Tag

Chemistry

All articles tagged with #chemistry

chemistry6 days ago•17 min saved

O-to-C Skeletal Editing Bridges Isoxazoles to Pyrroles in One Pot

Nature reports a one-pot O-to-C skeletal edit that converts isoxazoles into pyrroles via a key N-propargylic enaminone intermediate. The method provides an orthogonal retrosynthetic disconnection to traditional pyrrole syntheses and enables regioselective pyrroles that were previously hard to access, with a predictive computational model describing conformational features governing outcomes. Full data, including crystallography, are in the Supplementary Information and associated deposits.

via Nature|

#chemistry #computational-modeling #isoxazole-chemistry

chemistry6 days ago•37 min saved

Single-Atom Copper Catalyst Enables Reusable, Light-Driven N-Demethylation

A recyclable, noble-metal-free photocatalyst composed of atomically dispersed Cu on functionalized graphitic carbon nitride (Cu@f-gC3N4) enables selective N-demethylation and N-dealkylation of a broad range of tertiary amines under 390 nm light in an O2 atmosphere. The reaction tolerates diverse substrates, including pharmaceutically relevant molecules, and can be scaled to 10 mmol with catalyst reuse exceeding ten cycles. Mechanistic studies (radical trapping, isotope labeling, in situ FTIR, EPR, XANES/EXAFS and DFT) support a photoredox pathway in which amine oxidation generates ammonium-like intermediates, O2 is reduced to superoxide to abstract a methyl hydrogen, forming an iminium that hydrolyzes to the secondary amine; the Cu single-atom sites and the functionalized g-C3N4 support drive charge separation and O2 activation, enabling practical late-stage amine diversification without sacrificial reagents.

via Nature|

#chemistry #copper #graphitic-carbon-nitride

science8 days ago•10 min saved

HCN forms stable mixed crystals with Titan's methane and ethane at frigid temps

Scientists reproduced Titan-like cryogenic conditions and found hydrogen cyanide can form stable mixed solids with methane or ethane, incorporating these nonpolar molecules into an HCN lattice without chemical reaction. Raman spectroscopy and crystal-structure modeling support plausible co-crystal arrangements that could persist near Titan's surface temperatures, a rare solid-state exception to 'like dissolves like'. The result hints at how cryominerals could influence Titan geology and prebiotic chemistry, though it depends on temperature and composition; further work will resolve long-range order and test multicomponent mixtures, with no implication of life but potential impacts on storage and transport of HCN.

via Space Daily|

#chemistry #co-crystal #cryominerals

science16 days ago•6 min saved

Catalyst Frees Electrons to Rewrite Redox Rules in Chemistry

UW–Madison chemists developed a catalyst that ejects electrons directly into solvent, bypassing traditional selectivity in single‑electron transfer and allowing reactions to proceed with molecules that normally wouldn’t receive the electron. Supported by CSU and CU Boulder, the team shows that selectivity can emerge after the electron transfer, potentially unlocking new coupling reactions and expanding redox chemistry, with findings published in Nature.

via ScienceDaily|

#catalysis #chemistry #electron-transfer

science24 days ago•12 min saved

Absinthe myth busted: science finds bans were driven by potent alcohol, not wormwood

A 2008 study of 13 pre‑ban absinthe bottles found thujone and other suspected toxins were not present at levels that would explain past claims of madness; the drink’s high alcohol content (~70% ABV) was the real intoxication factor, with no secret wormwood cure‑all. The widespread bans in the early 20th century were driven more by political and economic pressures and sensationalism than by science, and absinthe has since been reintroduced under regulation.

via Space Daily|

#absinthe #chemistry #prohibition

features1 month ago•120 min saved

Abiogenesis: how life may have begun from nonliving matter

Abiogenesis refers to the emergence of life from nonliving matter through chemical processes. While there is no consensus on exactly how it happened on early Earth, theories include lightning-driven chemistry that could form amino acids and sugars and reactions at deep-sea vents. It’s distinct from the older idea of spontaneous generation, which Louis Pasteur disproved in the 1860s by showing microbes arise from preexisting microbes.

via Live Science|

#abiogenesis #chemistry #evolution

space1 month ago•11 min saved

Twin mystery molecule surfaces on Pluto and Titan confound scientists

New JWST data show an unidentified absorption feature in the spectra of both Titan and Pluto, indicating a shared molecule on their surfaces (not in their atmospheres). Scientists cannot identify it yet; possible candidates include allenes, benzene when mixed with other species, or ketene, with acetylene ice also considered. Further JWST observations are planned to map where the molecule is strongest, and NASA’s Dragonfly mission to Titan could help narrow down the candidate chemicals in the mid‑2030s.

