Study of reaction between activated acetylenes and N,N′-diethyl-2-thiobarbituric acid in the presence of isocyanides or triphenylphosphine

✍ Scribed by Ghasem Marandi; Malek Taher Maghsoodlou; Nourallah Hazeri; Reza Heydari; Sayyed Mostafa Habibi Khorassani; Ali Ebrahimi; Sakineh Mollaee Poor; Hassan Hosseini Mahdiabad; Mahmoud Nassiri; Roya Kabiri

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 322 KB
• Volume: 21
• Category: Article
• ISSN: 1042-7163
• DOI: 10.1002/hc.20601

✦ Synopsis

Abstract

In a series of separate experiments reaction between N,N′‐diethyl‐2‐thiobarbituric acid and acetylenic diesters in the presence of isocyanides or triphenylphosphine led to highly functionalized 4__H__‐pyrano[2,3‐d]thiopyrimidine or 1,4‐di‐ionic organophosphorus derivatives. The ^1^H NMR spectra of diethyl‐7‐(2,6‐dimethylphenylamino)‐4‐oxo‐2‐thio‐ 1,3‐diethyl‐4__H__‐pyrano[2,3‐d]pyrimidine‐5,6‐dicarboxylate showed dynamic NMR effect that was attributed to restricted rotation around the aryl‐nitrogen single bond. Activation free energy (Δ__G__^≠^) for this process is about 54.85 ± 2 kJ mol^−1^. Betaines as 1,4‐diionic organophosphorus compounds in this reaction are possessed of two vicinal stereogenic centers and exist in the solution as a mixture of two diastereoisomers. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:228–235, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20601