A Short Synthesis of Carbazole Alkaloids Murrayanine and Mukonine (original) (raw)
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A Concise Synthesis of the Natural Carbazole Mukonine
HETEROCYCLES, 2002
A short and total synthesis of the natural carbazole mukonine (1) is described, based on a regioselective Diels-Alder reaction of N-phenyl 4,5dimethylidene-2-oxazolidinone (9) with methyl propiolate (10). Successive transformation of the cycloadduct in one step to the corresponding phenylarylamine (16), and palladium promoted cyclization of the latter provided carbazole (1). Given the biological importance of natural carbazole alkaloides, 1 an intensive effort has been directed toward their isolation, 2 and total synthesis. 1c,3 Among them, mukonine (1) has been isolated from Murraya koenigii 4 and Clausena excavata. 2c,2f From a biogenetical viewpoint, carbazole (1) probably arises from in vivo oxidation of the 3-methyl precursor called murrayafoline A. 1j,4,5 Several synthetic routes have been reported for its preparation.
Two carbazole alkaloids from Murraya koenigii
Phytochemistry, 1994
The non-cyclized possible biogenetic precursors of girinimbine and mahanimbine, 2-hydroxyl-3-methyl-l-(3-methyl-2-butenyl)arbazole (girinimbilol) and 2-hydroxyl-3-methyl-1-(3,7-dimethyl-2,6-octadienyl)carbazole (mahanimbilol) have been isolated from the stem bark of Murraya koenigii. The structures were established by cyclization to dihydrogirinimbine and a new bicyclocarbazole, bicyclomahanimbiline, respectively.
Synthesis, 2004
A new synthesis of the natural carbazoles Murrayanine (1) and Murrayafoline A (3) is described. The key step in the synthetic route involved the regioselective cycloaddition of the diene 4,5-dimethylene-3-phenyl-1,3-oxazolidin-2-one (4) to acrolein (6) catalyzed by Lewis acids at low temperature. Direct aromatization of the substituted cyclohexene moiety of adduct 7, and further hydrolysis of the 2-oxazolidinone ring, proved to be a more efficient strategy than the opposite synthetic sequence for the preparation of the corresponding arylphenylamines 14 and 18. Palladium-promoted cyclization of the latter furnished the desired carbazoles 1 and 3 in high overall yields.
C23-carbazole alkaloids from malayan Murraya koenigii (L.) spreng
Murraya koenigii (Curry leaf tree), from the Rutaceae family, is a medicinally important herb of Indian origin and now were widely distributed throughout southern Asia. The bark of Malayan Murraya koenigii was selected for phytochemical investigation. The isolation of chemical constituents from its hexane and dichloromethane extract was carried out by using different chromatographic techniques. Six carbazoles with C23-framework was isolated and identified as mahanimbine, murrayamine-J, murrayazolinol, mahanimbilol, murrayakoeninol and bicyclomahanimbine. The structural characterization of the isolated compounds was supported by spectroscopic methods, including NMR, IR, UV, MS spectra data.
C23-Carbazole Alkaloids from the Bark of Murraya koenigii (L.) Spreng
Murraya koenigii (Rutaceae), locally known as curry leaf tree, is a medicinally important herb of Indian origin and now were widely distributed throughout southern Asia. The bark of Murraya koenigii was selected for phytochemical investigation. The isolation of chemical constituents from its hexane extract was carried out by using different chromatographic techniques. Four C23-carbazole alkaloids was isolated and identified as mahanimbine 1, murrayamine-J 2, murrayazolinol 3 and bicyclomahanimbine 4. Spectroscopic methods, including NMR, IR, UV, MS spectra data, were used for the structural characterization.
Quantitative Analysis of Bioactive Carbazole Alkaloids in Murraya koenigii
Carbazole alkaloids induce apoptosis in HL-60 cells through activation of the caspase-9/caspase-3 pathway and they are targeted as potential anticancer agents. Thus, the naturally occurring carbazole alkaloids become important as precursors for lead optimization in drug development. A method based on ultra performance liquid chromatography coupled with photodiode-array detection was developed using reverse phase isocratic elution with 85:15 acetonitrile and ammonium acetate buffer (5 mM). Seven samples of Murrya koenigii (L.) Spreng. from northcentral India (Uttar Pradesh) were analyzed. All three targeted analytes, koenimbidine (mk1), koenimbine (mk2) and mahanimbine (mk3), were well separated within 4.0 min with linearity of the calibration curves (r 2 > 0.999). The limits of detection and quantification of mk1, mk2 and mk3 were 0.7, 0.4, 0.04 µg/mL and 2.14, 1.21, 0.12 µg/mL, respectively. The natural abundance of mk1, mk2 and mk3 was 0.06 -0.20, 0.04 -0.69 and 0.13 -0.42%, w/w, respectively, in the dried powdered leaves, whereas, the tissue specific distribution of carbazole alkaloids was observed in the order of predominance, mk1 leaf>root>fruit>stem, mk2 fruit>leaf >stem>root, and mk3 fruit>leaf>root>stem. The developed method was validated for limits of detection and quantification, repeatability, accuracy, precision and stability. This is the first report on the natural abundance of the major carbazole alkaloids in M. koenigii and the method developed can be used in HPLC/UPLC systems.
Carbazole Alkaloids from Stem Bark of Murraya koenigii (L.) Spreng
Journal of Basic & Applied Sciences, 2015
Murraya koenigii (L.) Spreng(curry patta) has different therapeutic uses and rich source of carbazole alkaloids. Phytochemical studies on the stem bark of M. koenigii yielded one new carbazole alkaloid, afifine, along with two known carbazole alkaloids, mahinimbine and girinimbine. These compounds were isolated using chromatographic methods and identified using spectroscopic techniques.