via The Independent|

#chemistry #nasa #pluto

science1 month ago•41 min saved

Cosmic Sugar Detected in Interstellar Space: First Sugar Molecule Found in the Milky Way

Astronomers detected erythrulose, a four-carbon sugar, in a gas cloud near the Milky Way’s center using radio telescopes and spectroscopy, marking the first sugar molecule found in interstellar space and suggesting sugars can form abiotically in space before stars and planets emerge.

via Good News Network|

#astronomy #chemistry #interstellar-space

science1 month ago•2 min saved

Mark Ratner, Pioneer of Molecular Electronics, 1942–2026

Tribute to Mark A. Ratner, a chemist who helped launch nanotechnology and molecular electronics at Northwestern, chaired multiple departments, co-founded the International Institute for Nanotechnology and the Institute for Sustainability and Energy, and proposed that by engineering environmental interactions at the molecular level, molecules could become tunable conductors, bridging chemistry and electrical engineering.

via Nature|

#chemistry #mark-ratner #molecular-electronics

science1 month ago•7 min saved

Inductive Effect Under Review: New Study Promotes a Molecule-Wide View of Electrons

A Newcastle University-led study challenges the long-standing inductive effect model used to explain how electron density shifts within organic molecules. Using modern computational analysis, the researchers argue that this traditional shortcut doesn’t always hold and propose explaining molecular behavior by considering the overall electron distribution across the entire molecule, not long-range inductive transmission. The finding could lead to updated chemistry textbooks and teaching, with implications for education, drug discovery, and materials science, though it does not overturn organic chemistry as a field.

via SciTechDaily|

#chemistry #chemistry-education #electron-distribution

science1 month ago•8 min saved

The enduring craft of total synthesis: Nicolaou reflects on a lifetime of molecules

In a preview interview ahead of his 80th birthday, K. C. Nicolaou reflects on a career that defined modern total synthesis, detailing his approach to assembling complex natural products, the challenges overcome, and the impact of his work on drug discovery and chemical biology, as shared with Stephanie Greed in Nature Reviews Chemistry.

via Nature|

#chemistry #interview #natural-products

science2 months ago•10 min saved

Ligand-guided remote desaturation converts simple aliphatic acids into gamma-lactones

Researchers report a ligand-enabled palladium-catalyzed method that activates distal γ-C(sp3)–H bonds in unbiased aliphatic carboxylic acids (from fatty and cyclic feedstocks) using designed O-allyl amido ester ligands, directly furnishing distal desaturated γ-lactones and double-desaturated γ-spirolactones. Mechanistic data support Pd(II)-mediated γ-C(sp3)–H activation, followed by dehydrogenation and intramolecular cyclization; the approach enables rapid assembly of biologically relevant scaffolds (e.g., muricatacin) from simple acids, offering a streamlined route to complex natural products and pharmaceuticals.

via Nature|

#c-h-activation #catalysis #chemistry

chemistry2 months ago•3 min saved

Sprayed water rewires aniline into pyridine: a green skeletal editing breakthrough

Water microdroplets enable a reagent-free conversion of aniline to pyridine via a rapid skeletal rearrangement at the air–water interface, suggesting a green route to heterocycles. The proposed mechanism starts with hydroxyl-radical initiation, forms a seven-membered lactone, eliminates CO to revert to a six-membered ring, and oxidizes to aromatic pyridine. The team also converted pharmaceutically relevant anilines to niacin, nicotinamide and isoniazid, highlighting green potential while noting scalability and isolated-yield challenges.

via Chemistry World|

#aniline-to-pyridine #chemistry #green-synthesis

science2 months ago•24 min saved

Radical cross-coupling preserves stereochemistry, enabling new chiral building blocks

Baran and coworkers report a nickel-catalyzed alkyl-alkyl cross-coupling that forms a C–C bond between a chiral sulfonylhydrazide radical and an alkyl halide without racemizing the stereocenter, achieved via a diazene-cage mechanism. This unusual radical process preserves enantioenrichment in the product, enabling direct access to chiral motifs like piperidines and pyrrolidines without chiral ligands or directing groups, though the method currently works best with cyclic sulfonylhydrazides and requires further scope expansion.

via Chemical & Engineering News|

#chemistry #nickel-catalysis #organic-synthesis

chemistry2 months ago•12 min saved

Non-covalent chiral assembly enables enantioselective hydrogen-atom transfer

Researchers report a new approach to enantioselective hydrogen-atom transfer by in situ non-covalent self-assembly of chiral phosphoric acids with 2-mercaptopyridines, turning an achiral thiol into a chiral HAT catalyst. This modular assembly steers hydrogen atom abstraction and delivery in a photochemical deracemization of 2-aryl pyrrolidines, expanding the accessible space for asymmetric radical transformations.

via Nature|

#chemistry #deracemization #enantioselective-catalysis