This article presents a synthesis of new naphthopyrandione derivatives with cycloalkanespirohydantoins. The target compounds were obtained by reaction of 4-bromo-1,8-naphthalic anhydride /6-bromo-1H,3H-naphtho[1,8-cd]pyran-1,3-dione/ with cyclopentanespiro-5-hydantoin /1,3-diazaspiro[4.4]nonane-2,4-dione/ and cyclohexanespiro-5-hydantoin /1,3-diazaspiro[4.5]decane-2,4-dione/. As a result of this interaction the following products were prepared: 3-(1,3-dioxo-1H,3H-naphtho[1,8-cd]pyran-6-yl)-1,3-diazaspiro[4.4]nonane-2,4-dione and 3-(1,3-dioxo-1H,3H-naphtho[1,8-cd]pyran-6-yl)-1,3-diazaspiro[4.5]decane-2,4-dione. The newly synthesized compounds were characterized by physicochemical parameters, elemental analysis and IR spectral data.
The fungicidal activity of the products cited above was investigated towards Monilia fructigena (brown rot). It was found that both compounds were able to completely inhibit the germination of the Monilia fructigena conidia.