engleski

Novel Chiral Stationary Phases Comprising 2, 4-(or 2, 6) Diamino-5, 6- (or 2, 5) dichloro-1, 3-dicyanobenzene and 1-Acyl (1R, 2R)-diaminocyclohexane

Novel chiral selectors 3-5 were prepared by regio-selective nucleophilic substitution of 2, 4, 5, 6-tetrachlorobenzene-1, 3-dicarbonitrile (TCBDC, 1) at C(4) by (1R, 2R)-trans-diaminocyclohexane, followed by acylation of the intermediary 2 with carboxylic acids containing π-acid or π-basic unit. On substitution of the second chlorine atom by the spacer 3-aminopropyltriethoxysilane (APTES), a 1:1 mixture of regioisomers of N-({; ; [3, 6-dichloro-2, 4-dicyano-5- (4, 4, 4-triethoxy-4- silabutyl)- amino]phenyl}; ; amino)cyclo-hexylcarboxamides and N-(5, 6 -dichloro-2, 4-dicyano-3- (4, 4, 4-triethoxy -4-silabutyl) -amino]phenyl}; ; amino)cyclohexylcarboxamides (6/7, 8/9, 10/11) was obtained. Their covalent binding to Nucleosil 100-5 provided three new chiral stationary phases (CSP-1-CSP-3). NMR spectra of model compounds 12-14 and MM2 calculations on model compounds 15, 16 revealed π-π interactions between persubstituted benzene ring and second aromatic ring. The results of the evaluation of new CSPs in the separation of 23 test racemates by HPLC are reported. CSP-2 and CSP-3, that have lower conformational freedom than CSP-1, allow for better separation. In particular, good results are obtained in the separation of some 1, 4-benzodiazepines and open-chain aromatic amides by CSP-2 and CSP-3.

chiral stationary phase ; enantioseparation ; 2, 4-(or 2, 6)-diamino-5, 6-(or 2, 5)-dichlorobenzene-1, 3-dicarbonitriles ; 1, 2-(1R, 2R)-diaminocyclohexane

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