Generation of o-quinodimethanes (o-QDMs) from benzo[c]oxepines and the synthetic application for polysubstituted tetrahydronaphthalenes

Synthesis of 6-oxa-Spiro[4.5]decane Derivatives by Merging Ring-Opening of Benzo[c]oxepines and Formal 1,2-Oxygen Migration

A facile one-pot synthetic method has been developed for constructing 6-oxa-spiro[4.5]decane skeletons by merging the ring-opening of benzo[c]oxepines and formal 1,2-oxygen migration reactions. More than 30 examples of the 6-oxa-spiro[4.5]decane derivatives have been synthesized under transition-metal-free conditions.

Indane-1,3-Dione: From Synthetic Strategies to Applications

Indane-1,3-dione is a versatile building block used in numerous applications ranging from biosensing, bioactivity, bioimaging to electronics or photopolymerization. In this review, an overview of the different chemical reactions enabling access to this scaffold but also to the most common derivatives of indane-1,3-dione are presented. Parallel to this, the different applications in which indane-1,3-dione-based structures have been used are also presented, evidencing the versatility of this structure.

Synthesis of Long-Term Stable Gold Nanoparticles Benefiting from Red Raspberry (Rubus idaeus), Strawberry (Fragaria ananassa), and Blackberry (Rubus fruticosus) Extracts-Gold Ion Complexation and Investigation of Reaction Conditions

We report synthesis of monodispersed, stable, and colloidal gold nanoparticles (Au NPs) using anthocyanin-riched red raspberry (Rubus idaeus), strawberry (Fragaria ananassa), and blackberry (Rubus fruticosus) extracts as functions of concentration of HAuCl₄·3H₂O and berries extract, reaction time, and reaction pH values (pHs) and demonstrate their unique stability in highly concentrated salt (sodium chloride, NaCl) solutions. The catecholamine group of anthocyanin molecules give preferential coordination reaction with gold ions (Au³⁺) for creating anthocyanin-Au³⁺ complexes, which may lead to initiation of nucleation for seed formation, and then, oxidation of catecholamine results in a flow of electrons from anthocyanins to Au seeds for anisotropic growth. Finally, the surface of the Au NPs is saturated with anthocyanins, and formation of monodispersed and stable Au NPs with narrow size distribution is completed. We also report the effects of some experimental parameters including concentrations of Au³⁺ ions and barrier extracts, reaction time, and pHs on formation of the Au NPs with rational explanations. The long-term colloidal stability of the Au NPs in the 400 mM NaCl solution was comparatively studied with commercial Au NPs (citrate capped). As results show that anthocyanin-riched berry extracts directed Au NPs we proposed here can be considered as promising and safe tools for biomedical applications owing to their highly much colloidal dispersibility and salt tolerance properties.

Novel diastereoisomers of C21H20O3 obtained from the cathodic reduction of methyl (2E)-3-[2-(2-{2-[(1E)-3-methoxy-3-oxoprop-1-en-1-yl]phenyl}ethyl)phenyl]prop-2-enoate

The diastereoisomeric title compounds, 5 and 6, were obtained as a result of intramolecular electrohydrocyclisation of methyl (2E)-3-[2-(2-{2-[(1E)-3-methoxy-3-oxoprop-1-en-1-yl]phenyl}ethyl)phenyl]prop-2-enoate. The common feature of the molecular structures is the presence of a central, eight-membered, –C(H)–C(H)–CC–(CH2)2–CC, ring appended to a cyclopentenyl and two phenyl rings. This study represents an unprecedented structural characterisation of such an atomic/bonding arrangement. The distinctive feature of the structures relates to the conformation of the central rings, i.e. approximating a boat in 5 and a chair in 6. This difference in molecular conformations arises from the different configurations at the methine-C atoms of the cyclopentenyl ring, i.e. R- and S- (or S- and R-) in 5 as opposed to R- and R- (or S- and S-) in 6. In each case, the hydroxyl-OH forms an intramolecular hydrogen-bond to the adjacent carbonyl-O atom so the molecular packing in each of 5 and 6 is sustained by non-conventional interactions. A three-dimensional architecture in 5 arises from a combination of phenyl-C–H…O(carbonyl) and methyl- and methylene-C–H…π contacts. In the crystal of 6, supramolecular chains with a zig-zag topology along the c-axis are formed via methyl-C–H…O(hydroxyl); the chains pack with no directional interactions between them.