Synthesis and some properties of 5-alkylamino-2-(phthalimidoalkyl)-1,3-oxazole-4-carbonitriles

5-Alkylamino-1,3-oxazole-4-carbonitriles containing a 2-phthalimidoethyl or 3-phthalimidopropyl substituent at position 2 of the oxazole ring were synthesized. In the reaction of 5-(morpholin-4-yl)-2-(2-phthalimidoethy)l-1,3-oxazole-4-carbonitrile with hydrazine hydrate, 2-(2-aminoethyl)-5-(morpholin-4-yl)-1,3-oxazole-4-carbonitrile is formed. In the case of the 3-phthalimidopropyl analog, the recyclization product 3-amino-2-(morpholin-4-ylcarbonyl)-6,7-dihydro-5H-pyrrolo[1,2-a]imidazole is formed.     

New transformations of 5-Hydrazino-2-phenyl-1,3-oxazole-4-carbonitrile

Treatment of 5-hydrazino-2-phenyl-1,3-oxazole-4-carbonitrile with acetylacetone lead to the formation of a substituted pyrazole residue on C⁵, which enhanced the electrophilicity of the cyano group in position 4 so that it became capable of reacting with hydrogen sulfide, sodium azide, and hydroxylamine. As a result, the corresponding azole fragments were introduced into position 4 of the 5-(1H-pyrazol-1-yl)-1,3-oxazole system.     

2-aryl-5-arylsulfanyl-1,3-oxazole-4-carboxylic acids and their derivatives

A convenient preparative procedure has been developed for the synthesis of previously unknown 2-aryl-5-arylsulfanyl-1,3-oxazole-4-carboxylic acids and their functional derivatives from accessible multicenter substrates of the general formula Cl₂C=C(NHCOR)C(O)OMe. The products turned out to be suitable for various subsequent transformations. Some oxazole-4-carboxylic acid hydrazide derivatives containing a substituted oxazol-5-yl fragment at the N² atom in the hydrazine moiety underwent recyclization on heating in acetic acid; as a result, one oxazole ring was converted into 1,3,4-oxadiazole.     

Synthesis and properties of 2-substituted 5-chloro-1,3-oxazole-4-carboxamides

Chlorination of 2-aryl-5-benzylsulfanyl-1,3-oxazole-4-carbonitrile in aqueous acetic acid at 50–60°C afforded new 2-aryl-5-chloro-1,3-oxazole-4-carboxamides. The reactivity of the chlorine atom with respect to the N-, O-, and S-nucleophiles was investigated.     

Synthesis of 4-tosyl-5-chloro-1,3-thiazole-2-carbonitrile and its transformations

Reaction of the available 1-tosyl-2,2-dichloroethenyl isothiocyanate with sodium cyanide yields new clearly electrophilic substrate of thiazole nature containing the nitrile group, the tosyl residue, and the chlorine atom at C², C⁴, and C⁵ respectively. The direction of the reaction of this substrate with nucleophile depends significantly on the nature of the latter. It was used in regioselective syntheses of a series of the unknown previously trifunctional thiazoles.     

5-(1,3-Benzothiazol-2-yl)furan-2-carbaldehyde in the Design of Antitumor Agents

Russian Journal of Organic Chemistry - Reactions of 5-(1,3-benzothiazol-2-yl)furan-2-carbaldehyde with 2-acetylfuran, 2-acetylthiophene, and some compounds containing an active methylene group gave...     

Interaction of 2-aryl-4-cyano-1,3-oxazole-5-sulfonyl chlorides with amidines

Reaction of 4-cyano-1,3-oxazole-5-sulfonyl chlorides with amidines results in new 7-amino-1,3-oxazolo[5,4-d]pyrimidines. Their structure was confirmed by spectral methods and X-ray diffraction analysis.     

Synthesis,Crystal Structure and Theoretically Study of 2-(Dimethylamino)-1,3-dithiocyanatopropane and Its Isomer

2-(Dimethylamino)-1,3-dithiocyanatopropane(1) has been prepared as a key intermediate synthesizing a natural insecticide Cartap by the reaction of 1-dimethylamino-2,3-dichloropropane with sodium thiocyanate. The crystal structures of compound 1 and its isomer 1-(dimethylamino)-2,3-dithiocyanotopropane(2) formed during the reaction were determined by X-ray single-crystal diffraction. Bond lengths in both the compounds are common and fall within normal ranges. There are some weak C―H×××N hydrogen bonds in the lattice of compound 1, which makes it form a three-dimensional network, which stabilize the crystal structure. No classic hydrogen bonds were founded in its isomer(2), only van der Waals forces contribute to the stability of the structure. In addition, DFT and MP2 calculations with 6-311+G(d, p) basis set have also been carried out to investigate the thermodynamic properties of compounds 1 and 2. The research will be applied to the further investigation of the tautomerization of compounds 1 and 2.     

2-(2-(Dimethylamino)vinyl)-4H-pyran-4-ones as Novel and Convenient Building-Blocks for the Synthesis of Conjugated 4-Pyrone Derivatives

A straightforward approach for the construction of the new class of conjugated pyrans based on enamination of 2-methyl-4-pyrones with DMF-DMA was developed. 2-(2-(Dimethylamino)vinyl)-4-pyrones are highly reactive substrates that undergo 1,6-conjugate addition/elimination or 1,3-dipolar cycloaddition/elimination followed by substitution of the dimethylamino group without ring opening. This strategy includes selective transformations leading to conjugated and isoxazolyl-substituted 4-pyrone structures. The photophysical properties of the prepared 4-pyrones were determined in view of further design of novel merocyanine fluorophores. A solvatochromism was found for enamino-substituted 4-pyrones accompanied by a strong increase in fluorescence intensity in alcohols. The prepared conjugated structures demonstrated valuable photophysical properties, such as a large Stokes shift (up to 204 nm) and a good quantum yield (up to 28%).     

