The methylation of 1,2,3-thiadiazole-4-carbothioamides

A study was carried out on the methylation of 5-(3-phenylureido)- and 5-amino-1,-2,3-thiadiazole-4-carbothioamides. A new rearrangement was observed for 5-amino-1,2,3-thiadiazole-4-S-methylcarbothioimidates to give 5-methylthio-1,2,3-triazole-4-carbothioamides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 938–940, April, 1990.     

Fruit Extract of Averrhoa bilimbi: A Green Neoteric Micellar Medium for Isoxazole and Biginelli-Like Synthesis

Research on Chemical Intermediates - A transition metal/ligand/additive/promoter-free synthesis of 3-methyl-4-arylmethylene-isoxazol-5(4H)-ones and the Biginelli-like synthesis is carried out in a...     

Decomposition of ozone in water at pH 4–8

A systematic study of the ozone decomposition in water in the pH range 4–8 was carried out.     

Growth and characterization of 2-amino-4-picolinium toluene sulfonate single crystal

2-Amino-4-picolinium toluene sulfonate (2A4PTS), a new organic material, was synthesized and grown as single crystals in room temperature by slow evaporation solution growth technique using water as solvent. The crystal structure of 2A4PTS has been determined using single crystal X-ray diffraction studies. 2A4PTS belongs to monoclinic crystal system. The molecular arrangements in the crystal were studied. The structural perfection of the grown crystals has been analysed by high-resolution X-ray diffraction (HRXRD) rocking curve measurements. Fourier transform infrared (FTIR) spectral studies have been performed to identify the functional groups. The optical transmittance window and the lower cutoff wavelength of the 2A4PTS have been identified by UV–Vis–NIR studies. The nonlinear optical properties have been investigated by Z-scan method. The nonlinear refractive index and linear absorption coefficient of the 2A4PTS are found to be in the order of 10⁻⁸ cm²/W and 10⁻⁴ cm/W, respectively. The laser induced surface damage threshold for the grown crystal was measured using Nd:YAG laser. Thermal analysis carried out on the compound reveals that 2A4PTS is stable up to 133 °C. The microhardness test was carried out and the load dependent hardness was measured.     

An efficient procedure for the preparation of 4‐methyl‐2‐thiocoumarins by the reaction of 4‐methylcoumarins with lawesson's reagent

A simple and convenient method has been worked out for the preparation of 4‐methyl‐2‐thiocoumarins by the reaction of the appropriate 4‐methylcoumarins with Lawesson's Reagent in hot anhydrous toluene.     

New synthetic method for 4-hydroxyproline

A new synthesis of 4-hydroxyproline was carried out starting from diethyl p-nitrobenzoylaminomalonate, which was converted by a three steps pathway into diethyl 4-hydroxy-1-(4-nitrobenzoyl)pyrrolidine-2,2-dicarboxylate, which afforded 4-hydroxyproline via acid hydrolysis.     

Influence of bromoalkyloxy side chain on mesomorphic behavior in heterocyclic 7-(4-bromoalkyloxy)-3-(4′-decyloxyphenyl)-4H- 1-benzopyran-4-ones

A new homologous series of isoflavone-based ethers,7-(4-bromoalkyloxy)-3-(4’-decyloxyprienyl)-4H-1-benzopyran-4-ones were synthesized and characterized.The mesomorphic properties of all homologues were investigated by differential scanning calorimetry(DSC) and polarizing optical microscopy(POM).Enantiotropic smectic A(SmA) phase was observed for all homologues.The structure-property study was carried out by comparing the mesomorphic behavior of the homologues with those previously reported analogues.The bromine atom from the alkyloxy side chain of the benzene ring fused to the heterocyclic moiety was found to be capable of changing the mesomorphic properties.     

N-取代乙醇胺对4-氟-1-酰基苯的选择性胺化反应

研究了4-氟-1-酰基苯和N-取代乙醇胺在酰胺类溶剂或不加溶剂中反应, 在不需要金属催化剂和另外加碱的条件下选择性地得到胺化产物, 实验操作简单, 符合S_NAr取代机理. 一系列羟乙基胺基酰基苯产物均经过元素分析(HRMS), IR, MS和NMR的测定.     

A practical synthesis of functionalized isoindolinones via [3 + 3] benzannulation of 1,3-bissulfonylpropenes and 4-arylmethylene-2,3-dioxopyrrolidines

A straightforward synthesis of isoindolinones has been developed via a [3?+?3] benzannulation of 4-arylmethylene-2,3-dioxopyrrolidines and 1,3-bissulfonylpropenes (or 4-sulfonylcrotonates). A series of functionalized isoindolinones were obtained in excellent yields. The reaction could be carried out under mild conditions without transition metal catalyst. The finding provides a practical approach for the preparation of isoindolinone derivatives with potential biological activities.     

4H-3,1-benzoxazin-4-ones thermal cyclodehydration of N-benzoylanthranilic acid

Water is split out to form 2-phenyl-4H-3,1-benzoxazin-4-one when N-benzoylanthranilic acid is heated. A mass spectrometric study of O¹⁸-labeled N-benzoylanthranilic acid and the product of its thermal cyclodehydration showed that the oxygen atoms of the carboxyl and benzoyl groups participate equally probably in splitting out of water.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 614–615, May, 1977.     

