Reactions of 1,2-diaza-1,3-dienes with thiol derivatives: a versatile construction of nitrogen/sulfur containing heterocycles

The synthesis of substituted 2,3-dihydro-1,4-thiazines, fused cycloalkyl-1,4-thiazines, 1,4-benzothiazines and fused cycloalkyl-1,4-benzothiazines by 1,4-addition of 1,2-aminothiols to 1,2-diaza-1,3-dienes bearing carboxylate, carboxamide, or phosphorylated groups and subsequent internal heterocyclization is described. The reaction of carboxylated 1,2-diaza-1,3-butadienes with 2-(butylamino)ethanethiol affords 1,4-thiazinan-3-ones. The solid-phase reaction of polymer-bound 1,2-diaza-1,3-butadienes with 1,2-aminothiols produces 2,3-dihydro-1,4-thiazines and 1,4-benzothiazines.     

Reactivity of N-arylsulfonyl-1,4-benzoquinone imines. Reaction with hydrazoic acid

N-Arylsulfonyl-2-halo-1,4-benzoquinone imines react with hydrazoic acid in boiling acetic acid via two pathways: the 1,4-addition and nucleophilic replacement of the halogen atom by an azido group, followed by the 1,4-addition of HN₃. In the reaction of N-arylsulfonyl-2,6-dihalo-1,4-benzoquinone imines with hydrazoic acid, both halogen atoms are replaced by azido groups, while N-p-tolylsulfonyl-2-methyl-1,4-benzoquinone imine takes up HN₃ molecule according to the 1,4-addition pattern.     

Synthesis of Poly（p-phenyleneethynylene）s with Crosslinkable End or Side Groups and Its Solid State Structure and Optical Properties Before and after Crosslinking

Two crosslinkable poly(p-phenyleneethynylene)s(PPEs): poly[2,5-di(2'-ethyl-hexyloxy)-1,4-phenylenee-thynylene] with end-capped vinyl(PPE1) and poly[2,5-di(allyloxy)-1,4-phenyleneethynylene-2,5-di(2'-ethyl-hexyloxy)-1,4-phenyleneethynylene](PPE2) were synthesized. Via the thermal addition reactions of vinyl end groups of PPE1 and allyloxy side groups of PPE2, crosslinked polymers C-PPE1 and C-PPE2 were obtained, respectively. The two polymers were characterized by wide-angle X-ray diffraction(WXRD), ultravio...     

Interaction of a lithiated nitronyl nitroxide with polyfluorinated 1,4-naphthoquinones

A 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl lithium derivative was found to react with 2-methoxypentafluoro-1,4-naphthoquinone to form a product of addition at the carbonyl function: radical 2-(3,5,6,7,8-pentafluoro-1-hydroxy-2-methoxy-4-oxo-1,4-dihydronaphthalen-1-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl. The yield of the addition product increased with temperature and reached 84% at 0?°C. The reaction of the lithium derivative with hexafluoro-1,4-naphthoquinone gave rise to a product of addition at both carbonyl groups, namely, nitronyl nitroxide diradical 2,3,5,6,7,8-hexafluoro-1,4-bis(4,4,5,5-tetramethyl-3-oxide-1-oxyl-4,5-dihydro-1H-imidazole-2-yl)-1,4-dihydronaphthalene-1,4-diol in a 16% yield. The structures of both mono- and diradical were solved by X-ray diffraction analysis, which revealed formation of an intramolecular H-bond between the OH group and nitroxide oxygen. According to electron paramagnetic resonance (EPR) spectroscopy, the obtained mono- and dinitroxide are prone to spontaneous deoxygenation in a toluene solution to give corresponding iminonitroxides. In water, they are much more stable.     