3-(2-萘基)-1-苯基-吡唑-4-甲醛腙衍生物的简便合成与表征

为寻找具有生物活性的先导化合物,以3-(2-萘基)-1-苯基-吡唑-4-甲醛为起始原料,在超声波辐射下经串联反应和一锅法合成两种途径制备了一系列新型的1-(3-β-萘基-1-苯基吡唑-4-亚甲基)-2-(4-芳基噻唑-2-基)-腙及其衍生物.与加热实验相比,在超声波辐射下可得到较好的产率.利用1H NMR,MS,IR谱和元素分析对产物进行了结构表征.初步的生物活性测试结果表明,化合物4b和4d对H2O2诱导的PC12细胞损伤具有明显的保护作用.     

Reaktion von 3-(Dimethylamino)-2H-azirinen mit 1,3-Thiazolidin-2-thion

Reaction of 3-(Dimethylamino)-2H-azirines with 1,3-Thiazolidine-2-thione Reaction of 3-(dimethylamino)-2H-azirines 1 and 1,3-thiazolidine-2-thione ( 6 ) in MeCN at room temperature leads to a mixture of perhydroimidazo[4,3-b]thiazole-5-thiones 7 and N-[1-(4,5-dihydro-1,3-thiazol-2-yl)alkyl]-N′,N′-dimethylthioureas 8 (Scheme 2), whereas, in i-PrOH at ca. 60°, 8 is the only product (Scheme 4). It has been shown that, in polar solvents or under Me₂NH catalysis, the primarily formed 7 isomerizes to 8 (Scheme 4). The hydrolysis of 7 and 8 leads to the same 2-thiohydantoine 9 (Scheme 3 and 5). The structure of 7a, 8c , and 9b has been established by X-ray crystallography (Chapt. 4). Reaction mechanisms for the formation and the hydrolysis of 7 and 8 are suggested.     

Synthesis of 2-aryl-4-cyano-1,3-oxazole-5-sulfonyl chlorides and N-substituted sulfonamides

Oxidative chlorination of 2-aryl-5-benzylsulfanyl-1,3-oxazole-4-carbonitrile results in the previously unknown 4-cyano-1,3-oxazole-5-sulfonyl chlorides and N-substituted sulfonamides.     

Synthesis and transformations of derivatives of 2-aryl-5-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3-oxazole-4-carboxylic acid

On the basis of methyl esters of 2-aryl-5-hydrazino-1,3-oxazole-4-carboxylic acids the earlier unknown methyl esters of 2-aryl-5-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3-oxazole-4-carboxylic acids as well as their functional derivatives were synthesized. The latter were used for further transformations, in particular, for introducing the residues of highly basic aliphatic amines into the 5 position of oxazole, and the oxazol-2-yl moiety into the 4 position of the oxazole ring.     

Synthesis and Antimicrobial Activity of 2-[5-(R-Benzyl)-4-oxo-1,3-thiazolidin-2-ylidene]-3-oxobutanenitrile and [2-(1-Cyano-2-oxopropylidene)-4-oxo-1,3-thiazolidin-5-ylidene]acetic Acid Derivatives

Russian Journal of Organic Chemistry - The reactions of 2-cyano-3-oxobutanethioamide with ethyl 3-aryl-2-bromopropanoates and dialkyl acetylenedicarboxylates afforded a combinatorial library of new...     

Synthesis of Open-Chain Dithioacetals from Thiophene-2-carbaldehyde and Its Analogs

A procedure for the synthesis of dithioacetals containing various thiophene fragments was developed on the basis of the reaction of thiophene-2-carbaldehyde and its analogs with thiols in chlorotrimethylsilane.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 7, 2005, pp. 973–976.Original Russian Text Copyright © 2005 by Papernaya, Levanova, Sukhomazova, Albanov, Deryagina.     

Reaktionen von 3-(Dimethylamino)-2H-azirinen mit 1,3-Benzoxazol-2(3H)-thion

Reaction of 3-(Dimethylamino)-2H-azirines with 1,3-Benzoxazole-2(3H)-thione The reaction of 3-(dimethylamino)-2H-azirines 2 with 1,3-benzoxazole-2(3H)-thione ( 5 ), which can be considered as NH-acidic heterocycle (pK_aca. 7.3), in MeCN at room temperature, leads to 3-(2-hydroxyphenyl)-2-thiohydantoins 6 and thiourea derivatives of type 7 (Scheme 2). A reaction mechanism for the formation of the products via the crucial zwitterionic intermediate A ′ is suggested. This intermediate was trapped by methylation with Mel and hydrolysis to give 9 (Scheme 4). Under normal reaction conditions, A ′ undergoes a ring opening to B which is hydrolyzed during workup to yield 6 or rearranges to give the thiourea 7. A reasonable intermediate of the latter transformation is the isothiocyanate E (Scheme 3) which also could be trapped by morpholine. In i-PrOH at 55–65° 2a and 5 react to yield a mixture of 6a , 2-(isopropylthio)-1,3-benzoxazole ( 12 ), and the thioamide 13 (Scheme 5). A mechanism for the surprising alkylation of 5 via the intermediate 2-amino-2-alkoxyaziridine F is proposed. Again via an aziridine, e.g. H ( Scheme 6 ), the formation of 13 can be explained.