Isolation,characterization, and NMR spectroscopic data of indole and oxindole alkaloids from Mitragyna speciosa

A new indole alkaloid, 7β-hydroxy-7H-mitraciliatine (1) and a new oxindole alkaloid, isospeciofoleine (2) together with nine known alkaloids were isolated from Mitragyna speciosa and characterized by NMR, CD, and MS spectroscopic data analyses. The ¹H and ¹³C NMR spectroscopic data of isospeciofoline (3), isorotundifoline (4), paynantheine (5), and 3-isopaynantheine (6) were also reported for the first time.     

Daphniglaucins D-H, J, and K, new alkaloids from Daphniphyllum glaucescens

Five new fused-hexacyclic alkaloids, daphniglaucins D (1), E (2), F (3), G (4), and H (5), and two new yuzurimine-type alkaloids, daphniglaucins J (6) and K (7), have been isolated from the leaves of Daphniphyllum glaucescens, and the structures and relative stereochemistry were elucidated on the basis of spectroscopic data and chemical means.     

Isolation, structure elucidation and biological activity of hederacine A and B, two unique alkaloids from Glechoma hederaceae

Preparative HPLC purification of a methanol extract of the aerial parts of Glechoma hederaceae has yielded two unique alkaloids, hederacine A (1) and hederacine B (2). The structures of these compounds were established unequivocally by UV, IR, MS and a series of 1D and 2D NMR analyses. These alkaloids were inactive against any of the 11 bacterial species at test concentrations, but showed prominent toxicity in the brine shrimp lethality assay (LC₅₀s=3.2, 14.0 and 2.7 μg/mL, respectively, for 1, 2 and the positive control, podophyllotoxin).     

Lyconadins C and F, new Lycopodium alkaloids from Lycopodium complanatum

New Lycopodium alkaloids, lyconadins C (1) and F (2), were isolated from the club moss Lycopodium complanatum. Lyconadin C (1) is a new C₁₆N₂-type Lycopodium alkaloid possessing unique fused-tetracyclic ring system consisting of a cycloheptene ring fused to a decahydroquinoline and pyridone rings. Lyconadin F (2) possesses a primary amide moiety in its molecular, which is the first example of Lycopodium alkaloids. Biogenetically, lyconadins C (1) and F (2) might be related to lyconadins A (4) and B (5). The structures and relative stereochemistry of 1 and 2 were elucidated on the basis of spectroscopic data. The absolute stereochemistry of 2 was elucidated by chemical correlations with lyconadin B (5) through hemiaminal form of lyconadin F (3).     

Monanchomycalins A and B, unusual guanidine alkaloids from the sponge Monanchora pulchra

New pentacyclic guanidine alkaloids, monanchomycalins A (1) and B (2) were isolated from the marine sponge, Monanchora pulchra and their structures elucidated using NMR, HRMALDI-TOF-MS, and HRESI MS, as well as by chemical transformations of 1. Compounds 1 and 2 exhibited potent cytotoxic activities against HL-60 human leukemia cells with IC₅₀ values of 120 and 140 nM, respectively.     

Bis-cephalezomines A-E from Cephalotaxus harringtonia var. nana

Five new dimeric Cephalotaxus alkaloids, bis-cephalezomines A-E (1-5), have been isolated from the leaves of Cephalotaxus harringtonia var. nana, and the structures and stereochemistry were elucidated on the basis of spectroscopic data including 2D NMR and FABMS/MS spectra, and chemical means.     

Structures of new alkaloids sessilifoliamides A-D from Stemona sessilifolia

Four new Stemona alkaloids, sessilifoliamides A-D (1-4), were isolated from the roots of Stemona sessilifolia, along with five known alkaloids, stenine (5), 2-oxostenine (6), stemoninoamide (7), tuberostemonone (8), and neotuberostemonol (9). The structures and absolute configurations of the new alkaloids were determined by the spectral studies (HRMS, IR, ¹H, ¹³C, and 2D NMR), single-crystal X-ray analyses, and chemical correlations. The absolute configuration of 7 was also determined by the modified Mosher's method.     

Pheromone synthesis. Part 255: Synthesis and GC–MS analysis of pheromonal triacylglycerols of male Drosophila fruit flies

Pheromonal triacylglycerols and their analogs, 1A, 1B, 2A, 2B, 3A, 3B, and 3C, of male Drosophila fruit flies were synthesized and analyzed by GC–MS. Their GC retention times were found to be a reliable measure to analyze and identify these triacylglycerols with acetyl, oleoyl and tigloyl groups, although the stereo- and regioisomers of 1 (1A and 1B), 2 (2A and 2B), and 3 (3A, 3B, and 3C) could not be distinguished from each other by MS alone.     

Agelasines O-U, new diterpene alkaloids with a 9-N-methyladenine unit from a marine sponge Agelas sp.

New diterpene alkaloids, agelasines O-U (1-7), have been isolated from an Okinawan marine sponge Agelas sp. The gloss structures and relative stereochemistries of 1-7 were elucidated from the spectroscopic data. Agelasines O-R (1-4) were the third examples of diterpene alkaloid with a 9-N-methyladenine and a pyrrole units. Agelasine O (1) has a halimane skeleton, while agelasines P-R (2-4) have a clerodane skeleton. Agelasines S-U (5-7) were new diterpene alkaloids with a 9-N-methyladenine unit consisting of a halimane skeleton, a labdane skeleton, and a clerodane skeleton, respectively. Agelasines O-R (1-4) and T (6) showed antimicrobial activities against several bacteria and fungi.     

Hyrtimomines,indole alkaloids from Okinawan marine sponges Hyrtios spp.

