I. A. Bessonova, Udc, nigripes Nevski
May 1, 2000
Citations
1
Influential Citations
12
Citations
Journal
Chemistry of Natural Compounds
Abstract
Haplophyllum bucharicum Litv. (H. nigripes Nevski, Rutaceae) is a bushy perennial common in Kashkadar'inskii and Surkhandar'inskii districts [l]. The aerial part of the plant from two sites, near Dekhkanabad in Kashkadar'inskii district [2] ,and Derbent in Baisunskii region of Surkhandar'inskii district [3] has been previously studied. A total of 13 quinoline alkaloids were isolated from this plant [4]. The main component in both instances was bucharaine, the content of which was >90% of the alkaloids. The plant is atypical because it produces quinoline alkaloids with a terpene fi-a~nent (bucharaine, bucharidine, bucharaminol) [5] that are unique to this species within not only the genus but also the family. Chromatographic investigation on Silufol UV-254 plates of the total alkaloids and the acidic and neutral fractions remaining after separation of bucharaine and other alkaloids and neutral compounds [3] revealed several spots belonging to components that previously had not been isolated from this plant. Acid-insoluble mother liquors remaining after isolation and purification of bucharaine were dried (8.5 g) and treated with NaOH solution (4%). The alkali-soluble portion developed a precipitate (2.38 g) upon acidification by glacial CH3CO2H that was cryst,'dlized from ethylacetate after treatment with hot CHCI 3. Yield 1.5 g of diphyllin, mp 285-286 C [6]. The solid was washed with hot CH3OH ,and crystallized from CH3CO2H (60%). Yield 0.23 g of 1. Bucharaine 13.8 g) was isolated from the alkali-insoluble part (5.1 g). The CHCl3-soluble fraction was chromatographed on a silica-gel column. Skimmianine (0.3 g) and three minor compounds 2-4 were isolated. Compound 1, Ct~H702N, mp 353-354 C (decom.). PMR (400 MHz, DMSO, ~, ppm, J, Hz): 5.69 ( I H, s, H-3), 7.05 and 7.40 ( IH each, t, J = 8, H-6, H-7), 7.21 and 7.75 ( IH each, dd, J = 8.0; 2.0, H-8, H-5), 11.09 (2H, br. s, NH, OH). Compound 2, CIoH,)O2N, mp 254-256 C (decom.) (acetone). PMR (100 MHz, CDCI3): 3.91 (3H, s, OCH3), 5.95 ( IH, s, H-3), 7.00-7.55 (3H, m, H-6, H-7, H-8), 7.85 ( IH, dd, J = 8.0: 2.5, H-5), 11.95 ( 1 H, br, s, NH). Compound 3, C_~jHI(,O(,, mp 231-232 C (MeOH). M 364. PMR ( 100 MHz, CDCI3): 3.75, 4.00 (3H each, s, 2xOCH3), 5.36 (2H, s, Ar-CH2-O), 6.01, 6.03 ( I H each, d, J = 1.2, O-CH-,-O), 6.76 ( I H, dd, J = 8.0: 1.5, H-6' ), 6.82 ( I H, s, H-2'), 6.96 ( 1 H, dd, J = 8.0; 1.0, H-5'), 7.07, 7.15 ( 1H each, s, H-5, H-8), 7.63 (IH, s, H-4). Compound 4, C2.~HisO 8, nap 231-232 C (C2H5OH), M 422. PMR ( 100 MHz, CDC[3): 2.46 (3H, s, OAc), 3,75, 4.00 (3H each, s, 2xOCH3), 5.19 (2H, s, Ar---CH-,-OI, 6.01, 6.04 ( 1H each, d, J = 1.2. O-CH.,-O), 6.76 ( I H, dd, J = 8.0: 1.5, H-6'), 6.81 ( I H, s, H-3'), 6.95 (1 H, dd, J = 8.0; 1.5, H-5'), 7.06, 7,12 { IH each, s, H-5, H-8). Comparison of the compositions, melting points, and PMR spectra of 1-4 with known quinoline alkaloids and arylnaphthalide ligands identified 14 as 4-hydroxyquinolin-2-one, 4-methoxyquinolin-2-one [7], justicidin B [8], and acetyldiphyllin [9], respectively. Compounds 1-4 were first isolated from H. bueharicum. It was previously established using labeled compounds that the biosynthetic pathway from anthranilic acid to quinoline ,alkaloids passes through 4-hydroxyquinolin-2-one as an intermediate [10], However, the last was not isolated from the plant. From this viewpoint, the preparation of 4-hydroxyquinolin-2-one from H. bucharicum is an important confirmation of its involvement in the biosynthesis ofquinoline alkaloids, in particular, bucharaine, from which bucharamine.and bucharidine are lbrmed by Claisen rearrangement [5]. Roots of H. bucharicum growing near Derbent of Surkhandar'inskii district contain 0.13% of a mixture of alkaloids, fi'om which known furanoquinolines (skimmianine, dictamnine, y-fagarine, robustine, haplopine) and p3n'anoquinolin-2-ones