10345-40-1

Upstream product

• 100-02-7 4-nitro-phenol 
• 16420-13-6 N,N-Dimethylthiocarbamoyl chloride 
• 1132-69-0 4-nitrophenyl chlorothionoformate 
• 124-40-3 dimethyl amine 

Downstream Products

• 1849-36-1 para-nitrobenzenethiol 
• 7305-12-6 S-(p-nitrophenyl) N,N-dimethylthiocarbamate 

Relevant academic research and scientific papers

The Newman-Kwart rearrangement: A microwave kinetic study

(Chemical Equation Presented) The kinetic profile of the Newman-Kwart rearrangement has been evaluated using microwave heating. After first demonstrating equivalence between conventional convective heating and microwave heating, data was gathered and anal

Potassium fluoride on alumina: Synthesis of O-aryl N,N-dimethylthiocarbamates and their rearrangement into S-aryl N,N-dimethylthiocarbamates under microwave irradiation

A series of O-aryl N,N-dimethyl thiocarbamates have been prepared by the reaction of dimethylthiocarbamoyl chloride with phenols absorbed on potassium fluoride on alumina. The rearrangement of O-aryl N,N-dimethylthiocarbamate into S-aryl N,N-dimethylthiocarbamate under microwave irradiation was also studied. The use of conductive support like graphite or silicon carbide allow these rearrangements although the O-aryl N,N-dimethylthiocarbamates have very low dielectric lost.

Electrochemically Catalyzed Newman-Kwart Rearrangement: Mechanism, Structure-Reactivity Relationship, and Parallels to Photoredox Catalysis

The facilitation of redox-neutral reactions by electrochemical injection of holes and electrons, also known as "electrochemical catalysis", is a little explored approach that has the potential to expand the scope of electrosynthesis immensely. To systematically improve existing protocols and to pave the way toward new developments, a better understanding of the underlying principles is crucial. In this context, we have studied the Newman-Kwart rearrangement of O-arylthiocarbamates to the corresponding S-aryl derivatives, the key step in the synthesis of thiophenols from the corresponding phenols. This transformation is a particularly useful example because the conventional method requires temperatures up to 300 °C, whereas electrochemical catalysis facilitates the reaction at room temperature. A combined experimental-quantum chemical approach revealed several reaction channels and rendered an explanation for the relationship between the structure and reactivity. Furthermore, it is shown how rapid cyclic voltammetry measurements can serve as a tool to predict the feasibility for specific substrates. The study also revealed distinct parallels to photoredox-catalyzed reactions, in which back-electron transfer and chain propagation are competing pathways.

Microwave-mediated Newman-Kwart rearrangement in water

For the first time the unimolecular Newman-Kwart rearrangement is performed in pure water. The elevated temperatures required for the 1,3-aryl shift are easily accomplished by microwave irradiation. Differently functionalized substrates underline the expe

Palladium-catalyzed intramolecular oxidative C-H sulfuration of aryl thiocarbamates

A palladium-catalyzed intramolecular C-H bond sulfuration reaction of aryl thiocarbamates has been developed. This strategy provides a new route to benzo[d][1,3]oxathiol-2-ones with tolerance of a wide range of substituents. Mechanistic studies suggested

The molecularity of the Newman-Kwart rearrangement

It was recently reported that the venerable Newman-Kwart rearrangement (1→2) proceeds via mixed first- and second-order kinetics. Prior to this, the rearrangement had been considered to proceed exclusively via an intramolecular OAr→SAr migration. A new bimolecular pathway, possibly involving an 8-membered cyclic transition state, was proposed to account for reaction rates that increased disproportionately with substrate concentration under microwave heating conditions. We report a reanalysis of the kinetics and molecularity of the rearrangement of N,N-dimethyl O-(p-nitrophenyl)thiocarbamate 1a in N,N-dimethylacetamide solvent. Using HPLC, isotopic labeling (2H, 18O, 34S), and ESI-ICRMS methods, we show that there is no evidence for a bimolecular pathway en route to 2a, with near-perfect exponential decay in 1a at concentrations ranging from 0.11 to 4.70 M. Instead, it is demonstrated that under the microwave heating conditions, a delayed negative feedback signal to the microwave power balancing loop results in oscillatory reaction overheating. Due to higher tan δ in the solute, the amplitude of this oscillation increases with the concentration of 1a, and this phenomenon best accounts for the kinetic behavior previously misinterpreted as being mixed 'irst- and second-order in nature.

A comparison of commercial microwave reactors for scale-up within process chemistry

Seven commercially available microwave reactors designed for limited scale-up have been investigated using a highly reliable and robust reaction (the Newman-Kwart rearrangement). The use of a single reaction has enabled the comparison to be made across the range of different reactor types and scales. Overall, all reactors gave reliable scale-up from small scale, and performance equivalent to one another on large scale. A more detailed comparison between them is given in the concluding section.

The Newman-Kwart rearrangement re-evaluated by microwave synthesis

The Newman-Kwart rearrangement (NKR) has been re-evaluated by microwave heating. Microwave technology has proven to be ideal for investigating this high temperature rearrangement and facilitated the confirmation of many aspects of this valuable reaction.