Azoles. part 12. 1 synthesis of thieno-extended purines: First example of the imidazo[4′,5′:4,5]thieno[3,2-d]pyrimidine ring system
作者:David W. Hawkins、Brian Iddon、Darren S. Longthorne
DOI:10.1016/0040-4020(95)00845-y
日期:1995.11
1 -Benzyl-4-bromoimidazole-5-carbonitriles were synthesised by several methods and shown to be surprisingly resistant to nucleophilic displacement of the bromine atom (e.g. by sulfanylacetamide under various conditions). 1 -Benzyl-4-bromo-2-(methylsulfanyl)imidazole-5-carbonitrile underwent Br → Li exchange with butyllithium (THF/-100 °C) and the resulting 4-lithiated imidazole was treated successively
通过几种方法合成了1-苄基-4-溴咪唑-5-甲腈,并且显示出令人惊讶地对溴原子的亲核取代有抵抗力(例如,在各种条件下被硫烷基乙酰胺)。将1-苄基-4-溴-2-(甲基硫烷基)咪唑-5-腈与丁基锂(THF / -100°C)进行Br→Li交换,然后依次用元素硫和氯乙酰胺处理所得的4-锂化的咪唑,得到2- [1-苄基-5-氰基-2-(甲基硫烷基)-咪唑-4-基硫基]乙酰胺。用乙醇中的乙醇钠将其环化,得到6-氨基-1-苄基-2-(甲基硫烷基)噻吩并[2,3- d咪唑-5-甲酰胺,用原甲酸三乙酯在乙酸酐中处理后,得到标题化合物的首次报道的衍生物。1-苄基-4-溴咪唑-5-甲醛是由1-苄基-2,4,5-三溴咪唑合成的,方法是将其初始转化为2-TBDMS保护的衍生物,然后通过Br→Li引入5-甲酰基。交换并用N-甲酰基哌啶淬灭所得的5-锂化的咪唑,最后除去2-TBDMS-基团(Bu4NF / THF)。