Selective cyclization modes of methyl 3′-heteroarylamino-2′-(2,5-dichlorothiophene-3-carbonyl)acrylates. Synthesis of model (thienyl)pyrazolo- and triazolo[1,5-α]pyrimidines
| Autor: | Musa Z. Nazer, Nuha I. Sweidan, Mustafa M. El-Abadelah, Wolfgang Voelter |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Zeitschrift für Naturforschung B. 75:1037-1042 |
| ISSN: | 1865-7117 0932-0776 |
| DOI: | 10.1515/znb-2020-0128 |
| Popis: | Interaction of methyl 3-ethoxy-2-(2,5-dichloro-3-thenoyl)acrylate (I) with 3-aminopyrazole and 3-amino-1,2,4-triazole generated the respective pyrazolo[1,5-α]pyrimidine (4) and triazolo[1,5-α]pyrimidine (7). The formation of 4 entails selective and consecutive displacement of the 3-ethoxy and methoxy (ester) anions in I by 3-NH2 and 1-NH of 3-aminopyrazole. On the other hand, the formation of 7 implies selective displacement of 3-ethoxy in I by the ring-NH followed by cyclocondensation involving the keto group in I and 3-NH2 of aminotriazole. This latter selective displacement sequence is also followed by 3-amino-5-hydroxypyrazole in its reaction with I. The structures of the new compounds are supported by microanalytical and spectral data. |
| Databáze: | OpenAIRE |
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