Polyethylene glycol mediated facile protocol for N-Cbz protection of amines

Figures & data

short-legendScheme 1. 

Table 1. N-Cbz protection of aniline with variety of polyethylene glycols (PEGs) in various conditions at room temperature (entry 3 gives the optimum conditions).

Entry	PEGs	Quantity of PEG (mL)	Solvent (mL)	Time (min)	Yield (%) Isolated
1	–	–	–	120	40
2	–	–	Tap water	100	45
3	PEG-400	0.1	–	30	80
4	PEG-400	0.5	–	5	93
5	PEG-400	1.0	–	5	93
6	PEG-400	0.5	DCM (5)	10	92
7	PEG-400	0.5	EtOH (5)	10	70
8	PEG-400	0.5	THF (5)	10	85
9	PEG-400	0.5	CH3CN (5)	10	75
10	PEG-400	0.5	Tap water	10	92
11	PEG-200	0.5	–	5	92
12	PEG-600	0.5	–	5	92
13	PEG-4000	0.5	–	5	93
14	PEG-4000	0.1	–	5	93
15	PEG-6000	0.5	–	5	93
16	PEG-6000	0.1	–	5	93

Table 2. PEG-400 mediated N-Cbz protection of amines at room temperature.