Elemental Sulfur-Mediated Aromatic Halogenation

A method for aromatic halogenation using a combination of elemental sulfur (S8) and N-halosuccinimide has been developed. A catalytic quantity of elemental sulfur (S8) with N-bromosuccinimide (NBS) and N-chlorosuccinimide (NCS) effectively halogenated less-reactive aromatic compounds, such as ester-, cyano-, and nitro-substituted anisole derivatives. No reaction occurred in the absence of S8, underscoring its crucial role in the catalytic activity. This catalytic system was also applicable to aromatic iodination with 1,3-diiodo-5,5-dimethylhydantoin.

Direct Transformation of Nitrogen-Containing Methylheteroarenes to Heteroaryl Nitrile by Sodium Nitrite

The cyanation reaction of methylheteroarenes with acetyl chloride and sodium nitrite via the radical process in high yields is reported. According to the control experiments, the reaction mechanism underwent radical progress. It is very useful in the pharmacy industry due to its metal-free and easy treatment conditions.

Scalable Subsecond Synthesis of Drug Scaffolds via Aryllithium Intermediates by Numbered-up 3D-Printed Metal Microreactors

Continuous-flow microreactors enable ultrafast chemistry; however, their small capacity restricts industrial-level productivity of pharmaceutical compounds. In this work, scale-up subsecond synthesis of drug scaffolds was achieved via a 16 numbered-up printed metal microreactor (16N-PMR) assembly to render high productivity up to 20 g for 10 min operation. Initially, ultrafast synthetic chemistry of unstable lithiated intermediates in the halogen-lithium exchange reactions of three aryl halides and subsequent reactions with diverse electrophiles were carried out using a single microreactor (SMR). Larger production of the ultrafast synthesis was achieved by devising a monolithic module of 4 numbered-up 3D-printed metal microreactor (4N-PMR) that was integrated by laminating four SMRs and four bifurcation flow distributors in a compact manner. Eventually, the 16N-PMR system for the scalable subsecond synthesis of three drug scaffolds was assembled by stacking four monolithic modules of 4N-PMRs.

Cu(OAc)2 catalysed aerobic oxidation of aldehydes to nitriles under ligand-free conditions

An economically efficient ligand-free oxidative conversion of aldehydes to nitriles has been achieved using Cu(OAc)2 and NH4OAc as inexpensive materials of low toxicity in the presence of aerial oxygen as an eco-friendly oxidant.

Utilization of nitriles as the nitrogen source: practical and economical construction of 4-aminopyrimidine and β-enaminonitrile skeletons

A highly practical and economical method for the synthesis of 4-aminopyrimidines and β-enaminonitriles from mixed organonitriles is reported.

A Practical Oxidative Conversion of Aldehydes into N-Chloroaldimines

A novel method for the preparation of N-chloroaldimines from commonly available aromatic aldehydes has been developed. The reaction proceeded effectively by two steps: aldehydes were initially transformed into imines and then chloro-substitution with NaClO2 gave the N-chloroaldimines. This simple protocol allows for the preparation of a variety of aromatic N-chloroaldimines in moderate to excellent yields without the isolation of the imine intermediate. We also found that 3-nitrobenzaldehyde and 4-cyanobenzaldehyde were converted into the related benzonitrile directly under the standard conditions.

A new approach toward the synthesis of 2,4-bis(fluoroalkyl)-substituted quinoline derivatives using fluoroalkyl amino reagent chemistry

The present work describes the unprecedented use of Fluoroalkyl Amino Reagents (FARs) to afford 2,4-bis(fluoroalkyl)-substituted quinoline derivatives in two steps under mild reaction conditions, in good yields and with a very good regioselectivity.

Iodine-catalyzed ammoxidation of methyl arenes

A metal-free direct ammoxidation of readily available methyl arenes leading to nitriles was established under mild conditions.