Preparation
1,3-Adamantanedicarboxylic acid was synthesized from 1-adamantane carboxylic acid by one-pot method. In this process, the ratio of mixed acid (nitric acid and sulfuric acid) have important effect on the yield, the role of sulfuric acid not only is solvent, but also can improve the oxidate ability of nitric acid.
Efficient Synthesis of 1,3-Adamantanedicarboxylic Acid and 1,3-Diaminoadamantane
Reaction: 1-Adamantane carboxylic acid (20 g), nitric acid (65 %, 20 mL) and sulfuric acid (98 %, 160 mL) were placed in a three-necked roundbottom flask fitted with an efficient magnetic stirrer and a thermometer. Cooled to 0 oC and held at 0 oC, anhydrous formic acid (80 %, 70 mL) was added dropwise in 5 h and reacted for 1 h. poured to crushed ice, filtered and then washed the precipitate several times with water to give a white solid. Then the white solid was dissolved in aqueous NaOH solution and the upper clear solution was separated and acidified by HCl to pH = 3. Filtered, washed with water, dried in vacuum, recrystallized from ethanol. White solid, yield 22.9 g (92 %). m.p.: 275- 276 oC
1H NMR (DMSO-d6, 400 MHz) δ: 1.616 (m, 2H), 1.691-1.727 (m, 4H), 1.759-1.791 (m, 4H), 1.850-1.882 (m, 2H), 2.059 (m, 1H), 12.062 (br, s, 2H, COOH); 13C NMR (100 MHz, DMSO-d6) δ 27.37 (C-5, C-7), 34.98 (C-6), 37.66 (C-4, C-8, C-9, C-10), 39.78 (C-2), 39.89 (C-2, C-3), 177.76 (COOH). IR (KBr, νmax, cm-1) : 2913, 2851, 2636, 1691, 1451, 1410, 1344, 1249, 1103, 1084, 952, 743, 670, 528; Anal. calcd for C12H16O4: C 64.29, H 7.14; found C 64.55, H 7.22.
