Recent synthetic strategies for the functionalization of fused bicyclic heteroaromatics using organo-Li, -Mg and -Zn reagents.

This review highlights the use of functionalized organo-Li, -Mg and -Zn reagents for the construction and selective functionalization of 5- and 6-membered fused bicyclic heteroaromatics. Special attention is given to the discussion of advanced syntheses for the preparation of highly functionalized heteroaromatic scaffolds, including quinolines, naphthyridines, indoles, benzofurans, benzothiophenes, benzoxazoles, benzothiazoles, benzopyrimidines, anthranils, thienothiophenes, purine coumarins, chromones, quinolones and phthalazines and their fused heterocyclic derivatives. The organometallic reagents used for the desired functionalizations of these scaffolds are generally prepared using the following methods: (i) through directed selective metalation reactions (DoM), (ii) by means of halogen/metal exchange reactions, (iii) through oxidative metal insertions (Li, Mg, Zn), and (iv) by transmetalation reactions (organo-Li and Mg transmetalations with ZnCl or ZnO(Piv)).

A Review on Functionalization of Benzo-5,6-Fused Bicyclic Heteroaromatic Compounds.

Over the decades, functionalized heteroaromatic compounds and their scaffolds have drawn significant attention in synthetic organic chemistry as well as in interdisciplinary sciences due to their prevalence in natural products, hormones, vitamins, and their applications in pharmaceuticals, agrochemicals, veterinary products, dyes and pigments, bio-imaging, semiconductors, and optoelectronics, etc. This review explores various synthetic strategies for functionalization of numerous 5,6 benzo-fused heteroaromatic derivatives such as indole, benzofuran, benzothiophene, benzimidazole, benzoxazole, benzothiazole and benzotriazole through various methods including C-H activation, cross-coupling, metal catalysis, photo-catalysis, electrocatalysis and organocatalysis in recent years (2019-2023). Highly functionalized heterocyclic scaffolds are the important precursors for synthesizing many bioactive drugs like fenbendazole, viozan, griseofulvin, zileuton, flunoxaprofen, natural products, and optoelectronic materials, etc.

Metal-free efficient synthesis of aryl sulfonamides from -hydroxy sulfonamide and amines.

A simple and novel approach has been developed for the synthesis of sulfonamides from -hydroxy sulfonamide. Notably, the iodine--butyl hydroperoxide (TBHP) system efficiently promoted the sulfonylation reactions of -hydroxy sulfonamides and amines the oxidative cleavage of an S-N bond. A variety of aryl sulfonamides were prepared in moderate to good yields using readily available starting materials and the biomass-derived 2-MeTHF solvent.

Metal-free oxidative coupling of aryl acetylene with elemental sulphur and amines: facile access to α-ketothioamides.

A simple and efficient oxidative coupling of aromatic alkynes with elemental sulphur and secondary amines has been reported. The iodine/DMSO system easily promoted the transformations, affording thioglyoxamides C-S, C-O, and C-N bond formations. In this context, acetylenic C-H bond oxidation has occurred through iodination, leading to the desired products.

Recent synthetic strategies for the construction of functionalized carbazoles and their heterocyclic motifs enabled by Lewis acids.

This article demonstrates recent innovative cascade annulation methods for preparing functionalized carbazoles and their related polyaromatic heterocyclic compounds enabled by Lewis acid catalysts. Highly substituted carbazole scaffolds were synthesized Lewis acid mediated Friedel-Crafts arylation, electrocyclization, intramolecular cyclization, cycloaddition, C-N bond-formations, aromatization and cascade domino reactions, metal-catalyzed, iodine catalyzed reactions and multi-component reactions. This review article mainly focuses on Lewis acid-mediated recent synthetic methods to access a variety of electron-rich and electron-poor functional groups substituted carbazole frameworks in one-pot reactions.

Synthetic Strategies of N-Heterocyclic Olefin (NHOs) and Their Recent Application of Organocatalytic Reactions and Beyond.

N-heterocyclic olefin (NHO) derivatives have an electron-rich as well as highly polarized carabon-carbon (C=C) double bond because of the electron-donating nature of nitrogen and sulphur atoms. While NHOs have been developing as novel organocatalysts and ligands for transition-metal complexes in various organic compound syntheses, different research groups are currently interested in preparing imidazole and triazolium-based chiral NHO catalysts. Some of them have been used for enantioselective organic transformations, but were still elusive.

