The nitroaldol reaction of nitro[11C]methane and formaldehyde, which yields 2-(hydroxymethyl)-2-nitro[2-11C]propane-1,3-diol, is explored. The fluoride-ion-assisted nitroaldol reaction using (C4H9)4NF was rapid and provided the desired nitrotriol in more than 97% radiochemical conversion (decay-corrected) in 3 min at room temperature. Neither 2-nitro[2-11C]ethanol nor 2-nitro[2-11C]propane-1,3-diol was observed under the reaction conditions. The preparation of 2-amino-2-(hydroxymethyl)-[2-11C]propane-1,3-diol ([11C]Tris) was described, which was followed by the nitro-group reduction using NiCl2 and NaBH4 in aqueous MeOH. The decay-corrected radiochemical conversion to [11C]Tris was 68.0+/-6.5% in two steps
