Synthetic studies on compounds related to aminoimidazolecarboxamide: Synthesis of angularly fused purine derivatives and a solid phase ring transformation (ANRORC) to imidazo [1,5-a] pyrazine

1-Benzyl-5-aminoimidazole-4-carboxamide 1a has been used as a convenient precursor for the synthesis of new triazolo [3,4-i] purines 6 and the corresponding tetrazolo analogue 7. A mesoionic isomer 8 seems to exist along with 7. Interesting heteroaryl-purine motifs have also been prepared via suitably substituted 9-benzylpurines. Imidazo [1,5-a] pyrazine derivative has been prepared in a solid phase exploitation of suitable imidazolium salt via ANRORC.