Fifteen new N′-tert-butyl-N′-(substituted benzoyl)-N-(chromane-5-carbonyl)hydrazine derivatives were synthesized from 3-hydroxybenzoic acid. The intermediate methyl 3-(prop-2-ynyloxy)benzoate was refluxed in N,N-diethylaniline to give methyl 2H-chromene-5-carboxylate as main product and methyl 2H-chromene-7-carboxylate as byproduct. The structures of the target compounds were confirmed by 1H NMR spectra, elemental analysis or high resolution mass spectra (HRMS). X-ray diffraction analysis of the target compound 1a shows that the pyran and the benzene rings of the chroman are not coplanar, and the C(1) and C(2) are at both sides of the plane of the corresponding benzene ring.

Key words: N,N′-diacylhydrazine, insect growth regulator, crystal structure, chromane