Abstract: 4-(4'-Fluorophenyl)-6,6,10,10-tetramethyl-6a,9-methano-5,6,6a,7,8,9,10,10a-octahydrobenzo[h] quinazolin-2-ylamine (FBQ) was synthesized by aldol condensation, to obtain 7-(4'-fluoro-benzylidene)-isolongifolanone (FBI) from isolongifolanone, and then cyclization with guanidine hydrochloride using t-BuOK as the catalyst in t-butanol. The effects of the sort and dosage of catalysts, reaction time, reaction temperature, and the molar ratio of FBI and guanidine hydrochloride on the cyclization were investigated. The optimum cyclization conditions were determined according to the orthogonal experiments. The results were as follows: n(t-BuOK):n(FBI) was 2.9:1, reaction temperature 75℃, reaction time 14 h, the molar ration of FBI and guanidine hydrochloride 1:4. The yield of final product reached 79.51% under the above conditions. The chemical structure of FBQ was determined by FT-IR, MS, ¹H NMR, and ¹³C NMR, respectively. Its spatial structure was examined by X-ray single crystal diffraction. According to single-crystal X-ray diffraction analysis, the target compound was of triclinic system, space group P-1 with a=0.660 85(9)nm,b=1.175 27(16)nm, c=1.340 65(17)nm, α=86.229(3)°, β=83.094(4)°, γ=77.558(4)°, V=1.008 6(2)nm³, Z=2, D_C=1.203 g/cm³, F(000)=392, M_r=365.48, μ=0.078 mm^-1, R=0.099 3 and wR=0.156 5.

Key words: isolongifolanone, aldol condensation, cyclization, quinazoline derivatives