UNEXPECTED CYCLOADDITION REACTIONS DURING QUATERNIZATION OF 6,7-DIMETHOXY-2H-1,3-BENZOTHIAZINE

Authors
SZABO J FODOR L BANIAKOTO E SOHAR P JERKOVICH G DOMBI G GUNTHER G BERNATH G
Citation
J. Szabo et al., UNEXPECTED CYCLOADDITION REACTIONS DURING QUATERNIZATION OF 6,7-DIMETHOXY-2H-1,3-BENZOTHIAZINE, ACH, models in chemistry, 131(3-4), 1994, pp. 345-350
Citations number
7
Categorie Soggetti
Chemistry
Journal title
ACH, models in chemistry → ACNP
ISSN journal
12178969
Volume
131
Issue
3-4
Year of publication
1994
Pages
345 - 350
Database
ISI
SICI code
1217-8969(1994)131:3-4<345:UCRDQO>2.0.ZU;2-9
Abstract
In the quaternization reaction of 6,7-dimethoxy-2H-1,3-benzothiazine ( 1) with 4-nitrobenzyl chloride, formation of 6,7-aimethoxy-2H-1,3-benz othiazinium chloride (3) was observed besides the expected quaternary salt (2). As by-products, the new heterocyclic ring systems H,13aH-[1, 3]benzothiazino[4,3-b][1,3]benzothiazine (4) and tetramethoxy-15-(4-ni trophenyl)-6H,7aH,13H-imidazo [1,2-c:3,4-c]bis(1,3-benzothiazine) (5) were formed via cycloaddition. A mechanism is proposed for the reactio n. The configuration of 5 was elucidated by means of NMR spectroscopy.