N′-tert-Butyl-N′-(3,5-dimethylbenzoyl)-2,2-dimethyl-4-oxochroman-6-carbohydrazide

In the crystal structure of the title compound, C25H30N2O4, the steric size of the tert-butyl group causes the 3,5-dimethylphenyl ring to adopt a transoid geometry with respect to the N—C(O) bond. The six-membered heterocyclic ring is disordered over two sites, with occupancies of 0.553 (4) and 0.447 (4). Intramolecular C—H⋯O interactions are present. In the crystal, molecules are linked by intermolecular N—H⋯O and C—H⋯O hydrogen bonds.

In the crystal structure of the title compound, C 25 H 30 N 2 O 4 , the steric size of the tert-butyl group causes the 3,5-dimethylphenyl ring to adopt a transoid geometry with respect to the N-C(O) bond. The six-membered heterocyclic ring is disordered over two sites, with occupancies of 0.553 (4) and 0.447 (4). Intramolecular C-HÁ Á ÁO interactions are present. In the crystal, molecules are linked by intermolecular N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds.

Comment
Dibenzoylhydrazines are well known as nonsteroidal ecdysone agonists that have the potential to control the Lepidopteran pests while exerting only a low toxicity against non-target insects. (Sawada et al., 2003). While chroman derivatives also have broad-spectrum biological activity. Hence, to search for novel lead compounds for crop protection, The title compound, (I), was designed and synthesized in our laboratory. In this paper, we present the X-ray crystallographic analysis of (I).
As shown in Fig. 1, the six-membered heterocyclic ring adopts a half-chair conformation. the dihedral angle between the phenyl ring and the benzene ring of the chromanone is 58.14 (2)°. The six-memebered heterocyclic ring is disordered over two sites with occupancies of 0.553 (4) and 0.447 (4). The steric size of the N-tert-butyl group causes the 3,5-dimethylphenyl group to be directed away from it.
One intermolecular N-H···O hydrogen bond and one intermolecular C-H···O hydrogen bonds exist in the crystal structure (Table 1 and Fig. 2), atoms N1 and C8 in the molecule act as donors, via the H atoms H1 and H8, to the O4 of a adjacent molecule(Tabel 2). As a result, an seven-membered ring is formed between molecules (Fig. 2). No π-π stacking interactions are observed in the crystal structure.

Experimental
To A solution of 2,2-Dimethyl-4-oxo-chroman-6-carboxylic acid N'-tert-butyl-hydrazide (1.5 mmol) in 10 ml of dichloromethane was added dropwise to a stirred mixture of 3,5-dimethylbenzoyl chloride (1.5 mmol), triethylamine (1.6 mmol) and dichloromethane (5 ml) in an ice bath.After stirring the mixture at room temperature for 3 h,ethyl acetate (30 ml) was added to the reaction mixture. The organic layer was separated and washed successively with water (15 ml) and brine (15 ml), and then dried with anhydrous sodium sulfate. After evaporating the solvent, the residue was purified by column chromatography on silicagel using hexane/ethyl acetate ( . Crystals suitable for an X-ray diffraction study were grown from methanol at 292 K.

Refinement
All H atoms were initially located in a difference Fourier map. The methyl H atoms were then constrained to an ideal geometry with C-H distances of 0.96 Å and U iso (H) = 1.5U eq (C), but each group was allowed to rotate freely about its C-C bond. All other H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C-H distances in the range 0.93-0.97 Å,an N-H distance of 0.86 Å and U iso (H) = 1.2U eq (C,N).  0.0718 (10) 0.0418 (7) 0.0416 (7) 0.0084 (7) 0.0097 (7) 0.0023 (6)  C9 0.0468 (7) 0.0375 (7) 0.0467 (7) 0.0039 (5)