两种四乙酸四氮杂环烷化合物的合成

在氢氧化钾存在下，1，4，7，10-四氮杂环十二烷与溴乙酸进行N-羧甲基化反应，得到N，N′N″N-四乙酸1，4，7，10-四氛杂环十二烷（DOTA，I），经重结晶纯化，产率88．1％．在碳酸钾存在下，1，4，8，11-四氮杂环十四烷与溴乙酸卡酯进行反应，生成N－乙酸苄酯中间体．该中间体在室温和4．04×105Pa氢气压力下，用Pd／C地催化氢解脱苄基得到N，N′N″N-四乙酸1，4，8，11－四氮杂环十四烷（TETA，Ⅲ），产率56．0％。

Synthesis of two tetraaza tetraacetic macrocycles

1, 4, 7, 10-Tetraazacyclododecane-N, N′, N″, N-tetraacetic acid (DOTA, Ⅰ) was synthesized by N-carboxylmethylation of 1, 4, 7, 10-tetraazacyclododecane with bromoacetic acid in the presence of potassium hydroxide. The product was purified by recrgntallization ftom water. The yield was 88. 1%. 1, 4, 8, 10-tetraazacyclotetradecane-N, N′, N″, N-tetraacetic acid (TETA, Ⅲ ) was syllthesized by the hydrogenolysis of N-benzyacetate of tetraaza macrocycle, which was prepared by the alky1ation of 1, 4, 8, 11-tetraazacy-clotertradecane with benzyl 2-bromoacetate in the presence of potassium carbonate, under 4. 04 ×105Pa H2 at room temperature for 24 hours. The procedure was a straightforward two-step synthesis of TETA with a reasonably good overall yteld (56.0%).