Trichloromethylation of Anhydrides. Ring—Chain Tautomerism<sup>1a</sup>

Winston, Anthony; Bederka, John P.; Isner, William G.; Juliano, Peter C.; Sharp, Joanne

doi:10.1021/jo01019a068

Cited by 18 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For each run, 1.0 mL of stock was diluted to 50 mL with 1 M KCI, making 0.0023 M ketone. I, I , I -Trichloroacetone was prepared according to the method of Winston et al (44) in 10% yield from sodium trichloroacetate and acetic anhydride; and purifiedby column chromatography on silica gel with 20:80 ether/~etroleum ether as eluant. followed bv distillation at 60"C/40Torr.…”

Section: Methodsmentioning

confidence: 99%

The chlorination of acetone: a complete kinetic analysis

Guthrie¹,

Cossar²

1986

Can. J. Chem.

View full text Add to dashboard Cite

. Rate constants are reported for all of the major steps followed in the chlorination of acetone, including the chlorination of mono-and 1 , 1-dichloroacetone, the chlorination of hydroxyacetone, the chlorination and hydroxide-catalyzed rearrangement of 1,l-dihydroxyacetone, and the haloform cleavage of trichloroacetone. pK, values are reported for hydroxyacetone and monochloroacetone. Rate constants for the hydrolyses of chloroacetone and 1,l-dichloroacetone are reported; these reactions are probably not SN2 displacements but proceed by addition of hydroxide and intramolecular displacement.

show abstract

Section: Methodsmentioning

confidence: 99%

The chlorination of acetone: a complete kinetic analysis

Guthrie¹,

Cossar²

1986

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

“…This occurs because even if GenX causes the transfer of a proton to acetone, the amount of protonated acetone is very small compared with the total amount of acetone as a solvent. In fact, the trichloromethyl anion produced by the decarboxylation of trichloroacetate salt is used as a nucleophile in chemical reactions . However, in the authors’ experiments, only Fluoroether E-1 was produced, at almost 100%, even when acetone was used, and no products of an addition reaction were observed in acetone.…”

mentioning

confidence: 86%

Comment on “Solvent Suitability for HFPO-DA (“GenX” Parent Acid) in Toxicological Studies”

Harada

Fujii

2020

Environ. Sci. Technol. Lett.

View full text Add to dashboard Cite

Metrics & MoreArticle RecommendationsT he paper by Liberatore et al. is an interesting study showing the instability of GenX, a perfluorooctanoic acid alternative, in aprotic polar solvents such as acetonitrile, acetone, and dimethyl sulfoxide. 1 The authors discussed the reasons for the instability and possible chemical processes, but we would like to raise some further points.The authors proposed that proton dissociation, autodecarboxylation, and solvent-mediated proton transfer lead to the decomposition of GenX in aprotic solvents. However, proton dissociation can also occur in protic solvents (e.g., methanol and water) and GenX (pK a = 2.84), which is a strong acid like other per-and polyfluoroalkyl substances, appears to be mostly dissociated in aqueous solutions. 2 Furthermore, hydronium ions formed from water in the presence of protons can transfer protons to other molecules (Figure 1A). Thus, these processes do not appear to be important because GenX showed almost no decomposition in aqueous solutions. Taking acetone as an example, we find it is reasonable to assume that the oxygen atom in the carbonyl group is first protonated by an acid catalyst under acidic conditions (Figure 1B). However, solvent-mediated proton transfer occurs and a resonance-stabilized carbocation is generated. As a result, the Lewis acidity of the carbonyl compound may be increased, allowing a nucleophile to attack the carbonyl carbon. Although the carbanion produced by GenX decarboxylation is relatively stable, it is considered a potent nucleophile. This carbanion may react with the carbocation of protonated acetone. In addition, even if the formation of a carbocation is rare under these conditions, if the carbanion produced from GenX causes an attack on the carbonyl carbon of acetone, then an addition reaction can occur (Figure 1C). This occurs because even if GenX causes the transfer of a proton to acetone, the amount of protonated acetone is very small compared with the total amount of acetone as a solvent. In fact, the trichloromethyl anion produced by the decarboxylation of trichloroacetate salt is used as a nucleophile in chemical reactions. 3 However, in the authors' experiments, only Fluoroether E-1 was produced, at almost 100%, even when acetone was used, and no products of an addition reaction were observed in acetone. Therefore, it seems difficult to reconcile the proposed mechanism from the observations of the authors. Future studies, including molecular dynamics simulations to study the decarboxylation mechanism, will be required. 4 Kouji H. Harada orcid.org/0000-0001-7319-123X

show abstract

“…Table 3 The KT constants are determined by: a UV method in dioxan; b Dissociation constants measuring and true dissociation estimating in water; , IR method in dioxan; d IH-NMR method in dioxan: , In the same way as b, but in 80% 2-methoxyethanol-water solution; fIR method in OM SO. A series of 3-trichloroacetylcarboxylic acids based on 3-trichloroacetyl propionic acid shows a heightened tendency to form the cyclic tautomers [13,34]' Obviously, the -I-effect of the trichloromethyl group enhances the electrophilicity of the carbonyl carbon atom. The relatively high stability of the ring form of bicyclic ketocarboxylic acids (6)-(9) is a result of the fixed mutually eclipsed conformation of the COOH and C=O groups providing the sterically most favorable condition for intramolecular addition.…”

Section: -Acylpropionic Acids and Substitutedmentioning

confidence: 99%

“…However, the dependence of the solid state struc-ture on the substituent R (10) is not straightforward. Some 2-acylbenzoic acids with R = alkyl or a more complicated substituent crystallize in the cyclic form [7,13,34,67], but others solidify in the open chain [68] or as mixtures of both forms [68][69][70][71][72][73].…”

Section: Footnotes Tomentioning

confidence: 99%

“…Contrary to earlier studies [74] it was established by IR comparison [163] that both isomeric cyclic chlorides, i.e., 3-benzoyl-3chlorophthalide (32) and 3-chloro-4-oxo-3-phenyl-3,4-dihydroisocoumarine (33) were observed. The six-membered chlorolactone easily undergoes isomerization involving ring contraction (33) It was recently shown [164] that the reaction of 2-(2-pyridylcarbonyl)benzoic acid with thionyl chloride leads to 4a-azoniaanthraquinone chloride (34), which in polar solvents isomerizes into 3-chloro-3-(2-pyridylcarbonyl)phthalide (35).…”

Section: Acyl Chloridesmentioning

confidence: 99%

See 1 more Smart Citation