Synthesis of α,β′- and β,β′-Linked Dimethoxycarbonyldipyrromethanes by Rothemund-Type Condensation
摘要:
The Rothemund-type condensation of methoxycarbonyl-pyrrole with acetone produces mainly the alpha,beta'-linked dipyrromethane, a building block for the synthesis of N-confused macrocycles. The influence of the reaction conditions on the regioselectivity of the process is reported. The X-ray structures of the alpha,alpha'-, alpha,beta'- and beta,beta'-linked dipyrromethanes show an interesting discrimination of the structurally different types of hydrogen bonds.