1,4-Dicyano-2,3,5,6-tetramethylbenzene

Weaker XBs usually result in less linear geometries and this accounts for the waved geometry in the copolymer given by 1,4-DITFB with 1,4-dicyano,2,3,5,6-tetramethylbenzene [123] and for the reduced linearity of the homopolymer given by 4-bromobenzonitrile compared to 4-iodobenzonitrile [71]. 

Photoinduced electron transfer from donors such as prenyl acetate, geranyl acetate, all-/ra/w-famesyl acetate, and all-/ra j-geranylgeranyl acetate to 1,4-dicyano-2,3,5,6-tetramethylbenzene, 1,4-dicyanonaphthalene, and 9,10-dicya-noanthracene in the presence of l,r-biphenyl as co-donor in acetonitrile produces the radical cation of biphenyl and the radical anion of the electron acceptors. Geranyl acetate is observed to photocyclise, and the mechanism of this process which involves reaction of its radical cation with water is discussed. Allyl glycosides (76) can be photodeprotected to give (77) via (78) by irradiating with di-t-butyl peroxide in the presence of bromotrichloro-methane. ... 

In a similar approach, Demuth and coworkers used PET and employed 1,4-dicyano-tetramethylbenzene (DCTMB) and l,l -biphenyl (BP) to form radical cations as 5-11 from tetraenes as 5-10. 

Dicyano-l,2,3,5-tetramethylbenzene added portionwise at -10 to -5° to stirred fuming HNOg (d. 1,5), and stored several days while the temp, is allowed to rise to room temp. 4-cyano-5,6,7-trimethylphthalide. Y 96%. F. e. s. H. Suzuki and T. Hanafusa, Synthesis 1974, 432. 

---