Synthesis of 1,6-dihydro-1,6-dihydroxybenzo[1,2-d:3,4-d′]bistriazole, 4- and 5-nitro-1,6-dihydro-1,6-dihydroxybenzo[1,2-d:3,4-d′]bistriazole and 4,7-dihydro-1,4,7-trihydroxy-1H-benzo-[1,2-d:3,4-d′:5,6-d″]tris[1,2,3]triazole

1,6-Dihydro-1,6-dihydroxybenzo[1,2-d:3,4-d′]bistriazole and 4- and 5-nitro-1,6-dihydro-1,6-dihydroxybenzo[1,2-d:3,4-d′]bistriazole were synthesized starting from 2,4-dinitrosore-sorcinol, whereas 4,7-dihydro-1,4,7-trihydroxy-1H-benzo[1,2-d:3,4-d′:5,6-d″]tris[1,2,3]-triazole was synthesized starting from phloroglucinol. The reaction of trinitrosophloroglucinol with hydrazine hydrate in acetic acid led to 2,4,6-tridiazocyclohexane-1,3,5-trione.     

Novel plant activators with thieno[2,3-d]-1,2,3-thiadiazole-6-carboxylate scaffold： Synthesis and bioactivity

The 1,2,3-thiadiazole-carboxylate moiety was reported to be an important pharmacophore of plant activators.In this study,a series of novel plant activators based on thieno[2,3-d]-1,2,3-thiadiazole-6-carboxylate were designed and synthesized and their biological activity as plant activators was studied.The structures of the novel compounds were identifed by1H NMR,19F NMR and HRMS.The in vivo bioassay showed that these novel compounds had good effcacy against seven plant diseases.Especially,compounds 1a and 1c were more potent than the commercialized plant activator BTH.Almost no fungicidal activity was observed for the active compounds in the in vitro assay,which matched the requirements as plant activators.     

Molecular structure and vibrational analysis of 2,4,6-trinitrotoluene and 2,4,6-trinitrotoluene-α-d3

The X-ray structures of 2,4,6-trinitrotoluene and 2,4,6-trinitrotoluene-α-d₃ have been determined at 130 K. The molecular structure and vibrational spectra are calculated by the MNDO-PM3 method, and are in agreement with experimental results. The short intra-and intermolecular hydrogen contacts correlate with the known thermal and ionization degradation pathways of 2,4,6-trinitrotoluene.     

Microwave,infrared and Raman spectra of thiacyclopentane-α-d4

The microwave spectrum of thiacyclopentane-α-d₄ has been recorded in the region from 18.0 to 26.5 GHz and the a-type R-branches assigned. From these data it is shown that the molecule has C₂ symmetry. The infrared spectra (3500–50 cm⁻¹) of gaseous and solid and the Raman spectra (3500–10 cm⁻¹ of gaseous, liquid and solid thiacyclopentane-α-d₄ have been recorded and a complete vibrational assignment is proposed.     

One-dimensional π-d conjugated coordination polymers: synthesis and their improved memory performance

Multilevel resistance random access memories(RRAMs) are intensively studied due to their potential applications in high density information storage. However, the low ternary device yields and high threshold voltages based on current materials cannot meet the requirement for applications. Improvement via material innovation remains desirable and challenging. Herein,five one-dimensional conjugated coordination polymers were synthesized via the reaction between metal ions(Zn~(2+), Cu~(2+), Ni~(2+),Pt~(2+) and Pd~(2+)) and 2,5-diaminobenzene-1,4-dithiol(DABDT) and fabricated into RRAM devices. The as-fabricated ternary memories have relatively low threshold voltages(V_(th1):-1 to-1.4 V, V_(th2):-1.8 to-2.2 V). Their ternary device yields were improved from 24% to 56%. The first and the second resistance switches are interpreted by the space charge limited current(SCLC) and grain boundary depletion limited current(GBLC) modes, respectively. The Pd-DABDT, which is of planar structure,smaller band gap and better crystallinity than others, shows the best performance among these five polymers. Our work paves a simple and efficient way to optimize the performance of ternary RRAM devices employing one-dimensional hybrid materials.     

Spectra and structure of organophosphorus compounds—XXX. Vibrational and conformational study of methoxy difluorophosphinoxide-d0 and -d3

The i.r. (4000-40 cm⁻¹) and Raman (4000-10 cm⁻¹) spectra of gaseous, liquid and solid methoxy difluorophosphinoxide, CH₃OP(O)F₂, and the deuterated analog have been recorded. Results obtained from variable solvent and matrix isolation studies are consistent with the existence of both trans (CO bond trans to the PO bond) and gauche (dihedral angle approximately 120° from the trans form) conformers in the fluid phases. From simulations of observed gas phase i.r. band profiles, it was possible for assignments to be made to the individual conformers for a number of the fundamentals. Variable temperature studies carried out for the gaseous and liquid phases give energy differences between the gauche and trans conformers of 451 ± 100 cm⁻¹ (1.29 ± 0.3 kcal/mol) and 69 ± 20 cm⁻¹ (197 ± 57 cal/mol), respectively. Furthermore, these data are consistent with the gauche form being the thermodynamically preferred conformer for the gas phase whereas the trans conformer is preferred in the liquid phase and the only conformer present in the annealed solid. The methoxy torsional mode of the gauche conformer has been assigned to a very strong band observed in the far i.r. spectrum of the gas phase at 42 cm⁻¹. The matrix isolation spectra of the normal compound in Ar, CO and N₂ matrices indicated no changes in the conformational equilibrium among these different matrices and this equilibrium remains unchanged upon annealing the matrices.     

