Qing-Gang Tang

Bio: Qing-Gang Tang is an academic researcher from Nanjing Tech University. The author has contributed to research in topics: Hydrogen bond & Enantioselective synthesis. The author has an hindex of 2, co-authored 2 publications receiving 23 citations.

Methyl 2‐amino‐4‐(3‐fluoro­phen­yl)‐4H‐benzo[h]chromene‐3‐carboxyl­ate methanol solvate

Abstract: The title compound, C21H16FNO3·CH3OH, was synthesized by the reaction of 1-naphthol with methyl cyano­acetate and 3-fluoro­benzaldehyde in methanol under microwave irradiation. The pyran rings of the two independent mol­ecules in the asymmetric unit adopt boat conformations. The crystal packing is stabilized by inter­molecular N—H⋯O, O—H⋯O and C—H⋯π inter­actions.

3,3′‐(4‐Chloro­phenyl­methanedi­yl)bis­(5‐meth­oxy‐1H‐indole)

Abstract: The title compound, C25H21BrN2O2, was synthesized by the reaction of 5-meth­oxy-1H-indole and 4-bromo­benzaldehyde in ethanol, using CuBr2 as a catalyst under microwave irradiation. In the crystal structure, there is an inter­molecular N—H⋯O hydrogen bond and two inter­molecular C—H⋯π contacts.

Asymmetric synthesis of chiral 1,2-oxazinane and hexahydropyridazin spirocyclic scaffolds by organocatalytic [4 + 2] cycloaddition

Abstract: A novel approach to synthesize chiral 1,2-oxazinane spirocyclic scaffolds by organocatalytic [4 + 2] cycloaddition reaction between methyleneindolinones and γ-aminooxy-α,β-unsaturated ester has been disclosed. Furthermore, a hydrazide 1,4-synthon is designed and synthesized to construct chiral hexahydropyridazin spirocyclic scaffolds with methyleneindolinones via [4 + 2] cycloaddition reaction. Both reactions give corresponding products in good to excellent yield, excellent diastereoselectivity and good enantioselectivity.

Design, synthesis, molecular docking, and biological evaluation of N -methyl-3-nitro-4-(nitromethyl)-4 H -chromen-2-amine derivatives as potential anti-cancer agents

Abstract: A series of N-methyl-3-nitro-4-(nitromethyl)-4H-chromen-2-amine derivatives 8 were synthesized from 2-((E)-2-nitrovinyl)phenol 7 and ((E)-N-methyl)-1-(methylthio)-2-nitroethenamine 5. The cytotoxic activity of these molecules was tested against two cancer cell lines namely HeLa (cervical cancer) and HEp-2 (epidermoid laryngeal carcinoma). Among them, two molecules (4H-chromenes 8h and 8i) displayed potent anti-proliferative activity with IC50 values of 115.04 and 18.96 μM for HeLa and 86.94 and 25.08 μM for Hep-2 cell lines, respectively. Morphological evaluation of the cell lines revealed that both 8h and 8i induce the apoptotic process. Molecular docking studies of all the 4H-chromenes 8 with anti-apoptotic Bcl-2, Bcl-w, and Bcl-xL proteins revealed that the 4H-chromenes 8h and 8i have good docking score and thus corroborated in vitro studies. Furthermore, evaluation of Lipinski and ADMET properties revealed their drug-like pharmacokinetic profiles. Thus, 4H-chromenes 8h and 8i exhibit promising anti-cancer properties and can be used as lead compounds for further development.

Design, synthesis, in vitro and in silico anti-cancer activity of 4H-chromenes with C4-active methine groups

Abstract: A combinatorial library of eighteen C4-active methine-substituted 4H-chromenes were synthesized, and their anti-cancer properties were evaluated against four human cancer cell lines, namely laryngeal carcinoma (Hep2), lung adenocarcinoma (A549), colon carcinoma (HT-29) and cervical cancer (HeLa). Out of them, six displayed significant anti-proliferative activity. The best among them, the 4H-chromene with C4-malononitrile substitution, was selected for further structure–activity relationship studies. Six analogues were synthesized and subjected to in vitro studies on above four cancer cell lines. The best among them was subjected to detail in silico studies by binding with Bcl-2 protein, and the results corroborated those obtained from in vitro studies. Our findings show that the C4-malononitrile and C2-N-phenyl-substituted 4H-chromene are the most promising lead molecules for treatment of cancer.

Dimethyl 2,2′-[(4-oxo-2-phenyl-4H-chromene-5,7-diyl)dioxy]diacetate: a more densely packed polymorph

Abstract: The title mol­ecule, C21H18O8, crystallizes in two crystal polymorphs, see also Nallasivam, Nethaji, Vembu & Jaswant [Acta Cryst. (2009), E65, o314–o315]. The mol­ecules of both polymorphs differ by the conformation of the oxomethyl­acetate groups. The title mol­ecules are rather planar compared to the mol­ecules of the other polymorph. In the title mol­ecule, one of the oxomethyl­acetate groups is disordered (occupancies of 0.6058/0.3942). The structures of both polymorphs are stabilized by C—H⋯O and C—H⋯π inter­actions. Due to the planarity of the title mol­ecules and similar inter­molecular inter­actions, the title mol­ecules are more densely packed than those of the other polymorph.

2-Methyl-4-(naphthalen-2-yl)-3a-nitro-3,3a,4,9b-tetra-hydro-2H-spiro-[chromeno[3,4-c]pyrrole-1,3'-indolin]-2'-one.

Abstract: In the title compound, C29H23N3O4, the 2-methylpyrrolidine ring adopts a twist conformation on the N—C bond involving the spiro C atom, while the hydropyran ring adopts an envelope conformation with the methine C atom bonded to the O atom as the flap. The mean plane of the indoline-2-one ring system is almost perpendicular to the mean plane of the pyrrolidine ring, making a dihedral angle of 89.73 (8)°. The latter ring makes dihedral angles of 47.80 (8) with the naphthalene ring system and 32.38 (8)° with the hydropyran ring mean plane. There is an intra­molecular C-H⋯O hydrogen bond involving the indoline-2-one O atom. In the crystal, adjacent mol­ecules are linked via N—H⋯O hydrogen bonds, forming chains propagating along [100]. The chains are linked via weak C—H⋯O hydrogen bonds, forming two-dimensional networks, lying parallel to (101), and consolidated by C—H⋯π inter­actions.