Recent Advances in the Practical Synthesis of C1 Deuterated Aromatic Aldehydes Enabled by Catalysis and Beyond.

C -selective deuteration of aromatic aldehydes is of great importance for isotopic labeling and for improving the characteristics of drug molecules. Due to the recent increase in the use of deuterated pharmacological drugs, there is a pressing need for synthetic procedures that are efficient to produce deuterated aromatic aldehyde analouges. Deuterium labeling approaches are typically used as an effective tool for researching pharmaceutical absorption, distribution, metabolism, and excretion (ADME).

-Heterocyclic Carbene Triazolium Salts Containing Brominated Aromatic Motifs: Features and Synthetic Protocol.

In this work, we provide a brief overview of the role of -aryl substituents on triazolium -heterocyclic carbene (NHC) catalysis. This synopsis provides context for the disclosed synthetic protocol for new chiral -heterocyclic carbene (NHC) triazolium salts with brominated aromatic motifs. Incorporating brominated aryl rings into NHC structures is challenging, probably due to the substantial steric and electronic influence these substituents exert throughout the synthetic protocol.

Unravelling mechanistic features of organocatalysis with in situ modifications at the secondary sphere.

Secondary-sphere interactions serve a fundamental role in controlling the reactivity and selectivity of organometallic and enzymatic catalysts. However, there is a dearth of studies that explicitly incorporate secondary-sphere modifiers into organocatalytic systems. In this work, we introduce an approach for the in situ systematic modification of organocatalysts in their secondary sphere through dynamic covalent binding under the reaction conditions.

Polyfunctional Lithium, Magnesium, and Zinc Alkenyl Reagents as Building Blocks for the Synthesis of Complex Heterocycles.

New conjunctive β-silylated organometallic reagents of Li, Mg, and Zn have been prepared and used for an expeditive construction of various polyfunctionalized 5-, 6-, and 7-membered heterocycles, such as furans, pyrroles, quinolines, benzo[b]thieno-[2,3-b]pyridine, naphthyridines, fused pyrazoles, and 2,3-dihydro-benzo[c]azepines. The latent silyl group has been converted into various carbon-carbon bonds in most heterocycle types.

Synthesis of polyfunctional secondary amines by the addition of functionalized zinc reagents to nitrosoarenes.

Addition of functionalized aryl, heteroaryl or adamantyl zinc reagents to various nitroso-arenes in the presence of magnesium salts and LiCl in THF produces after a reductive work-up with FeCl2 and NaBH4 in ethanol the corresponding polyfunctional secondary amines in high yields.

Synthesis of substituted adamantylzinc reagents using a Mg-insertion in the presence of ZnClâ‚‚ and further functionalizations.

The LiCl-mediated Mg-insertion in the presence of ZnCl2 allows an efficient synthesis of adamantylzinc reagents starting from the corresponding functionalized tertiary bromides. The highly reactive adamantylzinc species readily undergo a broad variety of functionalizations such as Negishi cross-couplings, Cu(I)-catalyzed acylations and allylations, and 1,4-addition reactions leading to the expected products in excellent yields. Furthermore, the adamantyl moiety could be introduced as α-substituent in terthiophene, increasing its solubility due to the higher lipophilicity and the prevention of π-stacking.

Double refraction of a Gaussian beam into a uniaxial crystal.

For a linearly polarized three-dimensional Gaussian beam in air that is normally incident upon a plane interface with a uniaxial crystal with optic axis in an arbitrary direction, we present integral representations for the transmitted field suitable for asymptotic analysis and efficient numerical evaluation and derive analytical expressions for transmitted nontruncated Gaussian beams for the cases in which the incident beam is polarized parallel to the plane containing the optic axis and the interface normal and transverse to it. The general solution for an arbitrary polarization state of an incident Gaussian beam follows by superposition of these two solutions.

7-Phenyl-sulfonyl-7H-benzofurano[2,3-b]carbazole.

