5- Amino-imidazole-4-carbonitrile, reaction with

The fourth route involved formation of the central ring of 6,7-dihydro-imidazo[l,2-a]purine derivatives by reaction of 4-amino-l/7-imidazol-5-carbonitrile (160) with 2-methylmercapto-imidazoline (159) to afford the 4-imino derivative 161 under various conditions (01JHC743) (Scheme 45). 

The scope of this methodology was established by forming imidazoles fused to five-, six- and seven-membered rings, 165, as outlined in Scheme 3856c,d. It was also found that while N-monosubstituted enaminonitriles such as 166 underwent photochemically mediated rearrangement to give imidazole 167, the reported conversion of 2-(dimethyl-amino)-1 -cyclohexene-1 -carbonitrile to 1,2-dimethyl-4,5,6,7-tetrahydrobenzimidazole could not be reproduced, i.e. no reaction was observed with A, 7V-disubstituted enaminonitriles5 6cd 58. 

Reaction of 5-amino-l-(2,3,5-tri-C)-benzyl-j -D-arabinofuranosyl)imidazole-4-carbonitrile with methyl isocyanate in pyridine followed by ammonia treatment yields 9-(/l-D-arabinofuranosyl)-1-mcthylisoguaninc 4. Dcbcnzylation to 5 was achieved wdth boron trichloride. ... 

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