Willgerodt-Kindler reaction at room temperature: Synthesis of thioamides from aromatic aldehydes and cyclic secondary amines

A simple method for the synthesis of thioamide derivatives in DMSO at room temperature and at 120 °C has been developed. Total 27 compounds were prepared under both conditions via a one-pot, three component reaction between substituted aromatic aldehydes, elemental sulfur powder, and cyclic secondary amines. By optimizing the mole ratio of sulfur powder and amines, we have successfully carried out Willgerodt-Kindler reaction of aromatic aldehydes at room temperature. At 120 °C, it is catalyst free reaction with lower reaction time whereas at room temperature, due to the additional amine molecule, Willgerodt-Kindler reaction of aromatic aldehydes is successfully carried out at room temperature. On gram-scale, the reaction is successfully attempted under both conditions with good yields.     

固相配位化学反应研究XXXIV. 室温下六氰合铁(II)及(III)酸钾 的固相酸碱反 应

本文研究了室温时K~3Fe(CN)~6,K~4Fe(CN)~6在酸碱条件下发生的固相配位化学反应。结果表明:K~3Fe(CN)~6与NaBH~4固相混合物室温下不反应,但加入固体氢氧化钠后,K~3Fe(CN)~6与NaBH~4的固相氧化还原反应在室温下很容易进行。K~4Fe(CN)~6与K~2S~2O~8的固相氧化还原反应在室温下能顺利进行,但当固体KOH存在时,反应明显受到抑制。K~3Fe(CN)~6与K~2C~2O~4.H~2O室温下无反应,但与H~2C~2O~4.2H~2O在室温时即发生固相取代反应。     

室温离子液体催化合成碳酸丙烯酯

碳酸丙烯酯(PC)是一种性能优良的高沸点高极性有机溶剂,在有机合成、化妆品、气体分离、电池介电质[1]及金属萃取[2]等领域得到广泛的应用. 近年来,许多尿素生产厂家将其用作脱碳剂,使其需求量大增. PC合成方法主要有光气法、酯交换法、氯丙醇法及环氧丙烷(PO)与CO2环加成等. 其中, 以PO与CO2为原料环加成制PC是一条低污染、环境友好的路线. 已报道的用于PO与CO2环加成的催化剂有碱、季铵盐、金属盐[3]、配合物[4～6]以及MgO[7], MgO-Al2O3[8], KI/ZnO[9],KI/冠醚和KI/聚乙二醇[10]等. 尽管品种繁多,但仍存在催化剂活性不高,产物分离及催化剂回收困难等问题.     

Potassium Fluoride on Alumina: One-Pot Synthesis of N-Allyl Trichloroacetamides by Cascade Condensation-Sigmatropic Rearrangement

Allyl alcohols adsorbed on Al₂O₃-KF at room temperature reacted with trichloroacetonitrile and gave rearranged trichloroacetamides at room temperature, in one pot reaction.     

Temperature- and substituent-dependence in the photosensitized oxygenation of N,N-disubstituted hydrazones

Methylene blue-sensitized photooxidation of N,N-disubstituted hydrazones $\text{1a-f}$ gave various products $\text{2-9}$, depending on the reaction temperature and N-substituents. The major reaction modes from the photo-oxidation of N,N-diphenylhydrazones were α-oxidation at room temperature and C=N cleavage at ?78 °C in contrast to C=N cleavage as an only reaction mode for the photooxidation of N,N-dimethylhydrazones at either room temperature or ?78 °C.     

Inorganic chemistry of vitamin B12; by J.M. Pratt. Academic Press,London and New York, 1972, £6.00 net

Action of dimethyllithium cuprate on α,α-dichloro esters at room temperature leads to the formation of α-chloro α-methyl esters together with non chlorinated α-methyl esters; the same reaction performed at ?70° produces α-chloro ester enolates which upon heating to room temperature are transformed into α-methyl ester enolates. The reaction is applied to β-functional α,α-dichloro esters and one α,α-dichloro ketone.     

Reaction of aluminacyclopentadienes with aldehydes affording cyclopentadiene derivatives

Aluminacyclopentadienes, prepared in situ from the reaction of AlCl₃ and 1,4-dilithio-1,3-dienes at room temperature, reacted with aldehydes at room temperature to afford cyclopentadiene derivatives including tetrahydroindenes in good to excellent yields. Both aromatic and aliphatic aldehydes undergo this reaction.     

