Table 2. Optimization of Support Loading Using CPG-2 (41 μmol/g) and CPG-3 (23 μmol/g)^a.

				coupling yield %
				trityl		LCMS
entry	activator	support loading μmol/g	monomer	1st	2nd	1st	2nd	average
1	HATU	41	2b	84	84	89	90	87
2b	HATU	41	2b	81	87	85	91	86
3	HATU	23	2b	90	90	92	93	91
4c	HATU	23	2b	89	92	92	93	92
5	PyAOP	23	2b	90	91	92	93	92
6d	PyAOP	23	2b	89	90	91	92	91
7	HATU	23	2c	95	94	96	93	95
8e	HATU	23	2c	95	95	96	93	95
9e,f	HATU	23	2c	94	95	95	93	94
10	PyAOP	23	2c	94	95	95	93	94
11	BTFFH	23	2c	90	91	94	91	92
12	TCFH	23	2c	70	76	83	67	74

^aAutomated 5 min couplings: pre-activation time 150 s; activator solutions: 0.18 M in DMF; base solutions: 0.2 M DIPEA with 0.3 M 2,6-lutidine in DMF; monomer solutions: 0.2 M in NMP.

^bActivator Solutions: 0.12 M in DMF.

^cPre-activation time 300 s.

^dMonomer solutions: 0.4 M in NMP (double monomer concentration).

^eMonomer solutions: 0.2 M in DMF.

^fDouble coupling of 2 × 5 min.