Dihydropyridazine Derivatives with Cyclopenta-, Benzo-, Furo-, Thiopyrano- and Pyrido-Annulation
作者:Miriam Penning、Jens Christoffers
DOI:10.1002/ejoc.201201158
日期:2013.1
Regioisomeric [c]annulated pyridazines were prepared from arylhydrazines and carbocyclic or heterocyclic β-oxo esters with an α-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
区域异构 [c] 环化哒嗪是由芳基肼和碳环或杂环 β-氧代酯与 α-苯乙酰基部分制备的。使用 AcOH/EtOH,腙优先在环内酮处形成,然后与三氟乙酸 (TFA)/CH2Cl2 进一步环化,得到 2,4a-二氢哒嗪。使用 TFA/CH2Cl2 导致环外苯甲酰基上的腙,进一步反应得到 1,4-二氢-4aH-哒嗪。在这项研究中,制备了罕见或未知的杂环系统呋喃 [3,4-c]-、噻喃 [4,3-c]- 和吡啶并 [4,3-c] 哒嗪的例子。