synthesis and chemical characterisation of some new diheteroaryl thienothiophene derivatives合成和化学描述一些新的diheteroaryl thienothiophene衍生品.pdfVIP

Molecules 2011, 16, 7706-7714; doi:10.3390/molecule OPEN ACCESS molecules ISSN 1420-3049 /journal/molecules Article Synthesis and Chemical Characterisation of Some New Diheteroaryl Thienothiophene Derivatives Yahia Nasser Mabkhot *, Abdullah Mohammad Al-Majid and Abdullah S. Alamary Department of Chemistry, Faculty of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia * Author to whom correspondence should be addressed; E-Mail: yahia@.sa. Received: 10 June 2011; in revised form: 15 August 2011 / Accepted: 5 September 2011 / Published: 8 September 2011 Abstract: Treatment of 1-(5-acetyl-3,4-dimethythieno[2,3-b]thiophene-2yl)ethanone (1) with dimethylformamide dimethyl acetal afforded enaminone derivative 2, which reacted with amino derivatives to give the corresponding bis-pyrimidine, bis-pyrazole, bis-triazolo-pyrimidine and bis-benzoimidazopyrimidine derivatives. Keywords: bis-heterocycles; DMF-DMA; bis-pyrimidine; bis-pyrazole; bis-triazolo pyrimidine 1. Introduction In the last 30 years, annulated heterocyclic systems have attracted considerable attention both from a theoretical standpoint and in view of their various practical applications [1-14]. Enaminones are valuable intermediates in synthetic organic chemistry [15-18], and Mabkhot and others [19-26] have reported a variety of syntheses of heteroaromatics developed using functionally substituted enaminones as readily obtainable building blocks