Crystal structure of flucetosulfuron

The title compound, C18H22FN5O8S, is used as a herbicide. The crystal structure is stabilized by N/C—H⋯O hydrogen bond, C—H⋯F and C—H⋯π interactions with weak π–π interactions contacts to form a three-dimensional architecture.


Chemical context
Flucetosulfuron, a relatively new herbicide, inhibits acetolactate synthase (ALS) in plants, as do other ALS inhibitors such as imidazolinones, pyrimidinyloxybenzoates, triazolopyrimidines, and sulfonylaminocarbonyltriazolinones (Lee et al., 2014). It is a novel post-emergence sulfonylurea herbicide providing excellent control of Galium aparine and other important broadleaf weeds with good safety to cereal crops, wheat and barley  In rice, the herbicide provides excellent control of Echinochloa crus-galli, which is not or only marginally controlled by common sulfonylurea products, and also controls annual broadleaf weeds, sedges and perennial weeds of rice with similar efficacy to other sulfonylurea rice herbicides . Until now, its crystal structure had not been reported and we describe it herein. ISSN 2056-9890

Structural commentary
The structure of flucetosulfuron is shown in Fig. 1. The dihedral angle between the mean planes of the pyridine and pyrimidine rings is 86.90 (7) . All bond lengths and angles are normal and comparable to those observed in similar crystal structures (Jeon et al., 2015;Chopra et al., 2004).

Figure 1
The molecular structure of the title compound with the atom labelling and displacement ellipsoids drawn at the 50% probability level. H atoms are shown as small spheres of arbitrary radius.
tecture with molecules stacked along the a-axis direction (black dashed lines in Fig. 3).

Database survey
We have reported the crystal structures of several pesticides including compounds with pyrimidinylsulfonylurea, dimethoxypyrimidin and sulfonylurea ring (Kang et al., 2015;Jeon et al., 2015;Kwon et al., 2016).

Synthesis and crystallization
The title compound was purchased from Dr Ehrenstorfer GmbH. Colourless single crystals suitable for X-ray diffraction were obtained from a CH 3 CN solution by slow evaporation at room temperature.

1-[3-({[(4,6-Dimethoxypyrimidin-2-yl)carbamoyl]amino}sulfonyl)pyridin-2-yl]-2-fluoropropyl 2-methoxyacetate
Crystal data 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.