The Mannich reaction in the synthesis of N,S-containing heterocycles 12. First example of aminomethylation involving 2-thioxonicotinamide derivative: synthesis of 3,5,7,11-tetraazatricyclo[7.3.1.02,7]tridec-2-ene-9-carboxamides

Piperidinium 6-amino-5-cyano-3-N-(4-methylphenyl)carbamoyl-4-phenyl-1,4-dihydro-pyridine-2-thiolate upon the action of primary amines and excess formaldehyde undergoes aminomethylation to form 3,5,7,11-tetraazatricyclo[7.3.1.0^2,7]tridec-2-ene-9-carboxamides in 36?C52% yields.     

On the use of 3-methyl-2-benzothiazolinone hydrazone to determine cell surface sialic acid: A simplified procedure and a caution

Membrane-bound sialic acid may be quantitated by colorimetric determination of formaldehyde released upon mild periodate oxidation. In the presence of washed erythrocyte membranes at 20% suspension the colorimetry based on 3-methyl-2-benzothiazolinone hydrazone has an extinction coefficient of 68.5 mM^?1 cm^?1. With intact erythrocytes large losses in color yield are experienced with suspensions in excess of 2% (2 × 10⁸ cells/ ml).     

σ-P Ligands: convenient syntheses of N-methyl-1,3-benzazaphospholes

A convenient three-step route to 1,5-dimethyl-1,3-benzazaphosphole via Cu- or Pd-catalyzed phosphonylation of 2-iodo-4-methylaniline, reduction to 2-phosphino-4-methylaniline, and disproportionative cyclization with excess formaldehyde is reported. N-Methylbenzazaphospholes can be functionalized in the 2-position via α-CH-lithiation with tBuLi and are π-acidic σ²P-ligands.     

The mannich reaction in the synthesis of N,S-containing heterocycles 4. Aminomethylation of 6-amino-3,5-dicyano-1,4-dihydropyridine-2-thiolates: A convenient regioselective route to 3,5,7,11-tetraazatricyclo[7.3.1.02,7]tridec-2-ene derivatives

Treatment of N-methylmorpholinium 4-R-6-amino-3,5-dicyano-1,4-dihydropyridine-2-thiolates (R = 2-ClC₆H₄ and 2-MeOC₆H₄) with primary amines in the presence of an excess of formaldehyde gave 13-R-8-thioxo-3,5,7,11-tetraazatricyclo[7.3.1.0^2,7]tridec-2-ene-1,9-dicarbonitrile derivatives in high yields (66–95%). In a similar way, aminomethylation of 3-R-10-amino-7,11-dicyano-9-aza-3-azoniaspiro[5.5]undeca-7,10-diene-8-thiolates (R = Me and Et) afforded 1′-alkyl-8-thioxospiro[3,5,7,11-tetraazatricyclo[7.3.1.0^2,7]tridec-2-ene-13,4′-piperidine]-1,9-dicarbonitriles in 43–91% yields. Alternatively, these compounds were obtained by multicomponent cyclocondensation of N-alkylpiperidin-4-ones, cyanothioacetamide, primary amines, and aqueous formaldehyde. The starting 3-R-10-amino-7,11-dicyano-9-aza-3-azoniaspiro[5.5]undeca-7,10-diene-8-thiolates were prepared by a new method from N-alkylpiperidin-4-ones and cyanothioacetamide. The structure of 5,11-bis(4-ethoxyphenyl)-13-(2-methoxyphenyl)-8-thioxo-3,5,7,11-tetraazatricyclo[7.3.1.0^2,7]tridec-2-ene-1,9-dicarbonitrile was examined by X-ray diffraction analysis. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1014–1022, May, 2007.     

A one-pot synthesis of 3,3′-methylenebis(2-arylamino-4H-chromen-4-one) from C-(4-oxo-4H-1-benzopyran-3-yl)-N-arylnitrone

2-(Arylamino)-4-oxo-4H-chromene-3-carbaldehyde 3 (R² = aryl) produces 12H-chromeno[2,3-b]quinolin-12-one 4 when treated with sarcosine, piperidine or diethylamine, but produces 3,3′-methylenebis(2-arylamino-4H-chromen-4-one) 8 when treated with the same amine in the presence of an excess of formaldehyde. Compound 3 (R² = alkyl) was found to be less reactive than the N-aryl analogues towards the deformylative Mannich-type reaction.     

