SYNTHESIS AND STRUCTURES OF 1,3,1',3'-TETRABENZYL-2,2'-BIIMIDAZOLIDINYLIDENES (ELECTRON-RICH ALKENES), THEIR AMINAL INTERMEDIATES AND THEIRDEGRADATION PRODUCTS

Benzyl (R) substituted enetetramines 9 and 3 have been studied. From H NR(CH2)(2)NRH and CH(NMe2),OBu' or CH(OMe)(2)NMe2, two new intermediat es along the pathway to 9, namely the orthoamide 11 and the bis(orthoa mide) 12 were isolated. Each of 11 and 12 was converted into 9 by refl uxing in toluene, Photolysis of 9 yielded the isomer 10, while thermol ysis of 9 gave the di(debenzylated) product 1,1'-dibenzyl-2,2'-biimida zoline 13. A route to 3 (R = R' = CH2Ph) similar to those used for 9, involving the condensation of 1,2-C6H4[N(R)H](2) with CH(OMe)(2)NMe2, or the reaction between 1,3-dibenzylbenzimidazolium chloride 8 (X = Cl ) and NaH, did not give the expected enetetramine 3 (the dibenzo-analo gue of 9), the bis(debenzylated) product 15 being obtained instead. He ating the orthoamide 1,2-RNC6H4N(R)C(H)NMe2, prepared from CH(NMe2)(2) OBu' and 1,2-C6H4[N(H)R](2), also gave 15, The reactions of S-8, PhNCS or KOH with a mixture of 8 (X = Cl) and NaH gave 17, 18 or 19, respec tively, consistent with the transient formation in each reaction of th e tetrabenzylenetetramine 3 (R = R' = CH2Ph), The molecular structure of each of the crystalline compounds 10, 11, 12 and 13 was established by X-ray diffraction.