对称和不对称的1，2，5-噻二唑-1，4-戊氧苯基取代的四氮杂卟啉化合物有机半导体场效应性质的密度泛函理论研究

在密度泛函理论基础上研究了一系列对称和不对称的1,2,5-噻二唑-1,4-戊氧苯基取代的四氮杂卟啉化合物（s4）PzH2,（A4）PzH2,（cis-S2A2）PzH2和（SA3）PzH2（S=1,2,5-噻二唑-环,A=1,4-戊氧苯基,Pz=四氮杂卟啉）有机半导体场效应性质．分别研究了这一系列化合物的最高占有和最低未占有轨道能量,离子化能,电子亲合能和电荷传导过程中的重组能．在Marcus电子传导理论基础上计算了具有晶体结构的这四种化合物的电子耦合和迁移率．计算结果表明：化合物（S4）PzH2的电子迁移率为0．056cm^2·V^-1·S^-1,其他三种化合物（cis—S2A2）PzH2,（SA3）PzH2和（A4）PzH2的空穴迁移率分别为0．075,0．098和8．20cm^2·V^-1·S^-1．目前的工作是对这一系列1,2,5-噻二唑--1,4-戊氧苯基取代的四氮杂卟啉化合物有机半导体场效应性质的理论研究．     

A novel free C-12 higher carbon sugar: asymmetric synthesis and reactivity with nucleophiles

A novel C-12 higher carbon sugar, (1R)-(1,4:3,6-dianhydro-d-mannitol-2-yl)-1,4:3,6-dianhydro-d-fructose, was firstly synthesized via a convenient aldol reaction of 1,4:3,6-dianhydro-d-fructose without any protection and activation of functional groups. The reactivity of the novel higher sugar with nucleophiles was also studied, through which a series of oxazolidines and other derivatives of the higher sugar were available. The study showed that the higher sugar possesses a highly reactive carbonyl group and a good stereo controlling ability in the reaction.     

Radical Reactions of 1,4-Bis(vinylsulfonyl)tetrafluorobenzene with Tetrahydrofuran

Homolytic addition of tetrahydrofuran at the vinylsulfonyl groups of 1,4-bis(vinylsulfonyl)tetrafluorobenzene in the absence of radical initiator at 20 and 55°C leads to formation of 1,4-bis[2-(2-tetrahydrofuryl)ethylsulfonyl]tetrafluorobenzene in 16 and 42% yield, respectively, and a mixture of telomers. The latter are formed as a result of opening of the tetrahydrofuran ring in the adduct.     

Competing cheletropic reactions of difluorocarbene with various 2-substituted norbornadienes

Norbornadienes substituted at C2 with electron donating, conjugating, and withdrawing groups react with difluorocarbene to give a ratio of 1,2 to homo-1,4 adducts, which reflects a diminishing response of electrophilic character in the carbene.     

Polymers with indane units by cationic polymerization

In spite of the difunctionality of the monomers, cationic polymerization of 1,3- and 1,4-diisopropenylbenzene does not lead to branched or cross-linked products. Instead, soluble polymers are obtained, containing the 1,1,3-trimethylindane system as repetitive unit along the backbone. These polymers are interesting materials because of their high glass transition temperature (200°C-250°C) and good thermal stability in air (2% weight loss at 450°C). Although the molar mass of the polyindanes seems to be limited due to a side reaction, it is possible to produce telechelic polyindanes. Substitution of an alkyl side chain onto the isopropenyl groups of 1,4-diisopropenylbenzene leads to monomers which yield substituted polyindanes with glass transition temperatures as low as 26°C. Such polymers still exhibit good thermal stability: at 340°C a weight loss of only 2% occurs. 1,4-Diisopropenylbenzene can even be anionically polymerized to linear polymers. In this case, the resulting polymer possesses isopropenyl phenyl side groups, which can be used as initiators for cationic polymerization of isobutene to obtain grafted copolymers.     

Bromination of Mono- and Bisammonium Salts with a 4-Penten-2-ynyl Side Group

Reaction of bromine with 1,4-bisammonium salts containing, along with a 2-chlorobutenylene common fragment, 4-penten-2-ynyl side groups, as well as of monoammonim salts containing the same side group and a 4-bromo-3-chlorobutenyl group, involve addition of two bromine molecules at each of the side groups, while the double bond of the chlorobutenyl group remains intact.     

