2-吡啶基咪唑并[1,2-a]吡啶的水中合成

2-乙酰基吡啶1经溴化反应后得到2-(2-溴乙酰基)吡啶氢溴酸盐2,2在水中与NaHCO3发生中和反应生成2-(2-溴乙酰基)吡啶,不经分离直接于水中和2-氨基吡啶衍生物3a-3h反应生成2-吡啶基咪唑并[1,2-a]吡啶4a-4h.采用核磁共振谱仪、红外光谱仪及质谱仪表征了产物的结构.结果表明,利用该方法可以在温和的反应条件下高产率得到目标产物,且方法操作简便、对环境友好.     

Selective Halogenation of 1,4-Benzoquinones and 1,4-Naphthoquinones with Copper(II) Halide Adsorbed on Alumina

1,4-Benzoquinone or 1,4-naphthoquinone and their derivatives have been halogenated selectively at quinonoid positions with copper(II) halide adsorbed on neutral alumina followed by refluxing in halobenzene to give mono- di-, tri- and tetra-halo-quinones.     

Pyridine-Containing schiff base derivatives for the struxtural determination of long-chain aldehydes by gas chromatography combined with mass spectrometry

Long-chain aldehydes, encountered as insect pheromones, were converted into Schiff bases with 3-aminopyridine, 3-(aminomethyl)pyridine, or 2-aminopyrimidine to provide derivatives suitable for revealing the alkyl chain structure by mass spectrometry. The two pyridine-containing derivatives were satisfactory in initiating a radical-induced cleavage. of the chain to give a series of fragment ions, the masses and relative abundance of which revealed the chain structure. The derivatives were applied to aldehydes having straight, branched (iso and anteiso), and unsaturated (delta-7, delta-9, delta-ll, and delta-13) structures; these all gave the fragmentation patterns that have been seen earlier for similar pyridine-containing derivatives of fatty acids (picolinyl esters) and alcohols (nicotinates).Of the two derivatives, those from 3-aminopyridine gave slightly simpler spectra. Derivatives formed from 2-aminopyrimidine were less satisfactory in revealing chain structure.     

Fluorescence properties of novel 6-butyl-2,3-dicyano-7-methyl-6H-1,4-diazepine styryl dyes containing ethyleneglycol units

The fluorescence properties of novel 6-butyl-2,3-dicyano-7-methyl-6H-1,4-diazepine styryl dyes having mono-, di-, tri-, and tetra(ethyleneglycol) units were examined. The mono(ethylenglycol) derivative was solid at room temperature, whereas the di-, tri-, and tetra(ethylenglycol) derivatives were oily. The monoethyleneglycol derivative showed weak aggregation-induced emission enhancement with fluorescence maximum at 649 nm, which comes from J-aggregates. The fluorescence of oily di-, tri-, and tetra(ethyleneglycol) derivatives in neat form was very weak. No aggregation-induced emission enhancement was observed for the oily derivatives.     

Reactions of 2-aminopyridine with picryl halides

2-Aminopyridine reacts with picryl halides to give mixtures of 1-picryl-2-(N-picrylimino)-1,2-dihydropyridine and 2-(N-picrylamino)pyridine. When picryl fluoride is treated with an excess of 2-aminopyridine, the 1-picryl-2-(N-picrylimino)-1,2-dihydropyridine reacts further with 2-aminopyridine to yield two molecules of 2-(N-picrylamino)pyridine in a reaction catalyzed by the by-product, hydrogen fluoride. In contrast, the compositions of the mixtures obtained from the reactions of picryl chloride and picryl bromide with excess 2-aminopyridine are stable in their reaction media.     

Functionalization of α-Aminonicotinonitrile: A New Entry for Synthesis of Pyrazolo[3,4-b]pyridine,Pyrido[2,3-d]pyrimidine,and 1,8-Naphthyridine Derivatives

Russian Journal of General Chemistry - Functionalization of α-aminopyridine to a new series of pyridine and fused pyridine derivatives has been achieved via its reaction with a variety of...     

