Efficient Synthesis of New Tetracyclic Benzofuro[3,2-d]-imidazo[1,2-a]pyrimidine-2,5-(1H,3H)-diones

• Published in: Chinese journal of chemistry Vol. 28; no. 2; pp. 309 - 312
• Main Authors: Hu, Yanggen, Liu, Min, Ding, Mingwu
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.02.2010; WILEY‐VCH Verlag; Wiley; Wiley Subscription Services, Inc
• Subjects: 2-a]pyrimidine-2; 2-d]imidazo; 3H)-dione; 5-(1H; aza-Wittig reaction; benzofuro; benzofuro[3,2‐d]imidazo[1,2‐a]pyrimidine‐2,5‐(1H,3H)‐dione; carbodiimide; Chemistry; Chemistry, Multidisciplinary; iminophosphorane; isocyanate; Physical Sciences; Science & Technology; benzofuro[3,2-d]imidazo[1,2-a]pyrimidine-2,5-(1H,3H)-dione; FUNGICIDAL ACTIVITIES; isocyanate; BIOLOGICAL-ACTIVITY; WITTIG/HETEROCUMULENE-MEDIATED ANNULATION; carbodiimide; aza-Wittig reaction; IMIDAZOLE ALKALOIDS; iminophosphorane; DERIVATIVES
• ISSN: 1001-604X; 1614-7065
• DOI: 10.1002/cjoc.201090072

The aza‐Wittig reaction of iminophosphorane (1) with aromaic isocyanates gave carbodiimides (2), which were allowed to react further with (‐amino ester in the presence of a catalytic amount of sodium ethoxide to give selectively new tetracyclic benzofuro[3,2‐d]imidazo[1,2‐a]pyrimidine‐2,5‐(1H,3H)‐diones (5) in good yields. X‐ray structure analysis of 5i verified the proposed structure and the reaction selectivity. An efficient synthesis of the new tetracyclic heterocyle from iminoposphorane was provided. The structure of the title compound was confirmed by X‐ray structure analysis.