. 2016 Aug 16;8(1):117–123. doi: 10.1039/c6sc02162j

Table 2. Optimization of reaction conditions for the formation of the cyclic urethane moiety on solid support ^a .


Entry	Pg	DSC (equiv.)	Solvent	Time (h)	Conv. ^b (%)
1	1b Fmoc	10	DCM	17	40
2	1b Fmoc	10	DCM : DMF	17	60
3	1b Fmoc	10	DMF	17	>99
4	1b Fmoc	5	DMF	17	70
5	1b Fmoc	10	DMF	3	30
6	1b Fmoc	10	DMF	7	90
7	1c Ac	10	DMF	17	>99
8	1d tosyl	10	DMF	17	>99
9	1e Boc	10	DMF	17	>99

^aReaction conditions: peptide 1 (25 mg, 0.87 mm g^–1) on solid support was reacted with DSC (5–10 equiv.), DIEA (5–10 equiv.), and a crystal of DMAP in different solvents (3 mL) at room temperature for 3–17 h.

^bConversion to cyclic urethane moiety 2 was calculated from the absorbance at 220 nm using HPLC.

Table 2. Optimization of reaction conditions for the formation of the cyclic urethane moiety on solid support a .

Table 2. Optimization of reaction conditions for the formation of the cyclic urethane moiety on solid support ^a .