Table 3. Radiolabelling aromatic ¹¹C-carboxylic acids ([¹¹C]1–6) with [¹¹C]CO₂ and silyl derivatives (see footnote ‡).

Entry a	Reagent		R	Product	Temp. (°C)	TE (%)	RCY (%)
1		1b	OEt		140	57 ± 18	90 ± 4
2		2a	Me		140	13 ± 8	0
3		2b	OEt		140	76 ± 8	84 ± 2
4		3a	Me		140	15 ± 8	0
5		3b	OEt		140	81 ± 2	78 ± 2
6		4a	Me		140	23 ± 15	18 ± 7
7		5a	Me		140	40 ± 1	87 ± 6
8		6a	Me		140	5 ± 4	0
9					100	3 ± 2	9 ± 8
10					30	21 ± 12	19 ± 15

^a n = 3.