Orthoamide. IL. Umsetzungen von Orthoamid-Derivaten mit Schwefel und Selen, Synthesen von 1,3-Thiazol- und 1,3-Selenazolderivaten

Autor: Michael Hauber, Markus Vettel, Willi Kantlehner
Rok vydání: 1996
Předmět:
Zdroj: Journal f�r Praktische Chemie/Chemiker-Zeitung. 338:403-413
ISSN: 1521-3897
0941-1216
DOI: 10.1002/prac.19963380180
Popis: Orthoamides. IL. Reactions of Orthoamide Derivatives with Sulfur and Selenium, Syntheses of 1,3-Thiazole- und 1,3-Selenazole Derivatives N,N-Dimethylformamide acetal reacts with elemental selenium to give a mixture of selenocarbonic acid derivatives 2 and 3, which can be converted to the pure N,N-dimethylcarbamidic acid Se-methylester 2 by treatment with methyl iodide. Analogously from the orthoformic acid derivatives 5 and 6 and selenium the N,N,N′,N′-tetramethyl-selenurea 7 can be prepared. In the reaction of 12 with elemental sulfur and selenium the amidines 14 and 15, respectively, are formed. By treatment of 14 and 15 with α-halogenated carbonyl compounds and triethylamine the 1,3-thiazoles 18 and 1,3-selenazoles 19 can be prepared. The synthesis of the propynoic acid orthoamide 26b is described. 26b reacts with the guanidinium salt 24b to give the bis-orthoamide of butynedioic acid 20b. Other orthoamides of butynedioic acid 20b–20e can be synthesized from the orthoamide 20a by transamination. The thiolation of the orthoamides affords the bisamidinium-dithiolates 21a–c, which can be alkylated to give the bisamidinium salts 27. By treatment with α-halogene carbonyl compounds and triethylamine the dithiolates 21a–c are cyclized to give thieno [3,2b] thiophenes 28a–n. The quadrupoles 21 undergo cycloadditions with dimethyl-butynedioate which afford the bis(3H-thiophene-2-ylidenes) 29a–c. Treatment of 29a with methyl tosylate gives rise to the dithiophene 30a. The dithiophene 30b can be obtained by heating 21b with dimethylbutynedionate.
Databáze: OpenAIRE
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