Synthesis of 2-pyrone-4-carboxaldehydes from acetylene dicarboxaldehyde monoacetal
摘要:
Reaction of acetylene dicarboxaldehyde rnonoacetal with substituted Meldrum's acid leads good yields in 2-pyranolies-4-carboxaldehydes substituted in position 3. (C) 2004 Elsevier Ltd. All rights reserved.
A mixture of iso-amyl nitrite/HBr is shown to be a mild and efficient reagent for electrophilic aromatic bromination. The reaction succeeds with slightly activated arenes and heterocyclic compounds. By using HCl instead of HBr, chlorination can also be performed in few cases. The i-amONO2/HBr mixture can also be utilized for bromination in the α-position of electron withdrawing groups. A possible mechanism
Reaction of acetylene dicarboxaldehyde rnonoacetal with substituted Meldrum's acid leads good yields in 2-pyranolies-4-carboxaldehydes substituted in position 3. (C) 2004 Elsevier Ltd. All rights reserved.