Supramolecular hydrogen-bonding patterns in two cocrystals of the N(7)–H tautomeric form ofN⁶-benzoyladenine:N⁶-benzoyladenine–3-hydroxypyridinium-2-carboxylate (1/1) andN⁶-benzoyladenine–DL-tartaric acid (1/1)

Abstract

Two novel cocrystals of the N(7)-H tautomeric form of N(6)-benzoyladenine (BA), namely N(6)-benzoyladenine-3-hydroxypyridinium-2-carboxylate (3HPA) (1/1), C12H9N5O·C6H5NO3, (I), and N(6)-benzoyladenine-DL-tartaric acid (TA) (1/1), C12H9N5O·C4H6O6, (II), are reported. In both cocrystals, the N(6)-benzoyladenine molecule exists as the N(7)-H tautomer, and this tautomeric form is stabilized by intramolecular N-H···O hydrogen bonding between the benzoyl C=O group and the N(7)-H hydrogen on the Hoogsteen site of the purine ring, forming an S(7) motif. The dihedral angle between the adenine and phenyl planes is 0.94 (8)° in (I) and 9.77 (8)° in (II). In (I), the Watson-Crick face of BA (N6-H and N1; purine numbering) interacts with the carboxylate and phenol groups of 3HPA through N-H···O and O-H···N hydrogen bonds, generating a ring-motif heterosynthon [graph set R2(2)(6)]. However, in (II), the Hoogsteen face of BA (benzoyl O atom and N7; purine numbering) interacts with TA (hydroxy and carbonyl O atoms) through N-H···O and O-H···O hydrogen bonds, generating a different heterosynthon [graph set R2(2)(4)]. Both crystal structures are further stabilized by π-π stacking interactions.

The salt–cocrystal spectrum in salicylic acid–adenine: the influence of crystal structure on proton-transfer balance

“…1) (Raghunathan & Pattabhi, 1981;Raghunathan et al, 1983;García-Terá n et al, 2004;Bo et al, 2006;Nirmalram et al, 2011;. The internal angles at N24 and N34 are in agreement with those reported for neutral adenine molecules at the N3 and N7 atoms (Raghunathan & Pattabhi, 1981; Karthikeyan et al, 2015). The C-O bond lengths of the deprotonated carboxylate groups in the salicylate anions in proton-transfer salt I range from 1.266 (3) to 1.282 (3) Å (Table 2) (Kö ferstein & Robl, 2015).…”

Cation tautomerism, twinning and disorder in the triclinic and monoclinic forms of 4-amino-5-chloro-2,6-dimethylpyrimidinium 5-chloro-2-hydroxybenzoate and a new disordered refinement of 2-amino-4,6-dimethoxypyrimidin-1-ium thiophene-2-carboxylate

“…A similar pattern of hydrogen-bonded rings is found in the structure of 2-amino-4,6-dimethoxypyrimidinium 2-hydroxybenzoate, (IV) (Thanigaimani et al, 2007), but a pair of S(6) rings is also present flanking the three central rings; the bond lengths in the cation again provide evidence for o-quinonoid-type bond fixation. Finally, we note that structures have been reported for a number of salts containing simpler substituted pyrimidines (Ebenezer et al, 2011;Ebenezer & Muthiah, 2012), as have those of some salts of substituted adenines (Tamilselvi & Muthiah, 2011;Karthikeyan et al, 2015). (Spek, 2009).…”

“…In the Crick-Watson model of DNA, the bases in the adeninethymine base pair are linked by one N-HÁ Á ÁN hydrogen bond and one N-HÁ Á ÁO hydrogen bond, while in the cytosineguanine pair, the bases are linked by one N-HÁ Á ÁN and two N-HÁ Á ÁO hydrogen bonds. Accordingly, there has been much ISSN 2053ISSN -2296 # 2017 International Union of Crystallography interest recently in the hydrogen-bonding properties of aminopyrimidines (Ebenezer et al, 2011;Tamilselvi & Muthiah, 2011;Ebenezer & Muthiah, 2012;Karthikeyan et al, 2015), prompted in part by the consideration that targeted drug action of pharmaceuticals containing this functionality is likely to depend heavily on molecular recognition processes involving hydrogen bonding. As part of a broader general study of hydrogen bonding in aminopyrimidine derivatives, we have now investigated the 1:1 salt formed between 4-amino-5chloro-2,6-dimethylpyrimidine and 5-chloro-2-hydroxybenzoic acid, which crystallizes as two tautomeric products, namely 6-amino-5-chloro-2,4-dimethylpyrimidin-1-ium 5-chloro-2hydroxybenzoate, (I), and 4-amino-5-chloro-2,6-dimethylpyrimidin-1-ium 5-chloro-2-hydroxybenzoate, (II), whose structures we report here (Figs.…”

Design of two series of 1:1 cocrystals involving 4-amino-5-chloro-2,6-dimethylpyrimidine and carboxylic acids

“…Hydrogen-bonding patterns, including base pairing formed by the aminopyrimidines, are important in the structure and functions of nucleic acids (Stanley et al, 2002;Baskar Raj et al, 2003). The hydrogen-bonding patterns present in several aminopyrimidine-carboxylates and cocrystals have been reported by us (Ebenezer et al, 2011;Tamilselvi & Muthiah, 2011;Ebenezer & Muthiah, 2012;Jegan Jennifer & Muthiah, 2014;Karthikeyan et al, 2015;Rajam et al, 2015Rajam et al, , 2017Swinton Darious et al, 2017).…”