Regioselective hydrolysis of ketenimines derived from NH-acids and acetylenic esters in the presence of tert -butyl isocyanide under neutral conditions

The regioselective hydrolysis of ketenimines derived from NH-acids, such as 2,2,2-trichloro-N-phenylacetamide or ethyl-2-anilino-2-oxoacetates and acetylenic esters in the presence of tert-butyl isocyanide in a THF/H₂O system (1/1) without any catalysis leads to a diastereomeric mixture of dialkyl 2-[(tert-butylamino)carbonyl]-3-[(2,2,2-trichloroacetyl)anilino]succinates and dialkyl 2-[(tert-butylamino)carbonyl]-3-[2-ethoxy-2-oxoacetyl)anilino]-succinates in good yields. Dynamic NMR effects were observed in the ¹³C NMR spectra of diethyl 2-[(tert-butylamino)carbonyl]-3-[(2,2,2-trichloroacetyl)anilino]succinate as a result of restricted rotation around the N-aryl single bond. The free energy of activation (ΔG ^#) for this process is 37.9 kJ mol⁻¹ which leads to an observable atropisomerism.     

An efficient chemoselective synthesis of O-vinylaryl systems using acetylenic esters and dihydroxybenzenes in the presence of triphenylphosphine or alkyl isocyanides

<正>The addition of 2,4-dihydroxyaceto(and benzo)phenone to propiolic ester is catalyzed by triphenylphosphine or tert-butyl isocyanide to form O-vinyl aryl derivatives in fairly good yields.     

Synthesis of novel rhodanine based functionalized furans from the reaction of tert-butyl isocyanide with acetylenic esters in the presence of rhodanine acetic acid derivatives

The reactive 1:1 intermediate produced from the reaction of tert-butyl isocyanide and dialkyl acetylenedicarboxylates was trapped by rhodanine-N-acetic acid derivatives to generate polyfunctionalized furan rings in fairly good yields.     

Stereoselective reaction between alkyl propiolates and phenols in the presence of sodium azide in tert-butyl alcohol

Abstract  

Stereoselective reaction of various substituted phenols with alkyl propiolates in the presence of a catalytic amount of sodium azide in tert-butyl alcohol at reflux temperature leads to alkyl (Z)-3-phenoxy-2-propenoates in good yields.     

Regioselective hydrolysis of ketenimines derived from NH-acids and acetylenic esters in the presence of <Emphasis Type="Italic">tert</Emphasis>-butyl isocyanide under neutral conditions

The regioselective hydrolysis of ketenimines derived from NH-acids, such as 2,2,2-trichloro-N-phenylacetamide or ethyl-2-anilino-2-oxoacetates and acetylenic esters in the presence of tert-butyl isocyanide in a THF/H₂O system (1/1) without any catalysis leads to a diastereomeric mixture of dialkyl 2-[(tert-butylamino)carbonyl]-3-[(2,2,2-trichloroacetyl)anilino]succinates and dialkyl 2-[(tert-butylamino)carbonyl]-3-[2-ethoxy-2-oxoacetyl)anilino]-succinates in good yields. Dynamic NMR effects were observed in the ¹³C NMR spectra of diethyl 2-[(tert-butylamino)carbonyl]-3-[(2,2,2-trichloroacetyl)anilino]succinate as a result of restricted rotation around the N-aryl single bond. The free energy of activation (ΔG ^#) for this process is 37.9 kJ mol⁻¹ which leads to an observable atropisomerism. Correspondence: Dr. Farough Nasiri PhD, Department of Chemistry, Faculty of Sciences, University of Kurdistan, P.O. Box 66315-416, Sanandaj, Iran.     

Kinetics and mechanism of the catalytic epoxidation of cyclohexene with tert-butyl hydroperoxide in the presence of molybdenum–squarate complex

The kinetics of the catalytic epoxidation of cyclohexene with tert-butyl hydroperoxide (TBHP) in the presence of a novel molybdenum–squarate complex was studied. Both the kinetics and mechanism of the process were found to be similar to those established with the “classical” homogeneous catalysts for epoxidation.     

Method for determination of methyl tert-butyl ether in gasoline by gas chromatography

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.     

Kinetics of vinylation of 4′-bromoacetophenone with n-butyl acrylate using palladacycle catalyst

The kinetics of vinylation of 4′-bromoacetophenone (4′-BAP) with n-butyl acrylate (n-BA) has been studied using palladacycle catalyst precursor 1, in the presence of sodium acetate (NaOAc) as a base and tetrabutylammonium bromide (TBAB) as a promoter in N-methyl-2-pyrrolidinone (NMP) solvent. The rate was found to be first order with respect to 4′-BAP, fractional order with the catalyst, and first order tending to zero order with NaOAc concentration. The rates passed through a maximum with variation of TBAB and n-butyl acrylate concentrations. The rate data have been analyzed to propose an empirical model, which is in good agreement with the mechanism already established for Heck reactions using palladacycle catalysts.     

