2-{[(4-Methoxyphenyl)dimethylsilyl]methyl}isoindoline-1,3-dione

In the course of our studies of silicon-containing anticancer compounds, the title compound, C18H19NO3Si, was synthesized. The molecular geometry including bond distances and angles involving the Si atoms are typical. Torsion angles associated with the isoindoline ring and the silyl group [C—N—Cmethylene—Si = 90.5 (2) and −93.1 (2)°] indicate that there is no interaction between the O and Si atoms despite silicon’s high affinity for oxygen.

In the course of our studies of silicon-containing anticancer compounds, the title compound, C 18 H 19 NO 3 Si, was synthesized. The molecular geometry including bond distances and angles involving the Si atoms are typical. Torsion angles associated with the isoindoline ring and the silyl group [C-N-C methylene -Si = 90.5 (2) and À93.1 (2) ] indicate that there is no interaction between the O and Si atoms despite silicon's high affinity for oxygen.
Organosilicon chemistry is a growing method of expanding chemical diversity (Franz, 2007;Franz et al., 2007;Tacke & Zilch, 1986;Showell & Mills, 2003), and it constitutes a powerful method of enhancing pharmacological properties in drug design (Bains & Tacke, 2003). In the course of our studies of silicon-containing anti-cancer compounds the title compound, (I), was synthesized and its structure is reported here.
The phthalate entity is planar within 0.0084 Å, and the methoxyphenyl group within 0.0044 Å. These groups are nearly parallel forming a 4.61 (8)° angle between their planes. There is one non-classical intermolecular interaction C4-H4···O2 with a C···O distance of 3.410 (3) Å and a C-H ···O angle of 134°. This weak interaction helps link the molecules of (I) into a three-dimensional framework.

Experimental
The protocol described by Tsuge and co-workers (Tsuge et al., 1985) was adopted. The required amount of potassium phthalimide (4.79 g, 25.88 mmol, 1.1 equiv) was placed into a 100 ml round-bottom flask, which was then sealed and flushed with nitrogen three times. Dry DMF (36 ml) was syringed into the flask followed by the addition of 4-methoxybenzylchloride (5.05 g, 23.53 mmol, 1 equiv.) The reaction was heated at 60°C for 6 h and the resulting mixture was then allowed to cool to room temperature. This slurry was poured onto a minimum quantity of water and extracted 3-5 times with ethyl ether. The organic extracts were subsequently collected, dried with magnesium sulfate, and filtered. The filtrate was mixed with silica gel and evaporated under reduced pressure to afford a powder of silica gel. This powder was loaded onto a dry-packed silica gel column and eluted using a gradient column. The fractions of interest were mobilized using a 8:2 hexane:ethyl acetate mixture but did not completely elute until a 1:1 hex:EtOAc mixture was employed. The fractions were then combined to afford the desired compound. Further recrystallization from dichloromethane afforded cream colored crystals (5.35 g, 16.44 mmol, 70% yield) for X-ray crystallography. Manipulation of air and moisture sensitive compounds was performed using supplementary materials sup-2 standard high-vacuum line techniques. All solvents and reagents were obtained from Aldrich. 4-Methoxybenzylchloride was purchased from Acros Organics. 1 H NMR spectra were obtained on a Varian Unity 500 spectrometer, 13 C {H} NMR spectra were obtained on a Varian 500 spectrometer operating at 125 MHz, 29 Si {H} NMR spectra were obtained on a Varian Unity spectrometer operating at 99 MHz. Mass spectra were determined on a Waters (Micromass) AutoSpec mass spectrometer.

Refinement
All H-atoms were placed in idealized locations and refined as riding with appropriate thermal displacement coefficients U iso (H) = 1.2 or 1.5 times U eq (bearing atom). The data were collected at room temperature on a Bruker SMART X2S diffractometer in the automated mode and manually processed thereafter. Fig. 1. Molecular structure of (I). The thermal ellipsoids are shown at 50% probability level. 0.0430 (9) 0.0418 (9) 0.0487 (9) 0.0035 (7) 0.0143 (7) 0.0013 (7)