Synthesis of 1,3,5-tris(2-chloroethyl)- and 1,3,5-tris(2-iodoethyl)benzenes

A new method has been elaborated for the synthesis of 1,3,5-tris(2-chloroethyl)- and 1,3,5-tris(2-iodoethyl)benzenes based on the commercially available 1,3,5-tribromobenzene.     

An efficient and facile one-pot synthesis of structurally unique 2,4,6-tris(arylchalcogeno)-1,3,5-triazine and 1,3,5-tris(arylchalcogeno)-2,4,6-trimethylbenzene

An efficient one-pot synthesis of a novel class of 2,4,6-tris(arylchalcogeno)-1,3,5-triazine (sulfur, selenium and tellurium) and 1,3,5-tris(arylchalcogeno)-2,4,6-trimethylbenzene (sulfur and selenium)-containing ligands has been developed based on the reaction of 2,4,6-trichloro-1,3,5-triazine and 1,3,5-tris(bromomethyl)-2,4,6-trimethylbenzene with the corresponding arylchalcogenide anions generated in aqueous tetrahydrofuran.     

Stereodynamics of 1,3,5-tris(trifluoromethylsulfonyl)-1,3,5-triazinane: experimental and theoretical analysis

Dynamic NMR of 1,3,5-tris(trifluoromethylsulfonyl)-1,3,5-triazinane reveals two dynamic processes: ring inversion leading to equilibrium between two degenerate rotamers of C_s symmetry (ΔG^≠ = 13.5 kcal/mol), and rotation about the S-N bond leading to equilibrium between the C_s (more stable) and C_3v (2.12 kcal/mol less stable) rotamers (ΔG^≠ = 13.0 kcal/mol).     

Trisubstituted 1,3,5-triazines 3. Synthesis of substituted 2,4,6-tris(hydroxyiminomethyl)-1,3,5-triazines

Previously undescribed substituted 2,4,6-tris(hydroxyiminomethyl)-1,3,5-triazines, including 2,4,6-(1,3,5-triazinetriyl)trinitrolic acid, have been synthesized.For Communication 2, see [1].N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, 117913. Institute of Chemical Physics in Chernoglovka, Chernoglovka, Moscow Oblast, 142432, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 76–78, January, 1999.     

The stereodynamics of 3,5-bis(trifluoromethylsulfonyl)-1,3,5-oxadiazinane and 1,3,5-tris(trifluoromethylsulfonyl)-1,3,5-triazinane—an experimental and theoretical study

Multinuclear dynamic NMR spectroscopy of 3,5-bis(trifluoromethylsulfonyl)-1,3,5-oxadiazinane (3) revealed the existence of two conformers with differently oriented CF₃ groups with respect to the ring, and two dynamic processes: ring inversion and restricted rotation about the N-S bond. Two transition states connecting the two conformers and corresponding to clockwise and counterclockwise rotations about the N-S bond were found; the calculated activation barriers of about 12 kcal/mol are in excellent agreement with those measured experimentally for the related molecule 1,3,5-tris(trifluoromethylsulfonyl)-1,3,5-triazinane (1). X-ray analysis proved the existence of the symmetric isomer of 3, which is the minor isomer in solutions but the only one in the crystal due to packing effects. The normal Perlin effect (JCH_ax<JCH_eq) was observed for 2(6)-CH₂ in 3, whereas the reversed Perlin effect was found for the 4-CH₂ group in 3 as well as for all CH₂ groups in 1 both experimentally and theoretically. The latter effect in compounds 1, 3, and 1-(methylsulfonyl)-3,5-bis(trifluoromethylsulfonyl)-1,3,5-triazinane (2) can be considered as a genuine reverse Perlin effect since larger values of ¹J_CH are observed for longer C-H bonds.     

Nucleophilic substitution reactions of 2,4,6-tris(trinitromethyl)-1,3,5-triazine. 2. interaction of 2,4,6-tris(trinitromethyl)-1,3,5-triazine with primary amines and hexamethyldisilazane

2-R-amino-4,6-bis (trinitromethyl)-1,3,5-triazines have been synthesized, and their structures have been established. Dynamic¹³C NMR spectroscopy has been used to measure the rotational barriers of the tertbutylamino group around the C₍₂₎-NHBu-t bond in 2-(tert-butylamino)-4,6-dichloro-1, 3, 5-triazine and 2-(tertbutylamino)-4,6-dimethoxy-1,3,5-triazine. X-ray diffraction was used to investigate the structure of 2-(tertbutylamino)-4,6-bis (trinitromethyl)-1,3,5-triazine. From the results obtained in this work it has been concluded that the bond between the NHBu-t group and the triazine ring has a partial double-bond character.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from ] Khimiya Geterotsikiicheskikh Soedinenii, No. 5, pp. 679–688 May, 1995. Original article submitted March 7, 1995.     

Synthesis and spectroscopic properties of 1,3,5-tris(arylalkynyl)-2,4,6-trimethoxybenzenes

A number of C₃-symetric 1,3,5-tris(arylalkynyl)-2,4,6-trimethoxybenzenes which carry electron withdrawing aryl substituents at the acetylenic periphery and donating methoxy groups on the central benzene ring are prepared via Sonogashira coupling. The utility of two different synthetic routes is evaluated as well as the effect of the nature of the aryl and ethynyl starting compounds in the coupling reaction. Finally, a correlation between the substitution pattern of the alkynyl compounds and their UV-vis and fluorescence spectroscopic properties is established.     