Synthesis and Structure of 1,9-Dinitro-5-oxa-11-azatricyclo[6.4.0.04,9]dodecan-2-one

A series of 6,11-disubstituted 1,9-dinitro-5-oxa-11-azatricyclo[6.4.0.0^4,9 ]dodecan-2-ones were prepared from anionic adducts of 2,4-dinitrophenol with propanone and 2-phenylethanone carbanions by successive selective reduction with sodium borohydride and aminomethylation with formaldehyde and primary amines. By spectral methods and by quantum-chemical calculations following PM3 method the structure of the molecules synthesized was shown to contain all the three rings in a chair form with equatorial substituents in positions 6 and 11.     

CuMgAlO_x复合氧化物催化甲醇乙醇Guerbet反应:M~(2+)/Al~(3+)比的影响

以类水滑石为前驱体,通过调控M~(2+)/Al~(3+)比制备了系列具有不同表面性质的MgAlO_x(MA)和CuMgAlO_x(CMA)催化剂,并分别应用于甲醛乙醛缩合反应(甲醇乙醇Guerbet反应的第二步反应)和甲醇乙醇Guerbet反应。采用NH_3/CO_2-TPD、XPS、H_2-TPR和H_2-TPD技术对催化剂表面酸碱性以及铜物种的性质进行了表征。结果表明,甲醇乙醇Guerbet反应性能与催化剂表面Cu~0比表面积和中强碱数目有关,提高Cu~0比表面积有利于甲醇乙醇脱氢生成甲醛和乙醛,增强中强碱数目能促进甲醛乙醛缩合反应。     

Thermodynamic study of 2-methyl-tetrahydrofuran with isomeric chlorobutanes

Excess molar volumes, V^E, isentropic compressibility deviations, Δκ_S, and excess molar enthalpies, H^E, for the binary mixtures 2-methyl-tetrahydrofuran with 1-chlorobutane, 2-chlorobutane, 2-methyl-1-chloropropane and 2-methyl-2-chloropropane have been determined at temperatures 298.15 and 313.15 K, excess molar enthalpies were only measured at 298.15 K. We have applied the Prigogine-Flory-Patterson (PFP) theory to these mixtures at 298.15 K.     

Reaction of dialkyl 2-butynoate with aniline and formaldehyde: revision of the structure of the product

Dimethyl 3-(aryl)-3,6-dihydro-2H-1,3-oxazine-4,5-dicarboxylate structure assigned for the products obtained in the Bronsted acid catalyzed reaction of dimethyl but-2-ynoates with anilines and an excess of formaldehyde in methanol has been revised to methyl 1-(aryl)-3-(methoxymethyl)-4,5-dioxopyrrolidine-3-carboxylate.     

Synthesis and x-ray crystal structure of OsBr2(CNBut)4·2CH2Cl2

Reaction of (NH₄)₂OsBr₆ with excess Na/Hg in THF in the presence of excess ^tBuNC yields trans-OsBr₂(CNBu^t)₄ in high yield. The bis-dichloromethane solvate crystallises from CH₂Cl₂ solutions and its X-ray crystal structure has been determined. Crystal data: C₂₂H₄₀Br₂Cl₄N₄Os, M = 852.40, monoclinic, space group P2₁/c, a = 9.702(3) Å, b = 10.143(5) Å, c = 18.497(5) Å, β = 104.28(3)°, U = 1764(1) ų, Z = 2 for D_c = 1.60 gcm^?3. λ(MoK_α) = 0.71069 Å (graphite monochromator), μ(MoK_α) = 65.44 cm^?1, final R = 0.044, R_w = 0.056 from 1105 observed reflections (1777 measured).     