σ-Complexes in the pyrimidine series. 13. Reaction of 7- and 5-methoxyfuroxano-[3,4-d]pyrimidines with some C-nucleophiles

We have studied the reaction of isomeric 7-and 5-methoxyfuroxano[3,4-d]pyrimidines with carbanions of some CH acids. We have shown that regardless of the position of the substituent in the pyrimidine ring, nucleophilic attack occurs regioselectively at the C₍₇₎ atom. As a result, we have obtained the products of substitution at the methoxy group, and also anionic complexes and covalent adducts.For Communication 12 see [1].Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, Kiev 253660. Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 34, No. 1, pp. 112–119, January, 1998.     

Synthesis and Bronchodilatory Activities of New Pyrazolo [4,3-d] pyrimidin-7-ones

Twelve novel pyrazolo [4,3-d] pyrimidin-7-ones were synthesized and their structures were confirmed by IR, ^1H NMR and MS. Their in vitro bronchodilatory activities were tested in guinea-pigs. The pharmacological results show that compound 11c has more potent activity than aminophylline.     

Vibrational spectra of cyanosubstituted cyclopropanes—III. Cyanocyclopropane and cyanocyclopropane-1-d1

The vibrational spectra of cyanocyclopropane have been reinvestigated with the gas phase i.r. spectrum reported for the first time. The i.r. spectra of cyanocyclopropane-1-d₁ have been measured from 4000 to 200 cm⁻¹ in the liquid and the gaseous phases and from 4000 to 400 cm⁻¹ in the polycrystalline state. Raman spectra of the liquid down to 50 cm⁻¹ were obtained. A vibrational assignment of all fundamentals is proposed. With the present data, we had to reassign several fundamentals published in the literature.     

Syntheses and Vasodilatory Activities of New Pyrazolo [ 4,3-d ] pyrimidin-7-ones

IntroductionAdenosine 3′,5′-cyclic monophosphate (cAMP)and guanosine 3′,5′-cyclic monophosphate(cGMP) areubiquitous second messengers that mediate biologicalresponses to a variety of extracellular cues, includinghormones, neurotransmitters, chemokines…     

Synthesis of benzotristriazole. 4-nitrobenzo[1,2-d:3,4-d′] bistriazole and 4,4′-dicarboxy-5,5′-1H-1,2,3-triazole

The treatment of 2,5,8-tri(2,4-dinitrophenyl)benzotristriazole, 2,7-di(2,4-dinitrophenyl)-4-nitrobenzo[1,2-d3,4-d]bistriazole, and 4,4-dicarboxy-5,5-bis[2- (2,4-dinitrophenyl)-2H-1,2,3-triazole with sodium methylate leads to loss of the 2,4-dinitrophenyl group as 2,4-dinitroanisole and formation of benzotristriazole, 4-nitrobenzo[1,2-d3,4-d]bistriazole, and 4,4-dicarboxy-5,5-bis-1H-1,2,3-triazole, respectively, in good yields.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1364–1367, October, 1993.     

Complexation of the antibiotic daunomycin with desoxytetraribonucleoside triphosphate 5’-d(CpGpCpG) in aqueous solution

This paper presents the results of our study of the complexation of the antibiotic daunomycin with desoxytetranucleotide 5’-d(CpGpCpG) in aqueous salt solution by one- and two-dimensional (2D-TOCSY and 2D-NOESY)¹H NMR spectroscopy (500 MHz). The concentration and temperature dependences of the proton chemical shifts of molecules were measured and used to calculate the equilibrium reaction constants, the relative contents of different types of complex as functions of concentration and temperature, the limiting values of the proton chemical shifts of daunomycin in various complexes, and the thermodynamic parameters of complexation δH and δS. It is concluded that the triplet nucleotide sequences are the preferable sites at which daunomycin is attached. The binding of the second daunomycin molecule to both single-stranded and duplex forms of tetramer is markedly anticooperative. This is explained by the presence in the antibiotic of a positively charged amino sugar residue creating steric hindrances for the attachment of the second antibiotic molecule to the short tetranucleotide sequence. The most plausible spatial structure of the 1:2 complex of antibiotic with desoxytetranucleotide is constructed using the calculated values of the induced proton chemical shifts of daunomycin and 2D-NOE data. Translated fromZhurnal Strukturnoi Khimii, Vol.40, No. 2, pp. 276–286, March–April, 1999.     