Crystal Structures and Packing of 2,4,6-tris(4-Fluorophenoxy)-1,3,5-triazine and 2,4,6-tris(3,4-Dimethylphenoxy)-1,3,5-triazine. New Materials for Octupolar Nonlinear Optics

The crystal structures and packing of 2,4,6-tris(4-fluorophenoxy)-1,3,5-triazine and 2,4,6-tris(3,4-dimethylphenoxy)-1,3,5-triazine are discussed. These structures have been determined as a continuation of a series of octupolar NLO materials we have been investigating. The crystal structures are characterized by C–H...F and C–H... hydrogen bonds, respectively. A characteristic of these triazine structures is the presence of dimeric Piedfort Units (PU) that are extended into more elaborate two-dimensional (2-D) networks. The structure of the fluoro derivative is compared with that of the corresponding unsubstituted and chloro/bromo-substituted derivatives. The structure of the dimethyl triazine is compared with that of the corresponding 4-methyl derivative. The noncentrosymmetric nature of the dimethyl derivative was confirmed by a powder SHG signal at 1.064 m of the order of 0.5 × KDP. Interestingly, the dimethyl derivative studied here is isostructural with the corresponding 4-methyl triazine. This H/Me isostructurality is shown to be an uncommon phenomenon by an analysis with the CSD.     

Synthesis and X-ray molecular structure of cis,cis-1,3,5-Tris(diphenylphosphino)- 1,3,5-tris(methoxycarbonyl) cyclohexane

The novel tripodal phosphine ligand cis, cis-1,3,5-tris(diphenylphosphino)-1,3,5-tris(methoxycarbonyl)cyclohexane (tdppcyme) (2) has been synthesized. ¹H, ¹³C and ³¹P NMR spectroscopy shows that in solution the sterically demanding diphenylphosphine groups occupy equatorial positions on the cyclohexane ring. An X-ray crystal investigation confirms this result for the solid state. Treatment of tdppcyme with Mo(η⁶-C₇H₈)(CO)₃ gives Mo(tdppcyme)(CO)₃ (3), with octahedral molybdenum coordination.     

1,3,5-Trimethyl-1,3,5-tris(hexafluoroalkyl)cyclotrisiloxanes. Basicity of ethoxysilanes and cyclosiloxanes

1,3,5-Trimethyl-1,3,5-tris(hexafluoroalkyl)cyclotrisiloxanes were synthesized by hydrolytic polycondensation of methyl(hexafluoroalkyl)dichlorosilanes, and 1,1,3,3,5-pentamethyl-5-(trifluoromethyltrifluorobicyclo[2.2.1]heptyl)cyclotrisiloxane was synthesized by heterofunctional condensation. The effect of hexafluoroalkyl substituents at the silicon atom on the reactivity of the siloxane bonds has been studied.     

Triprotic 2,4,6-tris(organoamino)-1,3,5-triazenes as precursors to multi-site triazenate ligands

2,4,6-Tris(2-fluoroanilino)-1,3,5-triazene successively undergoes one-, two- and three-fold deprotonation in the presence of BunLi; the dilithiated triazenate exists as the dimeric complex (thf)6Li4[(RN)2(RNH)C3N3]2 in the solid state (R = 2-F-C6H4) featuring bidentate Nendo-C-Nexo chelation sites.     

Titanium imido complexes containing 1,3,5-triazacyclohexane ligands

The syntheses of the 1,3,5-trimethyl- and tri-tert-butyl-1,3,5-triazacyclohexane-supported imido complexes [M(NR)(R′₃tach)Cl₂] (M = Ti or Zr (NMR only); R = Bu^t or 2,6-C₆H₃Prⁱ₂; R′ = Me or Bu^t) are reported, along with that of the thermally robust dibenzyl derivative [Ti(NBu^t)(Me₃tach)(CH₂Ph)₂]. The tert-butylimido ligand in [Ti(NBu^t)(Me₃tach)Cl₂] undergoes exchange with ArNH₂ (Ar = 4-C₆H₄Me or 2,6-C₆H₄Me or 2,6-C₆H₃Prⁱ₂) to form the corresponding arylimides [Ti(NAr)(Me₃tach)Cl₂]. The Me₃tach ring in [Ti(NR)(Me₃tach)Cl₂] undergoes slow exchange with Bu^t₃tach or Me₃tacn (1,4,7-trimethyl-1,4,7-triazacyclononane) to give the ring-exchanged products [Ti(NR)(Bu^t₃tach)Cl₂] and [Ti(NR)(Me₃tacn)Cl₂], respectively. The complexes [Ti(NR)(Me₃tach)X₂] (R = Bu^t or 2,6-C₆H₃Prⁱ₂; X = Cl or CH₂Ph) exhibit room-temperature dynamic NMR behaviour via an unusual trigonal twist of the facially coordinated Me₃tach ligand, and the activation parameters for these processes have been measured and are discussed. The X-ray structures of [Ti(NR)(Bu^t₃tach)Cl₂] (R = Bu^t or 2,6-C₆H₃Prⁱ₂) and [Ti(NBu^t)(Me₃tach)(X)₂] [X= Cl or CH₂Ph) are reported. Me₃tach and Bu^t₃tach = 1,3,5-trimethyl- and tri-tert-butyl-1,3,5-triazacyclohexane, respectively.     

Reaction of DMSO with ureas- a one step route to 1,3,5-tris(methylthiomethyl)-1,3,5-triazine-2,4,6-trione

Chemistry of Heterocyclic Compounds -