The Mannich reaction in the synthesis of N,S-containing heterocycles. 7. Effective one-pot synthesis of derivatives of spiro[3,5,7,11-tetraazatricyclo-[7.3.1.0<Superscript>2,7</Superscript>]tridec-2-ene-13,4′-piperidine]

5,11-Disubstituted derivatives of 1′-isopropyl-8-thioxospiro[3,5,7,11-tetrazatricyclo[7.3.1.0^2,7]tridec-2-ene-13,4′-piperidine]-1,9-dicar bonitrile was obtained by the interaction of 10-amino-9-aza-3-azonia-7,11-dicyano-3-isopropylspiro[5,5]undeca-7,10-diene-8-thiolate with 2 equiv. of a primary amine and excess of formaldehyde. An anomalous reaction product was obtained with o-toluidine — 7,9-dicyano-1′-isopropyl-3-(2-methylphenyl)-1,2,3,4-tetrahydrospiro[pyrido[1,2-a][1,3,5]triazine-8,4′-piper idinium]-6-thiolate. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, 1709–1713, November, 2007.     

Co2(CO)8-catalyzed carbonylation of acetals using N-silylamines

Formaldehyde dialkyl acetals and cyclic acetal, 1,3-dioxolane, are smoothly carbonylated using N-silylamines at 140–160 °C under 70–88 kg cm⁻² CO pressure in the presence of a catalytic amount of Co₂(CO)₈ to give the corresponding 2-alkoxyamides in moderate to good yields. In the carbonylation of formaldehyde dialkyl acetals using N-silylamines, addition of pyridine drastically enhances the catalytic activity.     

Ab initio study of mechanism of forming bis-heterocyclic compound with Si and Ge between silylene germylene (H2Si=Ge:) and formaldehyde

The mechanism of the cycloaddition reaction between singlet state silylene germylene (H₂Si=Ge:) and formaldehyde has been investigated with the CCSD(T)//MP2/cc-pvtz method, from the potential energy profile, it could be predicted that the reaction has one dominant reaction pathway. The reaction rules presented is that [2?+?2] cycloaddition reaction between two reactants firstly generates a Si-heterocyclic four-membered ring germylene. Because of the 4p unoccupied orbital of the Ge atom in (the) Si-heterocyclic four-membered ring germylene and the ?? orbital of formaldehyde forming a ??????p donor?Cacceptor bond, the Si-heterocyclic four-membered ring germylene further combines with formaldehyde to form an intermediate. Because the Ge atom in intermediate happens sp ³ hybridization after transition state, then, intermediate isomerizes to a bis-heterocyclic compound with Si and Ge via a transition state.     

Excess parameters for binary mixtures of alkyl benzoates with 2-propanol at different temperatures

Density (ρ), viscosity (η), and speed of sound (U) values for the binary mixture systems of methyl benzoate + 2-propanol and ethyl benzoate + 2-propanol including those of pure liquids were measured over the entire mole fraction range at five different temperatures (303.15, 308.15, 313.15, 318.15, and 323.15) K. From these experimentally determined values, various thermo-acoustic parameters such as excess isentropic compressibility $ \left( {K_{\text{s}}^{\text{E}} } \right) $ , excess molar volume (V ^E) and excess free length $ \left( {L_{\text{f}}^{\text{E}} } \right) $ , excess Gibb’s free energy (ΔG ^*E), and excess enthalpy (H ^E) have been calculated. The excess functions have been fitted to the Redlich–Kister type polynomial equation. The deviations for excess thermo-acoustic parameters have been explained on the basis of the intermolecular interactions present in these binary mixtures. The theoretical values of speed of sound in the mixtures have been evaluated using various theories and have been compared with experimentally determined speed of sound values in order to check the applicability of such theories to the liquid mixture systems under study. Viscosity data have been used to test the applicability of standard viscosity models of Grunberg–Nissan, Hind–Mc Laughlin, Katti–Chaudhary, Heric and Brewer, Frenkel, Tamura and Kurata at various temperatures for the binary liquid systems under study.     

