.alpha.-Methoxy-.alpha.-trifluoromethylphenylacetic acid. Configuration by asymmetric synthesis

Abstract

Appropriate corrections were made for increase in reactant volume due to added titrant.Registry No. syn-syn-, 26309-06-8; anti-1oximinoacetone, 17280-41-0. Acknowledgment. -This work was carried out under Contract DA-18-108-AMC-207(A) Task 1C622401A-10204, Department of Defense, whose support is gratefully acknowledged.

Insight into GEBR-32a: Chiral Resolution, Absolute Configuration and Enantiopreference in PDE4D Inhibition

“…This methodology is well-established and has been exploited to assign the absolute configuration of a large number of different compounds [21]. Its rationale is based on the assumption that the diastereoisomeric esters obtained by derivatization adopt a s-cis conformation with the C=O and the CF 3 group laying in the same plane [20,22,23]. In this conformation, the OMe and the Ph substituent of the MTPA moiety perturbate the signals of L 1 and L 2 groups belonging to the alkoxy residue (Figure 4): the aromatic ring will cause a high field shift of the substituent sitting on its side, while the substituent on the OMe side will remain unaffected or undergo an opposite change of δ.…”

“…Molecules 2020, 25, x 6 of 14 CF3 group laying in the same plane [20,22,23]. In this conformation, the OMe and the Ph substituent of the MTPA moiety perturbate the signals of L 1 and L 2 groups belonging to the alkoxy residue (Figure 4): the aromatic ring will cause a high field shift of the substituent sitting on its side, while the substituent on the OMe side will remain unaffected or undergo an opposite change of δ.…”

Dimer of Trifluoropyruvic Acid: Synthesis and Molecular Structure

“…Broadly, applied trifluoromethylcontaining, three-carbon, 1,2-dielectrophilic building blocks are the hydrate (i.e., gem-diol 1) and esters of trifluoropyruvic acid (2: R 1 = alk). Their reactivity towards various nucleophiles is well documented, [2][3][4][5][6][7][8] allowing one to obtain certain important fluorinated products, e.g. butan-4-olides, 2 6-azaurazil and a related β-D-deoxyribonucleoside and nucleotide, 3 (S)-3,3,3-trifluoro-2-hydroxy-2-phenylpropionic acid, 4 and derivatives of malic acid.…”

“…Their reactivity towards various nucleophiles is well documented, [2][3][4][5][6][7][8] allowing one to obtain certain important fluorinated products, e.g. butan-4-olides, 2 6-azaurazil and a related β-D-deoxyribonucleoside and nucleotide, 3 (S)-3,3,3-trifluoro-2-hydroxy-2-phenylpropionic acid, 4 and derivatives of malic acid. 6 A few methods for obtaining trifluoropyruvic acid hydrate and esters have been reported, 3,4,[9][10][11] but apparently the most convenient is a procedure comprising the reaction of perfluoropropene-1,2-oxide with corresponding nucleophiles as an initial step.…”

An Efficient Method for Preparation of Chiral Arylmenthol Glyoxylates

“…Finally, we examined an approach using reduction of alkoxy oxalyl chlorides with tributyltin hydride that has been successfully used to obtain menthyl glyoxylate. 10 As it stands, this approach presents two drawbacks: inefficient separation of the target compound from the tin coproducts, which reduces the yield of the former; and the use of distillation for isolation of the product, ruling out this approach for preparation of glyoxylates with high boiling point or those which are unstable at high temperatures. To circumvent these problems and to improve the efficiency of this approach, we set about modifying it.…”