Methyl 9-hydroxy-15-methyl-2-oxo-11-(pyren-1-yl)-10-oxa-15-azatetracyclo[7.6.0.01,12.03,8]pentadeca-3(8),4,6-triene-12-carboxylate

In the title compound, C32H25NO5, the furan and pyrrole rings each adopt an envelope conformation, the respective flap atoms being the C atom bearing the pyrene substituent and the CH2 atom adjacent to the N atom. The molecular conformation is stabilized by an intramolecular O—H⋯N hydrogen bond. In the crystal, C—H⋯O contacts link the molecules, forming a two-dimensional network parallel to (001).

In the title compound, C 32 H 25 NO 5 , the furan and pyrrole rings each adopt an envelope conformation, the respective flap atoms being the C atom bearing the pyrene substituent and the CH 2 atom adjacent to the N atom. The molecular conformation is stabilized by an intramolecular O-HÁ Á ÁN hydrogen bond. In the crystal, C-HÁ Á ÁO contacts link the molecules, forming a two-dimensional network parallel to (001).

Comment
Owing to their electronic, optical and geometric properties, mono-functionalized pyrenes, attachable to a receptor platform, are of special interest for the development of fluorescent sensors (Bren et al., 2001).
The pyrene moiety alone shows no significant deviations of bond lengths and angles compared with those of the unsubstituted analogue (Robertson et al., 1947;Camerman et al., 1965;Allmann et al., 1970;Hazell et al., 1972;Kai et al., 1978). The furan and pyrole rings adopt an envelope conformation. C17 and C20 are displaced by -0.2843 (2) Å and 0.2851 (2) Å, respectively, from the least-square planes formed by the remaining ring atoms. The dihedral angle between the furan and pyrole ring being 65.50 (6)°. The carboxylate group (C30/05/C31) is almost perpendicular to the furan ring with dihedral angle of 85.05 (1)°. The molecular conformation is stabilized by an intramolecular O-H···N hydrogen bond and the crystal packing is stabilized by intermolecular C-H···O contacts.

Experimental
To a reaction mixture of 2-((3a2, 4-dihydropyren-1-yl)(hydroxy)methyl)acrylate (1 mmol), ninhydrine (1.1 mmol) and sarcosine (1.1 mmol) was refluxed in methanol until completion of the reaction was evidenced by TLC analysis. After completion of the reaction the solvent was evaporated under reduced pressure. The crude reaction mixture was dissolved in dichloromethane and washed with water followed by brine solution. The organic layer was separated and dried over sodium sulfate, filtering and evaporation of the organic solvent under reduced pressure. The product was separated by column chromatography using hexane and ethyl acetate (3:7) as an eluent to give colorless solid. The product was dissolved in chloroform and heated for five minutes. The resulting solution was subjected to crystallization by slow evaporation of the solvent resulting in single crystals suitable for XRD studies.

Refinement
All the H atoms were positioned geometrically, with C-H = 0.93-0.97Å and constrained to ride on their parent atom, with U iso (H) =1.5U eq (C) for methyl H atoms and 1.2U eq (C) for other H atoms. The hydroxyl H atom was freely refined.     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.