Structural, analytical and DSC references to resolution of 2-methoxy-2-phenylacetic acid with chiral 1-cyclohexylethylamines through gas-antisolvent precipitation

Zodge, Amit; Bombicz, Petra; Székely, Edit; Pokol, György; Madarász, János

doi:10.1016/j.tca.2016.11.017

Cited by 3 publications

(3 citation statements)

References 32 publications

(32 reference statements)

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“…In overall, the thermal (DSC, TG/DTA‐EGA‐MS and TG‐EGA‐FTIR), analytical (FTIR) and structural (XRD, indexing) comparisons 55–57 indicate, in overall, that the key‐intermediate crystalline diastereomeric salts—as solvates and co‐crystals—inherit a kind of structural similarity from their related additives—solvents (DMF, DMAA, and DMSO) or (thio)ureas, respectively 58…”

Section: Resultsmentioning

confidence: 96%

“…In overall, the thermal (DSC, TG/DTA-EGA-MS and TG-EGA-FTIR), analytical (FTIR) and structural (XRD, indexing) comparisons [55][56][57] indicate, in overall, that the key-intermediate crystalline diastereomeric salts-as solvates and co-crystals-inherit a kind of structural similarity from their related additivessolvents (DMF, DMAA, and DMSO) or (thio)ureas, respectively. 58 If we compare the results of our reproduction experiments with those obtained with thiourea and mixtures of thiourea and urea, we can conclude that the result of the solvate salt obtained from the solvent DMA (F: 0.41) was obtained with the use of thiourea, but even with the mixture of ureas improved (F: 0.53).…”

Section: Crystallographic Unit Cell Parametersmentioning

confidence: 99%

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Enantiomeric separation of racemic amlodipine by sequential fractional crystallization through formation of diastereomeric salt solvates and co‐crystals of solvate‐like compounds with specific structure — A tandem resolution

et al. 2021

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A new resolution method of racemic amlodipine has been developed. The racemic compound is reacted in a suitable solvent with 0.25-mol equivalent of (R,R)-tartaric acid. After the decomposition of the diastereomeric salt, the remaining racemic fraction is precipitated with half-equivalent of fumaric acid, and the pure amlodipine enantiomer is obtained. A quarter equivalent of the same resolving agent, (R,R)-tartaric acid has been also added to the mother liquor to obtain the other enantiomer. The advantage of this method is that both of the enantiomers of amlodipine could be obtained with high enantiomeric excess with the same resolving agent. The racemic excess can also be isolated and re-resolved. Achiral reagents (urea and thiourea) have been added to the resolving agent. These neutral additives are incorporated as co-crystals in the structure of the diastereomeric salts. The used solvate-former solvents and achiral additives are structurally similar, and their presence can enable the fractional separation of the diastereomers. In addition, the racemate, the enantiomers, and some intermediate salts with high diastereomeric excess obtained in the resolution process of amlodipine have been also subjected to thermal (DSC, TG/DTA-EGA-MS, and -FTIR), analytical (FTIR spectroscopic), and structural (XRD) comparisons, which indicate that the key-intermediate crystalline diastereomeric salts-as solvates and co-crystals-inherit a kind of structural similarity from their related additives-solvents (DMF, DMAA, and DMSO) or (thio)ureas, respectively.

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Section: Resultsmentioning

confidence: 96%

Section: Crystallographic Unit Cell Parametersmentioning

confidence: 99%

Enantiomeric separation of racemic amlodipine by sequential fractional crystallization through formation of diastereomeric salt solvates and co‐crystals of solvate‐like compounds with specific structure — A tandem resolution

et al. 2021

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“…Nonetheless, the most unambigous evidence for the existence of the double salt is when one has its crystal structure in hand. Racemic 1-cyclohexylethylamine can be successfully resolved with mandelic acid 9 , O-methylmandelic acid with 1cyclohexylethylamine 10 and para-chloromandelic acid with phenylethylamine 11,12 . Therefore, it could be presumed that 1cyclohexylethylamine would be a suitable resolving agent for the optical resolutions of 2-and 4-chloromandelic acids.…”

Section: Introductionmentioning

confidence: 99%

A bug in enantiomer separation: double salt formation – diastereomeric and double salt structures of 1-cyclohexylethylammonium 2- and 4-chloromandelate

et al. 2021

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Direct Synthesis of α-Methoxyphenylacetic Acid Via Tandem Catalysis from Styrene and Methanol with Co3O4/CuCo2O4 Heterostructures

Liu

Jian

2022

Catal Lett

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Structural, analytical and DSC references to resolution of 2-methoxy-2-phenylacetic acid with chiral 1-cyclohexylethylamines through gas-antisolvent precipitation

Cited by 3 publications

References 32 publications

Enantiomeric separation of racemic amlodipine by sequential fractional crystallization through formation of diastereomeric salt solvates and co‐crystals of solvate‐like compounds with specific structure — A tandem resolution

Enantiomeric separation of racemic amlodipine by sequential fractional crystallization through formation of diastereomeric salt solvates and co‐crystals of solvate‐like compounds with specific structure — A tandem resolution

A bug in enantiomer separation: double salt formation – diastereomeric and double salt structures of 1-cyclohexylethylammonium 2- and 4-chloromandelate

Direct Synthesis of α-Methoxyphenylacetic Acid Via Tandem Catalysis from Styrene and Methanol with Co3O4/CuCo2O4 Heterostructures

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