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This article provides an overview of recent advancements in quinoline-based macrocycles, which are large ring-shaped compounds with various applications. The focus is on nitrogen-containing macrocycles, such as porphyrins, and their functional properties, including photophysical characteristics, host-guest chemistry, and catalytic reactions. The authors specifically discuss three quinoline-based macrocycles: TriQuinoline (TQ), oxa-TriQuinoline (o-TQ), and TEtraQuinoline (TEQ), examining their structures, synthesis, and properties. The article also explores potential applications of these macrocycles in DNA intercalation, catalytic dehydrogenative oxidation, and gem-difluoroalkenylation reactions. Furthermore, the article delves into the synthesis and properties of tetrameric quinoline macrocycles (TEQ), which have a rigid saddle-shaped structure and can form metal complexes with transition metal cations. The authors also discuss modifications of TEQ and its fluorescence properties. Additionally, the article touches on larger quinoline-based macrocycles with bridges and their synthesis, highlighting their potential applications in organometallic chemistry and supramolecular chemistry. Overall, the chemistry of quinoline macrocycles is an evolving field with opportunities for further research and applications. [Extracted from the article]

A new family of 16‐membered macrocycles comprising two indole (In) and two quinoline (Q) units, coined In2Q2, was synthesized. Each unit is diagonally located and concatenated in a head‐to‐tail fashion, furnishing a non‐flat saddle‐shaped architecture with C2 symmetry. The synthetic protocol utilizing macrocyclic diamide as a pivotal precursor allowed us to access a series of In2Q2 derivatives bearing various substituents on the periphery. The In2Q2 derivatives and their Zn2+ complexes were emissive in both solution phase and solid state. While the entire architecture of In2Q2 is similar to that of quinoline tetramer TEtraQuinoline, a couple of contrasting physicochemical properties were revealed. [ABSTRACT FROM AUTHOR]

A chemoselective dehydrogenation protocol for benzylic amines catalyzed by the TEtraQuinoline (TEQ)/FeCl2 complex is described. In combination with 2 equiv of tert‐butyl hydroperoxide, as little as 0.1 mol% of catalyst loading was sufficient to convert primary and secondary benzylic amines to the corresponding imines and dimerized imines, respectively. Subsequent hydrolysis of the imines allowed for removal of the benzyl group on the nitrogen atom. Nonaromatic carbon‐carbon multiple bonds and the O‐Bn group remained intact in the present protocol, providing a complementary deprotection procedure to reductive removal conditions exerted by Pd catalysis. [ABSTRACT FROM AUTHOR]

A new 15‐membered‐macrocyclic molecular entity, oxa‐TriQuinoline (o‐TQ), was designed and synthesized. In o‐TQ, three oxygen atoms were joined onto three quinoline units at the 2‐ and 8‐positions in a head‐to‐tail fashion by three‐fold SNAr reactions, giving rise to the characteristic N3O3 aza‐oxa‐crown architecture. o‐TQ can serve as a new tridentate nitrogen ligand to capture a CuI cation and adopt a bowl shape, before supramolecular complexation with corannulene and [12]cycloparaphenylene (CPP) occurs through π–π and CH–π interactions. In the presence of the CuI cation, the non‐emissive o‐TQ becomes a highly emissive material in the solid state, whereby the emission wavelengths depend on the ancillary ligand on the CuI cation. The o‐TQ/CuI complex is able to promote carbene catalysis to provide a range of enamines with a gem‐difluorinated terminus. [ABSTRACT FROM AUTHOR]

Patients with secondary adrenal insufficiency can present with impaired free water excretion and hyponatremia, which is due to the enhanced secretion of vasopressin (AVP) despite increased total body water. AVP is produced in magnocellular neurons in the paraventricular nucleus of the hypothalamus (PVH) and supraoptic nucleus and in parvocellular corticotropin-releasing factor (CRF) neurons in the PVH. This study aimed to elucidate whether magnocellular AVP neurons or parvocellular CRF neurons coexpressing AVP are responsible for the pathogenesis of hyponatremia in secondary adrenal insufficiency. The number of CRF neurons expressing copeptin, an AVP gene product, was significantly higher in adrenalectomized AVP -floxed mice (AVP fl/fl) than in sham-operated controls. Adrenalectomized AVP fl/fl mice supplemented with aldosterone showed impaired water diuresis under ad libitum access to water or after acute water loading. They became hyponatremic after acute water loading, and it was revealed under such conditions that aquaporin-2 (AQP2) protein levels were increased in the kidney. Furthermore, translocation of AQP2 to the apical membrane was markedly enhanced in renal collecting duct epithelial cells. Remarkably, all these abnormalities observed in the mouse model for secondary adrenal insufficiency were ameliorated in CRF-AVP −/− mice that lacked AVP in CRF neurons. Our study demonstrates that CRF neurons in the PVH are responsible for the pathogenesis of impaired water excretion in secondary adrenal insufficiency. [ABSTRACT FROM AUTHOR]

The catalytic asymmetric carbon-carbon bond formation is a major focus of modern synthetic organic chemistry. The increasing demand for efficient and environmentally benign processes requires the development of atom-economic asymmetric catalysis in which enantiomerically enriched compounds are produced using unmodified substrates.

