Online article for Non-subscribers

Pay per view

Heterocycles has a pay-per-view service for Non-subscribers.
You will be able to directly purchase the full text article through PayPal.
Your purchased Paper can be downloaded after the payment is completed.
An e-mail will be sent the URL to download the paper.
If you have any questions, please contact:

Price: ¥ 4,400 (Yen only)
Period: This Article can be accessed for 7 days.

Paper | Regular issue | Vol 45, No. 7, 1997, pp.1319-1336
Published online, 1st January, 1970
DOI: 10.3987/COM-97-7810
An Efficient Synthesis for Pyrimido[4',5':4,5]thieno[2,3-c]pyridazine Derivatives via Intramolecular Aza-Wittig Reaction-Heterocyclization Strategy

José M. Quintela,* Rafael Alvarez-Sarandés, M. Carmen Veiga, and Carlos Peinador

*Departamento de Química Fundamental Industrial, Facultad de Ciencias, Universidad de La Coruña, Campus de A Zapateria, s/n, E-15071, La Coruña, Spain


A ready one-pot preparation for substituted pyrimidothienopyridazines is reported. Aza-Wittig reaction of iminophosphorane (3), derived from ethyl 5-amino-3,4-diphenylthieno[2,3-c]pyridazine-6-carboxylate (2), with isocyanates, followed by heterocyclization on addition of amines provided a novel synthetic route to the functionalized pyrimido[4’,5’;4,5]thieno[2,3-c]pyridazines (6). The guanidine-type intermediate compounds (5) derived from addition of amines to the carbodiimides (4) could be isolated and characterized, thus confirming the suggest reaction pathway.