Naphtho[1′,2′:5,6] pyrano[2,3‐ c ] pyrazole derivatives
1975; Wiley; Volume: 12; Issue: 1 Linguagem: Inglês
10.1002/jhet.5570120106
ISSN1943-5193
AutoresG. ROMA, A. ERMILI, Mauro Mazzei,
Tópico(s)Synthesis of heterocyclic compounds
ResumoAbstract Reaction of 1‐oxo‐3‐dialkylamino‐1 H ‐naphtho[2,1 ‐b ]pyrans with N,N ‐dimethylformamide in the presence of phosphorus oxychloride afforded the corresponding 1‐oxo‐2‐formyl‐3‐dialkyl‐amino‐1 H ‐naphtho[2,1 ‐b ]pyrans. Condensation of 1‐oxo‐2‐formyl‐3‐dimethylamino‐1 H ‐naphtho[2,1 ‐b ]pyran with hydrazine or monosubstituted hydrazines was found to lead to the formation of 8‐alkyl(aryl)‐1 1‐oxo‐8 H ,1 1 H ‐naplitho[1′,2′:5,6] pyrano[2,3‐c]pyrazoles through the intermediate hydrazones and subsequent cyclization. The same result was achieved starting from other 3‐dialkylamino derivatives but in a lower yield.
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