Copyright of Synthesis is the property of Georg Thieme Verlag Stuttgart and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A direct catalytic asymmetric addition of acetonitrile to aldehydes that realizes over 90 % ee is the ultimate challenge in alkylnitrile addition chemistry. Herein, we report achieving high enantioselectivity by the strategic use of a sterically demanding NiII pincer carbene complex, which afforded highly enantioenriched β‐hydroxynitriles. This highly atom‐economical process paves the way for exploiting inexpensive acetonitrile as a promising C2 building block in a practical synthetic toolbox for asymmetric catalysis. [ABSTRACT FROM AUTHOR]

A fluorine‐containing tetrasubstituted stereogenic center is a highly valued structural feature in medicinal chemistry. Herein, we describe the direct coupling of racemic α‐fluoronitriles and aldehydes promoted by a chiral CuI/Barton's base catalytic system, delivering α‐tetrasubstituted α‐fluoro‐β‐hydroxynitriles with satisfactory stereoselection. The stereochemical course was positively biased by the combined use of asymmetrical achiral thiourea as a supplementary ligand for CuI, which significantly enhanced the stereoselectivity. Both aromatic and aliphatic aldehydes were implemented to provide densely and stereoselectively functionalized chiral building blocks with aliphatic and aromatic tails. [ABSTRACT FROM AUTHOR]

The synthesis of (2R,3S)‐3,4,4,4‐tetrafluorovaline, a fluorinated derivative of the canonical α‐amino acid l‐valine, is reported for the first time. A highly enantio‐ and diastereoselective direct catalytic asymmetric Mannich‐type reaction was applied as the key C–C bond‐forming step to afford gram quantities of a central synthetic intermediate. The conformation of the novel fluorinated α‐amino acid was analyzed by X‐ray crystallography, NMR spectroscopy, and computational methods, which, together with its calculated and experimental physicochemical properties, indicated that the fluorinated valine is a bioisostere of l‐isoleucine. [ABSTRACT FROM AUTHOR]

A hard Lewis base has affected the reaction efficiency of direct catalytic asymmetric [gamma]-addition of allyl cyanide to ketones promoted by a soft Lewis acid/hard Bronsted base catalyst. The second-generation catalyst has allowed efficient access to highly enantioenriched tertiary alcohols under nearly ideal atom-economical conditions.

Direct catalytic asymmetric aldol reaction of thioamides with a soft Lewis acid/hard Bronsted base cooperative catalytic system comprising (R,R)-Ph-BPE/[Cu[(C[H.sub.3]CN).sub.4]]P[F.sub.6]/LiOAr is described. Facile reduction of the thioamide functionality and a catalyst-controlled second aldol reaction has provided 1,3-diols in a highly stereoselective manner.

Full details of La[(N[O.sub.3]).sub.3]*6[H.sub.2]O- and H-D-Val-[O.sup.t]Bu-promoted catalytic asymmetric amination with a lanthanum/amide-based ligand catalyst system are described. The high catalytic performance and enantiocontrol of the reaction with highly coordinative substrates are observed to be achieved by the activation/recognition of the substrates exerted by coordination to lanthanum and hydrogen bonding cooperatively in the transition state.

anti-Selective catalytic asymmetric nitroaldol reaction promoted by a heterobimetallic catalyst comprised of [Nd.sub.5]O[(O[super i]Pr).sub.13], an amide-based ligand, and NaHMDS (sodium hexamethyldisilazide) are described. Inductively coupled plasma (ICP) and X-ray fluorescence (XRF) analyses have shown that the precipitate has included both neodymium and sodium, which is supported by high-resolution ESI TOF MS spectrometry.

The functional diversification of proteins in response to external stimuli has allowed for an orderly progression of intra- and extracellular events. The features of conformationally flexible asymmetric ligands and the variable coordination patterns of rare earth metals are used for showing the dynamic structural and functional changes of a catalyst in asymmetric catalysis, which has led to two distinct reaction outcomes in a single flask.

