Application of Residual Dipolar Couplings and Selective Quantitative NOE to Establish the Structures of Tetranortriterpenoids from Xylocarpus rumphii.

Nine triterpenoid derivatives were isolated from the heartwood of Xylocarpus rumphii and were identified as xylorumphiins E (1), C (2), L (3), and M-R (4-9). Compounds 4-9 have a hemiacetal group in the triterpenoid side chain, making them impossible to purify. Purification was achieved after acetylation and subsequent separation of the epimeric mixtures of acetates; however differentiaition of the R and S epimers was not possible using standard NMR techniques.

2-(2,4,5-Trimeth-oxy-phen-yl)-2,3-dihydro-quinolin-4(1H)-one.

In the title aza-flavanone, C(18)H(19)NO(4), an intra-molecular cyclization product of chalcone, the central heterocyclic ring is in an envelope conformation and the dihedral angle between the benzene rings is 51.03 (10)°. The meth-oxy groups at the ortho and para positions are slightly twisted from the benzene ring to which they are bound [C-O-C-C = 21.

ent-(15S)-Pimar-8(14)-ene-15,16-diol.

The title compound {systematic name: (S)-1-[(2S,4aR,8aR)-2,4b,8,8-tetra-methyl-2,3,4,4a,4b,5,6,7,8,8a,9,10-dodeca-hydro-phenanthren-2-yl]ethane-1,2-diol}, C(20)H(34)O(2), is an ent-pimarane diterpenoid which was isolated from the stem bark of Ceriops tagal. In the asymmetric unit, there are two crystallographically independent mol-ecules, which are conformationally almost identical. In each mol-ecule, the two cyclo-hexane rings of the fused three-ring system adopt chair conformations, while the cyclo-hexene ring is in an envelope conformation, with the methylene C atom next to the side chain as the flap atom.

Redetermination and absolute configuration of pruniflorone M monohydrate.

THE TITLE XANTHONE KNOWN AS PRUNIFLORONE M (SYSTEMATIC NAME: (2R)-5,10-dihy-droxy-2-hy-droxy-methyl-1,1-dimethyl-1H-furo[2,3-c]xanthen-6-one), crystallized in a monohydrate form, C(18)H(16)O(6)·H(2)O. It was isolated from the green fruits of Cratoxylum formosum ssp. pruniflorum.

New cytotoxic steroids from the fruits of Syzygium siamense.

A new sterol, stigmast-5-ene-3beta,17alpha-diol (1), together with six known compounds, stigmast-5-ene-3beta-yl formate (2), stigmast-5-ene-3beta,7alpha-diol (3), stigmast-5-ene-7alpha-methoxy-3beta-ol (4), stigmast-5-ene-3-one (5), 3beta-sitostanol (6), and 3beta-sitosterol (7), was isolated from the fruits of Syzygium siamense, of which compound 2 is reported for the first time from a natural source. Their structures were elucidated by spectroscopic methods. The isolated compounds (1-7) were evaluated for their cytotoxic activities against human oral epidermoid carcinoma cancer (KB), human breast cancer (BC), and human small cell lung cancer (NCI-H187) cell lines.

Chromene and prenylated xanthones from the roots of Cratoxylum formosum ssp. pruniflorum.

Two new xanthones, namely pruniflorone K (1) and L (2), have been isolated from the roots of Cratoxylum formosum ssp. pruniflorum, along with thirteen known xanthones (3-15). Their structures were mainly established using the spectroscopic methods.

Brasilixanthone.

THE TITLE XANTHONE [SYSTEMATIC NAME: 5,13-dihy-droxy-3,3,10,10-tetra-methyl-3H-dipyrano[3,2-a:2',3'-i]xanthen-14(10H)-one], C(23)H(20)O(6), was isolated from the roots of Cratoxylum formosum ssp. pruniflorum. There are two mol-ecules (A and B) in the asymmetric unit, which show chemical but not crystallographic inversion symmetry.

Cassane diterpenoids from the stem of Caesalpinia pulcherrima.

