One-Pot Total Synthesis of Natural Products Nitramarine, Nitraridine, and Analogues via a Cascade Oxidation/Pictet-Spengler Condensation/Annulation Process

A cascade oxidation/Pictet-Spengler condensation/annulation process has been developed for the one-pot total synthesis of nitramarine, nitraridine, and their analogues. The procedure proceeded with easily available quinolines and tryptophan derivatives. A simple and metal-free approach, wide substrate scope, and functional group tolerance make it applicable for the synthesis of diverse bioactive nitramarine, nitraridine, and their derivatives. Furthermore, the bioactivity evaluation has identified two promising leading compounds 5d and 5e with potent antitumor proliferative activity against breast cancer cells.

Iodine-Promoted Oxidative Cyclization of Methyl Azaarenes and α-Amino Ketones for One-Pot Synthesis of 2-Azaaryl-5-aryl Oxazoles

A high efficiency protocol was developed for the synthesis of 2,5-disubstituted oxazoles via iodine-promoted oxidative domino cyclization. These reactions were performed with readily available methyl azaarenes and α-amino ketones under metal-free conditions. This protocol is a simple method with high functional group compatibility, a wide range of substrates, and excellent yield, providing a new way to synthesize azaarene-attached oxazoles.

Electrochemically Enabled Cascade Cyclization Reaction of Aromatic Aldehydes and Pyrazol-5-amines: Synthesis of Bis-pyrazolo[3,4-b:4',3'-e]pyridines

A facile method for the synthesis of bis-pyrazolo[3,4-b:4',3'-e]pyridines from easily available aromatic aldehydes and pyrazol-5-amines was developed via electrochemistry. The reaction proceeded smoothly under metal and external chemical oxidant-free conditions, giving a variety of bis-pyrazolo[3,4-b:4',3'-e]pyridines in moderate yields.

Iodine-catalyzed oxidative annulation: facile synthesis of pyrazolooxepinopyrazolones via methyl azaarene sp3 C-H functionalization

An iodine-catalyzed methyl azaarene sp³ C-H functionalization has been developed for the synthesis of a seven-membered O-heterocyclic architecture containing three different heterocyclic aromatic hydrocarbons. This method can be applied to a wide range of substituted methyl azaarenes and diverse 2,4-dihydro-3H-pyrazol-3-ones, and brings about the efficient preparation of 2,9-dihydrooxepino[2,3-c:6,5-c']dipyrazol-3(7H)-ones in high yields with the merits of low catalyst loading, good functional group tolerance and metal-free conditions.

Electrochemical synthesis of dipyrazolo/dipyrimidine-fused pyridines via oxidative domino cyclization of C(sp3)–H bonds

An electrochemically oxidative domino cyclization reaction of methyl azaarenes/ketones with pyrazol-5-amines and 6-amino-pyrimidine-2,4-diones was developed, providing a variety of dipyrazolo[3,4-b:4',3'-e]pyridines and dipyrimidine-fused pyridines with moderate to good yields. The reaction...

I2-Promoted site-selective C–C bond cleavage of aryl methyl ketones as C1 synthons for constructing 5-acyl-1H-pyrazolo[3,4-b]pyridines

A novel iodine promoted [1 + 3 + 2] cleavage cyclization reaction for the synthesis of 1H-pyrazolo[3,4-b]pyridines from aryl methyl ketones, 5-aminopyrazoles and enaminones has been established.

Generation of azaarene nitrile oxides from methyl azaarenes and t-BuONO enabling the synthesis of furoxans and 1,2,4-oxadiazoles

A high-efficiency strategy for the synthesis of furoxans and 1,2,4-oxadiazoles has been developed, using tert-butyl nitrite (TBN) as the nitrogen source. Azaarene nitrile oxides were generated in situ via methyl azaarenes functionalization.

Iodine-imine Synergistic Promoted Povarov-Type Multicomponent Reaction for the Synthesis of 2,2'-Biquinolines and Their Application to a Copper/Ligand Catalytic System

An efficient iodine-imine synergistic promoted Povarov-type multicomponent reaction was reported for the synthesis of a practical 2,2'-biquinoline scaffold. The tandem annulation has reconciled iodination, Kornblum oxidation, and Povarov aromatization, where the methyl group of the methyl azaarenes represents uniquely reactive input in the Povarov reaction. This method has broad substrate scope and mild conditions. Furthermore, these 2,2'-biquinoline derivatives had been directly used as bidentate ligands in metal-catalyzed reactions.

I2-Catalyzed oxidative dehydrogenative tandem cyclization of 2-methylquinolines, arylamines and 1,4-dioxane

A novel I2-catalyst oxidative dehydrogenative tandem cyclization of 2-methylquinolines, arylamines and 1,4-dioxane for the construction of 2-([2,2′-biquinolin]-3-yloxy)ethan-1-ol derivatives has been developed under metal-free conditions.

Metal-free oxidative cyclization of trifluoroacetimidohydrazides with methylhetarenes: a facile access to 3-hetaryl-5-trifluoromethyl-1,2,4-triazoles

A metal-free oxidative cyclization of trifluoroacetimidohydrazides with methylhetarenes for the efficient synthesis of 3-hetaryl-5-trifluoromethyl-1,2,4-triazoles has been developed.