The direct catalytic asymmetric addition of allyl cyanide to ketones with a bimetallic catalytic system comprising (R,R)-Ph-BPE/[Cu[(C[H.sub.3]CN).sub.4]]Cl[O.sub.4]/LiOAr is described. The reaction has proceeded under proton-transfer condition by using soft Lewis acid/hard Bronsted base bifunctional catalysis.

A direct catalytic asymmetric addition of allylic cyanides to ketoimines is developed. Facile and divergent conversion of the product has streamlined the synthesis of chiral nitrogen synthons with tetrasubstituted carbon.

The development of a chiral quaternary stereocenter is reported and a dynamic association of the substrate/ligand/metal mixture is exposed to produce a defined transition state assembly.

An efficient asymmetric synthesis of AS-3201 is described by using a catalytic asymmetric amination of succinimide with a newly developed lanthanum-amide complex.

Efficient catalytic activation of acetonitrile as a nucleophile under mild basic conditions with cooperative catalysis of a cationic Ru complex, DBU, and NaPF6 is presented. Soft Lewis acidic metals are used for chemoselective activation of simple alkylnitriles in the presence of carbonyl compounds.

A direct catalytic asymmetric Mannich-type reaction of a hydroxyketone using a Et(sub 2)Zn/linked-BINOL complex is described. Anti- or syn-beta-amino alcohol was obtained in good diastereomeric ratio by selecting appropriate protective clusters on imine nitrogen.

Full details of newly developed catalyses with asymmetric zinc complexes as mimics of class II zinc-containing aldolase are described. The first generation Et(sub 2)-Zn/linked-BINOL 1= 2/1 system was initially developed, which promoted the direct aldol reaction of 2-hydroxy-2'methoxy acetophenone with 1 mol percent ligand loading.

The B3NO2 six‐membered heterocycle (1,3‐dioxa‐5‐aza‐2,4,6‐triborinane=DATB), comprising three different non‐carbon period 2 elements, has been recently demonstrated to be a powerful catalyst for dehydrative condensation of carboxylic acids and amines. The tedious synthesis of DATB, however, has significantly diminished its utility as a catalyst, and thus the inherent chemical properties of the ring system have remained virtually unexplored. Here, a general and facile synthetic strategy that harnesses a pyrimidine‐containing scaffold for the reliable installation of boron atoms is disclosed, giving rise to a series of Pym‐DATBs from inexpensive materials in a modular fashion. The identification of a soluble Pym‐DATB derivative allowed for the investigation of the dynamic nature of the B3NO2 ring system, revealing differential ring‐closing and ‐opening behaviors depending on the medium. Readily accessible Pym‐DATBs proved their utility as efficient catalysts for dehydrative amidation with broad substrate scope and functional‐group tolerance, offering a general and practical catalytic alternative to reagent‐driven amidation. A general and facile synthetic strategy that uses a pyrimidine‐containing scaffold for the reliable installation of boron atoms is disclosed. This strategy gave rise to a series of B3NO2 heterocycles Pym‐DATBs (DATB=1,3‐dioxa‐5‐aza‐2,4,6‐triborinane) from inexpensive materials in a modular fashion. The dynamic nature of the B3NO2 ring system was investigated for a soluble derivative and Pym‐DATBs proved their utility as efficient catalysts for dehydrative amidation. [ABSTRACT FROM AUTHOR]

A new scaffold for producing efficient organic fluorescent materials was identified: 2,5‐diamino‐4,6‐diarylpyrimidine featuring a C4N4 elemental composition. Single‐step installation of two aryl groups at the 4,6‐positions of the pyrimidine core delivered fluorescent organic materials in a modular fashion. A range of fluorescent compounds with distinct absorption/emission properties was readily accessed by changing the aromatic attachments. A generally high absorption coefficient and quantum yield were observed, including C4N4 derivatives that could fluoresce even in the solid state. The two amino groups at the 2,5‐positions of the pyrimidine were essential for intense fluorescence with a large Stokes shift, which was corroborated by structural relaxation to a p‐iminoquinone‐like structure in the excited state. Besides live‐cell imaging capabilities, fluorescent labeling of a protein involved in autophagy elucidated a new protein–protein interaction, supporting potential utility in bioimaging applications. A new scaffold for producing efficient organic fluorescent materials was identified: 2,5‐diamino‐4,6‐pyrimidine featuring a C4N4 elemental composition (see figure). Single‐step installation of two aryl groups at the 4,6‐positions of the pyrimidine core delivered fluorescent organic materials in a modular fashion. [ABSTRACT FROM AUTHOR]

Catalytic asymmetric syntheses of syn aldols with a methyl ketone functionality were studied to confirm the generality of the methodology. In addition, catalytic asymmetric synthesis of anti aldols with a thioamide group was carefully examined, giving the desired products, albeit with moderate diastereoselectivity. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)