A New Facile Synthesis of exo-Methylene 3,1-Benzothiazines

Abstract

A facile synthesis of exo-methylene 3,1-benzothiazines from ortho-alkynylated aniline 1 with alkyl or aryl isothiocyanates is described. The reaction can be set up both in a discontinuous or continuous process, the latter protocol explored with a Cellular Process Chemistry (CPC) reactor.

Key words

thiazine - cyclization - continuous process

References

• 1 Millonig RC. Goldlust MB. Maguire WE. Rubin B. Schulze E. Wojnar RJ. Turkheimer AR. Schreiber WF. Brittain RJ. J. Med. Chem.  1973,  16:  780 
• 2 Hari A. Miller BL. Org. Lett.  2000,  2:  3667 
• 3 Hull R. van den Broek P. Swain ML. J. Chem. Soc., Perkin Trans. 1  1975,  922 
• For the synthesis of 4-aryl and unsubstituted 4H-3,1-benzothiazines.
• 4a Nishio T. J. Org. Chem.  1997,  62:  1106 
• 4b El-Desoky SI. Kandeel EM. Abd-el-Rahman AH. Schmidt RR. J. Heterocycl. Chem.  1999,  36:  153 
• 4c Besson T. Guillaumet G. Lamazzi C. Ress CW. Synlett  1997,  704 
• 5 Fathalla WM. Pazdera P. Molecules  2000,  7:  96 
• 6a Ebel M. Bull. Soc. Chim. Fr.  1971,  187 
• 6b Lohse C. Pedersen CT. Ebel M. Callendret R. J. Chem. Soc. Perkin Trans. 1  1978,  1432 
• 6c Latif N. Zeid IF. Mishriky N. Assad FM. Rec. Trav. Chim. Pays-Bas  1981,  100:  95 
• 7 Xiao W.-J. Alper H. J. Org. Chem.  1999,  64:  9646 
• 8 Thorand S. Krause N. J. Org. Chem.  1998,  63:  8551 
• 9 Taghavi-Moghadam S. Kleemann A. Golbig KG. Org. Proc. Res. Dev.  2001,  5:  652 

10

For additional information: www.cpc-net.com.