T-butyl Compounds Research Articles

Exhaustive methylation by trimethylaluminium

Trimethylaluminium exhaustively methylates tertiary alcohols to alkanes, ketones to gem-dimethyl compounds, and carboxylic acids to t-butyl compounds.

Internal solvation effects on the conformation of acyclics

Experiments attempting to discern internal solvation (or H—bonding) of COOH or COO − by OH are outlined. In aqueous solutions little evidence for internal solvation exists. In basic methanol this effect appears due to poor solvation by the solvent. The origin of anomalous coupling constants in t-butyl compounds is discussed briefly.

A calorimetric and PMR study of the chlorination of some t-butyl compounds by antimony pentachloride

t-BuCl and t-BuOH are instantaneously chlorinated by SbCl 5 in dilute solution to give 1,2-dichloro-2-methylpropane, SbCl 3 and HCl or H 2O, respectively. The enthalpy changes, in kJ-mol −1 for the chlorination reaction with reactants and reaction products in 1,2-dichloroethane solution are: t-BuCL - 72·0 ± 0·2 and t-BuOH - 93·6 ± 1·2. Rapid chlorination of t-BuOAc does not take place unless SbCl 5 is present in excess, the enthalpy change for the reaction being -100 ± 2 kJ · mol −1. The initial step of the chlorination reaction is considered to be interaction between SbCl 5 and a lone electron pair at the atom bound to the t-Bu group.

Strain in tertiary butyl derivatives

Starting from the geometry of the 2,3-di-t-butylquinoxaline molecule repulsion energy curves were obtained for the interaction between two t-Bu groups and between two Me groups. From these curves the geometry and the strain energy have been predicted for a number of t-butyl compounds.

Kinetics of reactions in heterocycles. Part VI. Replacement of 2-alkylthio, 2-alkylsulphinyl, and 2-alkylsulphonyl groups from quinoxalines by methoxide ion

Kinetic studies of the reactions of 2-alkylsulphonyl-, 2-alkylsulphinyl-, and 2-alkylthio-quinoxalines with sodium methoxide showed that for the methyl, ethyl, isopropyl, and t-butyl compounds a decreased reactivity was observed with increasing size of the group. This effect was least for the sulphides (1·8 fold difference) and greatest (140 fold) for sulphoxides. U.v. and 1H n.m.r. spectra are recorded and discussed.

Protonenresonanz-spektroskopie ungesättigter ringsysteme—VII : 7-Monosubstituierte cycloheptatriene

The 1H-NMR-spectra of 7-methyl-, 7-phenyl-, 7-isopropl- and 7-t-butyl-cyclohepta-1,3,5-triene have been analysed. On the basis of the observed coupling constants and resonance frequencies a preference for the conformation with the substituent quasi-equatorial is indicated. The phenyl compound has an energy difference of ca. 1100 cal/mole in favour of this conformation which was calculated from the temperature dependence of the resonance frequency of the proton H 7 with the help of a nonlinear method of least squares. The same value is obtained for the t-butyl compound. The limiting parameters for the coupling constant J 17, obtained on the basis of these energy differences by an iterative procedure, allow conclusions concerning the structural angle α.

Synthesis of Poly-p-oxyperfluorobenzylene and Related Polymers. A Novel Synthesis of the Monomer 2,3,5,6-Tetrafluoro-4-trifluoromethylphenol.

The synthesis and polymerization of 2,3,5,6-tetrafluoro-4-trifluoromethylphenol (heptafluoro-p-cresol) is described. The polymer, poly-p-oxyperfluorobenzylene (polyperfluoro-p-benzylene oxide), is probably formed through the perfluoro-p-quinonemethide intermediate obtained by the intramolecular loss of either hydrogen fluoride or a metal fluoride. The polymer has a structure analogous to that reported for the polymer derived from p-trifluoromethylphenol under similar conditions. In the course of the synthesis of the monomer, heptafluoro-p-cresol, a novel synthetic method was discovered. The synthesis consists in the prior preparation of 1-t-butoxy-2,3,5,6-tetrafluoro-4-trifluoromethylbenzene and its subsequent thermal decomposition into the isobutylene and the desired cresol. Similarly, N-t-butyl-2,3,5,6-tetrafluoro-4-trifluoromethylaniline undergoes a similar liquid phase pyrolysis into isobutylene and 2,3,5,6-tetrafluoro-4-trirluoromethylaniline. However, during the course of this pyrolysis, practically all of the aniline undergoes polymerization with the concomitant loss of hydrogen fluoride. The polymer is formed by the same mechanism operative in the thermal polymerization of p-heptafluorocresol except that additional quantities of hydrogen fluoride can be eliminated from the - NHCF2 - segments of the polymer chain thereby introducing - N = CF - units into the polymer backbone. Other t-butyl derivatives were synthesized and their thermal decomposition studied. Several possible mechanisms for the decomposition of these t-butyl compounds are considered.

Eliminations promoted by thiolate ions. Part III. Reactions of t-butyl chloride and t-butyldimethylsulphonium iodide

The effect of the leaving group on the relative reactivities of benzenethiolate and alkoxide ions in bimolecular eliminations from t-butyl compounds is investigated. The substrates studied are t-butyl chloride and t-butyldimethylsulphonium iodide. There is a correlation between the relative reactivities of these bases and Bronsted β coefficients, obtained by using substituted benzenethiolates as bases, for the two reaction series. The variation of the rate ratio with the change in leaving group is explained in terms of alterations in the nature of the E2 transition states.

Microwave Spectrum of Tertiary Butyl Chloride. A Comparison of Tertiary Butyl Structures

The rotational constants of (C12H3)3C12Cl35, (C12H3)3C12Cl37, (C12H3)3C13Cl35, (C12H3)3C13Cl37, and (C13H3) (C12H3)2C12Cl35 have been measured. The rs structure of the t-butyl chloride skeleton calculated from these constants is: r(CCl) = 1.803±0.002 Å, r(CC) = 1.530±0.002 Å,∠CCC=110.9°±0.1°. The quadrupole coupling constant for Cl35 is −66.9±1.5 Mc. The structures of a number of t-butyl compounds are compared. The t-butyl group is practically unaffected by substitution, while the CX bond in (CH3)3CX is systematically longer than in CH3X molecules. Conventional concepts of valence theory do not provide a satisfying explanation for this behavior.