Murraya

Two possible structures, A and B, were initially considered for a naturally occurring coumarin isolated from Murraya paniculata. Its nOe difference and H-NMR spectra are presented. The relevant H chemical shift values are given around structure A. On the basis of the nOe data, identify the correct structure of the coumarin. 

Rubiandin-1-methyl ether Stephania verosa Murraya simensis SiOj T + AcOEt... 

Negi N, Ochi A, Kurosawa M, Ushijima K, Kitaguchi Y, Kusakabe E, Okasho F, Kimachi T, Teshima N, Ju-Ichi M, Abou-Douh AM, Ito C and Furukawa H. 2005. Two new dimeric coumarins isolated from Murraya exotica. Chem Pharm Bull (Tokyo) 53(9) 1180—1182. 

Fuostifoline (47), a furo[3,2-a]carbazole, was isolated from Murraya euchrestifolia. Timdri s total synthesis of 47 commenced with alkylation of bromocresol 43 with bromoacetaldehyde diethyl acetal and P4Oio-promoted cyclization to furnish 5-bromo-7-methylbenzofuran (44) [47]. The Suzuki coupling of boronic acid 45, derived from 44, with o-bromonitrobenzene yielded biaryl 46. Nitrene generation, achieved via deoxygenation of nitro compound 46 using triethyl phosphite, was followed by cyclization to fuostifoline (47). 

Fig. 1 Blooming plant of Murraya koenigii (curry-leaf tree). (Courtesy of Calvin Lemke, Department of Botany and Microbiology, University of Oklahoma)...

The dimeric carbazole alkaloids often occur along with the corresponding monomeric carbazoles in terrestrial plants [7,62] (Scheme 7). Clausenamine-A was obtained by Wu from the stem bark of Clausena excavata [63]. Clausen-amine-A and its synthetic analogs, like bis(O-demethylmurrayafoline-A), show cytotoxic activities against diverse human cancer cell lines [64] and exhibit moderate antimalarial activity [65,66]. Furukawa isolated l,r-bis(2-hy-droxy-3-methylcarbazole) and bismurrayaquinone-A, the first dimeric car-bazolequinone alkaloid found in nature, from Murraya koenigii [67]. 

Dineshkumar et al. investigated the antidiabetic efficacy of mahan-imbine (33), a carbazole alkaloid isolated from Murraya koenigii... 

Dineshkumar B, Mitra A, Mahadevappa M. (2010) Antidiabetic and hypolipidemic effects of mahanimbine (carbazole alkaloid) from Murraya koenigii (rutaceae) leaves. Int J Phytomed 2 22-30. 

Murraya paniculata Eupenicillium sp. alanditrypinone A and B, alantryphenone, alantrypinene, alantryleunone 246... 

The isolation of carbazole (1), 3-methylcarbazole (2), and several oxidized derivatives of 3-methylcarbazole from taxonomically related higher plants of the genera Glycosmis, Glausena, and Murraya (family Rutaceae) indicates that the aromatic methyl group of the biogenetic key intermediate 3-methylcarbazole can be eliminated oxidatively (5,6). Most of the carbazole alkaloids isolated from the... 

In 1966, Chakraborty et al. described the isolation of (+)-mahanimbine (139a) from M. koenigii (132). Two years later, Narasimhan et al. corrected the structural assignment of Chakraborty. Although alkaloid 139a was obtained in optically active form ([a]o +52), the absolute configuration is still unknown (111,133). Later, the racemic alkaloid, (+ )-mahanimbine (139b), was isolated independently from two different Murraya species, M. euchrestifolia (29) and M. siamensis (85). 

In 1969, Kapil et al. reported the isolation of bicyclomahanimbine (160) from the leaves of M. koenigii. Although, bicyclomahanimbine was isolated in optically active form [a]p —1.23 (CHCI3), the absolute configuration is not known (143). One year later, the same authors isolated from the same natural source bicyclomahanimbicine (161), an isomer of bicyclomahanimbine (160). The absolute configuration of this alkaloid is also not known (136). Four years after their isolation, Bandaranayake et al. revised the original structure of these alkaloids (144). In 1995, Wu et al. reported the isolation of bicyclomahanimbine (160) from the leaves of a different Murraya species, M. euchrestifolia (151) (Scheme 2.32). 

In 1988, Furukawa et al. isolated murrafoline-E (184) and murrafoline-F (185) from the root bark of M. euchrestifolia. Murrafoline-E was the third example of an N-benzyl-linked bis-carbazole alkaloid from a Murraya plant, while murrafoline-F was the first N-methoxy-bis-carbazole alkaloid (22). 

Wu et al. studied a range of natural carbazole alkaloids isolated from Murraya euchrestifolia for platelet aggregation inhibitory activity, and found that murrayamine A (7-hydroxygirinimbine, mukoenine-C) (120) (see Scheme 2.22) and murrayamine-M... 

Furukawa et al. reported the total synthesis of murrayaquinone A (107) by a palladium(II)-mediated oxidative cyclization of the corresponding 2-arylamino-5-methyl-l,4-benzoquinones. 2-Anilino-5-methyl-l,4-benzoquinone (842) was prepared starting from 2-methyl-l,4-benzoquinone 841 and aniline 839, along with the regio-isomeric 2-anilino-6-methyl-l,4-benzoquinone (844). The oxidative cyclization of 2-anilino-5-methyl-l,4-benzoquinone (842) with stoichiometric amounts of palla-dium(ll) acetate provided murrayaquinone A (107) in 64% yield. This method was also applied to the synthesis of 7-methoxy-3-methylcarbazole-l,4-quinone (113) starting from 3-methoxyaniline (840) (623). Seven years later, Chowdhury et al. reported the isolation of 7-methoxy-3-methylcarbazole-l,4-quinone (113) from the stem bark of Murraya koenigii and named it koeniginequinone A (113) (49) (Scheme 5.101). 

The bis-carbazole alkaloids typically contain previously known monomeric carbazoles as structural subunits. To date, bis-carbazole alkaloids have been isolated from plants of two genera of the family Rutaceae, Murraya and Clausena, and are linked either by a methylene unit, a bisbenzylic ether bridge, a bond joining one aromatic portion directly to an annotated dihydropyran unit, or by a biaryl bond. Many reviews have appeared on the monomeric carbazole alkaloids. However, in these articles only a few bis-carbazole alkaloids were listed (3,5-7). For the first time, in 1992, Furukawa et al. compiled all of the bis-carbazole alkaloids that were known to the end of 1992 (158). Taster and Bringmann summarized to the end of 2001, the occurrence, stereochemistry, synthesis, and biological activity of the bis-carbazoles linked through a biaryl bond (159). We compiled to the mid of 2002, the occurrence, stereochemistry, synthesis, and the biological activity of all classes of bis-carbazoles (8). In this section, we cover the total syntheses of the natural bis-carbazole alkaloids reported since 1990. 

Recently, Tripathi et al. reported a new pyrano[3,2-a]carbazole alkaloid, 7-isovaleryl-oxy-8-methoxygirinimbine (1569) from the leaves of Murraya koenigii (896) (Scheme 6.2). 

Rahman, M. M. and Gray, A. I. 2005. A benzoisofuranone derivative and carbazole alkaloids from Murraya koenigii and their antimicrobial activity. Phytochemistry, 66 1601-1606. 

Biologically active carbazole alkaloids from Murraya koenigii. Journal of Agriculture and Food Chemistry, 47 444 47. 

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