[2 + 2] Dimerization of norbornadiene and its derivatives in the presence of nickel complexes and zinc metal

Norbornadiene undergoes [2 + 2] reaction in THF in the presence of NiX₂ and zinc metal powder to give an exo-trans-exo dimer and an exo-trans-exo-trans-exo trimer. In these products, the norbornadiene molecules are linked to each other by forming cyclobutane rings with all cyclobutane carbons occupying exo positions relative to the bridging carbons on the two norbornadiene fragments. Polymerization of norbornadiene occurs if the catalyst NiX₂ is replaced by Ni(PPh₃)₂Cl₂. 1,4-Dihydro-1,4-epoxynaphthalene, 5,8-dimethoxy-1,4-dihydro-1,4-epoxynaphthalene, 5-methoxy-1,4-dihydro-1,4-epoxynaphathalene and methyl 1,4-dihydro-1,4-iminonaphthalene-9-carboxylate also dimerize to give exo-trans-exo products in excellent yields in toluene in the presence of Ni(PPh₃)₂Cl₂ and Zn powder. For the dimerization products of 5-methoxy-1,4-dihydro-1–4-epoxynaphthalene, cis and trans isomers with respect to the orientation of methoxy groups in about 1 : 1 ratio were oberved. Under similar reaction conditions for the dimerization of norbornadiene, norbornene undergoes reductive dimerization to afford a product which consists of two norbornyl groups. The structure of this product is also exo-trans-exo.     

Metal-organic frameworks from copper dimers with cis- and trans-1,4-cyclohexanedicarboxylate and cis,cis-1,3,5-cyclohexanetricarboxylate

Single crystals of three coordination networks containing the Cu(2)(COO)(4) core bridged by cyclohexane have been hydrothermally prepared by the reaction of 1,4-cyclohexanedicarboxylic (1,4-H(2)chdc) or 1,3,5-cyclohexanetricarboxylic (1,3,5-H(3)chtc) acid and Cu(NO(3))(2) x 6H(2)O. We report their characterizations by single-crystal X-ray structure determinations, IR spectroscopy, thermal analyses, and their magnetic properties. [Cu(2)(trans-1,4-chdc)(2)] (1) consists of 4 x 4 grids with the dimeric nodes connected by the trans-1,4-chdc, and these grids are then connected to each other by Cu-O bonds, resulting in a porous network (void volume of 130 Angstrom(3) per cell or 25%) with no solvent in its cavities. [Cu(2)(cis-1,4-chdc)(2)(H(2)O)(2)] (2) consists of two-legged ladders where the dimer nodes are bridged by pairs of cis-1,4-chdc and the water molecules cap the ends of the Cu dimers. [Cu(2)(1,3,5-Hchtc)(2)] (3) displays 4 x 4 grids, but each dimeric node is connected to its neighbors within the same grid by Cu-O bonds to form a layered network which further makes hydrogen-bond interactions with its neighbors. 2 and 3 have compact structures without any space for solvents. IR and DT-TGA confirm the absence of water in the empty channels of 1, while IR shows the presence of both protonated and deprotonated carboxyl groups for 3. The magnetic properties of all three compounds are dominated by the strong Cu-Cu antiferromagnetic interaction resulting in singlet-triplet gaps of 450-500 K.     

Conversion of 1,4-diketones into para-disubstituted benzenes

Reaction of acetylides with aldehydes to form but-2-yne-1,4-diols, followed by triple bond reduction and oxidation of the hydroxyl groups, gives 1,4-diketones; these react with vinyllithium, and the resulting diols undergo ring-closing metathesis to form 2-cyclohexene-1,4-diols. Dehydration, usually by acid treatment, then gives benzenes carrying substituents in a 1,4 relationship. Use of substituted vinyllithiums provides further substitution on the final benzene rings. The method can be applied to the synthesis of C5-aryl carbohydrates.     

Effect of methyl groups on the thermal properties of polyesters from methyl substituted 1,4-butanediols and 4,4′-biphenyldicarboxylic acid

Results are reported on the effect of lateral methyl groups on the thermal properties of a series of polyesters prepared from diethyl 4,4′-biphenyldicarboxylate and various methyl substituted 1,4-butanediols. The diols were 1,4-butanediol; 2-methyl-1,4-butanediol; 2,2-dimethyl-1,4-butanediol; 2,3-dimethyl-1,4-butanediol; 2,2,3-trimethyl-1,4-butanediol; and 2,2,3,3-tetramethyl-1,4-butanediol. Apart from the tetramethyl derivatve, the transition temperatures of the methyl substituted polyesters were lower with respect of the unsubstituted polyester. On the basis of polarized photomicrographs, a smectic A mesophase was found for the unsubstituted polyester, whereas a nematic mesophase was observed for the 2-methyl substituted polyster. The 2,2-dimethyl, 2,3-dimethyl, and the 2,2,3-trimethyl substituted polyesters showed no liquid crystalline behavior. The 2,2,3,3-tetramethyl derivative displayed a birefringent melt phase although the DSC measurements were not unambiguous. A copolyester based on diethyl 4,4′-biphenyldicarboxylate, 1,4-butanediol, and 2,2,3,3-tetramethyl-1,4-butanediol showed a broad nematic mesophase. Further evidence for the nematic mesophase of this copolyester and the 2-methyl substituted polyester was provided by dynamic rheological experiments. Based on thermogravimetric analysis, it was concluded that the thermal stability was affected only when four methyl side groups were present in the spacer. © 1995 John Wiley & Sons, Inc.     

