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Confining polymers to nanometric sizes often interferes with the characteristic length scales of structure formation and thus significantly alters crystallization or nucleation behavior at the nanoscale. To investigate such effects in nanometric samples, past studies relied either on heavily constraining environments like block copolymer mesophases or on deposited droplets that exhibit significant variation in size, thus requiring extensive analysis to assign size classes. This studypresents a novel method to create nanometer‐sized polymer droplets of narrow volume distribution and to study their dynamic and thermodynamic behavior using the change in orientational polarization. A combination of gold‐nanoparticle deposition with a grafting‐to reaction and a nanostructured electrode setup enabled the measurement of poly‐ε‐caprolactone (PCL) droplets consisting of ten chains on average for a relatively small molecular weight. Distinct crystallization and melting signatures in spin‐cast droplets demonstrate the sensitivity of this approach. In contrast, the grafted aggregates exhibit no signs of crystallization, which is attributed to considerable constraints in this configuration, like limited chain motion or too wide chain spacing. Nevertheless, the presented setup is capable of studying ensembles of individualized (macro‐) molecules. [ABSTRACT FROM AUTHOR]

Background. Is to evaluate the color stability of rhodium-coated aesthetic archwires after immersion in two types of mouthwashes (fluoridated and nonfluoridated), study the effect of immersion time, and to compare the effect of these solutions on color stability of the aesthetic archwires. Materials and Methods. 35 rhodium-coated aesthetic archwires were prepared and divided two halves, arranged in seven strips (each strip contains 10 wires) and immersed in Deionized water, Sidrazac and Biofresh solution. The measurements of the color have been carried out through a computed spectrophotometer based on Commission Internationale de I'Eclairage L ∗ a ∗ b ∗ system, and color variations (Δ E ∗), color measurements were repeated 7 and 21 days after immersion in the solution. Statistical analyses include mean, standard deviation, minimum, maximum, and inferential statistics which include ANOVA and Tukey (HSD) for testing for any statistically significant differences in light reflection of the groups; t-test was used to test for differences in immersion time intervals. The significance level has been set at P ≤ 0.05. Results. Both types of mouthwashes resulted in color changes in different degrees and a higher color instability amount has been noted with Sidrazac-fluoridated mouthwashes, The color change amount has been increased with the time being statistically higher in 3 weeks of immersion, while there is nonsignificant color change after immersion in the Biofresh mouthwash. Conclusion.Rhodium-coated archwire shows high color changes in Sidrazac-fluoridated mouthwashes and nonsignificant color change after immersion in the Biofresh mouthwash. [ABSTRACT FROM AUTHOR]

Diazenyl 1,2,4‐triazol‐5(4H)‐thione derivatives were synthesized in good yields via Eschenmoser‐coupling reaction and nucleophilic attack between 1,4‐disubstituted thiosemicarbazides and 2,3,5,6‐tetrachloro‐1,4‐benzoquinone (p‐CHL). The structure of the synthesized compounds was confirmed by IR, NMR and mass spectral data as well as single crystal X‐ray analysis. Nucleophilic attack of 1,4‐disubstituted thiosemi‐carbazides on 2,3,5,6‐tetrachloro‐1,4‐benzoquinone (p‐CHL), afforded the formation of heterocyclic triazolethione derivatives via multistep reaction. The cyclization reaction required the presence of p‐CHL as a mediator and used to activate the C=S toward nucleophilic addition and elimination a molecule of substituted amine followed by cyclization and oxidation with p‐CHL. The products were confirmed by X‐ray analyses. [ABSTRACT FROM AUTHOR]

Several methods for the preparation of thiazolidin‐4‐ones from thiocarbohydrazides over the last 15 years are highlighted. Thiosemicarbazides, thiocarbohydrazides, thioamides, and hydrazinecarbothioamides as well as thioureas were used to obtain different substituted thiazolidinones under reaction conditions. Thiazolidinones can be synthesized either by a one‐pot three‐component condensation or a two‐step process. Also, the mechanism of formation, regioselectivity issues, and biological activities of different thiazolidinones were discussed. [ABSTRACT FROM AUTHOR]

