Synthesis of some 4-substituted and 4,6-disubstituted dibenzothiophenes

The synthesis is described of various 4-substituted ( 1 ) and 4,6-disubstituted ( 2 ) dibenzothiophenes by lithiation reactions. The factors controlling the formation of 4,6-disubstituted dibenzothiophenes by the lithiation of 4-methyl- and 4-ethyl-dibenzothiophene at the 6-position versus lithiation at the α-carbon of the 4-substituent are examined.     

N'-取代苯磺酰基N-(4,6-二取代均-三氮苯-2-基)乙二胺的合成

N-芳基磺酰乙二胺与三聚氰氯反应获得三个新缩合产物, 缩合产物再与醇钠反应得到六个N-取代苯磺酰基-N'-取代均三嗪基乙二胺衍生物, 所有化合物都表现出对植物生长的抑制作用, 可用于筛选除草剂.     

Synthesis and properties of derivatives ofsym-triazines 14. Cyanoethylation of 4,6-disubstituted 2-amino-sym-triazines

The cyanoethylation of 4,6-disubstituted 2-amino-sym-triazines containing alkyl trichloromethyl, and pyridyl groups was studied, and the corresponding dicyanoethyl derivatives were synthesized. It was shown that the yield of the latter and the duration of the reaction depend on the nature of the substituents in the ring of the initial amino-sym-triazines. A method of obtaining 2-(2-cyanoethyl)amino-sym-triazines is proposed based on the decyanoethylation and disproportionation of the dicyanoethyl derivatives as well as the trans-cyanoethylation.I. M. Gubkin State Petroleum and Gas Academy, Moscow 117917. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 111–129, January, 1995. Original article submitted November 2, 1994.     

Synthesis of 4,6-disubstituted pyrimidines via Suzuki and Kumada coupling reaction of 4,6-dichloropyrimidine

A series of 4,6-disubstituted pyrimidines were synthesized via Suzuki and Kumada coupling reaction of 4,6-dichloropyrimidine.     

Synthesis and spectroscopic properties of some dideuterated cyanopyridines

4‐Cyanopyridine‐2,6‐d₂ ( 5a‐2,6‐d₂ ), 3‐cyanopyridine‐2,6‐d₂ ( 5b‐2,6‐d₂ ), and 2‐cyanopyridine‐4,6‐d₂ ( 5c‐4,6‐d₂ ) were synthesized from the corresponding 2‐, 3‐ or 4‐pyridinecarboxylic acid N‐oxides. These dideuterated products were characterized by their mass and NMR spectra.     

Tautomerism in some quinaldyl sulfones

A series of quinaldyl sulfones was synthesized and their tautomeric composition was determined by ¹H nmr.     

Synthesis of 4,6-disubstituted 2-methylpyridines and their 3-carboxamides

A new one-pot synthesis of title compounds by the reactions of α,β-unsaturated carbonyl compounds with β-aminocrotononitrile in the presence of sodium hydroxide is described.     

Tautomerism of some amino aza-containing heterocycles

With the aim of checking potential amino/imino tautomerism in heterocyclic series, some uv/visible spectroscopic properties of 2-N-(2,4,6-trinitrophenyl)pyridine, 2-N-(2,4,6-trinitrophenyl)pyrimidine and of 2-N-(2,4,6-trinitrophenyl)thiazoleamine are reported and discussed. In dimethyl sulphoxide the imino tautomer of the thiazole derivatives is the more populated form, while in toluene the amino aromatic form predominates. The more populated tautomer of the pyridine and pyrimidine derivatives is the amino aromatic form in both polar and apolar solvents. For the thiazole derivatives the tautomeric equilibrium in toluene is shifted toward the imino form by adding small amounts of tetrabutylammonium bromide or of dimethyl sulphoxide. The position of the tautomeric equilibrium is quantitatively evaluated and discussed.     

