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Reaktionen von Benzothiet mit Iminen

1993; Wiley; Volume: 1993; Issue: 3 Linguagem: Inglês

10.1002/jlac.199319930152

0170-2041

Herbert Meier, Klaus Saul, Dominic Jacob,

Organic Chemistry Cycloaddition Reactions

Reactions of Benzothiete with Imines A 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%.