Dihydropyridazine Derivatives with Cyclopenta-, Benzo-, Furo-, Thiopyrano- and Pyrido-Annulation

作者：Penning Miriam; Christoffers Jens^*

来源：European Journal of Organic Chemistry, 2013, 2013(2): 389-400.

DOI：10.1002/ejoc.201201158

• Synthetic methods
• Nitrogen heterocycles
• Ketones
• Hydrazones
• Amines

Regioisomeric [c]annulated pyridazines were prepared from arylhydrazines and carbocyclic or heterocyclic beta-oxo esters with an alpha-phenacetyl moiety. With AcOH/EtOH, the hydrazones were preferentially formed at the endocyclic ketone, which are further cyclized with trifluoroacetic acid (TFA)/CH2Cl2 to give 2,4a-dihydropyridazines. Use of TFA/CH2Cl2 led hydrazones at the exocyclic benzoyl group, which reacted further to give 1,4-dihydro-4aH-pyridazines. In this investigation, examples of the rare or unknown heterocyclic systems furo[3,4-c]-, thiopyrano[4,3-c]- and pyrido[4,3-c]pyridazine were prepared.

• 出版日期2013-1