There were two overall aims for the project - developing and optimising the aza-Prins (and related) reactions for the preparation of nitrogen-containing heterocyclic structures, and second applying this to the total synthesis of JBIR-102.
During the project, the aza-Prins and aza-silyl-Prins reactions have been developed as a rapid method to prepare piperidines and related nitrogen-containing heterocycles. Specifically, the aza-Prins reaction has been:
a) optimised i.e. many different reaction conditions have been screened to find the best conditions. Variables studied included the choice of acid employed to catalyse the reaction (Bronsted or Lewis acids), solvents, temperature and reaction times.
b) the reaction was developed initially in a racemic form but crucially developed into an asymmetric version to give piperidines as a single enantiomer in very high yields. This involved the development of a novel chiral auxiliary.
c) an additional novel reaction - the aza-silyl-Prins reaction - related to the aza-Prins reaction, has also been developed and optimised.
d) adapted and modified to produce fused aza-bicycles (the core structural architecture found in JBIR-102).
Concerning the total synthesis and biological evaluation of JBIR-102, a large number of fused aza-bicyclic containing compounds have been prepared using the methodology prepared in the first part of the project. These are simplified versions of JBIR-102, containing some (but not all) of the structural features of the natural product. These are crucially undergoing biological evaluation to give an indication of the mode of action of JBIR-102. As a result of the action, additional funding has been secured (from the University Alliance DTA Co-FUND scheme) to continue the project and complete the synthesis of JBIR-102.
The work has been presented either by the Fellow or by the PI at several international conferences, including:
1. Royal Society of Chemisty Heterocyclic & Synthesis Group Grasmere International Heterocyclic Meeting (May 2017)
2. International Society of Heterocyclic Chemistry (ISHC), Regensburg Germany, September 2017
3. Anglo-Indian RSC-NOST Meeting, Leeds, September 2017
4. SCI-RSC Celebration of Organic Chemistry (UCB, Belgium, Sept 2018)
5. Action Mesothelioma Days (Leeds, UK) in July 2017 and July 2018
The first paper was accepted for publication in Organic Letters in November 2018, and at least 3 more are being drafted for submission.