organic papers o1408 Cunha et al. C 20 H 18 N 4 O doi:10.1107/S1600536806009111 Acta Cryst. (2006). E62, o1408–o1410 Acta Crystallographica Section E Structure Reports Online ISSN 1600-5368 Polyfunctionalized pyridinium N-benzoyl- guanidine: N 2 -benzoyl-N 1 -(4-methylphenyl)- N 3 -pyridinioguanidin-3-ide Silvio Cunha, a Ivo Vencato, b * Manoel T. Rodrigues Jr, a Fernando C. de Macedo Jr a and Jose R. Sabino c a Instituto de Quı ´mica – UFBA, Campus de Ondina, 40170-290 Salvador, BA, Brazil, b Cie ˆ ncias Exatas e Tecnolo ´ gicas – UEG, BR 153, Km 98, 75133-050 Ana ´polis, GO, Brazil, and c Instituto de Fı ´sica -– UFG, Caixa Postal 131, 74001-970 Goia ˆnia, GO, Brazil Correspondence e-mail: vencato@if.ufg.br Key indicators Single-crystal X-ray study T = 297 K Mean (C–C) = 0.006 A ˚ R factor = 0.046 wR factor = 0.154 Data-to-parameter ratio = 6.6 For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e. Received 8 February 2006 Accepted 10 March 2006 # 2006 International Union of Crystallography All rights reserved The title compound, C 20 H 18 N 4 O, is an example of a recently described pyridinium N-benzoylguanidine. This work repre- sents the second structural study of this kind of compound. The structure is stabilized by C—H, C—HN and C— HO interactions. Comment Pyridinium N-benzoylguanidines are a new kind of poly- subtituted guanidines that can be envisioned as cycloiminium ylides (Johnson, 1996). Recently, we described the first synthesis of polysubstituted pyridinium N-benzoylguanidines through reaction of thioureas with a pyridinium N-ylide (Cunha et al., 2005), being the first example of a nitrogen ylide as the nucleophilic component in the guanylation reaction. To gain insight into intra- and intermolecular interactions of such compounds, we have undertaken a structural analysis through X-ray diffraction, and here we describe the structural study of one polyfunctionalized pyridinium N-benzoylguanidine, namely N 2 -benzoyl-N 1 -(4-methylphenyl)-N 3 -pyridinioguan- idin-3-ide, (I). The polysubstituted pyridinium N-benzoylguanidine, (I), afforded good single crystals for X-ray analysis and several structural features emerged which deserve comment. Fig. 1 shows the molecular structure of (I) with the atomic numbering scheme. Thus, the E configuration of (I) was unambiguously confirmed. Selected geometrical parameters are given in Table 1. A least-squares plane through the ring N4 ! C15C19 shows that atom N3 is 0.133 (6) A ˚ out of that plane. This might be due to steric repulsion between the ring and the methyl group of the neighboring molecule through the short contact H20AC17 (2.873 A ˚ ). Comparing (I) with (4) (Cunha et al., 2005), three differences are observed. The double bond distance C2 N2 is 1.360 (5) A ˚ in (I) and it is shorter in (4) [1.348 (4) A ˚ ]. The distance N1—C3 is elongated in (I); this is mainly ascribed to the change of substituent group from