the corresponding trisulfoxides 3 as follows. Oxidation with m-chloroperoxybenzoic acid (m-CPBA) in dichloromethane leads to the formation of a distribution of the four possible diastereomers that is relatively close to the statistical outcome, in which the C3-symmetric stereoisomers are the minor species. In contrast, the optically active Davis reagent [oxaziridine (+)-4] in carbon tetrachloride at room temperature leads to a biased (73 %) distribution in favor of the C3-symmetric MRRR/PSSS diastereomer of 3 with 56 % ee (PSSS enantiomer according to the model of Davis). Interestingly, when th…
Halogen bond preferences of thiocyanate ligand coordinated to Ru(II) via sulphur atom
2017
Halogen bonding between [Ru(bpy)(CO)2(S-SCN)2] (bpy = 2,2’-bipyridine), I2 was studied by co-crystallising the metal compound and diiodine from dichloromethane. The only observed crystalline product was found to be [Ru(bpy)(CO)2(S-SCN)2]⋅I2 with only one NCS⋅⋅⋅I2 halogen bond between I2 and the metal coordinated S atom of one of the thiocyanate ligand. The dangling nitrogen atoms were not involved in halogen bonding. However, computational analysis suggests that there are no major energetic differences between the NCS⋅⋅⋅I2 and SCN⋅⋅⋅I2 bonding modes. The reason for the observed NCS⋅⋅⋅I2 mode lies most probably in the more favourable packing effects rather than energetic preferences between …
CCDC 1530606: Experimental Crystal Structure Determination
2017
Related Article: Huayan Yang, Juanzhu Yan, Yu Wang, Haifeng Su, Lars Gell, Xiaojing Zhao, Chaofa Xu, Boon K. Teo, Hannu Häkkinen , and Nanfeng Zheng|2017|J.Am.Chem.Soc.|139|31|doi:10.1021/jacs.6b10053
CCDC 996584: Experimental Crystal Structure Determination
2014
Related Article: Matteo Atzori, Flavia Pop, Pascale Auban-Senzier, Carlos J. Gómez-García , Enric Canadell, Flavia Artizzu, Angela Serpe, Paola Deplano, Narcis Avarvari, and Maria Laura Mercuri|2014|Inorg.Chem.|53|7028|doi:10.1021/ic501001r
Pt(II) and Pd(II)-assisted coupling of nitriles and 1,3-diiminoisoindoline : Synthesis and luminescence properties of (1,3,5,7,9-pentaazanona-1,3,6,8…
2017
Treatment of trans-[PtCl2(NCR)2] 1 (R = Me (1a), Et (1b), o-ClC6H4 (1c), p-ClC6H4 (1d), p-(HCdouble bond; length as m-dashO)C6H4 (1e), p-O2NC6H4CH2 (1f)) with 1,3-diiminoisoindoline HNdouble bond; length as m-dashCC6H4C(NH)double bond; length as m-dashNH 2 gives access to the corresponding (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato)Pt(II) complexes [PtCl{NHdouble bond; length as m-dashC(R)Ndouble bond; length as m-dashC(C6H4)NCdouble bond; length as m-dashNC(R)double bond; length as m-dashNH}] 3a–f, in good yields (65–70%). The reaction of trans-[PdCl2(NCMe)2] 4a with 2 furnishes (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato)Pd(II) complex [PdCl{NHdouble bond; length as m-dashC(Me)Ndouble bond…
Stability of Cannabinoids in Hair Samples Exposed to Sunlight
2000
It has been well recognized that hashish and marihuana lose potency during storage because of a decrease in the content of tetrahydrocannabinol (THC), which is the major psychoactive constituent of cannabis (1). The effect of oxygen on stored plant and resin materials or solutions of pure cannabinoids seems much less significant than that of higher temperatures (≥37 °C) or light (2)(3)(4)(5)(6)(7). A few data are available on the stability of THC and major metabolites in blood (8)(9)(10)(11). However, the stability of cannabinoids in the hair shaft has not been addressed, although scalp hair represents one of the most exposed parts of the body. Therefore, a study was performed to elucidate …