Rhodium-Catalyzed Regioselective Synthesis of Isocoumarins through Benzothiadiazine-Fused Frameworks
作者:Prashant B. Dalvi、Kuang-Ling Lin、Manohar V. Kulkarni、Chung-Ming Sun
DOI:10.1021/acs.orglett.6b01408
日期:2016.8.5
An unprecedented two-step, one-pot synthesis of benzimidazothiadiazine 5,5-dioxides is presented. Reaction condition based regioselectivity has been achieved where fused benzimidazo[1,2-b][1,2,4]thiadiazines are exclusively formed under thermal conditions, whereas benzimidazo[2,1-c][1,2,4]thiadiazines were created only under microwave irradiation. The salient features of this protocol include a regioselective
提出了前所未有的两步,一锅法合成苯并咪唑并二嗪5,5-二氧化物。当在热条件下仅形成稠合的苯并咪唑[1,2- b ] [1,2,4]噻二嗪时,已经达到了基于反应条件的区域选择性,而苯并咪唑[2,1- c ] [1,2,4]噻二嗪则在热条件下形成。仅在微波辐射下产生。该方案的显着特征包括2-氨基苯并咪唑与邻卤代磺酰氯的区域选择性磺酰化,随后形成NC键。这些稠合的区域异构体的酸形式已用于引入新型的含胍的异香豆素骨架。