Six new indole alkaloids, hyrtimomines F–K (1–6), were isolated from Okinawan marine sponges Hyrtios spp. The structures of 1–6 were elucidated on the basis of spectroscopic analysis. Hyrtimomine F (1) is a structurally unique bisindole alkaloid possessing an α-keto-?-caprolactam ring, while hyrtimomine G (2) is a symmetrical bisindole alkaloid. Hyrtimomines H–K (3–6) are indole alkaloids possessing β-carboline skeleton with an imidazolium unit. Antimicrobial activities of hyrtimomines F–K (1–6) were evaluated.     

Four novel gelsedine-type oxindole alkaloids from Gelsemium elegans

Four new gelsedine-type oxindole alkaloids (1-4) were isolated from the leaves and branches of Gelsemium elegans, together with 10 known alkaloids. The structures of the new alkaloids were determined by spectroscopic analyses and partial synthesis from known compounds. Gelsecrotonidine (1), 14-hydroxygelsecrotonidine (2), and 11-methoxygelsecrotonidine (3) possess an additional C₂ unit with an acetic acid residue compared to gelsenicine-related monoterpenoid indole alkaloids. 14-Hydroxygelsedilam (4) is an 18,19-nor-type monoterpenoid indole alkaloid.     

Daphcalycinosidines A and B, new iridoid-alkaloids from Daphniphyllum calycinum

Three new alkaloids, daphcalycinosidines A (1) and B (2) and daphcalycic acid (3) have been isolated from the seeds of Daphniphyllum calycinum. The structures and relative stereochemistries were determined on the basis of spectral studies including 2D NMR, mass spectrometry and chemical transformations. Structures 1 and 2 are characterized by an iridoid glucoside moiety linked to new Daphniphyllum alkaloid moieties.     

Chabamides F and G, two novel dimeric alkaloids from the roots of piper chaba hunter

Two new dimeric alkaloids, chabamide F (1) and chabamide G (2), containing pyrrolidine rings, were isolated from the roots of piper chaba hunter. The structures of 1 and 2 were established on the basis of spectroscopic data, especially 2D NMR and mass spectral data.     

Aminocadambines A and B, two novel indole alkaloids from Neolamarckia cadamba

Two novel monoterpenoid indole alkaloids, aminocadambines A (1) and B (2), characterized by tetrahydrofuran and 1,2,3,4-tetrahydropyridine rings, were isolated from the leaves of Neolamarckia cadamba. Their structures were elucidated on the basis of spectroscopic and computational methods. The absolute configuration of 1 was established by CD analysis. A plausible biosynthetic pathway for 1 and 2 is proposed.     

Complanadine B, obscurumines A and B, new alkaloids from two species of Lycopodium

A new dimer of C₁₆N₂ type alkaloid, complanadine B (1), and two new C₁₆N type alkaloids, obscurumines A (2) and B (3), have been isolated from the club moss Lycopodium complanatum and L. obscurum, respectively. The structures and stereochemistry of 1-3 were elucidated by combination of 2D NMR spectra and chemical transformation. Complanadine A (4) isolated together with 1 induced secretion of neurotrophic factors from human astrocytoma cells.     

Lannotinidines A-G, new alkaloids from two species of Lycopodium

Seven new Lycopodium alkaloids, lannotinidines A-G (1-7), have been isolated from the club moss Lycopodium annotinum and L. annotinum var. acrifolium. Stereochemistry of 1-7 was elucidated by combination of NOESY correlations and chemical transformation. Lannotinidines B-E (2-5) elevated NGF mRNA expression.     

Calyciphyllines H-M, new Daphniphyllum alkaloids from Daphniphyllum calycinum

Six new Daphniphyllum alkaloids, calyciphyllines H-M (1-6), were isolated from the leaves and stems of Daphniphyllum calycinum (Daphniphyllaceae). The structures and relative stereochemistry of 1-6 were elucidated on the basis of spectroscopic data, and the absolute stereochemistry of 3 was assigned by PGME method.     

Novel alkaloids, paxdaphnines A and B with unprecedented skeletons from the seeds of Daphniphyllum paxianum

Two novel Daphniphyllum alkaloids with unprecedented skeletons, namely paxdaphnines A (1) and B (2), have been isolated from the seeds of Daphniphyllum paxianum. Paxdaphnine A (1) is a 19-nor-Daphniphyllum alkaloid with highly caged skeleton, and paxdaphnine B (2) is the first 1,19-bisnor-Daphniphyllum alkaloid. The relative structures of 1 and 2 were elucidated by spectral methods, and their unique biosynthetic pathway postulated. The absolute structure of 1 was determined by X-ray diffraction of the iodide derivative (1a) of 1, and the absolute stereochemistry of 2 was proposed by correlation with the biosynthetic pathway for 1.     

Senepodines B-E, new C22N2 alkaloids from Lycopodium chinense

Four new C₂₂N₂Lycopodium alkaloids, senepodines B-E (2-5), consisting of an octahydroquinoline ring and a quinolizidine ring have been isolated together with senepodine A (1) from the club moss Lycopodium chinense. The relative and absolute stereochemistry of 2-5 were determined by combination of NOESY correlations and chemical transformation, while the absolute configuration of 1 was assigned by exciton chirality method.     

Lycopladines F and G, new C16N2-type alkaloids with an additional C4N unit from Lycopodium complanatum

Two new Lycopodium alkaloids, lycopladines F (1) and G (2), have been isolated from the club moss Lycopodium complanatum, and the structures and relative stereochemistries of 1 and 2 were elucidated on the basis of spectroscopic data. Lycopladine F (1) is a rare C₁₆N₂-type Lycopodium alkaloid possessing an amino acid residue (C₄N).