Synthesis of cytotoxic sinapll alcohol derivatives form ligularia nelumbifolia

Total synthesis of two cytotoxic natural products, nelumol A (1) and nelumal A (2), were carried out by two different paths. 4-O-Benzyl substitute analogues 26 and 27, as well as the 4-O-(2-methyl-butenyl) derivatives 29 and 30 were also synthesized for a SAR investigation. 1 and 2 were also measured on different tumor cell line.     

The synthesis of 1-[(2-thiazolyl)methyl]quinolones. The reactivity of the methylene bridge at position-1 and its involvement in the formation of a stable carbon-nitrogen ylid

A series of 7-chloro-1,4-dihydro-6-fluoro-1-[(2-methylthiazolyl)methyl]-4-oxoquinoline carboxylic esters 5 has been prepared. Dehydration of the intermediates 4-hydroxythiazolines 4 with trifluoroacetic anhydride resulted in the formation of a ylid 11 . Evidence for this was obtained by the X-ray analysis of the analogous product obtained in reactions carried out with 4-pyridone.     

Synthesis of Cytotoxic Sinapyl Alcohol Derivatives fromLigularia nelumbifolia

Total synthesis of two cytotoxic natural products, nelumol A(1) and nelumal A(2), were carried out by two different paths. 4-O-Benzyl substitute analogues 26 and 27, as well as the 4-O-(2-methyl-butenyl) derivatives 29 and 30 were also synthesized for a SAR invesigation. 1 and 2 were also measured on different tumor cell line.     

A novel synthesis and transformations of isothiochroman 2,2-dioxide

A convenient synthesis of isothiochromen-4-one 2,2-dioxide was carried out via cyclisation of o-cyanobenzyl thioacetate by a Thorpe reaction. The reactions of isothiochromen-4-one 2,2-dioxide with nitrogen-containing nucleophilic reagents have been investigated.     

A simple synthesis of (±) 4-demethoxydaunomycinone

A new and simple synthesis of 4-demethoxy-7-deoxydaunomycinone has been carried out essentially in three steps starting from 1,4-dimethoxy-6-tetralone.     

Synthesis of 4-methyl-2,3,4-trichlorotetrahydropyran and several features of the stereochemistry of the nucleophilic substitution of the α-chlorine atom

A convenient method has been developed for the synthesis of 4-methyl-2,3,4-trichlorotetrahydropyran by the chlorination of 4-methyl-4-chlorotetrahydropyran, 4-methyl-5,6-dihydro-2H-pyran and its dichloride. A study was carried out on the reactions of 4-methyl-2,3,4-trichlorotetrahydropyran with alcohols, with sodium thiocyanate and Grignard reagents. PMR spectroscopy was used to study the stereochemistry of 4-methyl-2,3,4-trichlorotetrahydropyran and its derivatives, 2-substituted 4-methyl-3,4-dichlorotetrahydropyrans. The dechlorination of these dichloro derivatives by metallic sodium leads to 2,4-disubstituted 5,6-dihydro-2H-pyrans with high regioselectivity.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 465–471, April, 1986.     

Simultaneous photoacoustic measurements of specific heat and thermal conductivity critical behaviour at a smectic A-nematic phase transition

Simultaneous measurements of the thermal conductivity and specific heat at the smectic A-nematic phase transition in 4-n-octyl-4'-cyanobiphenyl (8CB) have been carried out with the photoacoustic technique. A critical increase in the thermal conductivity is reported. A critical decrease in the thermal diffusivity data confirms that the transition in 8CB is fluctuation dominated as also shown by the critical behaviour of the specific heat.     

Synthesis of the sulfones of leukotriene C4, D4, and E4

A simple one-step preparation of the sulfones of Leukotriene C₄, D₄ and E₄ has been developed by the direct oxidation of the parent compounds. An alternative synthesis of these sulfones has also been carried out by reduction of an acetylenic precursor.     

A new method of preparing 1, 2, 4-triazole carboxylic-3 acids

A new convenient method of preparing 1, 2, 4-triazole carboxylic acids-3 is worked out. Aminoguanidine bicarbonate and oxalic acid give 5-amino-1, 2, 4-triazole carboxylic acid-3, and this is converted, via the diazotriazole carboxylic acid and treatment of the latter with methanol, to 1, 2, 4-triazole carboxylic-acid-3.     

Biocatalytic deacylation studies on tetra-O-acyl-β-D-xylofuranosyl nucleosides: synthesis of xylo-LNA monomers

A Novozyme-435 catalytic methodology has been developed for selective deacylation of one of the acyloxy functions involving a primary -OH group over the other acyloxy functions involving primary and secondary -OH groups in 4'-C-acyloxymethyl-2',3',5'-tri-O-acyl-β-D-xylofuranosyl nucleosides. Optimization of the biocatalytic reaction revealed that tetra-O-butanoyl-β-D-xylofuranosyl nucleosides are the best substrates for the enzyme. The possibility of acyl migration during enzymatic deacylation reactions has been ruled out by carrying out biocatalytic deacylation reactions on mixed esters of 4'-C-hydroxymethyl-2',3',5'-tri-O-acetyl-β-D-xylofuranosyl nucleosides. The developed methodology has been used for the efficient synthesis of xylo-LNA monomers T, U, A, and C in good yields.