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1.
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
2.
Boris A. Trofimov Svetlana F. Malysheva Nina K. Gusarova Vladimir A. Kuimov Nataliya A. Belogorlova Boris G. Sukhov 《Tetrahedron letters》2008,49(21):3480-3483
Red phosphorus reacts with 1-(tert-butyl)-4-vinylbenzene in a superbase media (KOH-DMSO, 90-100 °C, 3 h) to give tris[4-(tert-butyl)phenethyl]phosphine oxide in 77% yield. Microwave activation of the reaction affords the phosphine oxide in 82% yield in 6 min. 相似文献
3.
Methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are oxygenated compounds added to gasoline to enhance octane rating and to improve combustion. They may be found as pollutants of living and working environments. In this work a robotized method for the quantification of low level MTBE, ETBE and TAME in human urine was developed and validated. The analytes were sampled in the headspace of urine by SPME in the presence of MTBE-d12 as internal standard. Different fibers were compared for their linearity and extraction efficiency: carboxen/polydimethylsiloxane, polydimethylsiloxane/divinylbenzene, and polydimethylsiloxane. The first, although highly efficient, was discarded due to deviation of linearity for competitive displacement, and the polydimethylsiloxane/divinylbenzene fiber was chosen instead. The analysis was performed by GC/MS operating in the electron impact mode. The method is very specific, with range of linearity 30-4600 ng L−1, within- and between-run precision, as coefficient of variation, <22 and <16%, accuracy within 20% the theoretical level, and limit of detection of 6 ng L−1 for all the analytes. The influence of the matrix on the quantification of these ethers was evaluated analysing the specimens of seven traffic policemen exposed to autovehicular emissions: using the calibration curve and the method of standard additions comparable levels of MTBE (68-528 ng L−1), ETBE (<6 ng L−1), and TAME (<6 ng L−1) were obtained. 相似文献
4.
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
5.
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
6.
Yiqian WanXiongyu Wu Mahalingam A. KannanMathias Alterman 《Tetrahedron letters》2003,44(24):4523-4525
A fast, mild and selective method for deprotection of tert-butyl aryl sulfonamides utilizing BCl3 as deprotection reagent has been developed. A variety of tert-butyl aryl sulfonamides used under these conditions gave the corresponding primary sulfonamides in high yields. The method does not cleave methoxy groups and prevents incorporation of tert-butyl groups onto electron-rich aromatic rings. 相似文献
7.
tert-Butyl isocyanide can serve as the convertible reagent in Groebke-Blackburn multi-component reactions. The effective removal of the tert-butyl group from the resulting imidazo[1,2-a]azines and -azoles is achieved on a gram scale in two steps without chromatographic purification. 相似文献
8.
Significant improvements in the synthesis of pyrido-fused heterocycles were observed when performing the reaction under solvent-free conditions, applying the tert-amino effect as the key ring closure methodology. An unexpected cyclization of ortho-(1′-azacycloalkyl)benzaldehydes has been studied in water and on solid support. 相似文献
9.
Kaliyamoorthy AlagiriKandikere Ramaiah Prabhu 《Tetrahedron》2011,67(44):8544-8551
Catalytic amount of vanadium reagent with tert-butylhydroperoxide as the oxidant was found to be an excellent oxidizing agent in aqueous medium. Vanadium pentoxide with aq tert-butylhydroperoxide readily oxidizes primary benzylic azides to the corresponding acids and secondary benzylic azides to the corresponding ketones in excellent yields. Further, vanadium pentoxide and aq tert-butylhydroperoxide combination turned out to be an effective catalyst for the oxidation of alcohols. Using vanadium pentoxide and aq tert-butylhydroperoxide primary alcohols were oxidized to the corresponding acids, whereas secondary alcohols underwent a smooth transformation to furnish corresponding ketones in excellent yields. All the oxidations are performed in water. 相似文献
10.
Zenghui LuXiaowei Xu Zhaozhen YangLichun Kong Gangguo Zhu 《Tetrahedron letters》2012,53(27):3433-3436
A mild and operationally simple approach to highly functionalized oxazolones has been developed, which involves an intramolecular oxypalladation of N-alkynyl tert-butyloxycarbamates, followed by either protonolysis of the alkenyl C-Pd bond to afford 3,5-disubstituted oxazolones or allylation with allyl halides in the presence of Ag2CO3 to generate 3,4,5-trisubstituted oxazolones, respectively. 相似文献
11.
The tandem sequence of the umpolung of α,β-unsaturated esters by an N-heterocyclic carbene (NHC) followed by annulation is demonstrated. The deoxy-Breslow intermediates are selectively generated from the reaction of NHC with methyl methacrylate, dimethyl itaconate, or methyl crotonate. Subsequently, they undergo annulation with isocyanates to give 4-(1,2,4-triazol-5-ylidene)pyrrolidine-2,5-diones in good isolated yields. In addition, the stoichiometric three-component reaction of NHC, methyl methacrylate, and phenyl isocyanate proceeded, accompanied by the formation of the 1:2 adduct of NHC with phenyl isocyanate. 相似文献
12.
