Mukonicine, a carbazole alkaloid from leaves of murraya koenigii

Synthesis of the Pyrano[3,2-a]carbazole Alkaloids Koenine, Koenimbine, Koenigine, Koenigicine, and Structural Reassignment of Mukonicine

“…Mukonicine has been described as 6,8-dimethoxygirinimbine (3). 10 Based on this structural assignment, our retrosynthetic analysis led to 2-hydroxy-6,8-dimethoxy-3methylcarbazole (17) (Scheme 3). Using carbazole 17 as precursor, annulation of the pyran ring by reaction with an appropriate C 5 -building block would lead directly to 6,8-dimethoxygirinimbine (3).…”

Pancreatic Lipase Inhibitory Alkaloids of Murraya koenigii Leaves

“…Four known carbazole alkaloids mahanimbin (MKE 1), koenimbin (MKE 2), koenigicine (MKE 3) and clausazoline-K (MKE 4) were isolated and identified by comparison of their spectral data with those published in literature [16][17][18][19][20][21].…”

Two New Carbazole Alkaloids from Murraya koenigii

“…The IR spectrum showed absorption at ν max 3440 and 3410 cm -1 , indicating the presence of -OH and -NH groups, 6 which was confirmed by the presence of two broad singlets at δ 4.75 and 9.73 in the 1 H NMR spectrum. 7 Inspection of the NMR data ( 1 H, 13 C, DEPT, HMQC, and HMBC) indicated the presence of a koenigine moiety 1,4,[8][9][10][11][12][13] and an 11-carbon residue. The latter was confirmed by the EIMS fragment ion at m/z 210 (M -307) and the NMR data.…”

“…[14][15][16] Methoxyl substitutions at C-6′′ and C-8′′ were revealed by analysis of NMR data, while the C-7′′ hydroxyl was determined with the aid of EIMS fragmentation and NMR data. [17][18][19] The obvious difference between the NMR data of 1 and koenigine 1,4,[8][9][10][11][12][13] was at C-8; the methine (δ C 97.9, d, δ H 5.72, 1H, s) in koenigine was replaced by a quaternary carbon (δ C 110.9s), indicating that 1 had carbon substitution at C-8. 7,9,12,13 This correlation was supported by 1 H-13 C longrange correlations between the proton at δ 3.88 (H-2′′) and the carbons at δ 148.3 (C-7), 110.9 (C-8), and 131.8 (C-1b), and between the methylene protons at δ 4.02 (2H, d, J ) 6.0 Hz, H-1′′) and the carbon at δ 110.9 (C-8).…”

“…[17][18][19] The obvious difference between the NMR data of 1 and koenigine 1,4,[8][9][10][11][12][13] was at C-8; the methine (δ C 97.9, d, δ H 5.72, 1H, s) in koenigine was replaced by a quaternary carbon (δ C 110.9s), indicating that 1 had carbon substitution at C-8. 7,9,12,13 This correlation was supported by 1 H-13 C longrange correlations between the proton at δ 3.88 (H-2′′) and the carbons at δ 148.3 (C-7), 110.9 (C-8), and 131.8 (C-1b), and between the methylene protons at δ 4.02 (2H, d, J ) 6.0 Hz, H-1′′) and the carbon at δ 110.9 (C-8). The connection between C-7 and C-3′′ via an oxygen was determined by the 1 H-13 C long-range correlation between δ H 5.46 (H-3′′) and the carbon at δ 148.3 (C-7) (Figure 1).…”