Results 181 to 190 of about 20,067 (277)

Pharmaceuticals Made with Hydrogen: A Sustainable and Efficient Approach Using Flow Synthesis

Chemistry – A European Journal, Volume 32, Issue 28, 25 July 2026.
We demonstrate a sustainable strategy for pharmaceutical manufacturing by combining hydrogen, heterogeneous catalysis, and continuous flow synthesis. The development of novel catalysts and their application in a multi‐step synthesis of donepezil enabled a highly productive process with no intermediate purification.
Shū Kobayashi, Haruro Ishitani
wiley   +1 more source

Anisotropic NMR as a Crucial Tool for Differentiation of Epimers With High Conformational Flexibility

Angewandte Chemie, Volume 138, Issue 30, 20 July 2026.
Epimer discrimination remains challenging due to subtle NMR differences. Here, we propose a methodology based on 13C‐RCSA and RDC anisotropic parameters, enabling the assignment of two flexible tetraprenyltoluquinol epimers (1a and 1b) with remote stereoclusters.
Juan Carlos C. Fuentes‐Monteverde, Abel M. Forero, Nilamoni Nath, Antonio Hernández Daranas, Carlos Jiménez, Jaime Rodríguez, Christian Griesinger   +6 more
wiley   +2 more sources

An HPLC-MS-Based Method for Determination of the D- and L- 5-Methyltetrahydrofolate Isomer Ratio in Dietary Supplements. [PDF]

J AOAC Int
Wang X, Pandey D, Vavilala S, Oh L, Gusev P, Andrews KW, Pehrsson P, Harnly JM, Sun J.   +8 more
europepmc   +1 more source

Dilithium Enediamide Derived From 1,4‐Diaza‐1,3‐Diene: An Electron Reservoir Enabling Variable Reactivity Toward Carbonyl Compounds

European Journal of Inorganic Chemistry, Volume 29, Issue 21, 25 July 2026.
Upon reduction of 1,4‐diaza‐1,3‐diene 1 to the dilithium enediamide 2, the polarity of the C = N bonds is reversed ‐ a classic case of umpolung. This behavior is particularly evident in reactions of the dianion 2 with carbonyl compounds and also explains why 1,4‐diaza‐1,3‐diene ligands do not always act merely as spectator ligands. 1,4‐Diaza‐1,3‐dienes
Muhan Liang, Michael Kunze, Helmar Görls, Joachim Scholz   +3 more
wiley   +1 more source

Catalytic Enantioselective Intramolecular Aza‐Michael Addition to α,β‐Unsaturated Esters

Angewandte Chemie, Volume 138, Issue 30, 20 July 2026.
A general method for accessing enantioenriched saturated N‐heterocycles via a catalytic enantioselective intramolecular aza‐Michael reaction to α,β‐unsaturated esters is described. A superbasic bifunctional iminophosphorane (BIMP) catalyst was key to enabling reactivity of the high pKa sulfonamide pronucleophile, whilst delivering good to excellent ...
Evan G. W. Rutter, Cameron J. MacRae, Haoran Xiong, Daniel Rozsar, Katherine F. P. Clarke, Darren J. Dixon   +5 more
wiley   +2 more sources

Enantiopure Pyridinium Bisretinoids of Ocular Lipofuscin with Hexahydrobenzofuran Structure: Total Synthesis and Structure-Dependent Aggregated Morphology. [PDF]

J Org Chem
Vidal B, Rodríguez R, Peña-Gallego A, Álvarez R, Martínez C, de Lera ÁR.   +5 more
europepmc   +1 more source

Diaryl Thiourea Catalysts Promote the Formation of Propargyl Enol Ethers in the Claisen Rearrangement Sequence

European Journal of Organic Chemistry, Volume 29, Issue 28, 25 July 2026.
The allenyl ketone products of an enol ether formation–propargyl Claisen rearrangement sequence are susceptible to acid‐catalyzed isomerization to yield the corresponding conjugated dienones. A diaryl thiourea catalyst was found to promote the desired reaction sequence while suppressing the competing isomerization.
Veera K. Bruce‐Salmenkivi, Kaveh Farshadfar, Kari Laasonen, Petri M. Pihko   +3 more
wiley   +1 more source

Enhanced Stereochemical Analysis of β‑Diastereomeric Amino Acids with Variants of Marfey's Reagent. [PDF]

ACS Omega
Studinski CI, Powers MK, Martin BK, Mosconi AL, Abraham JA, Koss KR, Bruffy SK, Campbell ME, Buller AR, Willoughby PH.   +9 more
europepmc   +1 more source

Epoxidation of Cashmeran and Unprecedented Rearrangement to an α‐Carbonyl δ‐Spirolactone

European Journal of Organic Chemistry, Volume 29, Issue 28, 25 July 2026.
A new strategy enables diastereoselective conversion of Cashmeran into a previously unknown α‐carbonyl δ‐spirolactone via epoxidation, Baeyer–Villiger oxidation, and acid‐catalyzed rearrangement. Structure and mechanism were confirmed by NMR, single crystal X‐ray diffraction, and computational studies. We report the epoxidation of Cashmeran followed by
Lukas Kell, Niklas Bartsch, Johannes Panten, Marcus Eh, Jan Paradies, Hans Egold, Anke Spannenberg, Thomas Werner   +7 more
wiley   +1 more source