Thermal isomerizations of 2-d-1-(E)-propenylcyclobutanes to 4-d-3-methylcyclohexenes

Racemic trans-2-d-1-(E)-propenylcyclobutane at 276 degrees C in the gas phase fragments to give ethylenes and pentadienes, equilibrates with its cis isomer, and rearranges to mixtures of 4-d- and 6-d-3-methylcyclohexenes through [1,3] carbon shifts. The time-dependent distributions of deuterium-labeled isomers of propenylcyclobutanes and 3-methylcyclohexenes reveal a significant secondary deuterium kinetic isotope effect favoring C1-C4 over C1-C2 bond breaking (kH/kD = 1.16 +/- 0.02) and a 72:28 preference for structural isomerizations giving (si + ar) rather than (sr + ai) products through conformationally flexible short-lived diradical intermediates.     

The conversion of isotopically labeled glycine to 1-methyl-2-amino-2-imidazolin-4-one (creatinine)

A procedure is presented which allows the conversion of glycine to creatinine (1-methyl-2-amino-2-imidazolin-4-one). The scheme was devised to optimize the yield based on the amount of glycine used so that the relatively readily available isotopically labeled glycines could be efficiently converted to the correspondingly labeled creatinines. In this case 1-(¹³C)-glycine was converted to 4-(¹³C)-1-methyl-2-amino-2-imidazolin-4-one.     

Studies on the mechanism of decomposition of 1-methyl-1-(1-naphthyl)ethyl hydroperoxides to 2-(1-naphthyloxy)propenes

Abstract  

Thermal decomposition of 1-methyl-1-(4-methyl-1-naphthyl)ethyl hydroperoxide under gas chromatography-mass spectroscopy (GC–MS) conditions gives 2-((4-methyl-1-naphthyl)oxy)propene as the main product (50.5%), without any detectable traces of the isomeric 2-((5-methyl-1-naphthyl)oxy)propene. This finding excludes the rearrangement pathway of 1-methyl-1-(1-naphthyl)ethyl hydroperoxides to the corresponding 2-(1-naphthyloxy)propenes, which involves formation of a naphthofuran derivative as an intermediate and transfer of the isopropenyloxy group to the 8 position. This result, as well as our previous density functional theory (DFT) calculations, points to the rearrangement pathway involving an oxirane-type intermediate as the most plausible pathway to 2-(1-naphthyloxy)propenes. This rearrangement is responsible for the unusual inhibition effects of 1-methyl-1-(1-naphthyl)ethyl hydroperoxide on the liquid-phase oxidation of isopropylarenes with oxygen.     

Vibrational spectra of succinonitrile and its [1,4-13C2]-,[2,2,3,3,-2H4]- and 1,4-13C-2,2,3,3-2H4]-isotopomers and a force field of succinonitrile

[1,4-13C2]-succinonitrile, [2,2,3,3-2H4]-succinonitrile, [1,4-13C2-2,2,3,3-2H4]-succinonitrile have been synthesized and, for the first time, the infrared and Raman spectra of these succinonitrile isotopomers have been discussed in detail. The spectra were recorded at ambient temperature and at the temperature of liquid nitrogen and assignments of the vibrational bands of all above isotopomers have been made. In addition to this, the force field of succinonitrile in its two configurations, gauche and trans, have been calculated using all experimental frequencies and the ab-initio method. Also, the assignments of the vibrational bands of the 'normal' succinonitrile molecule have been achieved using the results of the force field calculations to support the assignments for the normal succinonitrile, as well as for the isotopomers.     

1,3-二联苯基-2，4-二吡啶基环丁烷的结构与光化学性质

通过反-1-(4-联苯基)-2-(4-吡啶基)乙烯(EI)在稀硫酸中的光二聚反应合成了r-1,c-2,t-3,t-4-1,3-双(4-联苯基)-2,4-二(4-吡啶基)环丁烷(II).用X射线衍射法测定了其结构.晶体II为单斜晶系,空间群为P2     

Synthesis,Crystal, Computational Study and Biological Activity of N-(1-(2,4-Dichlorophenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-yl)-4-(N,N-dipropylsulfamoyl)benzamide

The title compound N-(1-(2,4-dichlorophenyl)-1 H-pyrazolo[3,4-d]pyrimidin-4-yl)-4-(N,N-dipropylsulfamoyl)benzamide was synthesized by the condensation of 4-(dipropylsulfamoyl)benzoic acid with 1-(2,4-dichlorophenyl)-1 H-pyrazolo[3,4-d]pyrimidin-4-amine. This intermediate was prepared from 5-amino-1-(2,4-dichlorophenyl)-1 H-pyrazole-4-carbonitrile by the condensation with triethyl orthoformate and then cyclisation with ammonium hydroxide solution in tetrahydrofuran at room temperature. The crystal structure of the title compound was determined. The optimized geometric bond lengths and bond angles obtained by using density functional theory(DFT) have been compared with X-ray diffraction values. In addition, the preliminary biological test showed that the compound possesses distinct effective inhibition on the proliferation of some cancer cell lines.     

