5-Chloro-3-hydroxy-2,2-dimethyl-2,3-dihydro- quinazolin-4(1H)-one: supramolecular aggregation through a two-dimensional network of N—H O and O—H O interactions

Department of Chemistry, Urumu Dhanalakshmi College, Tiruchirappalli 620 019, India, Department of Chemistry, Durham University, Durham DH1 3LE, England, Centre for Synthesis and Chemical Biology, Department of Pharmaceutical and Medicinal Chemistry, Royal College of Surgeons in Ireland, 123 St. Stephen’s Green, Dublin 2, Ireland, and School of Pharmacy, Royal College of Surgeons in Ireland, 123 St. Stephen’s Green, Dublin 2, Ireland

The molecular structure of (I) is shown in Fig. 1 and selected geometric parameters are given in Table 1. The 1,3diaza ring exists in a skew-boat conformation, with puckering parameters (Cremer & Pople, 1975) Q T = 0.396 Å , = 64.6 and ' = 295.08 . This is also evident from the torsion angles involving the 1,3-diaza ring ( Table 1). The axial orientation of the C10 methyl group, the equatorial orientation of the C8 methyl group, the equatorial orientation of the O atom of the N-OH group, and the relative synclinal orientation of the carbonyl O atom and the O atom of the N-OH group are evident from the corresponding torsion angles (Table 1).
Experimental 6-Chloroanthranilic hydroxamic acid was prepared according to reported methods (Devocelle et al., 2003;Lee et al., 2005). During our attempts to recrystallize the above product from acetone-ethanol (1:1), crystals of the title compound were produced after standing for 30 d. These may have been formed by a condensation reaction of 6chloroanthranilic hydroxamic acid with acetone. Such a reaction mechanism has already been reported for the formation of 2,3dihydro-1H-quinazolin-4-one derivatives (Yoo et al. 2005).  Table 1 Selected torsion angles ( ).
The molecular structure of the title compound, showing 50% probability displacement ellipsoids
All H atoms were located in a difference map, and their positions and isotropic displacement parameters were refined.
Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: MERCURY (Macrae et al., 2006); software used to prepare material for publication: SHELXL97. Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.