Continuing a study of the chemical composition of the epigeal part of Haplophyllum bucharicum Litv., from the neutral fraction of the methanolic extract by chromatography on columns of alumina and silica gel, a new alkaloid buchapine (C19H23NO2, mp 134-135°C (hexane)) was obtained. Its mass spectrum of (I) -- m/z (%) 297 (M+ 10), 229 (M-68, 34), 228 (M-69, 100), 214 (20), 212 (24), 200 (16), 186 (38), 174 (24), 69 (20) -- almost coincides with that of 3-dimethylallyl-4-dimethylallyloxy-2-quinoline (II) with only slight differences in the intensities of some peaks. These results, and also the presence in the IR spectrum of buchapine of absorption bands at 1692 cm-1 together with the band of an amide carbonyl group at 1660 cm-1 have permitted the suggestion that it is based on a 1,2,3,4-tetrahydroquinoline-2,4-dione nucleus with two prenyl substituents in position 3. This conclusion is in harmony with the UV spectrum of (I): λ (nm) 234, 238 (shoulder), 242 inflo, 244 infl., 258 max shoulder, 324, 329 shoulder, 325 infl. (logε4.44, 4.41, 4.32, 3.72, 3.60, 3.41, 3.50, 3.40), which differs from those of the 4-alkoxy-2-quinolone alkaloids, in particular (II), by the absence of maxima in the 260-290 nm region characteristic for this group of substances, but it is close to those of 3,3-diprenyl-1,2,3,4-tetrahydroquinoline-2,4-dione compounds. The structure of buchapine follows from its PMR spectrum (CDCl3, δ scale), which contains signals at 7.74 and 7.5-6.82 ppm (doublet, 1 H, J = 8.5 Hz, and multiplet, 3H) relating to the H-5 and H-6,7,8 aromatic protons, and also at 5.76 and 4.81 ppm (A2B system, 1 H and 2 H respectively: --CH=CH2), 4.65 and 2.77 ppm (triplet, 1 H; doublet, 2 H, J = 7.5 Hz, =CH--CH2), and 1.88, 1.40, and 1.09 ppm (singlets, 3 H, 3 H, and 6 H, respectively), belonging to the protons of two prenyl substituents one of which has the structure --C(CH3)2--CH=CH2 and the other --CH2--CH=C(CH3)2. Consequently, buchapine has the structure of 3-(α,α-dimethylallyl)-3-(γ,γ-dimethylallyl)-1,2,3,4-tetrahydroquinoline-2,4-dione. Buchapine is the only alkaloid of the 1,2,3,4-tetrahydroquinoline-2,4-dione type with phenyl substituents of different structures in position 3. From the total bases obtained by chloroform extraction from the epigeal organs of Hippeastrum equestre Herb. (family Amaryllidaceae) (2 kg) collected in the Peoples' Republic of Bangladesh in the flowering period, on the basis of solubility differences in organic solvents, 2.36 g of lycorine, 0.30 g of galanthine, and 0.28 g of galanthamine were isolated. Chromatography of the residual material on a column of type KSK silica gel using as solvents mixtures of chloroform and methanol with successive increases in the concentration of methanol has yielded 0.54 g of hippeastrine, 0.76 g of tazettine, 0.40 g of hemanthamine, and 0.32 g of a base (III) with mp 243-245°C (decomp, methanol). The identification of the compounds mentioned was carried out with the aid of the determination of physicochemical constants, thin-layer chromatography, and UV, NMR, and mass spectroscopy. This is the first time that any of the alkaloids mentioned has been isolated from the epigeal organs of Hippeastrum equestre.