|
Z. Naturforsch. 2013,
68b, 905 – 912
doi:10.5560/ZNB.2013-3117
Facile Synthesis of Thiazole, Thiazine and Isoindole Derivatives via EDA Approach and Conventional Methods
Chemistry Department, Faculty of Science, Minia University, El-Minia, A. R. Egypt
Reprint requests to Dr. Kamal M. El-Shaieb. Fax: +2-086-2342601. E-mail:
kmelshaieb@yahoo.com
Received April 17, 2013 / published online July 25, 2013
The reactivity of N-amidinothiourea (1) as an electron donor towards several electron-accepting functional groups via electron-donor-acceptor (EDA) interaction has been studied. Thus on treatment of 1 with either 1,1,2,2-tetracyanoethylene (TCNE, 2), 2,3-dicyano-1,4-naphthoquinone (DCNQ, 4), 2,3,5,6-tetrabromo-1,4-benzoquinone (BHL-p, 6), 2,3-dichloro-1,4-naphthoquinone (DCHNQ, 8), 2,3,5,6-tetrachloro-1,4-benzoquinone (CHL-p, 13), 2,3-dicyano-5,6-dichloro-1,4-benzoquinone (DDQ, 15), 2-dicyanomethyleneindan-1,3-dione (CNIND, 17), 2-(2-oxoindolin-3-ylidene)malononitrile (19), and/or dimethyl acetylenedicarboxylate (DMAD, 21), the reaction proceeds to give thiazole and thiazine derivatives, respectively. However, isoindole derivatives 24 and 26 were formed on heating of 1
with either tetrabromophthalic anhydride and/or o-phthalaldehyde, respectively. The products were fully characterized according to their spectral data. The mechanisms of formation of the products have been rationalized.
Key words: N-Amidinothiourea, Thiazoles, Thiazines, Isoindole, EDA Interaction