Iridium-catalyzed cascade dehydrogenation,ring-closure reaction leading to 2,4,6-triaryl-1,3,5-triazines

An efficient iridium-catalyzed dehydrogenation, ring-closure reaction, has been developed via a cascade sequence, in which [Cp*IrI₂]₂/Xantphos proved to be the most efficient catalyst for the synthesis of 2,4,6-triaryl-1,3,5-triazines from stable aryl-substituted alcohols and amidines. It was the first case of iridium catalyst successful application in such transformation.     

Synthesis, characterization and fluorescent property evaluation of 1,3,5-triaryl-2-pyrazolines

A series of 1,3,5-triaryl-2-pyrazolines was synthesized by dissolving the corresponding 4-alkoxychalcones in glacial acetic acid containing a few drops of concentrated hydrochloric acid. This step was followed by the addition of (3,4-dimethylphenyl) hydrazaine hydrochloride. Finally the target compounds were precipitated by pouring the reaction mixture onto crushed ice. The structures of the synthesized compounds were established by physicochemical and spectroscopic methods. The 1,3,5-triaryl-2-pyrazolines bearing homologous alkoxy groups were found to possess fluorescence properties in the blue region of the visible spectrum when irradiated with ultraviolet radiation. The fluorescent behavior of these compounds was studied by UV-Vis and emission spectroscopy, performed at room temperature.     

Synthesis of N 3,N 5,4-triaryl-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxamides

Russian Journal of Organic Chemistry -     

Synthesis of Novel 1,3,5-Dithiazine Derivatives

The reactions of benzoylacetylene, propiolic acid, and methyl propiolate with 2,4-dithiobiuret and 1-substituted and 1,5-disubstituted 2,4-dithiobiurets in glacial AcOH in the presence of HClO₄ or BF₃·Et₂O were used to obtain 2-substituted 4-amino-6-imino-1,3,5-dithiazinium perchlorates or trifluoroborates, respectively.     

Synthesis and some properties of 1,3,5-triformylbenzene

Conclusions A convenient method was proposed for the synthesis of 1,3,5-triformylbenzene and some of its properties were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1886–1888, August, 1975.     

Synthesis of 1,3,6-triaryl-6-trifluoromethyl-5,6-dihydro-1,3,5-triazine-2,4(1H,3H)-diones by reaction of aryl trifluoromethyl ketone imines with aryl isocyanates

Russian Journal of Organic Chemistry -     

Synthesis of some new N,N''-diaryisubstituted methylene-bis-dihydro-2H-1,3-benzoxazines

The synthesis of a new series of six-membered N,N'-diarylsubstituted methylene-bis-dihydro-2H-1,3-benzoxazines (Sa-e) was achieved in excellent yields by Mannich-type condensation of N,N'-diarylsubstituted methylene-bis-o-hydroxybenzyl amines (4a-e) with formaldehyde in chloroform at reflux. These amines (4a-e) were obtained by the reduction of N,N'-diarylsubstituted methylene-bis-o-hydroxybenzyl imines (3a-e) with NaBH4, which inturn were obtained by the condensation of methylene-bis-salicylaldehyde (2) with various substituted arylamines.     

Synthesis of 3, 4, 6-triaryl-2-pyrones

A preparative method was worked out for the synthesis of 3,4,6-triaryl-2-pyrones by 1,3-dipolar cycloaddition of selenium arylacylmethylides to diphenylcyclopropenone.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1475–1478, November, 1977.     

1,3,5-三芳基吡唑类化合物合成的新方法

发现了一种以查耳酮(1a～1g)等不饱和酮(1h)和苯肼为主要原料,二氢铬酸四吡啶合钴(TPCD)为脱氢芳构化试剂,经“一锅法”合成1,3,5-三芳基吡唑(3a～3g)等吡唑类化合物的新方法.合成过程中首先生成的1,3,5-三取代吡唑啉不需要分离,直接在二氢铬酸四吡啶合钴氧化下脱氢芳构化成相应的吡唑类化合物,反应物分子中的碳-碳双键不受加入的二氢铬酸四吡啶合钴影响.该合成方法原料易得,反应条件温和,产率较高(65%～93%).     

