Structures of two novel monoterpene alkaloid glucosides from Lonicera Xylosteum L.

The structures of loxylostosidine A and B, two new sulfoxide - containing monoterpene alkaloid glucosides, are described.     

A novel alkaloid from Mitrephora maingayi

A novel alkaloid, maingayinine, together with dicentrinone, dicentrinene, L-2-O-methyl-chiro-inositol, allantoin, glaucine, N-phenyl-2-naphthylamine, terephthalic acid and ayanin, was isolated from the twigs of Mitrephora maingayi Hook (Annonaceae). Their structures were established predominantly by IR, MS and NMR spectral data.     

Liquid-crystalline behaviours of novel chitosan derivates containing singular and cholesteryl groups

A series of esters of chitosan with cholesteryl hexanoate and cholesteryl decanoate side chains were synthesised. These compounds had higher solubilities than chitosan itself and all formed cholesteric lyotropic liquid crystalline phases. They had enhanced mesogenic properties as compared with the parent polymer. We consider that these compounds may prove to be of value as vehicles for drug delivery.     

Kalashine,a novel type aporphine-benzylisoquinoline alkaloid

$\text{Berberis orthobotrys}$ produces the new dimer kalashine ($\text{1}$), together with the previously reported pakistanamine ($\text{2}$) and pakistanine ($\text{3}$). Kalashine is the first aporphine-benzylisoquinoline known to be substituted at C-11. Acid catalyzed rearrangement of pakistanamine ($\text{2}$) in 3N HCl leads to 1-0-methylpakistanine ($\text{6}$) together with small amounts of 1-0-methylkalashine ($\text{7}$) and (+)-armepavine ($\text{8}$). Rearrangement of $\text{2}$ using methanol containing a little 3N HCl gives about equal amounts of $\text{6}$ and 1,10-di-O-methylpakistanine ($\text{9}$).     

Cohirsine - a novel isoquinolone alkaloid from

A novel alkaloid, cohirsine (1) was isolated from . Its structure has been investigated by extensive NMR studies including 2D NMR experiments. Its stereochemistry has been determined by 2D NOESY and NOE difference measurements.     

Synthesis of aaptamine,a novel marine alkaloid

The novel sponge alkaloid aaptamine has been synthesized for the first time by an efficient route starting from 6-methoxy-7-hydroxy-3,4-dihydrolsoquinoline.     

Synthesis of the novel isoquinoline enamide alkaloid polycarpine

The synthesis of the novel enamide isoquinoline alkaloid polycarpine, (Z)-1-(2′-hydroxy-3′,4′-dimethoxy-benzylidene)-3,4-dihydro-6,7-dimethoxy-2-(1H)isoquinolinecarboxaldehyde, proceeding from commercially available 2′,3′,4′-trimethoxyacetophenone in seven steps is described. The O-methyl and O-benzyl derivatives were also obtained.     

Benhamycin, novel alkaloid from terrestrial Streptomyces sp

During our screening for bioactive natural compounds from microorganisms, a novel alkaloid has been isolated from a terrestrial Streptomyces sp. isolate NR12, and named as benhamycin (1). This was along with the known metabolites, uracil, thymine, p-hydroxybenzoic acid, 2'-deoxyuridin, tryptophol, indolyl-3-carboxylic acid, and indolyl-3-carbaldehyde. Chemical structure of the novel compound was determined by detailed analysis of its spectroscopic data (extensive NMR experiments, 1 & 2D, MS spectroscopy, and MS high resolution). Structurally, Benhamycin (1) is a pentacyclic aromatic compound bearing an acridine moiety lactamized with benzene. Biological studies showed that the strain extract was moderately active against Gram-positive, Gram-negative bacteria and fungi.     

Enantioselective total syntheses of the Ipecacuanha alkaloid emetine, the Alangium alkaloid tubulosine and a novel benzoquinolizidine alkaloid by using a domino process

The first enantioselective syntheses of the Ipecacuanha alkaloid emetine (1) and the Alangium alkaloid tubulosine (2) is described employing a domino Knoevenagel/hetero-Diels-Alder reaction and an enantioselective catalytic transfer hydrogenation of imines as key steps. Thus, hydrogenation of the imine 15 with the catalyst (R,R)-16 gives the tetrahydroisoquinoline 14 with 95 % ee which was transformed into the aldehyde (1S)-7. The three-component domino reaction of (1S)-7 with 6 and 8 led to 19, which in a second domino process was treated with K(2)CO(3) in methanol followed by a hydrogenation to give the benzoquinolizidine 4 together with the diastereomers 22 and 23 in a overall yield of 66 %. Further transformation of 4 with the amines 3 and 5 yielded enantiopure emetine (1) and tubulosine (2), respectively. In addition, starting from 19 the novel benzoquinolizidine alkaloid 34 was synthesised; this compound resembles the vallesiachotamine alkaloid dihydroantirhin 31, which has not been isolated so far but probably must also exist in nature.     

Daphnioldhamine A,a novel alkaloid from Daphniphyllum oldhami

Daphnioldhamine A, the first Daphniphyllum alkaloid with transannular effect, easily tautomerized under acidic or alkaline conditions, was isolated from the fruits of Daphniphyllum oldhami. The structure was elucidated by spectroscopic and computational approaches and chemical transformation. A plausible biosynthetic pathway of daphnioldhamine A was also proposed.     

Aristomakine,a novel indole alkaloid from aristotelia serrata

The isolation and structural determination of aristomakine (I), an unusual indole alkaloid with an N-isopropyl group, is reported.     

Ileabethoxazole: a novel benzoxazole alkaloid with antimycobacterial activity

Ileabethoxazole (1), a new perhydroacenaphthene-type diterpene alkaloid containing the uncommon benzoxazole moiety, was isolated from the Caribbean sea whip Pseudopterogorgia elisabethae. The structure of 1 was elucidated by extensive spectroscopic data interpretation. Ileabethoxazole showed 92% inhibition of Mycobacterium tuberculosis (H₃₇Rv) at the concentration range of 128-64 μg/mL.     

Gindarudine,a novel morphine alkaloid from Stephania glabra

A novel morphine alkaloid,named gindarudine 1 has been isolated from ethanol extract of Stephania glabra tubers,together with four known alkaloids,palmatine,dehydrocorydalmine,stepharamne,and 8-(4'-methoxybenzyl)-xylopinine.Compound 1 was elucidated as 3,6-O,N-detrimethyl-10-hydroxy-1-methoxy-thebaine by means of spectroscopic data including 2D NMR studies.     

A novel norsesquiterpene alkaloid from the mushroom-forming fungus Flammulina velutipes

A new norsesquiterpe alkaloid（1） was isolated from the solid culture of mushroom-forming fungus Flammulina velutipes fermented on rice.The structure of 1 was elucidated by spectroscopic methods.The absolute configuration of C-1 in 1 was determined using the circular dichroism data of their [Rh₂（OCOCF₃）₄]complex.