New approaches to pyrimido[4,3-b][1,3,5]selenadiazines

The Mannich reactions of (arylmethylidene)(cyano)selenoacetamides with primary amines and formaldehyde gave 3,7-disubstituted 8-R-3,4,7,8-tetrahydro-2H,6H-pyrimido[4,3-b]-[1,3,5]selenadiazine-9-carbonitriles. Alternatively, these compounds can be obtained by reactions of 4-R-2,6-diamino-4H-selenopyran-3,5-dicarbonitriles with primary amines and form-aldehyde or by multicomponent condensation of an appropriate aldehyde, cyanoselenoacet-amide, a primary amine, and formaldehyde.     

Molecular constants for the ã 3A2 state of formaldehyde

The 0⁺–0 and 1⁺–0 bands of the ā ³A₂X? ¹A₁ transition of formaldehyde have been reinvestigated using higher resolving power than was available in the earlier work of Raynes. The rotational analyses have been considerably extended, and improved molecular constants for the ā ³A₂ state have been obtained with the aid of a new triplet—singlet computer programme.^sSR branches of the K′ = 7K″ = 5 and K′ = 5K″ = 3 subbands have been observed in the 0⁺–0 band using 7m atm of absorbing gas. These results provide the first example of the observation of ΔK = ±2 transitions in triplet—singlet bands of a polyatomic molecule. The “perpendicular” transition moment is found to be about 10% of the “parallel” transition moment.     

Plasma-induced chemical etching generating Ni3S2 for formaldehyde detection

In this paper,Ni₃S₂ nanosheet （NS） was generated by chemical etching with sodium sulfide directly on the nickel foam （NF）,which was induced by dielectric barrier discharge plasma in liquid.Compared with other chemical etching methods of nickel-based nanomaterials,this method was not only rapid （40 min）and mild （at room temperature and atmospheric pressure）,but also showed consistent stability and good reproducibility.The Ni₃S₂NS/NF electrode showed exc...     

Asymmetric ring opening of meso-epoxides with B-halobis(2-isocaranyl)boranes 2-dIcr2BX

Hydroboration of commercially available (+)-2-carene (96% ee) with either BH₂Cl·SMe₂ or BCl₃/Me₃SiH, provides chemically pure B-chlorobis(2-isocaranyl)borane (2-^dIcr₂BCl) whereas B-bromobis(2-isocaranyl)borane (2-^dIcr₂BBr) could only be prepared by Matteson’s BBr₃/Me₃SiH procedure in high chemical yield and purity. The enantiomeric excess achieved with 2-^dIcr₂BCl (78%), was significantly higher than those realized with the previously explored reagent, ^dIpc₂BCl (41%), especially for meso-cyclohexene oxide. The new reagent, 2-^dIcr₂BBr also showed considerable improvements in enantiomeric excesses, in the cases of meso-cyclopentene oxide (67%) and meso-cis-2,3-butene oxide (78%) than those achieved with the previously reported reagent, ^dIpc₂BBr (57% and 61%, respectively).     

Free energies of aqueous mixtures of NaH2PO4 and NAClO4: Evidence for the species (H2PO4) 2 −2

The system NaH₂PO₄?NaClO₄ has been studied from 0.15 to 7.0 mole-kg^?1 at 25°C by the isopiestic method. The excess free energy of mixing is large and positive. The results confirm the formation of (H₂PO₄) ₂ ^?2 dimers with a stoichiometric association constantK _a=0.25±0.1 kg-mole^?1 at 25°C.     

Electronic transport properties and electrically induced p-n junction in ZrO2 + 10 m/o Y2O3

Through the application of voltages to cubic ZrO₂, stabilized by 10 m/o Y₂O₃, using a nitrogen/Ag and an air/Pt electrode, concentration gradients of the electronic species and p-n junctions in the sample have been created. The transient relaxation of the voltage is investigated and is interpreted in terms of the mobilities of both excess and defect electrons between 700 and 900°C. The movement of the p-n junction is characterized by a shoulder-type voltage-time relation. At 900°C the mobilities of the electrons and holes are 2.3 × 10^?2 and 1.5 × 10^?4 cm²/Vsec, respectively. The activation energy of transport is much smaller for the excess electrons than the holes. The electronic conductivities are determined from the steady-state polarization current.