The inherent reactivity of thiocarbohydrazides and thiosemicarbazides makes them valuable as building blocks for the synthesis of other heterocyclic motifs. This review article discusses the recent applications of classes of compounds in syntheses of five‐membered to seven‐membered heterocycles of biological activities and remarkable number of metal complexes. Many previous reviews dealt with the reactivity of either thiosemicarbazides or thiocarbohydrazides. However, a large number of publications have recently dealt with the reactivity of thiosemicarbazides and thiocarbohydrazides. Consequently, we have found that it is of importance to shed new light on these interesting molecules. [ABSTRACT FROM AUTHOR]

A series of ( Z)-methyl 2( Z)-3-substituted-2-(cycloalkylidenehydrazono)-4-oxothiazolidin-5-ylidene)-acetate derivatives were synthesized via condensation alkylidene- N-substituted hydrazinecarbothioamides with dimethyl acetylenedicarboxylate. The synthesized compounds were characterized by using different spectroscopic methods and confirmed by single crystal X-ray analysis. The behavior of (cyclic-alkylidene) hydrazinecarbothioamides in cyclization was presented. The mechanism of transformation of ( Z)-methyl 2-(( Z)-3-(cyclopentylideneamino)-4-oxo-2-(phenylimino)thiazolidin-5-ylidene)acetate ( 14) into the more stable ( Z)-Methyl 2-[( Z)-2-(cyclopentylidenehydrazono)-4-oxo-3-phenylthiazolidin-5-ylidene]acetate ( 5a) was discussed and confirmed. [ABSTRACT FROM AUTHOR]

A simple and efficient synthesis of (substituted ylidene)(2-oxoindolylidene)thiocarbohydrazones and bis(2-oxoindolylidene)urea was achieved by the reaction of (substituted ylidene)thiocarbonohydrazides with isatylidene malononitrile. Rational for this conversation involving the on the dicyanomethylene carbon atom is presented. The structures of the products have been confirmed by using spectral and single-crystal X-ray analyses. [ABSTRACT FROM AUTHOR]

Diaminomaleonitrile and N-arylbenzamidrazones reacted together to give 4-amino-5-iminopyrazoles. A probable reaction mechanism involves firstly removal of ammonia, followed by addition and cylization of the hydrazino- N2 of amidrazone to the nitrile group in diaminomaleonitrile. The structure of the obtained products was proved by IR, mass, NMR spectra and elemental analyses. [ABSTRACT FROM AUTHOR]

Phthaloyl chloride reacts with N-arylbenzamidrazones to give 1,2,4-triazolium salts in very good yields. The mechanism described the products formation was discussed. The structure of the obtained products was proved by IR, mass, NMR spectra, and elemental analyses. [ABSTRACT FROM AUTHOR]

( Z)-2-(2-Oxoindolin-3-ylidene)-2-(substituted amino)acetonitriles, 2-thioxoimidazolidine-1-carbothioamides, and 2-thioxotetrahydropyrimidine-1(2 H)-carbothioamides were synthesized via conventional thermal or microwave-assisted reaction of isatylidene malononitrile with N,N″-1,ω-alkanediyl-bis-[ N′-organylthiourea] derivatives. Rationale for these conversations involving the on the dicyanomethylene carbon atom and of the title compounds is presented. The structure of the ( Z)-2-(2-oxoindolin-3-ylidene)-2-(phenylamino)acetonitrile has been confirmed by the X-ray analysis. [ABSTRACT FROM AUTHOR]

A one step synthesis protocol for the conversion of heteroylthiosemicarbazides and 2,3-dichloro-1,4-naphthoquinone to naphtho[2,3- d]thiazoles, naphtho[2,3- e][1,3,4]thiadiazines as well as bis(naphtho[2,3- d]thiazolyl)copper(II) derivatives is described. The products were conclusively confirmed by single crystal X-ray analyses. A mechanism for the formation of the products is presented. [ABSTRACT FROM AUTHOR]

1,3-Thiazine-5,6,6-tricarbonitrile and 2-thioxo-2,3-dihydropyrimidine-4,5-dicarbonitriles derivatives were synthesized via interactions between (1-aryl ethylidene)hydrazinecarbothioamides and tetracyanoethylene to give the derivatives of tetracyanoethane and tricyanovinylation intermediates, followed by . The structures of the products have been confirmed by different spectroscopic analyses. A rational for the formation of the products is presented. [ABSTRACT FROM AUTHOR]

New series of substituted aminothiadiazolylhydrazonoindolin-2-ones were prepared in high yields (89-94%) via the of thiocarbonohydrazides ( 1a, 1b, 1c, 1d) with 3-(dicyanomethylene)-2-indolone in (ethanol/piperidine) at room temperature. Explanations of these conversations involve the on the dicyanomethylene carbon atom. The structures were established by spectroscopic data and single crystal X-ray crystallography. [ABSTRACT FROM AUTHOR]

