Synthesis, Antiproliferative Evaluation, and Structure-Activity Relationships of 3-Arylquinolines

Bioisosteric heterocyclic analogues of natural bioactive flavonoids by scaffold-hopping approaches: State-of-the-art and perspectives in medicinal chemistry

The flavonoid family is a set of well-known bioactive natural molecules, with a wide range of potential therapeutic applications. Despite the promising results obtained in preliminary in vitro/vivo studies, their pharmacokinetic and pharmacodynamic profiles are severely compromised by chemical instability. To address this issue, the scaffold-hopping approach is a promising strategy for the structural optimization of natural leads to discover more potent analogues. In this scenario, this Perspective provides a critical analysis on how the replacement of the chromon-4-one flavonoid core with other bioisosteric nitrogen/sulphur heterocycles might affect the chemical, pharmaceutical and biological properties of the resulting new chemical entities. The investigated derivatives were classified on the basis of their biological activity and potential therapeutic indications. For each session, the target(s), the specific mechanism of action, if available, and the key pharmacophoric moieties were highlighted, as revealed by X-ray crystal structures and in silico structure-based studies. Biological activity data, in vitro/vivo studies, were examined: a particular focus was given on the improvements observed with the new heterocyclic analogues compared to the natural flavonoids. This overview of the scaffold-hopping advantages in flavonoid compounds is of great interest to the medicinal chemistry community to better exploit the vast potential of these natural molecules and to identify new bioactive molecules.

Hydride transfer-initiated synthesis of 3-functionalized quinolines by deconstruction of isoquinoline derivatives

Under transition metal catalyst-free conditions, we herein present a hydride transfer-initiated construction of novel 3-(2-aminomethyl)aryl quinolines from N-isoquinolinium salts and 2-aminobenzaldehydes, proceeding with the merits of operational simplicity, high step and atom efficiency, good substrate and functional group compatibility, and mild conditions. The products are formed by reacting with the isoquinolyl motif as a two-carbon synthon along with the cleavage of its C3-N bond. Given the interesting applications of 3-aryl quinolines, the developed chemistry is anticipated to be further applied to develop new functional products.

Chemistry of 3-hydroxy-2-aryl acrylate: syntheses, mechanisms, and applications

3-Hydroxy-2-aryl acrylate is important scaffold which is widely used for the synthesis of pharmacologically active compounds. This review summarises the synthetic methods of the 3-hydroxy-2-aryl acrylate including mechanisms and applications.

Iodine monobromide catalysed regioselective synthesis of 3-arylquinolines from α-aminoacetophenones and trans-β-nitrostyrenes

A simple and efficient method for regioselective synthesis of 3-arylquinolines is described from α-aminoacetophenones and trans-β-nitrostyrenes using 20 mol% iodine monobromide as a catalyst in acetonitrile solvent at 80 °C.

Ethyl 2-(3-amino-4-hydroxyphenyl)acetate

The asymmetric unit of the title compound, C₁₀H₁₃NO₃, contains two crystallographically independent mol­ecules with different conformations of the eth­oxy­carbonyl groups; the terminal C—C—O—C torsion angles in the two mol­ecules are 83.6 (6) and −171.1 (3)°, resulting in twisted and straight chain conformations, respectively. The crystal structure is stabilized by inter­molecular N—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds. Intra­molecular hydrogen bonds occur between the amino N and phenolic O atoms.

(Z)-Ethyl 2-(4-chloro-phen-yl)-3-[(2,4-difluoro-phen-yl)amino]-prop-2-enoate

In the title compound, C(17)H(14)ClF(2)NO(2), the amino-acrylo-yloxy group makes dihedral angles of 47.55 (11)° with the 4-chloro-phenyl group and 8.74 (12)° with the difluoro-phenyl group; the dihedral angle between the rings is 52.32 (11)°. The structure of the title compound reveals a Z configuration with respect to the C=C double bond in the amino-acrylate fragment. A bifurcated intramolecular N-H⋯(O,F) hydrogen bond occurs. In the crystal, molecules are linked into chains by C-H⋯O hydrogen bonds.

(Z)-Ethyl 3-(2,4-difluoro-anilino)-2-(4-methoxy-phen-yl)acrylate

The title compound, C₁₈H₁₇F₂NO₃, consists of three individually planar subunits, namely two benzene rings and one amino­acrylate group. The amino­acrylate group forms dihedral angles of 5.92 (7) and 50.21 (6)° with the difluoro and methoxy benzene rings, respectively. The dihedral angle between the two benzene rings is 55.25 (7)°. The mol­ecules exhibit intra­molecular N—H⋯O and N—H⋯F inter­actions and form a three-dimensional network via inter­molecular C—H⋯O and C—H⋯π hydrogen bonds.

Bis(1,2,3,4-tetra-hydro-quinolin-6-yl)methane

The asymmetric unit of the title compound, C(19)H(22)N(2), contains one half-mol-ecule. The 1,2,3,4-tetra-hydro-quinoline units are linked by a methyl-ene bridge, which lies on a twofold rotation axis. The non-aromatic ring adopts a flattened-boat conformation. The dihedral angle between the two symmetry-related benzene rings is 64.03 (7)°.