Regioselective cycloaddition of acetylenic esters: a one-pot synthesis of novel dihydrobenzo[a]carbazoles

A one-pot procedure for the synthesis of highly substituted dihydrobenzo[a]carbazole derivatives via a regioselective cyclocondensation reaction between 2-(2,3,4,9-tetrahydro-carbazol-1-ylidene)-propanedinitrile and acetylenic esters is described.     

Isothermal vapour–liquid equilibria in the ternary system tert-butyl methyl ether + tert-butanol + 2,2,4-trimethylpentane and the three binary subsystems

Vapour–liquid equilibrium data are reported for the ternary tert-butyl methyl ether+tert-butanol+2,2,4-trimethylpentane and the three binary tert-butyl methyl ether+tert-butanol, tert-butyl methyl ether+2,2,4-trimethylpentane, tert-butanol+2,2,4-trimethylpentane subsystems. The data were measured isothermally at 318.13, 328.20, and 339.28 K covering pressure range 15–100 kPa. Azeotropic data are presented for the tert-butanol+2,2,4-trimethylpentane system. Molar excess volumes at 298.15 K are given for the three binary systems. The binary vapour–liquid equilibrium data were correlated using Wilson, NRTL, and Redlich–Kister equations; the parameters obtained were used for calculation of phase behaviour in ternary system and for subsequent comparison with experimental data.     

Three-component reaction between 5,5-diarylthiohydantoins and acetylenic esters in the presence of trialkyl phosphite

Abstract  

The adducts produced in the reaction between trialkyl phosphites and acetylenic esters were trapped by thiohydantoins to produce highly functionalized 5-oxo-2-thioxoimidazolidines and 4,5-dihydro-2-(methylthio)-5-oxoimidazoles in good yields.     

Catalytic reactivity of Cr/SiO2 in the liquid phase oxidation of cyclohexanol by tert-butyl hydroperoxide

Silica supported chromium is a heterogeneous, active and selective catalyst for the liquid phase oxidation of cyclohexanol by tert-butyl hydroperoxide (TBHP) in the presence or absence of oxygen. It is also active for the decomposition of TBHP. The reactivity at 70ºC and atmospheric pressure is higher than over other catalysts and the cyclohexanone selectivity is 100%.     

The stereoselective construction of fluoroalkenoates via the Peterson olefination reaction using tert-butyl α-fluoro-α-(trialkylsilyl)acetates

A new version of the Peterson fluoroolefination reaction employing tert-butyl α-fluoro-α-(trialkylsilyl)acetates was developed to construct various fluoro-alkenoates.     

Excess molar enthalpies of the ternary mixtures: methyl tert-butyl ether + 3-methylpentane + (n-decane or n-dodecane) at 298.15 K

Excess molar enthalpies, measured at 298.15 K in a flow microcalorimeter, are reported for the two ternary mixtures formed by mixing either methyl tert-butyl ether with binary mixtures of 3-methylpentane and either n-decane or n-dodecane. Smooth representations of the ternary results are presented and used to construct constant excess molar enthalpy contours on Roozeboom diagrams. It is found that the Liebermann and Fried model also provided good representation of the ternary results, using only the physical properties of the components and their binary mixtures.     

Trifluoroacetylation of amines with trifluoroacetic acid in the presence of trichloroacetonitrile and triphenylphosphine

We developed a mild and convenient trifluoroacetylation process for amines using a combination of trichloroacetonitrile and triphenylphosphine. The reaction that we designed is applicable to the trifluoroacetylation of a wide variety of amines, including amines with stereogenic centers, which underwent trifluoroacetylation without racemization.     

Adducts of 2-aminothiophenol with acetylenic nitriles or esters and their conversion into benzothiazoles and/or 1,4-benzothiazines

The reaction between 2-aminothiophenol 1 and acetylenic nitriles or esters 2a-d leads to the vinyl thio-ethers 3a-d. The conversion of 3 into benzothiazoles 8 and/or 1,4-benzothiazines 9 , in boiling dimethyl sulfoxide, has been achieved. A possible pathway involving benzothiazolines 5 as key intermediates is suggested.     

Synthesis of new phosphonato esters by reaction between triphenyl or trialkyl phosphite and acetylenic diesters in the presence of NH‐containing compounds

The reaction between triphenyl or trialkyl phosphite and acetylenic esters in the presence of some heterocyclic or aromatic NH compounds such as thiazolidine‐2,4‐dione, 2‐methyl indole, 5‐bromoisatine, 3‐nitroacetanilide, saccharin, 5,5‐dimethylhydantoin, 2‐nitroaniline, 4‐nitroaniline, benzophenon hydrazine, and anthranilic acid led to the formation of phosphonato esters in high yield. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:630–639, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20725