15N NMR studies of amino acids and their reaction products with formaldehyde

Natural abundance ¹⁵N NMR spectroscopy has been used to investigate the effect of pH on the ¹⁵N chemical shifts of lysine and of ε-hydroxymethyllysine. A computer calcualtion which fits the chemical shifts of both α-and ε-nitrogen atoms versus pH has been used to predict the pK_a values. ¹⁵N chemical shifts and some ¹J(¹⁵NH) values of some other amino acids and of their reaction products with formaldehyde are also reported.     

Reactions of 1,3,5-triazinylnitro-formaldoximes. 2*. The reaction of 1,3,5-triazinylnitroformaldoximes with monosubstituted acetylenes

1,3,5-Triazinylnitrile oxides were prepared in situ from 2-R-4-R′-1,3,5-triazin-6-ylnitroformaldoximes and were treated with substituted acetylenes to give 3,5-disubstituted isoxazoles. The X-ray data obtained for 5-hydroxymethyl-3-(4′-dimethylamino-2′-methoxy-1,3,5-triazin-6′-yl)isoxazole is discussed.     

Synthesis and structure of new 1,3,5-triazine-pyrazole derivatives

We have studied the reaction of methylenedicarbonyl compounds with 4,6-disubstituted 2-hydrazinyl-1,3,5-triazine in order to obtain novel coupled biheterocyclic aromatic systems with potential bioactivity. Reaction conditions were studied and optimized, and a series of 4,6-disubstituted 2-(1H-pyrazolyl)-1,3,5-triazines were obtained with good yield.     

Synthesis and spectroscopic properties of some new N,N'-disubstituted thiorueas of potential biological interest

Thirty-six new N,N'-disubstituted thioureas have been synthesized by the reaction of phenyl-, p-fluorophenyl- and benzoylisothiocyanates with various substituted anilines, aminopyridines and 4-aminoquinolines. The uv, ir and nmr spectral data are presented and discussed.     

Synthesis and stereochemistry of some new 1,3,5-tris(1,3-dioxan-2-yl)-benzene derivatives

The synthesis and the stereochemistry of new 1,3,5-tris(1,3-dioxan-2-yl)-benzene derivatives are reported. The anancomeric structure and the axial orientation of the aryl group with respect to all 1,3-dioxane rings, and the cis-trans isomerism of some of the compounds are revealed. The data are supported by NMR investigations and by the molecular structure of one compound determined by single crystal X-ray diffractometry.     

Kinetics of CN radical reactions with formaldehyde and 1,3,5-trioxane

Absolute rate constants were measured for the reaction CN + CH₂O over the temperature range 297–673 K and CN + 1,3,5-trioxane over the range of 297–600 K by the laser photolysis/laser induced fluorescence technique. The rate constants for these reactions can be effectively represented, in units of cm³/s, by: k(CH₂O) = 2.82 × 10^?19 T^2.72 exp(718/T), and k(1,3,5-trioxane) = 1.39 × 10^?23 T^4.26 exp(1333/T), respectively. Transition state theory calculations were able to fit the temperature dependence of the CN + CH₂O rates relatively well. We attempted to correlate the CN reaction rate with CH₂O and other molecules which occur through simple abstraction with the corresponding OH reaction rates, yielding only a qualitative linear correlation for a majority of the processes. The reactions which deviated significantly from linearity include those which contain strong dipoles, highlighting the significant role long-range attractive forces play in CN and OH reactions. Using a simple electrostatic potential, cross-sections were determined for reactions with CN. No linear correlation was found between the calculated and experimental cross sections for the majority of the reactions studied. © 1993 John Wiley & Sons, Inc.     

Synthesis of Novel 1,3,5-Trisubstituted Pyrazoles as Potential Hypoglycemic Agents

A novel series of 1,3,5-trisubstituted pyrazoles was synthesized. Thus, ethyl 2,4-dioxo-6-phenylhex-5-enoate (I) was condensed with phenylhydrazine to afford 3-ethoxycarbonyl-1-phenyl-5-styrylpyrazole (II) which on fusion with hydrazine hydrate gave the corresponding acid hydrazide (III). Reaction of III with the appropriate isothiocyanate yielded the disubstituted thiosemicarbazides (IVa-e) which were cyclized into thiotriazoles (Va-e), thiadiazoles (Vla-e) and oxadiazoles (VIIa-). The structure of the newly synthesized compounds was elucidated by elemental analyses, IR and ¹H NMR spectra.