In the title compound, C(24)H(15)NO(3)S, the dihedral angle between the phenyl ring and the carbozole system is 74.91 (6)°. The S atom exhibits a distorted tetra-hedral geometry [N-S-C = 104.

7H-1-Benzofuro[2,3-b]carbazole.

In the title compound, C(18)H(11)NO, the carbazole and benzofuran rings are almost co-planar, making a dihedral angle of 3.31 (3)°. The crystal structure is stabilized by weak C-H⋯π inter-actions.

Synthesis of 2-substituted 17β-hydroxy/17-methylene estratrienes and their in vitro cytotoxicity in human cancer cell cultures.

Synthesis of various types of 2-(alkylaminomethyl) and 2-(aroyl) 17β-estradiol analogs are reported. The synthesis of similar types of 2-substituted 17-methylene estratriene analogs was also achieved. Synthesis of chalcone derivatives of 17β-estradiol and 17-methylene estratriene were also realized.

Diethyl 2-{[3-(2-meth-oxy-benz-yl)thio-phen-2-yl]methyl-idene}malonate.

In the title compound, C(20)H(22)O(5)S, the dihedral angle between the mean planes through the thio-phene and benzene rings is 75.2 (1)°. The meth-oxy group is essentially coplanar with the benzene ring, the largest deviation from the mean plane being 0.

Ethyl 3-[2-(3,4-dimeth-oxy-benz-yl)-1-phenyl-sulfonyl-1H-indol-3-yl]acrylate chloro-form hemisolvate.

In the title compound, C(28)H(27)NO(6)S·0.5CHCl(3), the ethyl acrylate substituent adopts an extented conformation with all torsion angles close to 180°. The chloro-form solvent mol-ecule is disordered across an inversion centre and is therefore half occupied.

5-Methyl-phenanthro[2,3-b]thio-phene.

The title compound, C(17)H(12)S, which crystallises with two molecules in the asymmetric unit, features four fused rings forming an essentially planar mol-ecule, with maximum deviations from the mean plane of 0.078 (2) and 0.080 (2) Å for C atoms of the thio-phene and phenanthrene groups in both the mol-ecules.

Phen-yl(3-methyl-1-phenyl-sulfonyl-1H-indol-2-yl)methanone.

In the title compound, C(22)H(17)NO(3)S, the N atom of the indole ring system deviates by 0.031 (3) Å from a least-squares plane fitted through all nine non-H ring atoms. The geometry around the S atom can be described as distorted tetra-hedral.

Phen-yl(1-phenyl-sulfonyl-1H-indol-2-yl)methanone.

The asymmetric unit of the title compound, C(21)H(15)NO(3)S, contains two crystallographically independent mol-ecules. As a result of the electron-withdrawing character of the phenyl-sulfonyl groups, the N-Csp(2) bond lengths are slightly longer than the anti-cipated value of approximately 1.35 Å for N atoms with planar configurations.

(1-Phenyl-sulfonyl-1H-indol-2-yl)(thio-phen-2-yl)methanone.

The crystal studied of the title compound, C(19)H(13)NO(3)S(2), was found to be a non-merohedral twin with a domain ratio of 0.877 (3):0.123 (3).

7-Phenyl-sulfonyl-2,3-dihydro-7H-1,4-benzodioxino[6,7-b]carbazole.

In the title compound, C(24)H(17)NO(4)S, the phenyl ring makes a dihedral angle of 88.12 (5)° with the carbazole unit. The mol-ecular structure is stabilized by weak intra-molecular C-H⋯O inter-actions and the crystal packing exhibits weak inter-molecular C-H⋯O and C-H⋯π inter-actions.

(4-Bromo-phen-yl)(1-phenyl-sulfonyl-1H-indol-2-yl)methanone.

In the title compound, C(21)H(14)BrNO(3)S, the indole ring system forms dihedral angles of 65.64 (8) and 59.30 (8)°, respectively, with the phenyl and bromo-phenyl rings.

(Phen-yl)(1-phenyl-sulfonyl-1H-indol-3-yl)methanone.

In the title compound, C(21)H(15)NO(3)S, the sulfonyl-bound phenyl ring forms a dihedral angle of 86.28 (5)° with the indole ring system. The mol-ecular structure is stabilized by intra-molecular C-H⋯O hydrogen bonds.