3-Phenyl-2-(pyrrolidin-1-yl)-5,6-dihydro-8H-thio-pyrano[4',3':4,5]thieno[2,3-d]pyrimidin-4(3H)-one.

In the title compound, C(19)H(19)N(3)OS(2), the thio-pyran ring adopts a twist-chair conformation and the pyrimidinone unit is essentially planar, with a mean deviation of 0.0497 Å. The thio-phene ring is essentially planar with a maximum deviation of 0.024 (2) Å, while the pyrrolidine ring exhibits an envelope conformation. The pyrimidinone and thio-phene rings are almost coplanar, forming a dihedral angle of 6.31 (15)°, while the dihedral angle between the mean planes of the phenyl ring and the pyrimidinone ring is 68.13 (10)°. In the crystal structure, adjacent mol-ecules are linked by C-H⋯O hydrogen bonds, forming a two-dimensional network in the ac plane.

In the title compound, C 19 H 19 N 3 OS 2 , the thiopyran ring adopts a twist-chair conformation and the pyrimidinone unit is essentially planar, with a mean deviation of 0.0497 Å . The thiophene ring is essentially planar with a maximum deviation of 0.024 (2) Å , while the pyrrolidine ring exhibits an envelope conformation. The pyrimidinone and thiophene rings are almost coplanar, forming a dihedral angle of 6.31 (15) , while the dihedral angle between the mean planes of the phenyl ring and the pyrimidinone ring is 68.13 (10) . In the crystal structure, adjacent molecules are linked by C-HÁ Á ÁO hydrogen bonds, forming a two-dimensional network in the ac plane.

Related literature
For the applications of pyrimidine derivatives as pesticides and pharmaceutical agents, see: Condon et al. (1993) and as antiviral agents, see; Gilchrist (1997 Table 1 Hydrogen-bond geometry (Å , ).   (Condon et al., 1993). Pyrimidine derivatives have also been developed as antiviral agents, such as AZT (azidothymidine), which is the most widely used anti-AIDS drug (Gilchrist, 1997). In order to discover further biologically active pyrimidine compounds, the title compound was synthesized, and its crystal structure was determined which is presented in this paper.
In the title compound ( Fig. 1) the tetrahydropyran ring adopts a twist chair conformation with S2 and C1 lying 0.451 (5) and 0.474 (5) Å, respectively, on the opposite sides of the plane formed by the rest of the ring atoms. The pyridinone unit is essentially planar with a mean deviation of 0.0497 Å; the maximum deviation of any atom from the plane is 0.0432 (14) Å for N3. The pyrimidone and the thiophene rings are almost coplanar with the dihedral angle 6.31 (15)° and the dihedral angle between the mean-planes of the phenyl ring and the pyridinone ring is 68.13 (10)°. The thiophene ring is essentially planar (max. dev. 0.024 (2) Å for C4) while the tetrahydropyrrole exhibits a C12-envelop conformation with C12 lying 0.568 (4) Å out of the plane formed by the rest of the atoms in the ring.
The bond distances and bond angles in the title compound are comparable to the corresponding distances and angles reported for a closely related compound (Xie et al., 2008). In the crystal structure, adjacent molecules are linked by C-H···O hydrogen bonding interactions (Tab. 1), and form a two-dimensional network (Fig. 2).

Experimental
To a solution of iminophosphorane (2.0 mmol) in absolute anhydrous dichloromethane (10.0 ml), isocyanatobenzene (2.0 mmol) was added under nitrogen atmosphere at room temperature. After the reaction mixture was stirred for 3.0 h at room temperature, the iminophosphorane had disappeared (TLC monitored). The solvent was removed under reduced pressure and EtOH/petroleum ether (1:3, 15.0 ml) was added to precipitate triphenylphosphine oxide. Removal of the solvent gave carbodiimides, which were used directly without further purification. To a solution of carbodiimides in dichloromethane (10.0 ml) was added pyrrolidine (2.0 mmol). The reaction mixture was left unstirred for 6 h. The solvent was removed and anhydrous EtOH (10.0 ml) with several drops of EtONa was added. The mixture was stirred for 6-12 h at room temperature.
The solution was condensed, workup and chromatography (hexane/AcOEt) gave the expected cyclic compounds in good yield. The crystals of the title compound were grown mother liquor by slowly evaporation from at room.

Refinement
The hydrogen atoms were placed in geometrically idealized positions with Csp 2 -H = 0.93Å and Csp 3 -H = 0.97 Å, and constrained to ride on their parent atoms with U iso (H) set to 1.2 × U eq (C). Fig. 1. The structure of (I), with displacement ellipsoids drawn at the 30% probability level for the non-H atoms.  as those based on F, and R-factors based on ALL data will be even larger.