Synthesis,structures, and properties of bis(4,6-disubstituted 1,3,5-triazin-2-yl) ethers

Reactions of (4,6-disubstituted 1,3,5-triazin-2-yl)trimethylammonium chlorides with glycine sodium salt in the presence of Et₃N afforded bis(triazin-2-yl) ethers instead of the expected triazinylaminoacetic acids. The structures of the resulting compounds were established by the independent synthesis, spectroscopic data, and X-ray diffraction analysis.     

Organocatalytic approach to 3,5,6-trisubstituted and 4,6-disubstituted tetrahydropyran-2-ones

The diarylprolinol ether-catalyzed Michael addition and subsequent cyclization of ethyl 3-methyl-2-oxobut-3-enoate with aldehydes, and γ-substituted β,γ-unsaturated-α-ketoesters with acetaldehyde, afforded the corresponding lactals, which were subjected to oxidation and stereocontrolled hydrogenation to provide 3,5,6-trisubstituted and 4,6-disubstituted tetrahydropyran-2-ones with excellent enantioselectivities.     

Syntheses and some spectroscopic properties of polyanions with pendant merocyanine dyes

Polymers tagged with a local pH reporter were synthesized. A methacrylate-type monomer containing a merocyanine dye residue as a reporter dye—1-(2-methacryloyloxyethyl)-4-(2-(4-hydroxyphenyl)-ethenyl)quinolinium bromide—was synthesized. Its homopolymer and copolymers with sodium 2-acrylamido-2-methylpropanesulfonate were prepared by free radical polymerization. These polymers showed a characteristic color change in aqueous solutions from yellow to red with increasing pH from acidic to basic conditions according to the acid-base equilibria of the merocyanine dye residues. Since the electrostatic potential and polarity of media have a strong effect on the acid–base equilibria, the pendant merocyanine residues are expected to serve as a reporter to provide information on the local environments around the polymer chain at which the dye molecules are incorporated.     

Synthesis of some 3,6-disubstituted pyridazines

Some novel 3-halo-6-(4-substituted-phenoxy)pyridazines and 3,6-di-(4-substituted-phenoxy)pyridazines were synthesized from 3,6-dichloropyridazine or 3,6-diiodopyridazine. 3,6-Diiodopyridazine was prepared from 3,6-dichloropyridazine using hydriodic acid/iodine monochloride.     

Chromatographic and spectroscopic properties of regioisomers of some 1H-1,5-benzodiazepines

The separation of the two regioisomeric derivatives of 1H-1,5-benzodiazepine yielded from the reaction of 1,2-diamino-4-methylbenzene with 4-substituted acetophenones was performed by reversed phase high performance liquid chromatography, and the absorption spectra of the separated isomers have been determined for three isomer pairs which have been obtained starting from acetophenones with substituents of different electronegativity. The isomer ratio then could be estimated as well from the ratio of the peak areas as from the absorption spectra. They agree well with the known ratio determined from nmr intensities.     

Synthesis,structure and spectroscopic properties of some thiosemicarbazone complexes of platinum

Reaction of salicyldehyde thosemicarbazone (H₂L¹), 2-hydroxyacetophenone thiosemicarbazone (H₂L²) and 2-hydroxynapthaldehyde thiosemicarbazone (H₂L³) (general abbreviation H₂L, where H₂ stands for the two dissociable protons, one phenolic proton and one hydrazinic proton) with K₂[PtCl₄] afforded a family of polymeric complexes of type [{Pt(L)}_n]. Reaction of the polymeric species with two monodentate ligands (D), viz. triphenylphosphine (PPh₃) and 4-picoline (pic), yielded complexes of the type [Pt(L)(D)]. These mixed-ligand complexes were also obtained from the reaction of the thiosemicarbazones with [Pt(PPh₃)₂Cl₂] and [Pt(pic)₂Cl₂]. The crystal structure of [Pt(PPh₃)(L²)] has been determined. The thiosemicarbazone ligands are coordinated, via dissociation of the two protons, as dianionic tridentate O,N,S-donors. The [Pt(L)(D)] complexes show characteristic ¹H NMR spectra and intense absorptions in the visible and ultraviolet region. They also fluoresce in the visible region at ambient temperature.