Transformations of (1E,3E)-1-(benzoylamino)-4-(dimethylamino)buta-1,3-diene-1,2,3-tricarboxylates into pyridine and pyrrole derivatives

New, highly functionalised (1E,3E)-1-(benzoylamino)-4-(dimethylamino)buta-1,3-diene-1,2,3-tricarboxylates proved to be useful and versatile reagents in the formation of highly substituted pyridine, N-aminopyridine, pyrrole and pyrido[3,4-c]pyridazine derivatives. The formation of the particular type heterocyclic system is dependent on the starting (1E,3E)-1-(benzoylamino)-4-(dimethylamino)buta-1,3-diene-1,2,3-tricarboxylate. By an appropriate choice of different ester groups it is possible to drive the reactions towards the formation of either pyridine or pyrrole derivatives.     

Axial Coordination of Pyridine- and Imidazole-Based Drug Molecules to Co(III)-Tetra(4-Carboxyphenyl)porphyrin

The substitutions of water molecules in the bisaqua axial complex of carboxy-substituted Co(III)-tetraphenylporphyrin by drug molecules based on amines and nitrogen-containing heterocycles are studied. The strongest bonded Co(III)-porphyrin complexes are formed with imidazole and pyridine derivatives. Depending on the nature and positions of functional groups in the heterocyclic moiety, imidazole- and pyridine- containing compounds can form either mono- or bis-axial complexes with Co(III) porphyrinate, these complexes having various stabilities. Aniline and quinuclidine drugs were found to react with Co(III) porphyrinate in aqueous media to produce only unstable monoaxial complexes.     

Reaction of α-chloro-α-isonitrosoacetone with aminopyridines

2-Amino, 2-amino-3-methyl-, and 4-aminopyridine react with -chloro--isonitrosoacetone at the heteroring nitrogen atom to give salts, which are converted to imidazo[1,2-a] pyridines or, in the case of 4-aminopyridine, to 1-(1-oximino-2-oxopropyl)-4-pyridoneimine when they are treated with alkali. Acetylpyridylurea was obtained from chloroisonitrosoacetone and 2-aminopyridine in pyridine.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1525–1529, November, 1978.     

Heteroarenium salts in synthesis. Highly functionalized tetra- and pentasubstituted pyridines

Activation of chloropyridines by heteroarenium substituents allows sequential substitutions by O-, N-, and S-nucleophiles. Reaction of 2,3,5,6-tetrachloropyridine and 4-ethylsulfanyl-2,3,5,6-tetrachloropyridine with 4-(dimethylamino)pyridine, 4-(pyrrolidin-1-yl)pyridine, or 4-aminopyridine results in the formation of 2,6-bis-heteroarenium substituted 3,5-dichloropyridines. On nucleophilic displacement of the heteroarenium substituents by O-, N-, or S-nucleophiles highly functionalized 3,5-dichloropyridines form which possess N²,S⁴,N⁶-, O²,S⁴,O⁶-, O²,O⁶-, N²,N⁶-, and S²,S⁶-substitution patterns.     

Interaction of pyridine derivatives with sepiolite

In this study, the adsorption behavior of pyridine derivatives, i.e., 2-aminopyridine and 2,2'-bipyridyl, onto sepiolite, a natural clay mineral, has been investigated by bottle adsorption and IR spectroscopic techniques. The results indicate that 2-aminopyridine and 2,2'-bipyridyl molecules adsorb onto sepiolite through hydrogen bonding of the amino groups to the water molecules in the octahedral sheet and to the surface hydroxyls (Si-OH) in the tetrahedral sheet. These findings reveal that pyridine molecules not only adsorb onto the external surface of sepiolite but are also incorporated in its channels and tunnels with adsorption taking place at corners and/or edges, depending on the position of water molecules. A structural model is proposed to account for the orientation of pyridine derivatives in the sepiolite matrix.     