Carbon Dioxide in Organic Synthesis: Preparation and Mechanism of Formation of N-(3)-Substituted Hydantoins

The preparation, isolation of intermediates, and the mechanisms of formation of N-(3)-substituted hydantions were investigated. The synthetic pathway involved the reaction of α-aminonitriles with carbondioxide, neat, at room temperature to yield disubstituted ureas and subsequent reaction with water at room temperature to give new N-(3)-substituted hydantoins.     

Room-temperature palladium-catalyzed direct 2-alkenylation of azole derivatives with alkenyl bromides

Pd-catalyzed direct C2-alkenylation of azole derivatives proceeds efficiently under mild conditions, and the reaction of substituted benzoxazoles, oxazole and benzothiazole occurred even at room temperature. The substrate scope of the reaction was turned out to include mono-, di- and trisubstituted alkenyl bromides. To validate the scalability of this method, 5-Methyl-2-(prop-1-en-2-yl)benzoxazole (3c) was prepared on one-gram scale at room temperature.     

Temperature-controlled divergent synthesis of 4-alkoxy- or 4-alkenyl-chromanes via inverse electron-demand cycloaddition with in situ generated ortho-quinone methides

The temperature-controlled divergent synthesis of 4-alkoxy- or 4-alkenyl-chromanes via inverse electron-demand cycloaddition with in situ generated ortho-quinone methides under identical reaction conditions except for thermal condition has been developed. At room temperature, the reaction generated 4-methoxychromanes, whereas the reaction performed at room temperature to 100?°C gave 4-alkenylchromanes. Trifluoromethanesulfonic acid was efficiently suitable in the reaction to give the 4-substituted chromanes. This divergent synthetic strategy exhibits a new method giving carbon–carbon or carbon–oxygen bond by controlling the reaction temperature.     

Rapid room temperature Buchwald-Hartwig and Suzuki-Miyaura couplings of heteroaromatic compounds employing low catalyst loadings

The use of second-generation [(NHC)Pd(R-allyl)Cl] complexes for Suzuki-Miyaura and Buchwald-Hartwig cross-coupling reactions involving heteroaromatic halides at room temperature is reported. The first examples of room temperature Suzuki-Miyaura cross-coupling of deactivated aryl chlorides with alkenyl boronic acids are also disclosed. Terminal substitution at the allyl moiety of the palladium complex facilitates its activation at room temperature leading to very active catalytic species enabling the present catalytic transformations to be performed rapidly using very mild reaction conditions. Catalyst loadings can be as low as 10 ppm for the Buchwald-Hartwig aryl amination and 50 ppm for the Suzuki-Miyaura reaction.     

Direct observation of thiolate displacement reactions on Au(111): the role of physisorbed disulfides

Line-of-sight mass spectroscopy (LOSMS) has been used to study the displacement reaction of ( radical3x radical3)R30 degrees methylthiolate on Au(111) by butylthiolate. The reaction was carried out at room temperature and constant saturation coverage, by exposing the methylthiolate-covered surface to dibutyl disulfide gas. The adsorbed methylthiolate was desorbed as dimethyl disulfide and the cross product methylbutyl disulfide, both identified by LOSMS. This shows that reaction occurs between adsorbed thiolates of different chain length at room temperature, while the kinetics indicate that a rapid equilibrium is established between immobile, chemisorbed thiolates, and highly mobile, physisorbed disulfides.     

All-carbon-substituted vinylsilane stable to TBAF: synthesis of allyldimethylvinylsilane and its Pd-catalyzed cross-coupling under mild conditions

[reaction: see text] Allyldimethylvinylsilanes 3 are easily synthesized by the reaction of silylallylmetals, generated from 1 by n-BuLi/t-BuOK, with carbonyl compounds in the absence or presence of metal halides. They can tolerate 2 equiv of TBAF in THF at room temperature for at least 6 h but can be easily activated in the presence of a palladium catalyst and TBAF to perform the cross-coupling reaction with aryl iodides at room temperature.     

固相配位化学反应——ⅩⅩⅩ.室温下铁氰化钾的固相反应

本文首次报道了铁氰化钾在室温下与碘化钾、硫化钾的固相氧化还原反应,实验发现在固相下铁氰化钾与碘化钾混合后,生成单质碘和亚铁氰化钾,而在溶液中该反应是反方向进行的.实验还发现,在固相下铁氰化钾与还原剂硼氢化钠不反应,而在溶液中,该反应却能进行.对反应机制进行了初步探讨.     

