In summary, protected pyrazole has been synthesized and characterized. In present research work on the utilization of PEG, we report here a simple and efficient method for the N-Boc protection of amines using PEG-400 as an ecofriendly reaction medium at room temperature (Scheme1 (3)) with 95% yield. No competitive side reactions leading to formation of isocyanate, urea or N,N-di-Boc derivatives were detected by thin-layer chromatography (TLC), infra red spectroscopy (IR), 1H NMR, and 13C NMR analysis.
Key words: Di-tert-Butyloxycarbonyl (Boc), Poly ethylene glycol (PEG-400), N,N-diisopropylethylamine (DIPEA), 4-dimethylamino pyridine (DMAP).
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