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.
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.
Ding
Ming-Wu
MW
Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, P. R. China. ding5229@yahoo.com.cn
Xu
Sheng-Zhen
SZ
Zhao
Jun-Feng
JF
D006571:Heterocyclic Compounds / Q000138:chemical synthesis*; D007659:Ketones / Q000138:chemical synthesis*; D015394:Molecular Structure; D009943:Organophosphorus Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D011743:Pyrimidines / Q000138:chemical synthesis*
D006571:Heterocyclic Compounds; D007659:Ketones; D009943:Organophosphorus Compounds; D011743:Pyrimidines