Yield, purity, and molar activity of [¹¹C]HCN.

Entry	Method	Routea	[11C]HCN			[11C]BnCNf
			Yield (%)		Purity (%)	Yield (%)	A m g (GBq μmol−1)
			EOBh	EOTi		EOSj	EOTi	EOSj
1	Current	Route 1b	60 ± 2.5	42 ± 1.6	94 ± 0.8	11 ± 1.4	349 ± 29	198 ± 18
2	Current	Route 2c	52 ± 4.1	37 ± 2.7	88 ± 1.6	9.5 ± 0.8	340 ± 62	193 ± 38
3	Traditional	Route 3d	51 ± 5.6	41 ± 4.8	>99%	11 ± 1.9	103 ± 69	53 ± 36
4	Traditional	Route 4e	—	—	—	7.8 ± 1.2	109 ± 35	55 ± 17

^aValues are presented as mean ± sd (n = 3). Synthetic route for the preparation of [¹¹C]HCN.

^bThe N-oxide layer of reaction column was prepared with the OMT solution.

^cA mixture of powdered OMT, DPSO, and SiO₂ granules was used as the N-oxide layer.

^dOrdinary synthetic route for [¹¹C]HCN preparation with NH₃ included in the carrier gas of [¹¹C]HCN (5% in N₂).

^eNH₃ in the carrier gas of [¹¹C]HCN was removed (<0.2 ppm).

^fReaction conditions: [¹¹C]HCN was transferred to a reaction vessel containing a DMF solution (300 μL) of benzyl bromide (BnBr, 1 μL) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 1 μL) at −20 °C until the radioactivity in the vessel reached a plateau. [¹¹C]HCN was then reacted at 120 °C for 5 min.

^gMolar activity.

^hAt the end of bombardment.

ⁱAt the end of [¹¹C]HCN transfer.

^jAt the end of synthesis (purification).