Search results for "Chlorine atom"
showing 10 items of 16 documents
Gas-liquid chromatographic analyses
1983
Abstract The gas chromatography of mixtures of n -alkyl acetates (CH 3 COOR, R = C 1 —C 8 ) and methyl esters of aliphatic n -carboxylic acids (R′COOCH 3 , R′ = C 1 —C 8 ) and certain of their monochlorinated derivatives has been studied on Carbowax 20M and SE-30 glass capillary columns under the same operating conditions. The separation of the isomeric monochlorinated esters was complete on Carbowax 20M, whereas on SE-30 the peaks of 6- and 7-chlorooctyl acetates and methyl (ω − 1)- and (ω − 2)-chlorooctanoates and -nonanoates partly overlapped. The complete separation of the mixtures could not be achieved, however, on Carbowax 20M, in spite of the use of various operating conditions. The …
13C NMR study on the methoxy carbon chemical shifts in chloro-substituted anisoles and guaiacols
1983
The 13C NMR chemical shifts of methoxy carbons in chlorinated anisoles and guaiacols have been measured for acetone-d6 solutions. Multiple linear regression analysis, and also ‘simple sum rule’ calculations, have been used to estimate the effects of the chlorine atoms (the position and degree of substitution) on the chemical shifts. The most important effects have shown to be due to the chlorine atoms adjacent to the methoxy and hydroxy substituents. For chlorinated guaiacols, the greatest effect is due to the chlorine atom adjacent to the methoxy group. For chlorinated anisoles, the substituents adjacent to the methoxy group (2,6-disubstitution) cause large effects. For both groups of comp…
Gas chromatographic study of acetyl derivatives of chlorinated 4-hydroxybenzaldehydes
1982
The GC retention times of 4-hydroxybenzaldehyde and its chloro derivatives have been measured on three nonpolar capillary columns. Multiple linear regression analysis has been used to explain the mobility of chlorinated compounds relative to the reference compound 4-hydroxybenzaldehyde. The most important effects have shown to be due to the number of chlorine atoms and the substituents ortho to the formyl group. Other effects have also been observed but found to be unable to explain the GC data.
Synthesis, Characterisation and Reactivity towards PdII and PtII of ortho-, meta- and para-Xylyl-Based Phosphorus-Containing Macrocycles
2002
The new meta- and para-xylyl-based phosphadithiamacrocycles 6-phenyl-6-phospha-3,9-dithiabicyclo[9,3,1]pentadeca-1(15),12,14-triene (L2) and 6-phenyl-6-phospha-3,9-dithiabicyclo[9,2,2]pentadeca-1(13),12,14-triene (L3) have been synthesised and characterised. The reactivity of these ligands and the previously described ortho-xylyl macrocycle 6-phenyl-6-phospha-3,9-dithiabicyclo[9,4,0]pentadeca-1(11), 12,14-triene (L1) with [PdCl2(cod)] and K2[PtCl4] has been studied. [MCl2(L)] complexes have been obtained and characterised by NMR spectroscopy. X-ray structural analyses have been carried out in the case of [PdCl2L2]·CH3CN (2·CH3CN) and [PdCl2L3] (3). In both compounds the PdII ion adopts a sl…
Asymmetric synthesis of chloroisothreonine derivatives via syn-stereoselective Mannich-type additions across N-sulfinyl-α- chloroimines
2014
Mannich-type reactions of O-Boc glycolic esters across chiral N-sulfinyl-α-chloroaldimines resulted in the efficient and syn-stereoselective synthesis of new γ-chloro-α-hydroxy-β-amino esters (dr > 99:1). The α-coordinating ability of the chlorine atom was of great importance for the diastereoselectivity of the Mannich-type reaction and overruled the chelation of the sulfinyl oxygen with the lithium ion of the incoming E-enolate in the transition state model. These novel chloroisothreonine derivatives proved to be excellent building blocks in asymmetric synthesis of novel syn-β,γ-aziridino-α-hydroxy esters and biologically relevant trans-oxazolidinone carboxylic esters.
Antimykotische wirkstoffe. XV. . Die halogensubstitution bei phenoxy-1,3,5-triazinen
1983
Durch die nucleophile substitution eines Chloratoms in 2, 4-Dichloro-6-diethylamino-1, 3, 5-triazine (1) mittels Halogenphenolen (2a-f) werden die 2-chloro-4-diethylamino-6-halogenphenoxy-1, 3, 5-triazine (3a-f) zuganglich. In Strukturtyp 3 finden sich Vertreter mit antimykotischer Wirksamkeit. Through the nucleophilic substitution of one chlorine atom in 2,4-dichloro-6-diethylamino-1,3,5-triazine (1) by halophenols (2a-f) the 2-chloro-4-diethylamino-6-halophenoxy-1,3,5-triazines (3a-f) are accessible. Structure 3 comprises representatives exhibiting antimycotic activity.
A practical ethylene polymerization for vinyl-polyethylenes: synthesis, characterization and catalytic behavior of α,α’-bisimino-2,3:5,6- bis(pentame…
2016
A series of α,α′-bis(arylimino)-2,3:5,6-bis(pentamethylene)pyridyliron chlorides was synthesized in a one-pot reaction and characterized by FT-IR and elemental analysis as well as X-ray crystallography for one representative iron complex, where the Fe center adopts a distorted square pyramidal geometry with three coordinating nitrogen and two chlorine atoms. The iron precatalysts, upon treatment with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), exhibit high activities in the range of 107 g of PE per mol of Fe per h toward ethylene polymerization, yielding highly linear and, more importantly, vinyl-polyethylenes. The correlation between the structural features of iron…
New qsar models for polyhalogenated aromatics
1994
Electronic properties of polychlorinated dibenzo p dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and polychlorinated diphenyl ethers (PCDEs) were calculated using the semi-empirical AM1 method The calculated electronic descriptors — the energy of the lowest unoccupied molecular orbital (ELUMO), the energy of the highest occupied molecular orbital (EHOMO), the ELUMO-EHOMO gap (dE), and molecular polarizability — are related to the Ah receptor binding affinity values of PCDDs, PCDFs, and PCBs and immunotoxicity values for PCDEs The quantitative structure activity relationships (QSARs) based on chlorine substitution patterns were also constructed, an…
Multiple linear regression analysis of RF values of chlorinated catechols and guaiacols
1981
The multiple linear regression analysis of the RF values of chlorinated catechols and guaiacols has been carried out. The resolved terms, in the regression equation have been used to explain the relative mobility of chlorinated compounds to the reference compound (catechol or guaiacol). The best correlations have been observed for solvent systems which give the greatest standard deviations and relative differences between the RF values. A good correlation between the standard deviation of the RF values and the term which represents the effect of the chlorine atom ortho to the hydroxyl group(s) have also been observed.
New potentially cytotoxic thiolatogold(I) complexes of 1,1′-bis(diphenylphosphino)ferrocene
1996
Abstract 1,1′-Bis[chlorogold(I) diphenylphosphino] ferrocene (1) was chosen as the starting material to synthesize new thiolato gold(I) complexes. This has been achieved by substituting the chlorine atoms by monofunctional and bifunctional thiolates affording ‘open’ thiolatogold complexes and trimetallic ferrocenophane-type structures, respectively. The new 1,1′-bis(2,6-dithia-1-phosphanyl)ferrocene (7) containing directly linked P and S atoms was also prepared but no gold complex was obtained. Compound 2 crystallizes in the monoclinic space group P21/n with a=10.2632), b=21.064(4), c=16.259(3) A , β=97.06(2)° and V=3.488(1) A 3 . The distance between the two gold atoms (3.06 A) indicates a…