Azines, reactions with bifunctional nucleophiles

Azines, reactions with bifunctional nucleophiles 85KGS1O11 84UK1648. 

Charushin, V. N., Chupakhin, O. N., van der Plas, H. C., Reactions of Azines with Bifunctional Nucleophiles Cyclizations and Ring Transformations, 43, 301. 

Reactions of Azines with Bifunctional Nucleophiles Cyclizations and Ring Transformations... 

There are several examples known of participation of azines in cyclizations with 1,5- and 1,6-dinucleophiles (77T981 84H743, 84H1017). Reaction of the thia analogue of isoalloxazine 11 with bifunctional nucleophiles has been... 

Reactions of pteridines, quinoxalinium, and alloxazinium salts with bifunctional nucleophilic reagents as exhibited above in Schemes 7, 9, and 10 show examples of ortho-cyclizations. They proceed mainly in the series of 1,4-diazines, although examples of the participation of other azine derivatives in ortho-cyclizations with dinucleophiles are also known (85KGS1011). 

The meta-bridging cyclizations of azines with bifunctional nucleophiles usually occur in two steps and differ substantially in that respect from the 1,3-dipolar addition reactions performed on 3-hydroxypyridinium salts, which also result in meta-bridged adducts (Scheme 55) (76JCS(P1)2285). 

Refs.] REACTIONS OF AZINES WITH BIFUNCTIONAL NUCLEOPHILES 347... 

Reactions of azines with bifunctional nucleophiles can give rise to several cycloadducts, the structure depending on the nature of reagents, the structure of the azine substrate, and the reaction conditions. As discussed above, three types of cycloadducts are proposed to be formed in reactions of azines with such l,3-N,C-dinucleophiles as acetamidines and acetimino esters (Schemes 44, 54, 58, 69, and 71). 

The longest chapter of this volume, authored by Roger Gallo and Christian Roussel (France) and Ulf Berg (Sweden), gives a comprehensive account of the quantitative treatment of steric effects in heteroaromatic compounds—a subject that has been advanced significantly by these authors. Finally, V. N. Charushin and O. N. Chupakhin (USSR) and H. C. van der Plas (The Netherlands) review reactions of azines with bifunctional nucleophiles. 

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