Synthesis and crystal structure of (5-amino-4-carboxamidoimidazol-1-yl) acetamide, a possible PDE inhibitor

5-Amino-1-[2-(diethylamino)ethyl]-1H-imidazole-4-carboxamide

“…Intramolecular hydrogen bonds form an extended planar heterocyclic structure in some potent anti-allergenics (Lunt, 1982;Ford et al, 1986). These hydrogen-bonded planar structures have also been observed in the structures of 5-amino-imidazole-4carboxamides (Banerjee, Roychowdhury, Chattopadhyay et al, 1991;Banerjee, Roychowdhury, Yamane et al, 1991;Banerjee et al, 1999).…”

“…The butterfly conformation of bulky groups such as diphenylmethyl and similar two-ring systems in well known anti-allergenics, such as chloropheniramine, bromopheniramine and promethazine, indicates that this conformation may play a vital role in the interaction of the compound at the receptor site. The effect of various substituents at different positions of the imidazole ring on the conformation of molecules and their crystal structures has been studied (Adamiak & Saenger, 1979;Simon et al, 1980;Banerjee, Roychowdhury, Chattopadhyay et al, 1991;Banerjee, Roychowdhury, Yamane et al, 1991;Banerjee et al, 1999). Against this background, we report here the crystal structure of the title compound, (I).…”

5-Amino-1-benzyl-4-cyano-3-methylimidazolium toluene-p-sulfonate

“…The electron-withdrawing effect of the cyano group and the lack of intramolecular hydrogen bonding in the imidazole group results in a net accumulation of electrons in the 1-benzyl region of the compound. This explains the differences in the bond distances of the imidazole ring from those found in other 5-aminoimidazole-4-carboxamide derivatives (Adamiak & Saenger, 1979;Simon et al, 1980;Allen et al, 1987;Banerjee, Roychowdhury, Chattopadhyay et al, 1991;Banerjee, Roychowdhury, Yamane et al, 1991;Banerjee et al, 1999). The lengthening of the N3-C3 bond distance to 1.4680 (18) Å compared with the Csp 3 -N (planar) distance of 1.454 (11) Å (Allen et al, 1987) that is normally observed for such bonds indicates delocalization of -electron density within the imidazolium ring.…”