144189-87-7Relevant articles and documents
Dimerizations of 2-alkylbenzotriazoles and chemical evidence of radical intermediates from X-ray studies
Katritzky, Alan R.,Jesorka, Aldo,Wang, Jin,Yang, Baozhen,Wu, Jing,Steel, Peter J.
, p. 745 - 755 (2007/10/03)
Treatment of 2-alkylbenzotriazoles with lithium diisopropylamide (LDA) at -78°C gave, depending on workup conditions, either dimers of the type Bt2CHR-CHRBt2 (2) (Bt2 = benzotriazol-2-yl), or mixtures of symmetrical Z and E olefins (3) (RCH=CHR), in high yields via radical intermediates. The racemic and meso isomers of 2, which differ substantially in properties such as melting points, 1H and 13C NMR, were isolated and characterized (three by X-ray crystallography). Both the meso and racemic dimers of 2 were reduced by Na to give mixtures of Z and E olefins in high yields with the elimination of the benzotriazole anion. 2-Alkylbenzotriazoles (1) were also converted by Na into the corresponding alkanes and benzotriazole. The intermediates were trapped by benzophenone to give, depending on the reaction procedure (see Scheme 2), adducts 6 or adducts 6 with dimers 2, benzotriazol-2-ylalkene 7 and compound 8 (R = H), compound 9 (R = CH3). Several compounds with dibenzotriazol-2-yl groups or benzotriazol-1-yl and benzotriazol-2-yl groups in the same molecule were synthesized and further investigated via lithiation followed by the addition of benzophenone or benzaldehyde. This further indicated that the radical reaction is faster than the nucleophilic reaction. VCH Verlagsgesellschaft mbH, 1996.
