Synthesis and Confirmation of Azacyclohexanes

In this thesis, the ring conformations of azacyclohexanes are studied using the 1,3,5-triazacyclohexanes and 3,7-diazabicyclo[3.3.1]nonanes as model structures. A review is presented of the synthesis of mono-, di-, tri- and tetraazcyclohexanes and of studies of their conformations in solution and in the solid state. The synthesis of the 1,3,5-trisubstituted 1,3,5-triazacyclohexanes (106), (107), (108), (110), (111), (112), (113), (114), (115), (116), (118) and (122) has been undertaken by condensation of formalin or paraformaldehyde with the corresponding aryl/alkylamines in an inert solvent, toluene, benzene or ethanol, sometimes with addition of strong base. Compound (117) was formed using the reported reaction of 4-nitroaniline with dimethylsulphoxide in presence of phosphorus pentoxide. Condensation of 2-trifluoromethylaniline with paraformaldehyde and of 4-nitroaniline with formalin gave the N,N'-diaryldiaminomethanes (122) and (123) probably as the result of steric hindrance in the former and decreased nitrogen basicity in the latter. Attempts to prepare the triazacyclohexane (119) by increasing reaction time and temperature gave the 2:1 adduct (122). Condensation of 2-trifluoromethylaniline with DMSO / P2O5 failed to give either (119) or (122). X-ray crystal structure analysis revealed that compounds (106) to (108), (110) to (113), and (114) exist in the solid state as chair conformations in which the nitrogen substituents adopt diaxial-equatorial substituents, whereas, for compounds (115) and (116), the nitrogen substituents are diequatorial-axial. The existence of eight of the ten 1,3,5-triazacyclohexanes studied as the aae conformers is considered to be a manifestation of the rabbit-ear (or generalised anomeric) effect. That the other two 1,3,5-triazacyclohexanes adopt, in the solid state, the aee conformers is most likely the result of crystal packing forces rather than of a major energy difference between the aae and aee conformers. The nitrogen atoms of all ten compounds are pyramidal and the syn-diaxial substituents are displaced apart. The triazacyclohexane (117) as the pyridine solvate adopts a twist-boat conformation with one nitrogen atom planar and the two other nitrogen substituents anti to each other. The diaryldiaminomethane (122) adopts a skewed conformation around the N-CH2 bonds with the trifluoromethyl groups remote from each other. The crystal structure of diaryldiaminomethane (123) was not refined. Compounds (182)-(186) were formed by reaction of the sulphonyl chlorides (RSC2Cl) with diazaadamantanone (144) or the diamine (181). An alternative approach to 3,7-diazabicyclo[3.3.1]nonanes by nucleophilic substitution of tetraiodide (189) by 4-fluoroaniline has led to the monocyclic piperidine (190). In the solid state, 3,7-diazabicyclo [3.3.1]nonanes (182) and (184) were found to adopt a twin-chair conformation with somewhat pyramidal character of the nitrogen atoms. The alternative boat-chair conformation was adopted by (183), and (185) exists in both twin-chair and boat-chair conformations in the solid state. Again, the different conformational preferences are considered to be due to crystal packing forces and not to marked differences in energy between the twin-chair and the boat-chair conformations. The piperidine (190) adopts the chair conformation with N atom pyramidal and with the equatorial orientation on the piperidine ring of all three substituents

Interaction of C10, C11 and C18 fatty acids with calcite surface as revealed by IR spectroscopy, X-ray diffraction and atomic force microscopy

The adsorption of C10, C11 and C18 fatty acids from aqueous solution is a phenomenon of major importance in flotation, geochemistry and oceanography. There is an approach that allows identifying the origin of the formation of aggregates of condensed molecules and the filling mechanism of the adsorbed layer. The different homogeneous domains of the surface are filled by decreasing energetic order. The size of different homogeneous domains controls the size of the lamellar aggregates to one layer and two layers for high concentration. Fatty acid adsorption was investigated at the calcite surface by infrared spectroscopy, atomic force microscopy and X-ray diffraction studies. The adsorption process was studied for different fatty acids in acid medium created by phosphoric acid at pH = 4.8-5.0

Synthesis and characterization of 1,3-bis(4-bromophenyl)-5-propyl-1,3,5-triazinane

Condensation of n-propyl amine and 4-bromoaniline with formaline in basic solution gives 1,3-bis(4-bromophenyl)-5-(propyl)-1,3,5-triazinane. Structure of the synthesized compound was characterized by FT-IR and 1H- and 13C-NMR spectroscopy

Synthesis and antimicrobial activity of 1,3-bis-butyl-5-(4-iodophenyl)-1,3,5-triazacyclohexane

This work describes the synthesis, structural characterization and antibacterial activities of 1,3,5-triazacyclohexane type of new compound 1,3-bis-butyl-5-(4-iodophenyl)-1,3,5-triazacyclohexane. The new triazacyclohexanes (R3TAC) with mixed aryl and alkyl N-substituents are synthesized by the reaction of a 1:2 mixture of 4-iodoaniline and n-butylamine with formalin. The synthesized compounds were characterized by spectral analysis IR, 1H NMR and 13C NMR. The compound was screened for it’s antibacterial activity against Gram-positive and Gram-negative bacteria by the diffusion method on agar medium

Interaction of C10, C11 and C18 fatty acids with calcite surface as revealed by IR spectroscopy, X-ray diffraction and atomic force microscopy

The adsorption of C10, C11 and C18 fatty acids from aqueous solution is a phenomenon of major importance in flotation, geochemistry and oceanography. There is an approach that allows identifying the origin of the formation of aggregates of condensed molecules and the filling mechanism of the adsorbed layer. The different homogeneous domains of the surface are filled by decreasing energetic order. The size of different homogeneous domains controls the size of the lamellar aggregates to one layer and two layers for high concentration. Fatty acid adsorption was investigated at the calcite surface by infrared spectroscopy, atomic force microscopy and X-ray diffraction studies. The adsorption process was studied for different fatty acids in acid medium created by phosphoric acid at pH = 4.8-5.0

Crystal structure of 3,5-bis(4-chlorophenyl)-1-propyl-1,3,5-triazacyclohexane

International audienceIn the title mol­ecule, C18H21Cl2N3, the tri­aza­cyclo­hexane ring adopts a chair conformation with both 4-chloro­phenyl substituents in axial positions and the propyl group in an equatorial site. The dihedral angle between the planes of the benzene rings is 49.5 (1)°. In the crystal, mol­ecules are arranged in a head-to-tail fashion, forming columns along [010], and pairs of weak C—H⋯π inter­actions form inversion dimers between columns

1,3,5-Tris(4-bromophenyl)-1,3,5-triazinane dichloromethane monosolvate

In the main molecule of the title compound, C21H18Br3N3·CH2Cl2, the triazinane ring adopts a chair conformation with three 4-bromophenyl substituents, two in diaxial positions and the third in an equatorial arrangement (eaa). The torsion angles around the N—C bonds in the triazinane ring are in the range 55.6 (5)–60.1 (5)°. The structure can be described as being built up of alternating layers along the b axis with the CH2Cl2 solvent molecules sandwiched between these layers. No classical hydrogen-bonding interactions are observed in the crystal structure

Synthesis and spectral studies of 3,5-bis(4-chlorophenyl)-1-propyl-1,3,5-triazinane

A hexahydrotriazine derivative was synthesized via a condensation reaction of 4-chloroaniline, propylamine and formalin. The structure of the synthesized compound was confirmed and characterized by using various spectral techniques like FT-IR, 1H NMR, 13C NMR and UV spectroscopy