Selective One-Pot Synthesis of Allenyl Phenyl Selenide and 1-(Phenylseleno)Propyne. Role of Sodium Benzeneselenolate as a Base in Dmf

The reaction of excess sodium benzeneselenolate with propargyl bromide in DMR-THF at room temperature produced allenyl phenyl selenide or l-(phenylseleno)propyne selectively, depending only on the reaction time.     

固相配位化学反应——ⅩⅩⅩ.室温下铁氰化钾的固相反应

本文首次报道了铁氰化钾在室温下与碘化钾、硫化钾的固相氧化还原反应,实验发现在固相下铁氰化钾与碘化钾混合后,生成单质碘和亚铁氰化钾,而在溶液中该反应是反方向进行的.实验还发现,在固相下铁氰化钾与还原剂硼氢化钠不反应,而在溶液中,该反应却能进行.对反应机制进行了初步探讨.     

Low-temperature reaction of trialkoxysilanes on silica gel: a mild and controlled method for modifying silica surfaces

The room temperature reaction of 4-(triethoxysilyl)butyronitrile, 4-TBN ((C2H5O)3Si(CH2)3CN), on weakly hydrated silica samples pretreated at 393 K has been studied by desorption experiments and by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy at different aging times under various water partial pressures. The reaction is demonstrated by the decrease of desorption of 4-TBN with time and the simultaneous disappearance of the 2980 and 1394 cm(-1) signals in the DRIFT spectra, assigned to the CH3 moiety of the ethoxy functions. Water partial pressure is shown to have a crucial effect on the rate and efficiency of the process as, after 6 days, for samples kept at room temperature under vacuum, ca. 50% of the silane has reacted, while for those kept in a water-saturated atmosphere the silane reaction reaches 96%. Although the silane appears to be irreversibly bonded to the surface, no definite conclusion may be drawn from these preliminary results as to the nature of the bonding (grafting or coating). These samples are compared to modified silicas prepared according to conventional methods. The same extent of silane reaction (50%) is achieved for preadsorbed samples kept under vacuum and either cured at 473 K for 30 h or kept at room temperature for 6 days. A mild and controlled modification of silica by triethoxysilanes can thus be achieved by first physisorbing known amounts of the modifying silanes from an organic solvent on pretreated silica and then letting the samples mature for a few days at room temperature in a water-saturated atmosphere.     

Surface modification of activated carbon and fullerene black by Diels–Alder reaction

Activated carbon and fullerene black react with cyclopentadiene at room temperature or slightly elevated temperature. At higher temperature a retro-Diels–Alder reaction takes place. The reaction with the diene and the retro-Diels–Alder reaction could be repeated. As a consequence of the reaction with cyclopentadiene or other suitable dienes and the retro reaction, the surface structure of different carbons changed considerably. The surface area of micropores on fullerene black was much higher than for the original sample. The influence on the surface area of porosity is reported for two different types of carbon.     

Highly anti–anti selective synthesis of bis-β-amino ketones via three-component direct Mannich-type reaction of terephthalaldehyde catalyzed by ZrOCl2·8H2O

At room temperature, zirconium oxychloride (ZrOCl₂·8H₂O) efficiently catalyzes the direct Mannich-type reaction of a variety of in situ generated bis-imines using terephthalaldehyde and anilines with ketones in a three-component reaction at room temperature. The reaction proceeds rapidly and affords the corresponding bis-β-amino ketones in good-to-high yields with good-to-excellent anti–anti selectivity.     

Chemospecific and ligand free CuI catalysed heterogeneous N-arylation of amines with diheteroaryl halides at room temperature

A ligand free, copper-catalyzed N-arylation reaction of amines with diheteroaryl halides in heterogeneous medium at room temperature has been developed. The protocol is very effective for low boiling amines and useful for amines available in aqueous solution. The reaction gives chemospecific arylation of amines with diheteroaryl halides in the mixture monoheteroaryl halides, diheteroaryl halides and carbocyclic aryl halides. The reaction is also chemospecific with respect to arylation of aliphatic amines. Monoarylated piperazines were also synthesized at room temperature following this protocol.