共查询到20条相似文献,搜索用时 15 毫秒
1.
A general method is presented for the preparation of tert-butyl esters by the gentle warming of the carboxylic acid in the presence of excess of tert-butyl acetoacetate and a catalytic amount of acid. This method generates only low pressures, and is therefore suitable for laboratory scale pressure glassware. 相似文献
2.
J.S. Yadav E. Balanarsaiah S. Raghavendra M. Satyanarayana 《Tetrahedron letters》2006,47(28):4921-4924
A simple, mild and efficient method for the hydrolysis of tert-butyl esters using molecular iodine as a catalyst is described. Acid labile protecting groups, such as N-Boc, OBn, OAc and double bonds, are compatible under the reaction conditions. 相似文献
3.
Anjanappa Prakash Mullick Dibakar Kumaravel Selvakumar Kandasamy Ruckmani Manickam Sivakumar 《Tetrahedron letters》2011,52(43):5625-5628
tert-Butyl sulfinamide is an ammonia equivalent for the palladium-catalyzed amination of aryl bromides and aryl chlorides. Using these amine derivatives, it has been observed that indoles and anilines with sensitive functional groups can be readily prepared. This surrogate has also been used for the synthesis of indoles from 2-halophenols using palladium catalyzed cross coupling reaction as the key step. 相似文献
4.
Nitin D. Arote 《Tetrahedron letters》2007,48(32):5661-5664
A general method, for the direct conversion of aldehydes to acyl azides using tert-butyl hypochlorite and sodium azide is described. The method is simple and occurs under mild conditions. 相似文献
5.
tert-Butyl 2-hydroxyalkyl sulfides, prepared by reaction of epoxides with 2-methylpropane-2-thiol, are converted directly to 1,3-oxathiolanes upon treatment with pivalaldehyde and boron trifluoride diethyl etherate in the presence of thioanisole. 相似文献
6.
Xiang-Rong Xu 《Microchemical Journal》2004,77(1):71-77
Degradation of methyl tert-butyl ether (MTBE) with Fe2+/H2O2 was studied by purge-and-trap gas chromatography-mass spectrometry. MTBE was degraded 99% within 120 min under optimum conditions. MTBE was firstly degraded rapidly based on a Fe2+/H2O2 reaction and then relatively slower based on a Fe3+/H2O2 reaction. The dissolved oxygen decreased rapidly in the Fe2+/H2O2 reaction stage, but showed a slow increase in the Fe3+/H2O2 reaction stage. tert-Butyl formate, tert-butyl alcohol, methyl acetate and acetone were identified as primary degradation products by mass spectrometry. A preliminary reaction mechanism involving two different pathways for the degradation of MTBE with Fe2+/H2O2 was proposed. This study suggests that degradation of MTBE can be achieved using the Fe2+/H2O2 process. 相似文献
7.
Scott D. Kuduk Robert M. DiPardo Ronald K. Chang Christina Ng Mark G. Bock 《Tetrahedron letters》2004,45(35):6641-6643
Addition of Grignard reagents to chiral tert-butyl sulfinimines derived from pyridine 2-carboxaldehyde affords protected 2-pyridyl amines in high yields and diastereoselectivities. The sense of chiral induction is opposite to that predicted via a chelation-controlled transition state. 相似文献
8.
A static total pressure apparatus was used to measure isothermal VLE for systems containing propanenitrile +n-butane (322.02 K), +1-butene (312.55 K), +2-methylpropane (307.85 K) and +2-methylpropene (312.59 K). Vapour liquid equilibrium (VLE) for propanenitrile + tert-butyl ethyl ether (ETBE) was measured both with the static total pressure apparatus at 312.85 K and 358.32 K and with a glass circulation still apparatus at 102.6 kPa and 65.2 kPa. The system of propanenitrile + ETBE evidenced azeotropic behaviour. 相似文献
9.
This work uses ab initio calculations to obtain harmonic frequencies and anharmonic constants for the O–H symmetric and asymmetric stretches of H2SO4 in its C2, Cs, C1a, and C1b configurations. In addition, a high-resolution potential energy surface is calculated as a function of both O=S–O–H dihedral angles in order to accurately obtain minimum and saddle point energies. The resulting peak positions and Boltzmann populations are compared to experimental frequencies and intensities and provide evidence for the assignment of rotamers in H2SO4 as suggested in recent work. 相似文献
10.
R. Krishnan 《European Polymer Journal》2004,40(10):2269-2276
Atom transfer radical polymerization (ATRP) of tert-butyl methacrylate (tBMA) was investigated using cuprous bromide with different ligands, solvents, deactivators, etc. The polymerization in bulk and diphenyl ether solvent system performed using Cu(I)Br complexed with N, N, N′, N″, N″-pentamethyldiethylenetriamine (PMDETA) catalyst in conjunction with 2-bromopropionitrile as an initiator at room temperature showed a curvature in the first-order kinetic plot. The controlled polymerization in methanol solution resulted in slower rate of polymerization and lower molecular weights. Well-defined diblock copolymers of PSt-b-PtBMA synthesized by polystyrene bromo macroinitiator (PSt-Br) with Cu(I)Cl/PMDETA catalyst system yielded predetermined molecular weights and lower polydispersities. Otherwise, the Cu(I)Br/PMDETA catalytic system showed an inefficient polymerization of tert-butyl methacrylate with lower molecular weights and higher polydispersities. Subsequent hydrolysis of the homopolymer refluxed in dioxane with addition of HCl afforded well-defined poly(methacrylic acid). 相似文献
11.
