Anderson Maxwell

Oxazoline Mediated Routes to a Unique Amino-acid, 4-Amino-13-carboxy[2.2]paracyclophane, of Planar Chirality

Abstract Efficient syntheses leading to 4-amino-13-carboxy[2.2]paracyclophane and derivatives are described. Novel oxazolinyl[2.2]paracyclophanes are used as intermediates and the oxazolinyl and amide groups are shown to be strong ψ-geminal directing groups. Compounds with potential as catalysts have been made.

Room-temperature (1H, 13C) and variable-temperature (1H) NMR studies on spinosin

Spinosin, a C‐glycoside flavonoid, was isolated from the plant Desmodium tortuosum (Sw.) DC. The 1H and 13C NMR data acquired at room temperature exhibited doubling of signals, suggesting the presence of two rotamers in solution. Variable‐temperature 1H NMR experiments confirmed this hypothesis. T‐ROESY experiments in conjunction with theoretical (MM2) calculations supported the proposal that the two rotamers interchange via rotation about the C‐6— C‐1′′ bond. The spectral data were completely assigned using 1H– 1H COSY, HMQC, HSQC and HMBC experiments. Copyright

The synthesis of homochiral ligands based on (2.2)paracyclophane

Abstract A new ortho -lithiation of homochiral 4- N , N -diethylamido[2.2]paracyclophane 8 is the key to the production of a wide variety of 4,5-disubstituted homochiral ligands. ψ-Geminal bromination of 8 proceeds in high yields and the resulting bromide may be converted into a variety of 4,13-disubstituted ligands. The o- lithiation and ψ-geminal reactions can be used sequentially to give 4,5,12-trisubstituted compounds in which two liganding groups have the same geometrical relationship as in ‘Phanephos’™. Homochiral oxazolines with only planar chirality have been made, one of which has been shown to be an effective catalyst for the Heck reaction.

Neolignans from Piper aequale

Abstract Two new benzofuran type neolignans were isolated from the aerial parts of Piper aequale . Their structures were elucidated on the basis of spectroscopic evidence as (2 R ,3 R )-2,3-dihydro-2-(4-hydroxyphenyl)-5-methoxy-3-methyl-7--propenylbenzofuran and 2-hydroxy-4,4′-bis[3-methyl-5-( E )-propenyl)benzofuran-2-yl] diphenylether, a dineolignan.

AN UNUSUAL ERYTHROLIDE CONTAINING A BICYCLO 9.2.1. TETRADECANE SKELETON

Abstract Erythrolide K (4), isolated from Erythropodium caribaeorum possesses an unusual bicyclo [9.2.1.] tetradecane skeleton. The structure was deduced by 2D NMR and confirmed by X-ray analysis. It was synthesised in two steps from erythrolide A (2), the first involving a thermal [1,5] sigmatropic hydrogen shift to give the intermediate (3).

Mabioside A, a new saponin from Colubrina elliptica

Abstract A new bitter saponin containing a novel seco ring D dammarane triterpenoid aglycone has been isolated from the bark of Colubrina elliptica . The structure was determined from a series of 2-D NMR experiments.

Two steroidal glycoalkaloids from Solanum arboreum

Abstract Two new steroidal glycoalkaloids have been found in the aerial parts of Solanum arboreum. Their structures have been elucidated as tomatidine 3-O-β- d -glucopyranoside and tomatidine 3-O-[O-β- d -xylopyranosyl -(1→6)-β- d -glucopyranoside by a combination of 2D NMR experiments and mass spectrometry.

Antimicrobial cholic acid derivatives from the Pitch Lake bacterium Bacillus amyloliquefaciens UWI-W23

HIGHLIGHTSFirst report of antimicrobial bile acids and bile salts from the Bacillus genus.First report of taurodeoxycholate (2) from a bacterial source.This is the first report of deoxycholate (4) from a Gram‐positive bacterium.Observed aggregation‐effect on NMR data of glycocholic acid (6) in CD3OD. ABSTRACT Six cholic acid derivatives (1–6) were isolated from broth cultures of Bacillus amyloliquefaciens UWI‐W23, an isolate from the Trinidad Pitch Lake. The compounds were extracted via solvent extraction and/or XAD resin adsorption and purified using silica gel column chromatography. Their structures were elucidated using 1D, 2D NMR and ESI‐MS spectrometry and FT‐IR spectrophotometry. One of the compounds, taurodeoxycholate (2) is for the first time being reported from a bacterial source while deoxycholate (4) is for the first time being reported from a Gram‐positive bacterium. The other compounds have not been previously isolated from Bacillus spp. viz. cholate (1), taurocholic acid (3); glycodeoxycholic acid (5) and glycocholic acid (6). All six compounds exhibited antimicrobial activity against P. aeruginosa and B. cereus with MICs ranging from 7 to 250&mgr;g/mL. Cholate (1) also showed activity against MRSA (MICs=125&mgr;g/mL) and glycocholic acid (6) against S. cerevisiae (MICs=15.6&mgr;g/mL).