Tert-Butyl isobutyrate

Another example of the nucleophilic chloro ligand substitution involves the reaction of the zirconium dichloride complex 468 with lithium ester enolates (Scheme 112). Its reaction with 2 equiv. of stable lithium ester enolates such as lithium tert-butyl isobutyrate in TF1F produces the bis(ester enolate) complex 499 as a crystalline solid.344 The same reaction but with the unstable lithium methyl isobutyrate leads to the isolation of the decomposition product, the bis(methoxide) complex 500, which exists as a dimer in the solid state. Treatment of the bis(ester enolate)... 

Complementary to the work with aqueous acidic media is the study of the homolytic decompositions of Co(III) carboxylates in carboxylic acid media by Lande and Kochi . For example, Co(III) is reduced in pivalic acid media with first-order kinetics with E = 30.6 kcal.mole , AS = 8 eu and k ko = 1.28+0.10 (69 °C). The main oxidation products were found to be isobutylene and tert-butyl pivalate, which suggests that (CH3)3C- is an intermediate. Oxidative decarboxylation is the probable course in the analogous oxidations of n-butyric and isobutyric acids, in view of the production of propane and CO2 under normal... 

The formation of isobutyric acid in the presence of the additives studied, and the results of additional studies (di-tert.-butyl peroxyoxalate/isobutyroal-dehyde/amine), point to the intermediate formation of acyl peroxy radicals. 

METHYL ISOBUTYL KETONE n-PENTYL FORMATE n-BUTYL ACETATE sec-BUTYL ACETATE tert-BUTYL ACETATE ETHYL n-BUTYRATE ETHYL ISOBUTYRATE ISOBUTYL ACETATE n-PROPYL PROPIONATE CYCLOHEXYL PEROXIDE DIACETONE ALCOHOL 2-ETHYL BUTYRIC ACID n-HEXANOIC ACID 2-ETHOXYETHYL ACETATE HYDROXYCAPROIC ACID PARALDEHYDE... 

This situation occurs in the presence of very low concentrations of tert. ROLi or of special activators (e. g. methyl or butyl isobutyrate). It is also induced in the presence of strongly solvating solvents (e. g. THF). 

In rats and mice exposed to MTBE, unchanged MTBE and tert-butyl alcohol were shown to be the main respiratory excretion products. MTBE has also been found to be metabolized to formaldehyde, methanol, formic acid, carbon dioxide, 2-methyl-1,2-propanediol, and a-hydroxy-isobutyric acid. MTBE has not been shown to bioaccumulate in the tissues (ATSDR, 1996). 

J. Julliard, J. P. Morel, and L. Avedikian, J. Chem. Phys., 69, 787 (1972). Conductivities of potassium formate, acetate, isobutyrate, cyclo-hexanecarboxylate and benzoate in water-tert butyl alcohol mixtures. 

One specialized and readily available carbodiimide, called dicyclohexyl-carbodiimide (usually abbreviated DCC), will be used to illustrate this transformation it has structure 78. Use of this reagent to form esters led to the discovery that adding a catalytic amount of an amine base gives higher yields. This observation will be used, but will not be explained further in this discussion. When 3-methylbutanoic acid (77 isobutyric acid) is stirred with tert-butanol in the presence of a catalytic amount of 4-pyrrolidinopyridine (79), for example, er -butyl 3-methylbutanoate (80) is isolated in 65% yield. In addition to the ester, one molar equivalent of dicyclohexyl urea (see 87) is also isolated. The mechanism that explains these results begins by noting that the diimide carbon in 78 is like a double imine and bond polarization makes the central carbon atom very electrophilic. 

Isobutyl nitrite Butyl alcohol scc-Butyl alcohol t r -Butyl alcohol Ethyl ether Isobutyl alcohol Ethyl sulfide Pyridine Isovaleraldehyde 3-Methyl 2-butanone Isobutyl formate Isopropyl acetate Methyl isobutyrate Isoamyl nitrite tert-Amyl alcohol Isoamyl alcohol... 

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