2-Substituted hydrazinecarbothioamides and N,2-disubstituted hydrazinecarbothioamides react, in high yields with dimethyl acetylenedicarboxylate to give 4-oxo- Z-(thiazolidin-5-ylidene)acetate derivatives. Several mechanistic options involving interaction are presented. The structures of thiazolidin-4-ones have been unambiguously confirmed by single crystal X-ray crystallography. [ABSTRACT FROM AUTHOR]

A series of ( Z)-methyl-2-[( Z)-3-substituted-4-oxo-2-(2-picolinoyl-/thiophene-2-carbonyl)-hydrazonothiazolidin-5-ylidene]acetates were synthesized by condensation N-substituted-(2-picolinoyl-, thiophene-2-carbonyl)hydrazinecarbothioamides with dimethylacetylenedicarboxylate. The structure of thiazolidin-4-one derivatives has been confirmed unambiguously by single crystal X-ray crystallography. [ABSTRACT FROM AUTHOR]

( E)-2-[2-(1-Substituted ethylidene)hydrazinyl]-5-oxo-9b-hydroxy-5,9b-dihydroindeno[1,2- d][1,3]-thiazine-4-carbonitriles and ( E)-5-oxo-[( E)-(1-substituted ethylidene)hydrazinyl]-2,5-dihydroindeno[1,2- d][1,3]thiazine-4-carbonitriles have been obtained from the reaction of 2-(substituted ethylidene)hydrazinecarbothioamides with 2-(1,3-dioxo-2,3-dihydro-1 H-inden-2-ylidene)propanedinitrile ( 1) in ethyl acetate solution. However, ( Z)-6′-amino-1,3-dioxo-3′-substituted-2′-[( E)-(1-phenylethylidene)hydrazono]-1,2′,3,3′-tetrahydrospiro(indene-2,4′-[1,3]thiazine)-5′-carbonitriles were observed during the reaction of N-substituted-2-(1-phenylethylidene)hydrazinecarbothioamides with ( 1). The structure assignment of products has been confirmed on the basis of 1H-, 13C-NMR, and , as well as theoretical calculations. [ABSTRACT FROM AUTHOR]

This review summarizes the literatures dealing with the synthesis of some important nitrogen or nitrogen/sulfur heterocyclic, spiroheterocyclic, and fused heterocyclic compounds. [ABSTRACT FROM AUTHOR]

1-Substituted 3-[3-methyl-1 H-pyrazol-5-yl]thioureas react with ω-bromoacetophenones forming N-substituted(thiazol-2-ylidene)pyrazol-5-amine derivatives. Rational for these conversations are presented. [ABSTRACT FROM AUTHOR]

Conjugated substituted (ylidene)hydrazinecarbothioamides react in high yield with dimethyl acetylenedicarboxylate to give substituted [(ylidene)hydrazono) ‐ 4 ‐ oxothiazolidin ‐ 5 ‐ ylidene]acetates; several mechanistic options involving nucleophilic interaction are presented. [ABSTRACT FROM AUTHOR]

1,4-Disubstituted thiosemicarbazides reacted with dimethyl acetylenedicarboxylate with formation of (2-hydrazono-4-oxothiazolidin-5-ylidene)acetates and, in one case, a (2-imino-1,3,4-thiadiazin-5-on-6-ylidene)acetate. Several mechanistic options involving interaction are presented. The structures of all newly synthesized compounds were identified by 1H NMR, 13C NMR, COSY, HMQC and HMBC spectral data. [ABSTRACT FROM AUTHOR]

The reaction of (substituted ethylidene)hydrazinecarbothioamides 4a 4b 4c 4d 4e 4f 4g with dimethyl ethynedicarboxylate ( DMAD, 2) gave [(substituted ethylidene)hydrazono)-4-oxothiazolidine-5-ylidene]acetates 7a 7b 7c 7d 7e 7f 7g (71-88 %). The structure of the new compounds was established by infrared spectroscopy, mass spectrometry, and NMR spectroscopy. [ABSTRACT FROM AUTHOR]