Cassane diterpenoids: pulcherrin A, pulcherrin B, pulcherrin C, neocaesalpin P, neocaesalpin Q and neocaesalpin R, together with eight known compounds: isovouacapenol C, 6beta-cinnamoyl-7beta-hydroxy-vouacapen-5alpha-ol, pulcherrimin E, pulcherrimin C, alpha-cadinol, 7-hydroxycadalene, teucladiol and bonducellin were isolated from the stem of Caesalpinia pulcherrima. The chemical structures were elucidated by analysis of their spectroscopic data.

Exploratory studies to investigate a linked prebiotic origin of RNA and coded peptides. 4th Communication. Further observations concerning pyrimidine nucleoside synthesis by stepwise nucleobase assembly.

As part of an ongoing investigation into a possible linked origin of RNA and coded peptides, we have (further) investigated the potentially prebiotic synthesis of pyrimidine ribonucleosides (ribonucleotides), by stepwise nucleobase assembly on sugar (sugar phosphate) scaffolds. In this paper, we complete our description of this assembly process on aldopentose scaffolds. Treatment of D-ribose (14) and D-xylose (20) with cyanamide smoothly produces the furanosylamino-oxazolines 15 and 21, respectively (Schemes 1 and 3).

Potent cytotoxic rocaglamide derivatives from the fruits of Amoora cucullata.

Two new rocaglamide derivatives, 1-O-formylrocagloic acid (1) and 3'-hydroxy rocagloic acid (2), together with five known compounds, rocaglaol (3), rocagloic acid (4), 3'-hydroxymethylrocaglate (5), 1-O-formylmethyl rocaglate (6), and methylrocaglate (7), were isolated from the fruits of Amoora cucullata. Their structures were elucidated by spectroscopic methods. Compounds 1-3, 6, and 7 exhibited potent cytotoxicity against KB, BC, and NCI-H187 cell lines, whereas 4 and 5 showed selective cytotoxicity against NCI-H187 cell line.

Antimalarial tetranortriterpenoids from the seeds of Lansium domesticum Corr.

Five tetranortriterpenoids, domesticulide A-E (1-5), were isolated from seeds of Lansium domesticum Corr. together with 11 known triterpenoids (6-16). Their structures were elucidated by analysis of their spectroscopic data.

Antimycobacterial flavonoids from Derris indica.

Flavonoids (1-4), together with ten known compounds (5-14) were isolated from the stems and roots of the mangrove plant Derris indica. Their chemical structures were elucidated by analysis of their spectroscopic data. All compounds except compounds 2 and 6 exhibited antimycobacterial activity with minimum inhibitory concentrations (MIC) between 6.

Cytotoxic and antimalarial prenylated xanthones from Cratoxylum cochinchinense.

A new prenylated xanthone, 5-O-methylcelebixanthone (1), together with six known compounds; celebixanthone (2), 1,3,7-trihydroxy-2,4-di(3-methylbut-2-enyl)xanthone (3), cochinchinone A (4), alpha-mangostin (5), beta-mangostin (6) and cochinchinone C (7) were isolated from roots of Cratoxylum cochinchinense. Their structures were elucidated by spectroscopic methods. Compounds 2 and 4-7 showed cytotoxic activity against the human lung cancer cell line (NCI-H187) with IC(50) values ranging from 0.

Antibacterial and cytotoxic xanthones from the roots of Cratoxylum formosum.

Chemical investigation of the roots of Cratoxylum formosum has resulted in the isolation and characterization of xanthones: three new, named formoxanthone A-C and three known together with three known anthraquinones. Their structures were established on the basis of analysis of spectroscopic evidence. In addition, antibacterial and cytotoxic activities of the isolates were also evaluated.

Dammarane triterpenes from the hypocotyls and fruits of Ceriops tagal.

Three new dammarane triterpenes, cereotagaloperoxide, cereotagalol A, and cereotagalol B, together with four known dammarane triterpenes, an oleanane triterpene, and 13 known lupane triterpenes were isolated from the hypocotyls and fruits of Ceriops tagal. The structures of 1-3 were characterized on the basis of their spectroscopic data.

