Table 2.

Optimization of [¹¹C]carbonyl difluoride trapping with aniline, followed by spontaneous [¹¹C]isocyanate formation, and coupling with benzylamine.

Entry	PhNH2 [μmol]	Solvent [0.5 mL]	Yield of [11C]3 [%]a	Yield of [11C]4 [%]a
1	10	MeCN	0 ± 0b	84 ± 9b
2	5	MeCN	0 ± 0	68 ± 9
3	20	MeCN	2 ± 1b	82 ± 9b
4	10	H2O/MeCN (1: 99 v/v)	1 ± 0	91 ± 0
5	10	H2O/MeCN (5: 95 v/v)	1 ± 0	62 ± 2
6	10	THF	4 ± 1	83 ± 2
7	10	DMSO	20 ± 0	45 ± 1
8	10	DMF	7 ± 3	39 ± 5

^[a]Yields are mean±range for n = 2, unless otherwise indicated.

^[b]Yields are mean±SD for n = 3. Total synthesis time was 6.5 min from the release of [¹¹C]carbon monoxide.