Synthesis,Photophysical and Electronic Properties of Mono-, Di-, and Tri-Amino-Substituted Ortho-Perylenes,and Comparison to the Tetra-Substituted Derivative

We synthesized a series of new mono-, di-, tri- and tetra-substituted perylene derivatives with strong bis(para-methoxyphenyl)amine (DPA) donors at the uncommon 2,5,8,11-positions. The properties of our new donor-substituted perylenes were studied in detail to establish a structure-property relationship. Interesting trends and unusual properties are observed for this series of new perylene derivatives, such as a decreasing charge transfer (CT) character with increasing number of DPA moieties and individual reversible oxidations for each DPA moiety. Thus, (DPA)-Per possesses one reversible oxidation while (DPA)₄-Per has four. The mono- and di-substituted derivatives display unusually large Stokes shifts not previously reported for perylenes. Furthermore, transient absorption measurements of the new derivatives reveal an excited state with lifetimes of several hundred microseconds, which sensitizes singlet oxygen with quantum yields of up to 0.83.     

Ruthenium Complex-Controlled Catalytic N-Mono- or N,N-Dialkylation of Heteroaromatic Amines with Alcohols

Heteroaromatic amines were N-alkylated with primary alcohols at 150-200 degrees C in the presence of a catalytic amount of various ruthenium complexes to give the corresponding monoalkylated and dialkylated amines in good to high yields. For example, 2-aminopyridine reacted with an excess of ethanol at 180 degrees C for 20 h in the presence of dichlorotris(triphenylphosphine)ruthenium [RuCl(2)(PPh(3))(3)] to give 2-(ethylamino)pyridine (1) and 2-(diethylamino)pyridine (2) in 9% and 70% yields, respectively. On the other hand, when (eta(4)-1,5-cyclooctadiene)(eta(6)-1,3,5-cyclooctatriene)ruthenium [Ru(cod)(cot)] was used as a catalyst, even in the presence of excess ethanol, 1 was obtained in 85% yield with high selectivity. The addition of tertiary phosphines and phosphites to Ru(cod)(cot) increased the yield of the dialkylated amine.     

Synthesis of nitrogen heterocycles underlain by application of 3-(4-Acetyl[phenyl)-2H-coumarin

3-(4-Acetylphenyl)-2H-chromen-2-one was obtained from 4-acetylphenyldiazonium chloride in the conditions of Meerwein reaction. Reactions of 3-[4-(2-bromoacetyl)phenyl]-2H-chromen-2-one with pyridine, 4-methylpyridine, quinoline, benzo[f]quinoline, and triphenylphosphine afforded quaternary salts, and with thioacetamide, thiourea, 2-aminopyridine, 2-aminopyrimidine, and 6-aminopurine provided the corresponding derivatives of thiazole, imidazo[1,2-a]pyridine, imidazo[1,2-a]pyrimidine, imidazo[2,1-i]purine. In the reaction of the same bromo derivative with thiosemicarbazide and aromatic aldehydes a thiazole ring is built and the corresponding hydrazones are formed.     

Synthesis and properties of dipyridinium betaines of derivatives of 1,4-benzoquinone and tetracyanoquinodimethane

Reaction of chloranil with excess pyridine gives the poorly stable 2,5-di(N-pyridinium)-3,6-dichloro-1,4-benzoquinone dichloride which is readily hydrolyzed to give the bisbetaine of 2,5-di(N-pyridinium)-1,4-benzoquinone-3,6-dioxide. Treatment with acid gives its mono- and bisprotonated derivatives as the perchlorate and dibromide and bromination gives the betaine 2-bromo-2,5-di(N-pyridinium)-5-cyclohexene-1,3,4-trione-6-oxide perbromide. The reaction of malonodinitrile with 2,5-di(N-pyridinium)-3,6-dichloro-1,4-benzoquinone dichloride in situ gives the poorly stable bisbetaine of 2,5-di(N-pyridinium)-7,7,8,8-tetracyanoquinodimethane-3,6-dioxide.Riga Technical University, Riga LV-1048. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 346–349, March, 1998.     

