Synthesis and X-Ray Crystal Structure of Two Acridinedione Derivatives

The two acridinedione derivatives 1 [3,3,6,6-tetramethyl-9-(4-methoxyphenyl)-3,4,6,7,9,10-hexahydro-2H,5H-acridine-1,8-dione (C 24 H 29 NO 3 )] and 2 [3,3,6,6-tetramethyl-9-(4-methylphenyl)-3,4,6,7,9,10-hexa-hydro-2H,5H-acridine-1,8-dione (C 24 H 29 NO 2 )] were synthesized and their crystal structures were determined by direct methods. The asymmetric unit of compound 1 contains two independent molecules. The 1,4-dihydropyridine (DHP) ring adopts boat conformation in both 1 and 2. In 1 the dione rings exist in sofa conformation (for both the crystallographically independent molecules) while the corresponding rings in 2 adopt half chair and sofa conformations, respectively.The crystal packing is stabilized by intermolecular N–H⋅ ⋅ ⋅O and C–H⋅ ⋅ ⋅O interactions in compound 1 and N–H⋅ ⋅ ⋅O interactions in compound 2.


Materials and Methods
All the chemicals were purchased from SD Fine Chem Limited and Thomas Baker, used as received without further purification.Melting point was determined on Labstar melting apparatus.The IR spectra were recorded on a Perkin-Elmer, FTIR-1600 spectrophotometer and expressed in cm −1 (KBr). 1 H NMR spectra were recorded on Bruker Avance (300 MHz) spectrometer in DMSO-d 6 using TMS as the internal standard.Elemental analysis was performed on a EURO-EA analyzer.cooled to RT and poured on ice water under stirring; solids were precipitated out.Filter the product and dry it.The crude products were recrystallized from ethanol and characterized by IR, 1 H NMR, and elemental and single crystal analysis.

X-Ray Analysis.
A summary of the crystallographic data is given in Table 1.The X-ray intensity data of a well-defined crystal for 1 and 2 (0.30 × 0.20 × 0.10 mm) were collected at room temperature (293 K) by using a CCD area-detector diffractometer (X' calibur system, Oxford diffraction, 2010) which is equipped with graphite monochromated MoK radiation ( = 0.71073 Å).The cell dimensions were determined by the least-squares fit of angular settings of 14203 (1) and 11474 (2) reflections in the  range 3.48 to 29.04 ∘ (1) and 3.99 to 23.48 ∘ (2), respectively.Data were corrected for Lorentz, polarization, and absorption factors.

Results and Discussion
Figures 1 and 2 show the perspective view of molecules 1 and 2, respectively [14].Table 2 presents selected geometrical parameters for both the structures.The asymmetric unit of compound 1 comprises two crystallographically independent molecules, A and B (Figure 2).Bond lengths and angles are normal and correspond to those observed in some related structures [15,16] [17].
Packing of molecules 1 and 2 in the unit cell is shown in Figure 3.The crystal packing is stabilized by the presence of few intermolecular N-H⋅ ⋅ ⋅ O and C-H⋅ ⋅ ⋅ O interactions

Figure 3 :
Figure 3: The crystal packing as seen along the direction of hydrogen bonded chains in 1 (a) and 2 (b).