Synthesis and mesomorphic properties of cyano derivatives of 2-(4-carbohydroxy-3-halogenphenyl)-5-alkyl-1,3,2-dioxaborinanes

Cyano derivatives of 2-(4-carbohydroxy-3-halogenphenyl)-5-alkyl-1,3,2-dioxaborinane have been synthesized. These compounds are characterized by low nematic-isotropic transition temperatures and a high positive dielectric anisotropy; they are promising for use in liquid-crystalline mixtures intended for high information electrooptic display devices.     

Conformational analysis of 2-methyl-5-alkyl- and 5-aryl-1,3,2-dioxaborinanes

Quantum chemical study of conformational isomerization of 2-methyl-5-alkyl- and 5-aryl-1,3,2-dioxaborinanes using RHF/6-31G(d) method led to the conclusion that the equilibrium between equatorial and axial sofa conformers is shifted to the latter form. Based on the experimental and theoretically calculated vicinal coupling constants J _HH the quantitative conformational composition and the values of ΔG ⁰ for substituents at the C⁵ ring atom were established.     

Synthesis of mesomorphic 2-alkyl-5-(p-cyanophenyl)pyridines

A new series of liquid-crystal derivatives of 2-alkyl-5-(p-cyanophenyl)pyridines were obtained by halogenation of 2-alkyl-5-phenylpyridines under the conditions of the Birckenbach-Gubo-Waters reaction with subsequent conversion of the 2-alkyl-5-(p-bromo- or iodophenyl) pyridines to the cyano derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 85–88, January, 1981.     

Synthesis and some properties of planar 4-diphenylphosphino-1,3,2-dioxaborinanes

Fused 1,3,2-dioxaborinanes, derivatives of 4-diphenylphosphino- and 4-diphenylphosphoryl-4H-1, 3-dioxa-2-boraphenanthrenes, and their complexes with amines have been synthesized. According to X-ray diffraction data, the complex of 2-phenyl-4-diphenylphosphoryl-4H-1, 3-dioxa-2-boraphenanthrene with butylamine exists as a dimer due to the formation of intermolecular hydrogen bonds.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1649–1655, September, 1994.The present work was financially supported by the International Science Foundation (grant No. RHBOOO).     

Synthesis and mesomorphic properties of aryl 5-alkyl-(and alkoxy) pyrimidine-2-carboxylates

Some aryl 5-alkyl(and alkoxy)pyrimidine-2-carboxylates (I) and 5-alkylpyrimidinoyloxybenzoates (II) have been obtained. It has been found the former do not display mesomorphism, but the latter are nematic liquid crystals with a range over which the mesophase exists of 50–90C. The transition to the liquid crystal state in these compounds takes place at approximately the same temperatures as in their benzene analogues, but the thermal stability of the mesophase is somewhat less. Cyano-derivatives of pyrimidine effectively increase the value of the dielectric anisotropy of the matrix mixture, but they have a marked effect on its clarification temperature.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, 1228–1235, September,1986.     

Stereochemistry of the formation of 2-alkyl-4,5-dimethyl-1,3,2-dioxaborinanes

It is demonstrated with the help of¹H and¹³C NMR spectroscopy and GLC that the formation of the stereoisomers of 2-alkyl-4,5-dimethyl-1,3,2-dioxaborinanes from 2-methyl-1,3-butanediol and acyclic boric acid esters occurs stereospecifically. This conclusion was confirmed by calculations of the optimal geometries and relative energies of the molecules of thecis-andtrans-isomers of model 4,5-dimethyl-1,3,2-dioxaborinanes and the proposed intermediate with a tetravalent boron atom using the method of molecular mechanics.A. V. Bogatskii Physicochemical Institute, National Academy of Sciences of Ukraine, Odessa 270080, Ukraine. Institute of Organic Chemistry, Ufa Science Center, Russian Academy of Science, Ufa 450054, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 400–404, March, 1998.     