Synthesis of Pyrido[2′,3′: 3,4]pyrazolo[1,5‐a]pyrimidine,Pyrido[2′,3′:3,4]pyrazolo[5,1‐c][1,2,4]triazine,and Pyrazolyl Oxadiazolylthieno[2,3‐b]pyridine Derivatives

6‐(2‐Thienyl)‐4‐(trifluoromethyl)‐1H‐pyrazolo[3,4‐b]pyridine‐3‐amine reacted with different active methylene compounds to afford pyridopyrazolopyrimidine derivatives. On the other hand, it reacted with some halo compounds to give the imidazo[1′,2′:1,5]pyrazolo[3,4‐b]pyridine derivatives. Also, it diazotized to give the corresponding diazonium chloride that is coupled with several active methylene compounds to give the corresponding triazine derivatives. Furthermore, compound 3‐amino‐6‐(2(thienyl)‐4‐(trifluoromethyl)thieno[2,3‐b]pyridine‐2‐carbohydrazide reacted with some β‐dicarbonyl compounds and some sulfur‐containing compounds to afford the corresponding pyrazolyl oxadiazolylthieno[2,3‐b]pyridine derivatives.     

Heterocyclic analogs of pleiadiene

Aceperimidine and its 1- and 2-substituted derivatives are nitrated in the 4 and 9 positions to give mono- or dinitro derivatives, depending on the amount of nitric acid.     

Synthesis, reactions and antimicrobial activities of 8-ethoxycoumarin derivatives

Condensation of 3-acetyl-8-ethoxycoumarin (3) with thiosemicarbazide gave ethylidenehydrazinecarbothioamide 5, which was transformed into the thiazolidin-4-one derivatives 6,7. Interaction of 3 with DMF/POCl(3) gave b-chloroacroline derivative 8. Treatment of 3 with malononitrile gave benzo[c]chromone and 2-aminobenzonitrile derivatives 9 and 10, respectively with respect to the reaction conditions. Condensation of 3-(2-bromoacetyl)-8-ethoxycoumarin (4) with o-phenylenediamine gave 3-(quioxaline-2-yl)-8-ethoxycoumarin hydrobromide (11), while 4 reacted with 2-aminopyridine to give chromenopyridopyrimidine derivative 12. Condensation of 4 with potassium thio-cyanate/methanol gave an unexpected derivative, 2H-chromeno-3-carboxy(methyl-carbonimidic)thioanhydride 16, which upon treatment with (NH(2))(2)·H(2)O gave 3-ethoxy-2-hydroxybenzaldehyde azine 19. Interaction of 4 with thiourea derivatives gave thiazole derivatives 20a-c. The structures of the newly synthesized compounds were confirmed by their spectra data. The newly synthesized compounds were also screened for their antimicrobial activity.     

Brominated and iodinated thiofluoresceins

Conditions were found for the synthesis of mono-, di-, tri-, and tetrabromo- and -iodo-substituted thiofluoresceins. Iodination and bromination of thiofluorescein with molecular iodine and bromine in 1 N aqueous sodium hydroxide gave mixtures of the corresponding 2,4,5,7-tetra- and 2,4,5-trihalo derivatives in 71/14 (Y = I) and 73/13% yield (Y = Br), respectively. In the reactions of thiofluorescein with bromine in acetic acid and with iodine in methanol at a substrate-to-halogen ratio of 1 : 2, 4,5-dibromo- and 4,5-diiodothiofluoresceins were isolated in 56 and 67% yield. Analogous reactions with equimolar amounts of the reactants produced 59% of 4-bromothiofluorescein and 51% of 4-iodothiofluorescein.     

Amidrazones in the synthesis of heterocycles (review)

Data on the synthesis, on the basis of amidrazones, of mono-, di-, tri-, and tetrazoles, diazoles containing boron, oxygen, silicon, phosphorus, and sulfur atoms in the ring, mono-, di-, tri-, and tetrazines, triazepines, and benzotriazepines, as well as a number of condensed heterocyclic derivatives, are systematized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 867–887, July, 1989.