2.2- Dimethylpropanoic acid, acidity

Chemical Name 2,2-Dimethylpropanoic acid 4-[ 1-hydroxy-2-(methylamino)ethyl] -1,2-phenylene ester... 

Pentanoic acid 3-Methylbutanoic acid 2,2-Dimethylpropanoic acid... 

The lithium enolates of cyclopentanone and cyclohexanone undergo addition-elimination to the 2,2-dimethylpropanoic acid ester of ( )-2-nitro-2-hepten-l-ol to give 2-(l-butyl-2-nitro-2-propenyl)cycloalkanones with modest diastereoselection. An analogous reaction of the enolate ion of cyclohexanone with the 2,2-dimethylpropanoic acid ester of (Z)-2-nitro-3-phenyl-2-propenol to give 2-(2-nitro-l-phenyl-2-propenyl)cyclohexanones was also reported. The relative configuration of these products was not however determined6. 

Butanoic acid, methyl ester Malonic acid, dimethyl ester 1,1-Dimethylpropanoic acid, 1,1-dimethylester... 

Merck scientists made changes to this process, resulting in fewer equivalents of acet-ylide and chiral ligand without the use of Ai-protection (Chen et al., 1998). In a general procedure, a solution of the chiral ligand (1.5 equivalents) is treated with either dimethyl or diethylzinc at 0°C to room temperature (Scheme 6.4). This mixture is stirred for 1 h followed by the addition of an additive. Most of the additives studied are either carboxylic acids or alcohols. The range of ee values from the different additives is 71.6% (2,2-dimethylpropanoic acid) to 96% (2,2,2-trichloroethanol). This solution is mixed... 

The trimerization of cyclopentadiene (6) is catalyzed by a homogeneous bifunctional palladium-acid catalyst system.7 The reaction gives trimers 7 and 8 as a 1 1 mixture in 70% yield with bis(acetylacetonato)palladium(II) [Pd(acac)2] or with bis(benzylideneacetone)-palladium(O) as the palladium component of the catalyst. As the phosphorus component, phosphanes like trimethyl-, triethyl-, or triphenylphosphane, and triisopropylphosphite or tris(2-methylphcnyl)phosphite, are suitable. A third component, an organic acid with 3 < pK < 5, is necessary in at least equimolar amounts, in the reaction with cyclopentadiene (6), as catalytic amounts are insufficient. Acids that can be used are acetic acid, chloroacetic acid, benzoic acid, and 2,2-dimethylpropanoic acid. Stronger acids, e.g. trichloroacetic acid, result in the formation of poly(cyclopentadiene). The new catalyst system is able to almost completely suppress the competing Diels-Alder reaction, thus preventing the formation of dimeric cyclopentadiene, even at reaction temperatures between 100 and 130°C. 

Exercise 24-21 Show how 2-methyl-2-nitropropane may be synthesized from (a) tert-butyl alcohol and (b) 2,2-dimethylpropanoic acid. (Review Sections 23-12E and 24-3B if necessary.)... 

By pA a measurements it can be shown that 1,1,1-bicyclopentanecarboxylic acid is 10 times more acidic than 2,2-dimethylpropanoic acid, even though both have a quaternary carbon attached to the carboxylic acid group. Account for this difference in pAa. 

Experiment 5.124 2,2-DIMETHYLPROPANOIC ACID (Trimethylacetic acid pivalic acid)... 

Biserni A, Giannessi F, Sciarroni AF, Milazzo FM, Maggi A, Ciana P. (2008) In vivo imaging reveals selective peroxisome prolifera-tor activated receptor modulator activity of the synthetic ligand 3-(l-(4-chlorobenzyl)-3-t-butylthio-5-isopropylindol-2-yl)-2,2-dimethylpropanoic acid (MK-886). Mol Pharmacol. 73(5), 1434—43. 

CN ( )-2,2-dimethylpropanoic acid 4-[l-hydroxy-2-(mcthylamino)ethyl]-l,2-phenylene ester... 

In this analysis, two outliers were detected, 2,2-dimethylpropanoic acid and 3-sulfopropanoic acid they were excluded from the final model. The physically reasonable nature of the relation is illustrated by noting that a decrease in pK (increase in acidity, less tendency to hold the proton) is associated with a smaller positive charge on the COO carbon and less negative charge on the RO oxygen. 

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