Uncommon reaction of 2-bromomethyl-1,3-thiaselenole with pyridine and its derivatives

Regioselective reaction of 2-bromomethyl-1,3-thiaselenole with pyridine and its derivatives is followed by rearrangement with ring expansion and the formation of a bond between a nitrogen atom and a carbon in the position 2. A set of derivatives of 2,3-dihydro-1,4-thiaselenine was obtained, substituted in the position 2 by a pyridinium residue functionalized by pharmacophoric groups.     

Reaction of methyl 3-phenyl-3-chloro-2-oxopropionate with 2-mercapto- and 2-hydroxy-ethanolamines: The products and some of their transformations

It was found that the nature of the SH and OH groups in 2-mercapto- and 2-hydroxyethanolamines plays a decisive role in the reactions between these compounds and methyl 3-phenyl-3-chloro-2-oxopropionate, the products comprising 1,4-thiazine and 1,4-oxazane derivatives, respectively. Some of the reactions of these products were investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 250–252, February, 1993.     

Raman-spectrum investigation of 2-butyne-1,4-diol 2-butyne-1,4-diol diacetate,and 1,4-dichloro-2-butyne

Summary 2-Butyne-1,4-diol, 2-butyne-1,4-diol diacetate, and 1,4-dichloro-2-butyne exist in cisoid and transoid forms because of the operation of factors hindering free rotation of individual groups of atoms in these molecules around the corresponding single bonds.     

Synthesis and study of copper(II), nickel(II), and cobalt(II) complex compounds with dihydrobenzoxazine derivatives

Complex compounds ML₂ of copper(II), nickel(II), and cobalt(II) with 2-(2-hydroxy-5-nitrophenyl)-4,4-diphenyl-1,4-dihydro-2H-3,1-benzoxazine and 2-(2-hydroxyphenyl)-4,4-diphenyl-1,4-dihydro-2H-3,1-benzoxazine (HL) were prepared by electrochemical and chemical syntheses. The complex formation involves the azomethine form of the ligand and gives a six-membered chelate cycle comprising deprotonated phenol and azomethine groups. The coordination entity has a planar structure with trans arrangement of the nitrogen and oxygen atoms.     

Gated channels in a honeycomb-like zinc-dicarboxylate-bipyridine framework with flexible alkyl ether side chains

Covalent functionalization of 1,4-benzenedicarboxylate (bdc) with methoxyethoxy groups induces conformational freedom in this molecule. Applying these 2,5-disubstituted bdc derivatives in metal-organic framework synthesis together with 4,4'-bipyridine as coligand yields novel honeycomb-like structures. The cylindrical channels of these materials are populated with flexible groups, which act as molecular gates for guest molecules. This allows highly selective sorption of CO(2) over N(2) and CH(4).     

Synthesis of 7-thio-substituted 4-oxoquinoline-3-carboxylic acids with antibacterial activity

A series of C-7 thio-substituted 1-cyclopropyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acids were prepared and tested for their antibacterial activity. Structure-activity relationships associated with the C-5 and C-7 substituents were discussed. Among the C-7 substituents including alkylthio, arylthio, heteroarylthio, and cyclic aminothio groups, a 2-aminoethylthio group was the best for enhancing in vitro antibacterial activity. The C-5 variants increased activity in the order OH less than F less than H less than NH2. Of compounds prepared in this work, 5-amino-7-(2-aminoethyl)thio-1-cyclopropyl-6,8-difluoro-1,4-dihydro-4 -oxo-quinoline-3-carboxylic acid (18) was the most active.