Three-component reaction between isatoic anhydride, amine and methyl-substituted furylacrylaldehydes: crystal structures of 3-benzyl-2-[(E)-2-(5-methylfuran-2-yl)vinyl]-2,3-dihydroquinazolin-4(1H)-one, 3-benzyl-2-[(E)-2-(furan-2-yl)-1-methylvinyl]-2,3-dihydroquinazolin-4(1H)-one and 3-(furan-2-ylmethyl)-2-[(E)-2-(furan-2-yl)-1-methylvinyl]-2,3-dihydroquinazolin-4(1H)-one

Three 3-arylmethyl-2-[(E)-2-(furan-2-yl)vinyl]-2,3-dihydroquinazolin-4-ones – the products of a three-component reaction between isatoic anhydride, amine and furyl-2-methylacrylaldehyde were studied by X-ray diffraction.


Chemical context
3-Aryl-and 3-hetaryl-substituted allylamines and allylic alcohols are readily available and are common starting materials for the synthesis of complex cyclic systems with useful properties (Frackenpohl et al., 2016;Celltech R&D Ltd, 2004).
Until now, only one example of the synthesis of 3-(furyl)allylamines linked to a quinazoline fragment has been described in literature (Zaytsev et al., 2015). 2-Vinylfurylquinazolinones containing no methyl groups were obtained by a three-component reaction between isatoic anhydride, a primary amine, and furylacrolein. Some further transformation of these quinazolinones has been demonstrated.
This communication pursues the aim of acquiring structural information about 2-vinylfurylquinazolinones bearing a methyl group on the furan ring or at the double bond of the allylamine fragment, with the aim of further elucidating all aspects of its interaction with ,-unsaturated acid anhydrides. Molecular structure of (II). Displacement ellipsoids are shown at the 50% probability level. H atoms are presented as small spheres of arbitrary radius.

Figure 1
One of the synthetic pathways for the exploration of 3-substituted allylamines and allylic alcohols.

Figure 2
Molecular structure of (I). Displacement ellipsoids are shown at the 50% probability level. H atoms are presented as small spheres of arbitrary radius.

Figure 4
Molecular structure of (III). Displacement ellipsoids are shown at the 50% probability level. H atoms are presented as small spheres of arbitrary radius. group P2 1 /n, while compounds (II) and (III) are isostructural and crystallize in the orthorhombic space group Pbca.
The tetrahydropyrimidine ring in (I)-(III) adopts a sofa conformation, with the C2 carbon atom deviating from the mean plane of the other atoms of the ring by 0.639 (2), 0.476 (3) and 0.465 (3) Å , respectively. The nitrogen atom N1 has a trigonal-pyramidal geometry [the sums of the bond angles are 345, 348 and 350 for (I)-(III), respectively], whereas the nitrogen atom N3 is flattened [the sums of the bond angles are 357.3, 356.2 and 356.8 for (I)-(III), respectively]. The furyl-vinyl substituents in (I)-(III) are practically planar and have an E configuration at the C9 C10 double bond. Interestingly, in (I) this bulky fragment occupies the axial position at the quaternary C2 carbon atom of the tetrahydropyrimidine ring, whereas in (II) and (III) it is equatorially disposed. Apparently, this may be explained by the different directions of the three-component reactions.
The molecules of (I)-(III) possess an asymmetric center at the C2 carbon atom. The crystals of (I)-(III) are racemates.

Table 3
Hydrogen-bond geometry (Å , ) for (III). molecules within the chains are rotated by 180 relative to each other. The chains are packed in stacks along the a-axis direction (Fig. 5).
In the crystals of (II) and (III), molecules also form infinite hydrogen-bonded chains propagating along [100] by strong intermolecular N1-H1Á Á ÁO2 i (Table 2, Fig. 6) and N1-H1Á Á ÁO3 i (Table 3, Fig. 7) hydrogen bonds, respectively, with neighboring molecules rotated by 180 relative to each other. However, despite the fact that compounds (II) and (III) are isostructural, steric differences between the phenyl and furyl substituents result in chains with different geometries. Thus, in the crystal of (II) the chains have a zigzag-like structure (Fig. 6), whereas in the crystal of (III) they are almost linear (Fig. 7). In both (II) and (III), the hydrogen-bonded chains are further packed in stacks along the b-axis direction (Figs. 6 and 7).

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 4. X-ray diffraction studies were carried out on the 'Belok' beamline of the National Research Center 'Kurchatov Institute' (Moscow, Russian Federation) using a Rayonix SX165 CCD detector. A total of 360 images for each compound was collected using an oscillation range of 1.0 (' scan mode, two different crystal orientations) and corrected for absorption using the SCALA program (Evans, 2006). The data were indexed, integrated and scaled using the utility iMosflm in the CCP4 programme suite (Battye et al., 2011).
A relatively large number of reflections (a few dozen) were omitted for the following reasons: (1) In order to achieve better I/ statistics for high-angle reflections, we selected a longer exposure time, which resulted in some intensity overloads in the low-angle part of the area. These corrupted intensities were excluded from final steps of the refinement.
(2) In the current setup of the instrument, the low-temperature device eclipses a small region of the detector near its high-angle limit. This resulted in zero intensity for some reflections. (3) The quality of the single crystals chosen for the diffraction experiments was far from perfect. Some systematic intensity deviations can be due to extinction and defects present in the crystals.   iMosflm (Battye et al., 2011); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008). where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.37 e Å −3 Δρ min = −0.31 e Å −3 Extinction correction: SHELXL, Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.085 (8) Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.    (7) Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.