1-Substituted 3-[3-(methyl/phenyl)-1 H-pyrazol-5-yl]thioureas react with the triple bond of dimethyl acetylenedicarboxylate forming ( Z)-methyl 2-[( Z)-3-substituted-2-(3-(methyl/phenyl-1 H-pyrazol-5-ylimino)-4-oxothiazolidin-5-ylidene)acetates. Rational for these conversations are presented. [ABSTRACT FROM AUTHOR]

( Z)-Methyl 2-[3-(arylideneamino)-2-(arylidenehydrazono)-4-oxothiazolidin-5-ylidene]acetate prepared during the reaction between thiocarbonohydrazides and dimethyl acetylene dicarboxylate. Rational for there conversations involving the nucleophilic addition on C/C triple bond of dimethyl acetylenedicarboxylate are presented. [ABSTRACT FROM AUTHOR]

The review summarizes published data on the behavior and reactions of acylthiosemicarbazides and their derivatives, which lead to the formation of heterocyclic systems, including methods of preparation in addition to synthesis of pyrrole, thiazole, thiadiazole, thiadiazolidine, and triazole derivatives as well as fused heterocyclic compounds. J. Heterocyclic Chem., (2012). [ABSTRACT FROM AUTHOR]

The review summarizes the literatures dealing with the synthesis of thiosemicarbazone derivatives, chemical reactions and their applications in the synthesis of important heterocyclic as well as fused heterocyclic compounds J. Heterocyclic Chem., (2012). [ABSTRACT FROM AUTHOR]

The reaction of 3-(dicyanomethylene)-2-indolone in a solution of ethanol/piperidine with 4-substituted thiosemicarbazides forms the derivatives of 5′-(substituted amino)-3′ H-spiro(indoline-3,2′-[1,3,4]thiadiazol-2-one. Rationales for these conversions involving the nucleophilic addition on the dicyanomethylene carbon atom are presented. The prepared compounds were evaluated each for antidepressant activity using tail suspension behavioral despair test and anticonvulsant activity against pentylenetetrazol induced seizures in mice. J. Heterocyclic Chem., (2011). [ABSTRACT FROM AUTHOR]

New imidazoles were easily prepared from 2,3-diamino-1,4-naphthoquinone and stoichiometric quantities of the appropriate aldehydes in dimethyl sulfoxide as a solvent. The reaction proceeded for few hours. The procedure can be generalized to different classes of aldehydes. 2-Methyl-1 H-naphtho[2,3- d]imidazole-4,9-dione was also obtained in good yield during refluxing of 2,3-diaminonaphthoquinone in acetic acid. The structure of the newly synthesized imidazoles was extensively investigated using NMR experiments. J. Heterocyclic Chem., (2011). [ABSTRACT FROM AUTHOR]

This review summarizes the preparation of substituted thiosemicarbazides with their application with synthesis of important linear and heterocyclic compounds. J. Heterocyclic Chem., (2011). [ABSTRACT FROM AUTHOR]

Reaction of N-arylisoindolines with benzyne afforded predominantly 10-arylisoindolo[2,1-f]phenanthridines. On the other hand, N-arylisoindolines react with dimethyl acetylenedicarboxylate to give dimethyl 2-(2-aryl-2H-isoindol-1-yl)fumarates. Possible reaction mechanisms are discussed. J. Heterocyclic Chem., (2010). [ABSTRACT FROM AUTHOR]

The review summarizes recent literatures dealing with the synthesis of carbohydrazide derivatives, chemical reactions and their applications in the synthesis of important heterocyclic as well as fused heterocyclic compounds. J. Heterocyclic Chem., (2010). [ABSTRACT FROM AUTHOR]

This review summarizes published data on the behavior and reactions of dithiobiurea and thioureidoalkylthiourea derivatives, which lead to the formation of heterocyclic systems, including methods of preparation in addition to synthesis of imidazolidine, thiazole, thioazolidine, triazolidine, thiadiazine, and spiro compounds. J. Heterocyclic Chem., (2010). [ABSTRACT FROM AUTHOR]

Nucleophilic attack by substituted hydrazides on C-2, C-3 of 2,3,5,6-tetrachloro-1,4-benzoquinone and 2,3-dichloro-1,4-naphthoquinone initiates the formation of benzo[e][1,3,4]oxadiazine and benzo- as well as naphthoxadiazepine derivatives. On the other hand, substituted hydrazides attack 1,4-naphthoquinone- 2,3-dicarbonitrile to form benzo[f]indazole-4,9-dione derivatives. A rationale for the conversions observed is presented. [ABSTRACT FROM AUTHOR]