Organocatalytic asymmetric synthesis of oxazolidino spiropyrazolinonesvia N,O-acetalization/aza Michael addition domino reaction betweenN-Boc pyrazolinone ketimines and γ-hydroxyenones

Gil, M. S.; Martin, Laura B.; Maestro, A.; Andrés, José M.

doi:10.1039/d2ob02290g

Cited by 3 publications

(3 citation statements)

References 41 publications

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“…Concurrently, NMP treatment may remove physically adsorbed substances from the coal’s surface or pores, thereby exposing more –COOH groups. The notable increase in carbonyl (CO) groups following NMP treatment can primarily be attributed to the dehydration of –COOH groups into CO . This process typically involves the –OH in the carboxyl reacting with a hydrogen atom on an adjacent carbon atom, releasing a water molecule and thus forming CO.…”

Section: Resultsmentioning

confidence: 99%

“…The notable increase in carbonyl (C=O) groups following NMP treatment can primarily be attributed to the dehydration of –COOH groups into C=O. 48 This process typically involves the –OH in the carboxyl reacting with a hydrogen atom on an adjacent carbon atom, releasing a water molecule and thus forming C=O. This reaction may be facilitated in the presence of NMP, a polar solvent, as it can stabilize intermediate products and help reduce the energy barrier.…”

Section: Resultsmentioning

confidence: 99%

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Impact of N-Methyl-2-pyrrolidone Erosion on Surface Functional Groups and Pore Evolution in Coals of Different Ranks

Lv,

Zhang,

Deng

et al. 2024

ACS Omega

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In low-permeability coal reservoirs, utilizing the organic solvent N-methyl-2-pyrrolidone (NMP) has emerged as an effective approach to improving the coal pore structure and enhancing coalbed methane productivity. However, the exact mechanisms of how solvent erosion alters functional groups and develops pores remain incompletely understood. This study utilized Fourier transform infrared spectroscopy and low-field nuclear magnetic resonance to assess the impact of NMP on the functional groups and pore structures of lignite, bituminous coal, and anthracite. The results indicate that a 6 h treatment with NMP led to an increased proportion of oxygen-containing functional groups in all coal samples, accompanied by a decrease in hydroxyls and aliphatic hydrocarbons. The aromaticity of the coal samples was enhanced to varying degrees, most notably for lignite. In terms of pore modification, the porosity of lignite and bituminous coal increased by 84.82 and 43.56%, while anthracite experienced a porosity increase of 3.04%, indicating a diminished effectiveness of NMP as the coal rank increased. These findings suggest that NMP selectively dissolves specific organic molecules in coals, thereby enhancing pore connectivity and promoting a transition from micro-to meso-and macropores. These findings highlight the potential of NMP in enhancing coalbed methane production and advance our understanding of the mechanisms behind solvent erosion.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Impact of N-Methyl-2-pyrrolidone Erosion on Surface Functional Groups and Pore Evolution in Coals of Different Ranks

Lv,

Zhang,

Deng

et al. 2024

ACS Omega

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“…In 2023, Andrés and co-workers reported the synthesis of chiral oxazolidino spiropyrazolinones 225 containing N , N -acetal moieties by the enantioselective additions of alcohols to pyrazolinone-type ketimines 7b and subsequent intramolecular 1,4-additions of the amines formed in situ from 7b (Scheme 99). 158 This tandem reaction is efficiently catalyzed by quinine-derived bifunctional squaramide 23e to afford 225 in good yields and high enantioselectivities.…”

Section: C(sp3)–n O S and P Bond Formationmentioning

confidence: 99%

Accessing unnatural α-amino acids with tetrasubstituted stereogenic centersviacatalytic enantioselective reactions of ketimine-type α-iminoesters/α-iminoamides

Yasukawa

Nakamura

2023

Chem. Commun.

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Organocatalytic Enantioselective Synthesis of [5.7]-Fused ε-Sultam N,O-Heterocycles via (3 + 2)-Annulation of Seven-Membered Cyclic N-Sulfonylimines with γ-Hydroxy-α,β-Unsaturated Ketones

Du,

Han,

Wang

et al. 2024

J. Org. Chem.

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A highly stereoselective protocol for the (3 + 2)-annulation of biphenyl-bridged seven-membered cyclic Nsulfonylimines with γ-hydroxy-α,β-unsaturated ketones was developed. The reactions afforded a wide range of chiral [5.7]-fused εsultams bearing N-adjacent 1,3-stereocenters in excellent yields (93−98% yields) and high enantio/diastereoselectivities (up to >99% ee, >20:1 d.r.) and two other examples with alkoxyl groups were obtained in 52−61% yields, 95% ee, and >20:1 d.r. by utilizing organocatalysis with quinine-derived squaramides.

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Organocatalytic asymmetric synthesis of oxazolidino spiropyrazolinonesvia N,O-acetalization/aza Michael addition domino reaction betweenN-Boc pyrazolinone ketimines and γ-hydroxyenones

Abstract: A squaramide-catalyzed asymmetric N,O-acetalization/aza Michael addition domino reaction between N-Boc ketimines derived from pyrazolin-5-ones and γ-hydroxyenones has been developed for the construction of pyrazolinone embedded spirooxazolidines. A hydroquinine derived bifunctional...

Cited by 3 publications

References 41 publications

Impact of N-Methyl-2-pyrrolidone Erosion on Surface Functional Groups and Pore Evolution in Coals of Different Ranks

Impact of N-Methyl-2-pyrrolidone Erosion on Surface Functional Groups and Pore Evolution in Coals of Different Ranks

Accessing unnatural α-amino acids with tetrasubstituted stereogenic centersviacatalytic enantioselective reactions of ketimine-type α-iminoesters/α-iminoamides

Organocatalytic Enantioselective Synthesis of [5.7]-Fused ε-Sultam N,O-Heterocycles via (3 + 2)-Annulation of Seven-Membered Cyclic N-Sulfonylimines with γ-Hydroxy-α,β-Unsaturated Ketones

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