Reagent-free continuous thermal tert-butyl ester deprotection

[Display omitted] Continuous processing enables the use of non-standard reaction conditions such as high temperatures and pressures while in the liquid phase. This expands the chemist’s toolbox and can enable previously unthinkable chemistry to proceed with ease. For a series of amphoteric amino aci...

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Bibliographic Details
Published in:Bioorganic & medicinal chemistry 2017-12, Vol.25 (23), p.6209-6217
Main Authors: Cole, Kevin P., Ryan, Sarah J., Groh, Jennifer McClary, Miller, Richard D.
Format: Article
Language:English
Subjects:
Amino Acids - chemistry
Continuous processing
Esters - chemistry
Flow chemistry
Hot Temperature
Plug flow reactor
Pressure
Solvents - chemistry
tert-Butyl ester deprotection
Thermolysis
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Summary:[Display omitted] Continuous processing enables the use of non-standard reaction conditions such as high temperatures and pressures while in the liquid phase. This expands the chemist’s toolbox and can enable previously unthinkable chemistry to proceed with ease. For a series of amphoteric amino acid derivatives, we have demonstrated the ability to hydrolyze the tert-butyl ester functionality in protic solvent systems. Using a continuous plug flow reactor at 120–240°C and 15–40min reaction times, no pH modification or additional reagents are needed to achieve the desired transformation. The method was then expanded to encompass a variety of more challenging substrates to test selectivity and racemization potential. The acid products were generally isolated as crystalline solids by simple solvent exchange after the deprotection reaction in good to high yield and purity.
ISSN:0968-0896
1464-3391
DOI:10.1016/j.bmc.2017.03.020