A simple method for the determination of methyl tert-butyl ether (MTBE) in gasoline has been developed. The separation of MTBE from other analytes was controlled by the use of gas chromatography–mass spectrometry in the full scan mode using the characteristic primary, secondary and tertiary ions m/z 73, 57 and 43. The sample mass spectrum did not show any superimposition of other analytes. The separation from the common gasoline component 2-methylpentane was sufficient for reliable quantitation. An application of the developed conditions using gas chromatography with flame ionization detection was performed by the analysis of regular, euro super, super premium unleaded and ‘Optimax’ gasoline from petrol stations in the area of Frankfurt/Main, Germany. Regular unleaded gasoline shows an average MTBE content of 0.4% (w/w), whereas the MTBE content in euro super gasoline varies between 0.4 and 4.2% (w/w). The blending of MTBE to super premium has increased from 8.2% (w/w) in 1998 to 9.8% (w/w) on average in 1999. The recently introduced gasoline ‘Optimax’ shows an average MTBE content of 11.9% (w/w). The presented method might also be used for the analysis of other ethers, such as ethyl tert-butyl ether, which requires the use of another internal standard. 相似文献
13.
Nonpolar protic reaction media such as t-amyl alcohol allow the aliphatic, nucleophilic fluorination reaction of primary haloalkane systems to fluoroalkanes, using tetrabutylammonium fluoride (TBAF), to proceed chemo-selectively at a reasonable reaction rate under mild conditions to afford the fluoro-product in high yield. As an example, the nucleophilic fluorination of 2-(3-iodopropoxy)naphthalene (1a) as the primary haloalkane model compound, with TBAF in acetonitrile as a polar aprotic solvent, CsF in t-amyl alcohol as a nonpolar protic solvent, and TBAF in t-amyl alcohol for 1 h provided 2-(3-fluoropropoxy)naphthalene (2a) in 38, 5, and 76% yields, respectively. 相似文献
14.
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
15.
Dongsik Yang 《Tetrahedron letters》2010,51(28):3691-3695
A convenient and efficient one-pot sequence has been developed for the synthesis of C-carbamoyl-1,2,3-triazoles from alkyl bromide using (i) sodium azide, (ii) methyl propiolate and copper iodide, and (iii) amines, zirconium tert-butoxide, and 1-hydroxybenzotriazole, under microwave irradiation. The sequential reactions in one-pot provided the desired C-carbamoyl-1,2,3-triazoles in excellent yields. 相似文献
16.
Arvind H. JadhavHern Kim 《Tetrahedron letters》2012,53(39):5338-5342
Selective deprotection of alkyl TBDMS ether in the presence of phenolic TBDMS ether using dicationic ionic liquid [tetraEG(mim)2][OMs]2 as a homogeneous catalyst showed significant catalytic activity in methanol at ambient temperature to produce respective alcohol in excellent yield. The present environmentally benign catalytic system is found to be very convenient, fast, high yielding, and clean method for selective desilylation of alkyl silyl ethers even in the existence of other sensitive organic functional groups such as aldehyde, methoxy, and acetate were also achieved. 相似文献
17.
Po-Yuan ChenTzu-Pin Wang Keng-Shiang HuangChai-Lin Kao Jui-Chi TsaiEng-Chi Wang 《Tetrahedron》2011,67(48):9291-9297
A mild, efficient, and regioselective carbanion-yne intramolecular cyclization mediated by t-BuOK for the synthesis of 2-substituted 3-benzylbenzofurans is developed. It was started from o-iodophenol (1), based on O-alkylation, and the Sonogashira reaction in sequence to produce 2-(2-phenylethynylphenoxy)-1-arylalkanones (5). An intramolecular carbanion-yne 5-exo-dig cyclization reaction of 5, which was mediated by t-BuOK, yielded title benzofurans in good yields. 相似文献
18.
We report here a novel in situ synthetic method for the preparation of poly(o-toluidine) and copper nanoparticle composite material. In this experiment, o-toluidine and cupric sulfate were used as the precursor; during the reaction o-toluidine was oxidized and forms poly(o-toluidine), while on the other hand cupric sulfate gets reduced and forms copper nanoparticle. IR, UV-vis and Raman spectra provide the information on the structure of the polymer. The TEM and SEM show the size of the nanoparticles and the morphology of the polymer, respectively. 相似文献
19.
The synthesis of two tert-amine-based, non-fluorescent, hole-transport molecules (4,4′-[bis-{(4-di-n-hexylamino)benzylideneamino)]stilbene (DHABS) and 4,4′-[bis-{(4-diphenylamino)benzylideneamino}]stilbene) (DPABS) that are suitable for spin coating on indium tin oxide (ITO) for electronic device fabrication is described and compared with the widely used TPD. Electroluminescence occurred at a turn-on voltage of 7-8 V in ITO/hole-transport layer (HTL, spin coated)/Alq3/Al devices. 相似文献
20.
Pallabi Saikia Partha Pratim KaishapRashmi Prakash Kommuri ShekarraoSanjib Gogoi Romesh C. Boruah 《Tetrahedron letters》2014
The preparation of steroid/nonsteroid fused 7-substituted pyrazolo[1,5-a]pyrimidines is described by a one-pot reaction of steroidal/nonsteroidal ketones, aromatic aldehydes and 3-amino-1H-pyrazoles/5-amino-1H-pyrazoles in the presence of potassium tert-butoxide in good yield under reflux condition in ethanol. 相似文献