Synthesis and antitumor activity of α-aminophosphonate derivatives containing thieno[2,3-d]pyrimidines

Two series of thieno[2,3-d]pyrimidine derivatives were designed and synthesized, in which bioactive a-aminophosphonate subunits were introduced at the N3 position through an N–N bond connection.The in vitro cytotoxic activity of the novel compounds was tested against human esophageal carcinoma cells(EC109), human hepatocarcinoma cells(Hep G2), human gastric carcinoma cells(MGC-803),respectively, by the MTT method. The evaluation results revealed that compounds 6mb, 6mf, 6mg, 6nd and 6nh exerted the most potent inhibition against Hep G2, MGC-803 and EC109 cells, respectively. In particular, compound 6mg presented excellent inhibitory effect against Hep G2(91.2%) and MGC-803(94.4%) cells.     

Coupling Reaction of 4-Chloro-7-H-Pyrrolo[2,3-d]Pyrimidine with 2,3,5-Tri-O-Acetyl-β-D-Ribofuranosyl Chloride

Tubercidin (4-amino-7--D-riobofuranosyl-7-H-pyrrolo[2,3-d]pyrimidine) 1, an antibio-tic substance produced in the culture broth of Streptomyces tubericidus1, is an adenosine analog in which N-7 is replaced by a carbon atom. It has attracted much attention due to the biological activities for the growth inhibition of certain tumors, and many derivatives of tubercidin have been synthesized2-5.For the synthesis of tubercidin analogs, 4-chloro-7-H-pyrrolo[2,3-d]pyrimidine-2,3,5-tri-O-acetyl--D-r…     

Ring‐Opening of Benzocyclobutenol with Mild Bases and Trapping with Dieneophiles

The treatment of benzocyclobutenol with a mild base has been investigated. This reaction results in an electrocyclic opening of the cyclobutene to the corresponding o‐quinodimethane, which has been successfully treated with aldehydes and electron‐deficient alkenes to form benzolactols and benzocyclohexenes respectively.     

Syntheses with heterocyclic β-enaminonitriles: A facile preparation of polyfunctionally substituted thiophene,thieno[3,2-b]pyridine and thieno[3,2-d]pyrimidine derivatives

Summary A convenientGewald synthesis of 3,5-diaminothiophene-2-carbonitrile derivatives (2) is reported. The synthetic potential of the -enaminonitrile moiety in2 has been explored; it proved to be a promising candidate for the synthesis of polyfunctionally substituted thieno[3,2-b]pyridines and thieno[3,2-d]pyrimidines.

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Synthesen mit heterocyclischen -Enaminonitrilen: Eine einfache Methode zur Herstellung polyfunktionell substituierter Thiophen-, Thieno[3,2-b]pyridin- und Thieno[3,2-d]pyrimidinderivate

Zusammenfassung Eine bequeme Methode zur Herstellung von 3,5-Diaminothiophen-2-carbonitril-Derivaten (2) nachGewald wird vorgestellt. Das synthetische Potential der -Enaminonitrilfunktion von2 wurde untersucht.2 ist ein geeignetes Ausgangsmaterial für die Synthese polyfunktionell substituierter Thieno[3,2-b]pyridine und Thieno[3,2-d]pyrimidine.

     

Complexation of zearalenone and zearalenols with native and modified β-cyclodextrins

The complexation of the oestrogenic mycotoxin zearalenone (ZEN) and its metabolites α- and β-zearalenol (ZOLs) with native β-cyclodextrins (β-CD) and modified hydroxypropyl-β-CD and dimethyl-β-CD was studied by fluorescence spectroscopy, nuclear magnetic resonance spectroscopy and electrospray-mass spectrometry. The formation of the inclusion complex was confirmed by NMR studies of zearalenone:β-CD solution. NMR, ESI-MS and fluorescence data are in agreement with the formation of a 1:1 complex between zearalenone and β-CD, characterized by the deep insertion of the phenolic moiety inside the cavity of the CD from its secondary side. The complexes formed between the guests and native β-CD are characterized by high stability constants (>10⁴), as measured by fluorescence titrations.     

Pyrido[2,3-d]pyrimidines 7. Reactions of 1,3-dimethyl-5,7-dichloro-6-nitropyrido-[2,3-d]pyrimidine-2,4-dione with amines. Synthesis of derivatives of triazolo(4′,5′:4,5)pyrido[2,3-d]pyrimidine

The reaction of 5,7-dichloro-6-nitropyrido[2,3-d]-pyrimidine-2,4-dione with amines gave products of the substitution of one or two chlorine atoms by ammo groups. The catalytic reduction of 6-nitro-5,7-disubstituted pyrido[2,3-d]pyrimidines with hydrogen over palladium oxide on carbon leads to 5,6-diamino- and 5,6,7-triaminopyridopyrimidines, the reaction of which with amyl nitrite in acetic acid gives triazolo(4,5:4,5) pyrido[2,3-d]pyrimidines.For communication 6 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 398–401, March, 1993.     

Electrochemical and Spectroelectrochemical Studies of Molybdenum and Neodymium Complex with Diethyld

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