Jie ZhangDarryl D DesMarteau Sharique ZuberiJing-Ji Ma Lixin XueSamuel M Gillette Hanne BlauRolf Gerhardt 《Journal of fluorine chemistry》2002,116(1):45-48
Synthesis of difunctional N,N′-difluoro perfluoroalkylsulfonamides, CF3SO2NFSO2(CF2)nSO2NFSO2CF3, where n=4, 6 is reported. A related compound with an oxygen linkage CF3SO2NFSO2(CF2)2O(CF2)2SO2NFSO2CF3 has also been prepared. These reagents showed good activity for electrophilic fluorination. 相似文献
12.
Reaction of tert-butyl isocyanide with dialkyl acetylenedicarboxylates in the presence of 2-acetylbutyrolactone leads to the formation of dialkyl (E)-2-{(tert-butylamino)[2-oxo-4,5-dihydro-3(2H)-furanylidene]methyl}-2-butenedioates. 相似文献
13.
Julia E. Barker 《Tetrahedron letters》2005,46(40):6805-6808
Mononuclear (Me3TACN)MnX3 compounds, where X is Cl−, Br−, or N3−, and Me3TACN is 1,4,7-N,N′,N″-trimethyl-1,4,7-triazacyclononane, have been tested for catalyzing both sulfide oxygenation and styrene epoxidation by tert-butyl hydroperoxide (TBHP) and display turnover frequencies (TOF) up to 200 h−1 at room temperature. Sulfoxides or sulfones may be produced selectively by varying reaction conditions. Product distribution from the oxygenation reactions of ethyl phenyl sulfide, 2-chloroethyl phenyl sulfide, and styrene is consistent with a mechanism involving an early single-electron transfer (SET) step. 相似文献
14.
Terézia Szabó-PlánkaJán Moncol Eszter TóthBéla Gyurcsik Nóra Veronika NagyZuzana Vasková Antal RockenbauerDušan Valigura 《Polyhedron》2011,30(14):2421-2429
EPR simulation method together with pH-potentiometry combined with UV-Vis spectrophotometry were used for the study of the ternary system 4-fuorosalicylic acid (HA)-N,N-diethylnicotinamide (B)-copper(II) in aqueous solution. The N,N-diethylnicotinamide ligand is a weak donor, its mixed-ligand complexes with 4-fluorosalicylate anions are more favoured. The number of coordinated N,N-diethylnicotinamide molecules increases with decreasing temperature: up to four ones were detected in the coordination sphere of copper(II) in frozen solutions. The formation of [CuH−1AB2] and [CuH−1A] was detected by all methods at neutral pH. At lower pH values, [CuA2B2] and [CuB] become dominant, and this fact is in good agreement with [CuA2B2(H2O)2] crystals obtained from similar solutions. The structural unit of the [CuA2B2(H2O)2] complex consists of a copper(II) ion, which is monodentately coordinated by a pair of 4-fluorosalicylate anions and by a pair of N,N-diethylnicotinamide in trans positions in the basal plane, and by two water molecules in the axial positions of a tetragonal bipyramid. 相似文献
15.
An efficient and general method for the oxidative cleavage of alkenes and alkynes using tert-butyl hydroperoxide and indium(III) chloride as catalyst in water to give the corresponding carboxylic acids or ketones has been achieved. The reaction conditions are compatible with sensitive moieties such as peptide bonds, tert-butyl carboxylic esters and N-Boc-protected tryptophan. The catalyst could be recycled. 相似文献
16.
Julien Maury Laurence Feray Michèle P. Bertrand Ajoy Kapat Philippe Renaud 《Tetrahedron》2012,68(47):9606-9611
In the presence of tert-butyl iodide, alkyl azides are converted into the corresponding iodides at room temperature, whereas, N-t-Bu anilines are obtained from aryl azides under the same experimental conditions. A mechanism is proposed to explain this unusual reactivity. 相似文献
17.
t-Butyl carbamates were obtained efficiently in high yields from the corresponding N-benzyl, N-trityl and N-diphenylmethyl precursors in a single-step reductive transformation employing polymethylhydrosiloxane and di-t-butyl dicarbonate under Pd(OH)2/C catalysis. 相似文献
18.
β-Tetra(tert-butyl)porphyrin was prepared from 2-dimethylaminomethyl-4-tert-butylpyrrole and converted into porphine, the mother compound of porphyrins, in 64% yield. The dealkylation smoothly proceeded in aqueous sulfuric acid over 15 min at 190 °C under nitrogen. 相似文献
19.
A new and simple PdCl2/DMA catalytic system for the alcohol oxidation has been developed using molecular oxygen as the sole oxidant under mild conditions. The catalytic system could be reused for three runs without significant loss of catalytic activity. A variety of active and non-active alcohols were oxidized to their corresponding carbonyl compounds in good to excellent yields. Gas-uptake kinetics for the catalytic system was also investigated. The ca. 1:1 molar ratio of O2 uptake to product yield is observed, suggesting the in situ formation of H2O2. 相似文献
20.
Cleavage of the N-(1-phenylethyl) unit of carboxamides using less than 1 equiv of MsOH in refluxing toluene was found to be simple and very efficient leading to the desired amides in good to excellent yields, and also proved to be more effective compared with reductive methods using hydrogen sources, or acid hydrolysis reagents such as TFA and TsOH. The method selectively cleaved only the N-(1-phenylethyl) group of N-benzyl-N-(1-phenylethyl)amides. 相似文献