Synthesis and mesomorphic properties of 3-(4-n-alkyloxyarylaminomethylene)chroman-2,4-diones

The synthesis, characterisation and mesomorphic properties of new liquid crystals are reported. The goal was to obtain amides starting from 7-decanoyloxychromone-3-carboxylic acid and 4-n-alkoxyanilines. However, instead of the expected amides, in each case a mixture of two isomeric E/Z enaminones was isolated, with a ratio 3/1. The mesophase behaviour of the five mixtures was characterised and studied using differential scanning calorimetry and polarising optical microscopy. The transitions are enantiotropic, the peaks being sharp and the mesomorphic range wide. All the compounds exhibit a smectic C phase and the derivatives with shorter chains also exhibit a nematic phase.     

Synthesis and liquid crystal properties of dinuclear cyclopalladated 5-alkyl-2-(4'-alkoxyphenyl)pyrimidine and 3-(4'-alkoxyphenyl)-6-alkoxypyridazine complexes

The dinuclear cyclopalladated complexes [Pd(L₁ or L₂)(µ-X)]₂ (HL₁=5-alkyl-2-(4'-alkoxyphenyl)pyrimidine, HL₂=3-(4'-alkoxyphenyl)-6-alkoxypyridazine, X=Cl^-, CH₂ClCOO^-, CH₂BrCOO^-, CH₃CHBrCOO^-, CH₂BrCH₂COO^-, CH₃COO^-) have been synthesized and characterized; their mesogenic properities were determined by DSC and polarizing microscopy. The effect of the bulk and the polarity of the bridging ligands on their mesogenic properties is discussed. The effect of the length of the alkyl chains on the mesogenic properties of these organometallic complexes has also been investigated.     

Synthesis and mesomorphic properties of 4-alkyl-3,4'-disubstituted biphenyls and terphenyls

Liquid-crystalline 4-alkyl-3-chloro(methyl)-4'-substituted biphenyls and terphenyls have been synthesized. Investigation of the mesomorphic properties of these compounds shows that unlike their unsubstituted analogues they form a liquid-crystalline phase at a lower temperature and over a narrower temperature range.     

1-芳胺羰基-3-苄硫基-4-乙氧羰基(或氰基)-5-氨基吡唑的合成及生物活性

利用5-氨基-4-乙氧羰基(或氰基)-3-苄硫基吡唑与异氰酸酯的加成反应合成了一系列1-芳胺羰基-3-苄硫基-4-乙氧羰基(或氰基)-5-氨基吡唑。利用分子力学计算,解释了¹HNMR谱中的取代基效应。生物活性测定结果表明部分化合物具有良好的除草活性。     

Conformational Composition of Stereoisomers of 2-Alkyl-5-isopropyl-4-methyl-1,3,2-dioxaborinanes

¹H and ¹³C NMR spectroscopy was used to assign the configuration of a mixture of stereoisomers of 2-alkyl-5-isopropyl-4-methyl-1,3,2-dioxaborinanes with different ratios of the cis and trans forms. These forms differ in the configuration of C⁽⁴⁾ in the ring. The results of MM+ and AM1 calculations for the optimal geometry indicate high conformational flexibility of both isomers, which exist in an equilibrium mixture of sofa and half-chair conformers.     

Synthesis and mesomorphic properties of 7-acyloxy-3-(4-acyloxyphenyl)-4H-1-benzopyran-4-one

A new homologous series of 7-acyloxy-3-(4-acyloxyphenyl)-4H-1-benzopyran-4-ones was synthesized and characterized by elemental analysis and spectroscopic techniques along with thermal behaviour study using differential scanning calorimetry. Texture observation was performed under the polarizing optical microscope from which the derivatives were found to exhibit different molecular organizations as exemplified by various mesophases. Whilst the compounds containing butanoyloxy and hexanoyloxy groups behave as nematogens, the other compounds with heptanoyloxy and longer side chains show a SmC phase. The octadecanoyloxy derivative was the only member showing a monotropic SmC phase. The difference in phase behaviour is discussed based on the molecular structure and the presence of a lateral dipole which can be associated with the intermolecular interaction within the mesophase.     

Reductive transformations of 3-alkyl- and 3-aryl-5-(4-pyridyl)-2-isoxazolines

The reactions of 3-R-(4-pyridyl)-2-isoxazolines and the products of their hydrogenolysis over Raney Ni/AlCl₃ with NaBH₄ and KBH(s-Bu)₃ as the reducing agents were studied. New polyhydroxyprostanoids were synthesized.Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, 220141 Minsk; Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 252–258, February, 1999.     

