One-pot reaction is an efficient synthesis method that allows multiple structural transformations to be carried out in a continuous manner, which leads to reduction of purification steps, waste, and time consumed. It also has safety benefits, such as the ability to proceed to the next step without isolating harmful and highly reactive intermediates.
We here discovered a one-pot reaction to directly synthesize various amines from alcohols using trichloroisocyanuric acid, an inexpensive chemical frequently used as a swimming pool disinfectant.
Click here for the original paper.
We discovered that the reaction was significantly accelerated by the LED light irradiation, and carried out the four steps consisting of 1) oxidation, 2) chlorination, 3) azidation, and 4) rearrangement in the same flask without purifying any unstable and harmful intermediates. The intended N-protected amines were obtained with a maximum yield of 83% (average yield of each step is over 95%).
Furthermore, using this method, we achieved the synthesis of memantine hydrochloride, an anti-dementia drug used worldwide.
The reaction can also be carried out on a gram scale, and by-products derived from trichloroisocyanuric acid, used as the oxidizing and chlorinating agent, can be easily removed by filtration. We hope that this reaction, which does not require excessive reagents, will be applied to the synthesis of various bioactive molecules including drug candidates, in line with green chemistry concept.
Inspiration and preliminary results for this research were discovered at University of Lincoln (UoL) when SK visited UoL as a research fellow. Although the concept of the reaction had been established at that moment, applicability and efficiency were insufficient, which hampered publication.
Since then, we have continuously searched and improved the reaction conditions with several students, and since last year, a brilliant graduate student Mr. Ryo Yamaguchi joined this project. Although it was hard to complete the mission, we were finally able to reach our goal.
Intensive discussions were made with Dr. Martin J. Lear and Dr. Louis Adriaenssens from UoL to publish these exciting results. Although there were some disagreements at times, in the end we were able to finalize a manuscript that we were both satisfied with. We are truly happy that first joint achievement between Osaka Institute of Technology (OIT) and the University of Lincoln (UoL) was published.
As a sign of friendship between OIT and UoL, I will post a photo of me with Dr. Adriaenssens, and Dr. Lear. I asked Mr. Ryo Yamaguchi, who was a key person of this project, to post his photo, but he declined, saying, ``Smiling doesn't suit me.'' This is very typical of Ryo, a kind-hearted and quiet cool guy! (^^)
