- N-Methylmelamines: Synthesis, Characterization, and Physical Properties
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N-Methylmelamines have recently gained importance as valuable compounds for manufacturing modified melamine formaldehyde resins and other polymer building blocks. A great advantage of these polymers is the reduction of the carcinogenic formaldehyde. Selecting the polymerization processes (e.g., substance polymerization, polymerization in solution) and controlling the polymerization reaction and properties of these novel materials requires knowledge of the properties of the individual melamine derivatives used as new building blocks. All possible permutations of N-methylmelamines were prepared, and reaction progress was monitored by GC/MS. 2,4,6-Tris(dimethylamino)-1,3,5-triazine was prepared to complete the series; this is, however, also a possible byproduct in various synthesis routes. The reaction conditions were optimized to obtain high yields of each derivative with the highest possible purity. The substances were characterized by NMR and IR spectroscopy, mass spectrometry, elemental analysis, and single-crystal X-ray diffraction. In addition, physical properties, such as solubility, melting points, and pKb values, were determined. The number of amino-, methylamino-, and dimethylamino groups has a significant effect on these properties. In summary, we found that by increasing the number of amino- and methylamino groups, solubility and pKb increase. With increasing number of amino groups, the compounds tend to form hydrogen bonds, and thus, the melting point shifts to higher temperature ranges where they start to decompose.
- List, Manuela,Puchinger, Helmut,Gabriel, Herbert,Monkowius, Uwe,Schwarzinger, Clemens
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p. 4066 - 4075
(2016/06/09)
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- Dialkylcyanamides are more reactive substrates toward metal-mediated nucleophilic addition than alkylcyanides
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The dialkylcyanamide complexes Q[PtCl3(NCNR2)] (Q = Ph3PCH2Ph, R2 = Me21, Et 22, C5H103, C4H8O 4; Q = NMe4, R2 = Me25; Q = NEt4, R 2 = Me26) were synthesized either by dissolving Q 2[Pt2(μ-Cl)2Cl4] in neat NCNR2 (1-4) or by substitution of a NCNR2 ligand with Cl- in [PtCl2(NCNR2)2] by its treatment with QCl (5, 6). Nucleophilic addition of dibenzylhydroxylamine, HON(CH2Ph)2, to 1-6 results in the formation of the complexes Q[PtCl3{NHC(NR2)ON(CH2Ph) 2}] (Q = Ph3PCH2Ph, R2 = Me 2, 7; Et2, 8; C5H10, 9; C 4H8O, 10; Q = Me4N, R2 = Me 211; Q = Et4N, R2 = Me2, 12) that further convert at room temperature in the solid state (1-24 h) or in a solution (0.5-2 h) to the imine complexes Q[PtCl3{N(CH2Ph)C(H)Ph}] (Q = Ph3PCH2Ph, 13; Me4N, 14; Et4N, 15) and the corresponding dialkylureas H2NC(O)NR2. The competitive reactivity study of the nucleophilic addition of HON(CH 2Ph)2 to (Ph3PCH2Ph)[PtCl 3(NCR′)] (R′ = Ph, NR2, CH2Ph) indicated that the reactivity of the coordinated NCNR2 is comparable to NCPh, while NCCH2Ph appeared to be much less reactive than the former two ligands. Compounds 1-6 and 13 were fully characterized by elemental analyses (C, H, N), high resolution ESI-MS, IR, and 1H and 13C{1H} NMR spectroscopy. The structure of 1 was additionally verified by a single-crystal X-ray diffraction.
- Anisimova, Tatyana B.,Bokach, Nadezhda A.,Dolgushin, Fedor M.,Kukushkin, Vadim Yu.
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p. 12460 - 12467
(2013/09/02)
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- The umpolung of substituent effect in nucleophilic aromatic substitution. A new approach to the synthesis of N,N-disubstituted melamines (triazine triskelions) under mild reaction conditions
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By the umpolung of substituent effect 1,3,5-triazines substituted with three dialkylamino groups were prepared under mild reaction conditions by treatment of cyanuric chloride with tertiary amines. Quaternary N-triazinylammonium salts were identified as reactive intermediates activating the triazine ring and strongly promoting the persubstitution of all chlorine atoms. The final degradation of intermediate N-triazinylammonium chlorides proceeded at room temperature or in boiling dichloromethane spontaneously within irreversible evolution of appropriate chloroalkane.
- Kolesinska, Beata,Kaminski, Zbigniew J.
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experimental part
p. 3573 - 3576
(2009/09/08)
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- Atom efficient cyclotrimerization of dimethylcyanamide catalyzed by aluminium amide: A combined experimental and theoretical investigation
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A novel method for the cyclotrimerization of dimethylcyanamide to form hexamethylmelamine has been developed using an aluminium amide catalyst; detailed DFT modelling of the catalytic cycle supports a triple insertion, nucleophilic ring closure, deinsertion mechanism. The Royal Society of Chemistry.
- Dornan, Peter,Rowley, Christopher N.,Priem, Jessica,Barry, Sean T.,Burchell, Tara J.,Woo, Tom K.,Richeson, Darrin S.
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supporting information; experimental part
p. 3645 - 3647
(2009/02/05)
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- Synthesis and cytotoxic activity of trisubstituted-1,3,5-triazines
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1,3,5-Triazine derivatives were screened for phototoxicity as well as the cytotoxic activities against leukemia and adenocarcinoma derived cell lines in comparison to the normal human keratinocytes. A simple and environmentally friendly procedure has been developed for the synthesis of 1,3,5-triazine derivatives under microwave irradiation in the presence of a HY zeolite. The catalyst can be recovered and reused. Thus, the procedure provides a simple and green synthetic methodology under environmentally friendly conditions. Structure-activity relationships between the chemical structures and antimycobacterial and photosynthesis-inhibiting activity of the evaluated compounds are also discussed.