Synthesis,Crystal Structure,and Antitumor Activity of 1-（4-Methoxybenzylidene）-2-（1-phenyl-6-trifluoromethyl- 1H-pyrazolo [3,4-d] pyrimidin-4-yl）hydrazine Monohydrate

The novel title compound 1-(4-methoxybenzylidene)-2-(1-phenyl-6-trifluoromethyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)hydrazine monohydrate(C20H15F3N6O·H2O, Mr = 430.40) has been synthesized by a four-step procedure including the cyclization, chlorination, hydrazinolysis and condensation reaction, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to orthorhombic, space group Pbca with a = 8.3779(13), b = 17.607(3), c = 26.774(4) , V = 3949.2(11) 3, Z = 8, Dc = 1.448 g/cm3, μ = 0.117 mm–1, F(000) = 1776, the final R = 0.0553 and wR = 0.1516 for 2354 observed reflections with I 2■(I). X-ray diffraction analysis reveals that the title compound is almost coplanar except for the trifluoromethyl and phenyl moieties. In the crystal packing, the molecules are linked by intermolecular O(1W)–H(1WA)···N(2), O(1W)–H(1WA)···N(4) and N(5)–H(5A)···O(1W) hydrogen bonds via water molecules and stacked through π-π stacking interactions. The preliminary bioassay suggested that the title compound exhibits relatively good antitumor activity against HepG2 and BCG-823.     

1,3-二苄基-4-(4-甲氧羰基丁基)-噻吩并[3,4-d]-咪唑-2-酮的合成

1,3-二苄基-4-(4-甲氧羰基丁基)-噻吩并[3,4-d]-咪唑-2-酮(Ⅰ)是合成生物素的一个关键中间体.在超声波促进下,用低价钛试剂对(4 aR)-1,3-二苄基-4-(1-己二酸单甲酯酰基硫甲基)-咪唑-2,5-二酮(Ⅱ)进行还原偶联,即生成1,3-二苄基-4-(4-甲氧羰基丁基)-噻吩并[3,4-d]咪唑-2-酮(Ⅰ).超声反应1.5 h,收率71%.     

1-异丙基-3-异丙烯基-1H-吡唑并[3,4-d]嘧啶-4-胺的合成、表征及抗肿瘤活性

以3-碘-1H-吡唑并[3,4-d]嘧啶-4-胺(2)为原料,经过N-烷基化、Suzuki偶联反应得到目标化合物1-异丙基-3-(异丙烯基)-1H-吡唑并[3,4-d]嘧啶-4-胺(1),两步反应总收率57.0 %。产物及中间体结构经₁^H NMR、_1³C NMR、ESI-MS以及X-射线单晶衍射进行表征。并对该Suzuki反应条件进行研究,确定最佳条件为：Pd(dppf)Cl₂的用量为n (Pd(dppf)Cl₂) : n (化合物3) = 0.06 : 1;物料比为n(异丙烯基硼酸): n(化合物3)= 1.6 : 1;反应溶剂为N,N-二甲基甲酰胺;反应温度为100 ℃;反应时间2 h,在最佳反应条件下,该Suzuki偶联反应收率达到68.2 %。体外抗肿瘤活性测试表明,产物(1)对MCF-7、A549、PC-3、HepG2和SGC-7901增殖均有明显的抑制活性,特别抑制MCF-7的IC₅₀值达到10.6 μmol?L_-1^。     

Thermal polymerizations of alkali 4-(1-bromoethyl)benzoates

Thermal reactions of alkali salts of 4-(1-bromoethyl)benzoic acid in bulk were investigated. These reactions were found to produce unexpectedly the graft copolymer, poly(4-vinylbenzoate)-graft-oligo(oxycarbonyl-1,4-phenylenethylidene) ( 1 ). The relative reactivity of the oligocondensation as well as the vinyl polymerization of the salts decreased in the following order: K > Na > Li. The reaction polymerization rate proceeded rapidly during the initial 15 min, and then slowed down.     

