(E)-1-[(1,3-Dioxan-4-yl)methyl]-2-(nitromethylidene)imidazolidine

In the title compound, C9H15N3O4, the 1,3-dioxane ring displays a chair conformation and the five-membered ring is close to planar (r.m.s. deviation = 0.054 Å). An intramolecular N—H⋯O hydrogen bond to one of the nitro-group O atoms generates an S(6) ring. In the crystal, intermolecular N—H⋯O hydrogen bonds link the molecules into C(6) chains propagating in [010] and a C—H⋯O link also occurs.

In the title compound, C 9 H 15 N 3 O 4 , the 1,3-dioxane ring displays a chair conformation and the five-membered ring is close to planar (r.m.s. deviation = 0.054 Å ). An intramolecular N-HÁ Á ÁO hydrogen bond to one of the nitro-group O atoms generates an S(6) ring. In the crystal, intermolecular N-HÁ Á ÁO hydrogen bonds link the molecules into C(6) chains propagating in [010] and a C-HÁ Á ÁO link also occurs.

Comment
By virtue of novel modes of action (targeting insect nicotinic acetylcholine receptors (nAChRs) (Ohno et al., 2009), low mammalian toxicity, broad insecticidal spectra, and good systemic properties (Jeschke et al., 2008), neonicotinoids has accounted for 18% of world insecticide sales in the past decades. Our interest was introducing oxygen atoms into the lead struture and synthesizing a series of new compounds, in which the title compound exhibited moderate insecticidal activities against pea aphids.
The structure of the title compound is shown in Fig. 1 with the atom-numbering scheme. The 1,3-dioxane ring displays an chair conformation with bond angles lying between 110.0 (2)° and 111.7 (2)°. The nitro moiety is in trans configuration relative to the 1,3-dioxane ring and coplanar with the olefin-amine plane [N3-C2-C1-N1 = -177.49 (18)°]. Around N2 and N3 atoms the sums of the angles are 360° and 359.72°, respectively, indicating that they are typical sp 2 hybridized and leading to an essentially planar imidazole ring.

Experimental
A solution of N-((1,3-dioxan-4-yl)methyl)ethane-1,2-diamine (2 mmol), and 1,1-bis(thiomethyl)-2-nitroethylene (2 mmol) in 30 ml of ethanol was refluxed for 8 h and then cooled to room temperature. Evaporation under reduced pressure gave the title product after purifiction by flash chromatography. Colourless prisms of (I) were obtained by slow evaporation of a solution of the title compound in dichloromethane and ethyl acetate.

Refinement
All H atoms were placed in their calculated positions and then refined using riding model with C-H = 0.93-0.99 Å, U iso (H) = 1.2 (1.5 for methyl groups) times U eq (C). Fig. 1. The molecular structure of (I) with displacement ellipsoids drawn at the 40% probability level. The H atoms are shown as spheres of arbitrary size.