Application of Bis(iminophosphorane) in Heterocyclic Synthesis:  New Entries to Symmetrically or Unsymmetrically Substituted Thieno[2,3-d:5,4-d‘]dipyrimidine-4,5(3H,6H)-diones

• Published in: Journal of organic chemistry 2004-11, Vol.69 (24), p.8366-8371
• Main Authors: Ding, Ming-Wu, Xu, Sheng-Zhen, Zhao, Jun-Feng
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; Heterocyclic compounds; Heterocyclic Compounds - chemical synthesis; Heterocyclic compounds with n hetero atom and also o and/or s, se, te hetero atoms; Ketones - chemical synthesis; Molecular Structure; Organic chemistry; Organophosphorus Compounds - chemical synthesis; Organophosphorus Compounds - chemistry; Preparations and properties; Pyrimidines - chemical synthesis
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo048691v

The bis(carbodiimides) 4, obtained from bis-aza-Wittig reactions of bis(iminophosphorane) 3 with 2 equiv of aromatic isocyanates, were reacted with secondary amine to give symmetrically substituted 2,7-diaminothieno[2,3-d:5,4-d‘]dipyrimidine-4,5(3H,6H)-dione 6 in the presence of a catalytic amount of EtO-Na+. Reactions of 4 with phenols or ROH in the presence of a catalytic amount of potassium carbonate or RO-Na+ gave symmetrically substituted 2,7-diaryl(alkyl)oxythieno[2,3-d:5,4-d‘]dipyrimidine-4,5(3H,6H)-diones 6 in satisfactory yields. However, iminophosphoranes 9 were obtained via reaction of bis(iminophosphorane) 3 with 1 equiv of aromatic isocyanate and subsequent reaction with an amine in the presence of a catalytic amount of EtO-Na+. Further reaction of iminophosphoranes 9 with aromatic isocyanates and various nucleophile generated unsymmetrically substituted thieno[2,3-d:5,4-d‘]dipyrimidine-4,5(3H,6H)-diones 12 in good yields.