Conformationally constrained, stable, triplet ground state (S = 1) nitroxide diradicals. Antiferromagnetic chains of S = 1 diradicals

Nitroxide diradicals, in which nitroxides are annelated to m-phenylene forming tricyclic benzobisoxazine-like structures, have been synthesized and characterized by X-ray crystallography, magnetic resonance (EPR and 1H NMR) spectroscopy, as well as magnetic studies in solution and in solid state. For the octamethyl derivative of benzobisoxazine nitroxide diradical, the conformationally constrained nitroxide moieties are coplanar with the m-phenylene, leading to large values of 2J (2J/k > 200 K in solution and 2J/k > 300 K in the solid state). For the diradical, in which all ortho and para positions of the m-phenylene are sterically shielded, distortion of the nitroxide moieties from coplanarity is moderate, such that the singlet-triplet gaps remain large in both solution (2J/k > 200 K) and the solid state (2J/k approximately 400-800 K), though an onset of thermal depopulation of the triplet ground state is detectable near room temperature. These diradicals have robust triplet ground states with strong ferromagnetic coupling and good stability at ambient conditions. Magnetic behavior of the nitroxide diradicals at low temperature is best fit to the model of one-dimensional S = 1 Heisenberg chains with intrachain antiferromagnetic coupling. The antiferromagnetic coupling between the S = 1 diradicals may be associated with the methyl nitroxide C-H- - -O contacts, including nonclassical hydrogen bonds. These unprecedented organic S = 1 antiferromagnetic chains are highly isotropic, compared to those of the extensively studied Ni(II)-based chains.     

Synthesis of 1-phenyi-1H-tetrazolo[4,5-d]tetrazole and 5-aryl-1-(4-bromophenyl)-1,2,4-triazolo[4,3-d]tetrazoles

l-Phenyl-lH-tetrazol-5-yIhydrazine (2) was reacted with nitrous acid to yield 1-phenyl-lH-tetrazolo[4,5-d]tetrazole (3). l-Arylidene-2-(l-phenyl-lH-tetrazol-5-yl)hydrazines (4) were generally reactive towards electrophilic reagents. When treated with bromine in acetic acid, 4 yielded mixtures of 1-arylidene-2-[1-(4-bromophenyl)-lH-tetrazol-5-yl]hydrazines (5a-d) and 2-[1-(4-bromophenyl)-lH-tetrazol-5-yl]hydrazidic bromides (6a-d). Solvolysis of 6a-d in aqueous acetone yielded 5-aryl-1-(4-bromophenyl)-1,2,4-triazolo[4,3-d]tetrazoles (7a-d). The structures of the synthesized compounds were confirmed on the basis of elemental analysis, IR and ¹H NMR data.     

Synthesis,Structure and Biological Activity of 2-[2-(4-Fluorobenzylidene)hydrazinyl]-4-(1-methyl-1H-indol-3-yl)thieno[3,2-d]pyrimidine

The title compound 2-[2-(4-fluorobenzylidene)hydrazinyl]-4-(1-methyl-1 H-indol-3-yl)thieno[3,2-d] pyrimidine(8) was synthesized by the condensation of 4-fluorobenzaldehyde(7) with 2-hydrazinyl-4-(1-methyl-1 H-indol-3-yl)thieno[3,2-d]pyrimidine(6). This intermediate was prepared from methyl 3-aminothiophene-2-carboxylate(1) by the condensation with urea, chlorination with phosphorus oxychloride and then condensation with hydrazine hydrate. The crystal of 8 belongs to monoclinic system, space group P21/c with a = 14.0453(18), b = 17.436(2), c = 18.0982(17) ? and β = 122.969(7)°. In addition, 8 possesses marked inhibition against the proliferation of human colon cancer cell line HT-29(IC50 = 6.09 μM) and human gastric cancer cell line MKN45(IC50 = 3.04 μM), displaying promising anticancer activity.     

Reaction of 2-substituted 1-phenyl-1,2-dihydro-4H-3,1,2-benzoxazaphosphinin-4-ones with bis(2,2,3,3-tetrafluoropropyl) 2-(4-chlorobenzylidene)malonate

Russian Journal of Organic Chemistry -     

A Convenient Synthesis of (1 1E, 13E)-11, 13-Hexadecadienal and (11Z, 13E)-Hexadecadienal

A simple method for synthesizing (11E, 13E)-11, 13-hexadecadienal 7, a component of the female sex pheromone of cabbage webworm, and its geometrical isomer (11Z, 13E)-11, 13-hexadecadienal 8 is described.