Synthesis of some 4-carboxy-3- and 5-(2-hydroxyalkyl)pyrazole lactone derivatives

The synthesis and biological activities of some 4-oxo-1-or-2-substituted 1H-or-2H-pyrano[4,3-c]pyrazole derivatives are described.     

3-芳基-5-(2-呋喃基)-4, 5-二氢吡唑衍生物的合成及其生物活性评价

二氢吡唑类化合物是一类具有良好生物活性的五元杂环化合物。本文以2-呋喃甲醛和4-氟苯乙酮为原料,经羟醛缩合和取代反应生成4’-二甲氨基呋喃查尔酮(2)后,与水合肼环化得到二氢吡唑中间体(3),再酰化得到9个未见报道的5-(2-呋喃基)-3-芳基-4, 5-二氢-1H-吡唑衍生物(4a-4i),其结构经IR、₁H NMR和₁₃C NMR确证。分别采用小鼠巨噬细胞Raw264.7模型和DHHP法初步测试了目标化合物的体外抗炎活性和抗氧化活性,结果表明,部分化合物具有潜在的抗炎活性和清除自由基活性,特别是化合物4b和4c的抗炎活性与阳性对照药地塞米松活性相当(IC₅₀值分别为7.84μM和10.52μM),而化合物3、4b、4c和4d在浓度为4mg/mL时对DPPH自由基的清除率均超过90%。     

Synthesis and mesomorphic properties of 4-(1,1,7-trihydroperfluoroheptyloxycarbonyl)phenyl 4'-n-alkoxybiphenyl-4-carboxylate

A family of 4-(1,1,7-trihydroperfluoroheptyloxycarbonyl)phenyl 4'-n-alkoxybiphenyl-4-car- boxylates has been synthesized. The compounds show the smectic A phase while the mesogens with intermediate terminal alkyl chain ( n 7-12) also exhibit a broad smectic C phase.     

Synthesis and anti-TMV activity of novel N-(3-alkyl-1H-pyrazol-4-yl)-3-alkyl-4-substituted-1H-pyrazole-5-carboxamides

In order to investigate the biological activity of novel bis-pyrazole compounds,a series of N-（3-alkyl-5-（N-methylcarbamyl）- 1H-pyrazol-4-yl）-3-alkyl-4-substituted-1H-pyrazole-5-carboxamides were designed and synthesized with ethyl 3-alkyl-1H-pyrazole -5-carboxylate 1 as starting materials.N-Methyl-3-alkyl-4-amino-1H-pyrazole-5-carboxamides 6 were obtained from 1 via 5 steps.3-Alkyl-4-substitued-1H-pyrazole-5-carboxyl chlorides 4a,4b,11a,11b,11c or 12 were also obtained from 1 via several steps.Target compounds 7a-7g were obtained after the reaction of 6 with the above 1H-pyrazole-5-carboxyl chlorides.Preliminary bioassay showed some compounds possessing good inactivation effect against TMV（tobacco mosaic virus）.Compound 7a showed higher activity superior to ningnanmycin at a concentration of 5.0×10^-4 g/mL and equal activity at 1.0×10^-4 g/mL;7b and 7c showed equal activity to virazole both at concentrations of 5.0×10^-4 g/mL and 1.0×10^-4 g/mL.     

Synthesis and mesomorphic properties on the series of 2-(4-alkylphenyl)-6-methylquinolines and 2-(4-alkoxyphenyl)-6-methylquinolines

Two homologous series of quinoline-containing liquid crystalline compounds were synthesised. Preparation of these compounds was completed in a short two-step reaction. Fair to good two-step overall yields of 63%–68%?and 50%–60%?were obtained respectively for the liquid crystalline compounds of 2-(4-alkylphenyl)-6-methylquinolines (nPQMe, n?=?4–8) and 2-(4-alkoxyphenyl)-6-methylquinolines (mOPQMe, m?=?3–7). Spectral analyses were in accordance with the expected structures. Polarising optical microscopy showed both series of compounds only display a nematic phase. Their thermotropic behaviours were further confirmed by differential scanning calorimetry.