ISSN:
0170-2041
Keywords:
[8 + 2] Cycloadditions
;
Benzothiete
;
Imines
;
Cyclization reactions
;
Ring opening
;
S,N-Heterocycles
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Reactions of Benzothiete with IminesA great variety of compounds 3a-w containing CN double bonds was studied in the reaction with benzothiete (1). H, alkyl, aryl, OR, SR and NR groups can be attached to the imino function. The azomethines 3a-f, the thiazolines 3g-i, the lactim 3n, the oximes 3r-t, the isoxazolinone 3u and the azine 3v show [8π + 2π] cycloaddition reactions yielding derivatives of 1,3-benzothiazine (4a-i, n, r-v). In the case of 4n, s, t secondary reactions occur, initiated by elimination processes. [8π + 2π] Cycloadditions account also for the reactions 3e → 10, 11, 3o → 18(I), and 3q → 19; however, CC double bonds are representing the 2π component in these examples. The thiazoline 3j and the oxazolines 3k-m afford dibenzo-1,8,4-thiazaundecine derivatives 14j-m, in which two benzothiete units are incorporated. The hydrazone 3w gives the linear adduct 22. Compounds with a heteroaromatic tautomeric form like 3p don't react at all. The reactions of 1 and 3 are very sensitive towards electronic and steric effects and have always to compete with the dimerisation 1 → 5. Thus, the product yields vary between 90 and 2%.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.199319930152
Permalink