- Arya, Kapil,Dandia, Anshu
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p. 3298 - 3304
(2008/02/09)
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- A novel series of potent cytotoxic agents targeting G2/M phase of the cell cycle and demonstrating cell killing by apoptosis in human breast cancer cells
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Breast cancer, a leading cause of mortality in women, warrants the development and biological evaluation of new anticancer agents. A novel series of thiopyridine triazine derivatives was synthesized and investigated in the human breast cancer cell line, MDA-MB-468. SM40, the most potent derivative, induced a G2/M arrest and apoptosis with a possible involvement of p53. The cytotoxicity of SM40 was also examined against the NCI 60 cell line panel and its potency was rationalized using molecular modeling. Results suggest that SM40 is a promising cytotoxic agent.
- Mandal, Soma,Berube, Gervais,Asselin, Eric,Mohammad, Iqbal,Richardson, Vernon J.,Gupta, Atul,Pramanik, Saroj K.,Williams, Arthur L.,Mandal, Sanat K.
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p. 4955 - 4960
(2008/02/12)
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- Reactions of bis(silyl-substituted) methyllithium with α-hydrogen- free nitriles into 1,3,5-triazines
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Bis(silyl-substituted) methyllithium has been found to catalyze a conversion of α-hydrogen-free nitriles directly to yield 2,4,6-trisubsituted s-triazines. The generally high yields and relatively mild reaction conditions of this procedure suggest an alternative to other aromatic nitrile cyclotrimerization reactions. Silicotropic rearrangements from C to N or N to N and an unusual elimination of LiCR2R (R=SiMe3, R=SiMe2NMe2) were observed.
- Chen, Xia,Bai, Sheng-Di,Wang, Li,Liu, Dian-Sheng
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p. 1425 - 1430
(2007/10/03)
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- A practical and easy synthesis of 2,4,6-trisubstituted-s-triazines
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Triflic anhydride was found to be efficient for the cyclotrimerization of dialkylcyanamides under mild conditions. The same reaction can be applied to aryl nitriles and thiocyanates.
- Herrera, Antonio,Martinez-Alvarez, Roberto,Ramiro, Pedro,Chioua, Mourad,Chioua, Rachid
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p. 503 - 505
(2007/10/03)
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- Addition reactions of bis(trimethylsilyl)methyl- and 1-azzallyl-lithium with cyanoamines into triazines or β-diketiminatolithium compounds
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Reactions of bis(trimethylsily)methyl lithium reagent Li[CHR2] (R = SiMe3) and 1-azaallyllithium, [LiN(R)C(But) CHR]2 with cyanoamines R′CN (R' = Me2N, 1-piperidyl or o, p-pyridyl) yielded β-diketiminatolithiums (1, 2, 5, 7, 8) or symmetrically and mixed substituted triazines (3, 4, 6, 9, 10), respectively. The mechanistic pathways involve silicotropic rearrangements from C to N or N to N and an unusual elimination of Li[CHR2]. The complexes 1, 6, 7, and 10 had been characterized by X-Ray diffraction.
- Chen, Xia,Du, Chenxia,Guo, Jian-Ping,Wei, Xue-Hong,Liu, Dian-Sheng
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- Reaction of disubstituted cyanamides with formamides under high pressure
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High pressure-assisted co-cyclization of disubstituted cyanamides with formamide or monosubstituted formamides gave 2-amino- or 2-monosubstituted amino-4,6-bis(disubstituted amino)-1,3,5-triazines in one pot.
- Shibuya, Isao,Oishi, Akihiro,Yasumoto, Masahiko
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p. 1659 - 1662
(2007/10/03)
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- Comparison of chemical and electrochemical reduction of cyanamides:an exmple of cathodic decyanation
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Most disubstituted cyanamides exhibit a very low cathodic activity and are therefore difficult to reduce.However, the cathodic cleavage of diarylcyanamides can be carried out directly and leads to the corresponding diarylamine; the action of sodium causes the same cleavage.Alkylarylcyanamides display no cathodic step, but can be reduced indirectly by redox catalysis; this allows the determination of the standard potential corresponding to the first electron transfer.The macroscale electrolysis, in the presence of the catalyst, leads to the alkylarylamine by cleavage, whereas the action of sodium gives mainly a cyanoguanidine.Dialkylcyanamides are electroreducible neither directly, nor indirectly, whereas by action of sodium they trimerize almost quantitatively into triazines. Key words: cyanamide, decyanation, electroreduction, redox catalysis.
- Cariou, Michel,Simonet, Jacques
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p. 861 - 864
(2007/10/02)
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- A Novel Synthesis of Primary Selenoamides from Nitriles by the Treatment of Bis(trimethylsilyl) Selenide and BF3*OEt2
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Reaction of nitriles with (Me3Si)2Se in the presence of BF3*OEt2 afforded the corresponding primary selenoamides in moderate yields.A selenourea and a selenothiocarbamate were also prepared in a similar manner from the corresponding cyanamide and thiocyanate.
- Shimada, Kazuaki,Hikage, Shigeki,Takeishi, Yoshiyuki,Takikawa, Yuji
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p. 1403 - 1406
(2007/10/02)
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