A new triterpenoid ester from the fruits of Bruguiera parviflora.

A new lupane caffeoyl ester (1), 3-(Z)-caffeoyllupeol, together with five known triterpenoids, lupeol caffeate (2), 3-(Z)-coumaroyllupeol (3), dioslupecin A (4), lupeol (5), and lupenone (6), were isolated from the fruits of Bruguiera parviflora. Their structures were elucidated by spectroscopic methods. Compound 1 exhibited antimalarial activity with an EC50 value of 8.

New cytotoxic cardenolide glycoside from the seeds of Cerbera manghas.

A new cytotoxic cardenolide glycoside, 3beta-O-(2'-O-acetyl-alpha-L-thevetosyl)-14beta-hydroxy-7-en-5beta-card-20(22)-enolide, (7,8-dehydrocerberin), together with five known cardenolides, 17beta-neriifolin, deacetyltanghinin, tanghinin, cerberin and 2'-O-acetyl-cerleaside A were isolated from the seeds of Cerbera manghas L. Their structures were elucidated by 1D- and 2D-NMR techniques as well as UV, IR and mass spectral data. 7,8-Dehydrocerberin, deacetyltanghinin and tanghinin exhibited cytotoxic activities against oral human epidermoid carcinoma (KB), human breast cancer cell (BC) and human small cells lung cancer (NCI-H187).

Pentacyclic triterpenoid esters from the fruits of Bruguiera cylindrica.

Six new pentacyclic triterpenoid esters (1-6) together with 3alpha- and 3beta-taraxerol were isolated from the fruits of Bruguiera cylindrica. The structures of the new compounds were characterized as 3alpha-E-feruloyltaraxerol (1), 3alpha-Z-feruloyltaraxerol (2), 3beta-E-feruloyltaraxerol (3), 3beta-Z-feruloyltaraxerol (4), 3alpha-E-coumaroyltaraxerol (5), and 3alpha-Z-coumaroyltaraxerol (6), respectively. Compounds 2 and 6 exhibited weak cytotoxicity against the NCI-H187 cell line.

Cytotoxic cardenolide glycoside from the seeds of Cerbera odollam.

A cardenolide glycoside, 3 beta-O-(2'-O-acetyl-l- thevetosyl)-15(14-->8)-abeo-5 beta-(8R)-14-oxo-card-20(22)-enolide (2'-O-acetyl cerleaside A), was isolated from a methylene chloride extract of the seeds of Cerbera odollam, together with four known compounds: cerleaside A, 17 alpha-neriifolin, 17 beta- neriifolin and cerberin. Their structures were elucidated by spectroscopic methods. All compounds except cerleaside A exhibited cytotoxic activities against oral human epidermoid carcinoma (KB), human breast cancer cell (BC) and human small cell lung cancer (NCI-H187).

Antimycobacterial activity of phorbol esters from the fruits of Sapium indicum.

Three new phorbol esters, 12-(2-N-methylaminobenzoyl)-4beta,5,20-trideoxyphorbol-13-acetate (1), 12-(2-N-methylaminobenzoyl)-4alpha,5,20-trideoxyphorbol-13-acetate (2), and 12-(2-N-methylaminobenzoyl)-4alpha, 20-dideoxy-5-hydroxyphorbol-13-acetate (6), together with six known compounds (3-5 and 7-9), were isolated from the fruits of Sapium indicum. The chemical structures of 1, 2, and 6 were elucidated by analysis of their spectroscopic data. Compounds 1-3, 5, and 7-9 exhibited antimycobacterial activity with minimum inhibitory concentrations (MIC) between 3.

Bis[14beta-hydroxy-3beta-O-(L-thevetosyl)-5beta-card-20(22)-enolide] methanol solvate monohydrate and 3beta-O-(L-2'-o-acetylthevetosyl)-14beta-hydroxy-5beta-card-20(22)-enolide.

The title compounds, 2C(30)H(46)O(8).CH(3)OH.H(2)O, (I), and C(32)H(48)O(9), (II), respectively, are cardenolide glycosides which were isolated from the seeds of Cerbera odollam.