A high-yielding two-step synthesis of paracetamol glucuronide (1) from methyl (trichloroacetimidoyl 2,3,4-tri-O-isobutyryl-alpha-D-glucopyranosid)uronate (6) is described.

Enzymatic hydrolysis of secologanin ethylene acetal at pH 5.0 resulted in stereoselective rearrangement of its aglucone to a dihydropyran aldehyde, which on reductive amination with tryptamine and cyclisation afforded 3-iso-ajmalicine, subsequently inverted to ajmalicine; analogous use of methyl S-tryptophanate gave 5S-methoxycarbonyl-3-iso-ajmalicine, whereas the R-enantiomer rather surprisingly yielded the ajmalicine derivative, whose anomalous CD spectrum has been rationalised.

Variation of the pH for hydrolysis of secologanin derivatives with beta -glucosidase controls rearrangement of the aglucone to afford different products, and hence stereoselective syntheses of heteroyohimbine, yobimbine and Aspidosperma-type alkaloids; with baker's yeast chemoselective reduction can also be achieved to give a precursor for antirhine and related alkaloids.

An all fiberglass decking panel has been designed to the requirements of the trilateral code for military bridging and the circular of requirements for new construction strategic sealift ships. The truss structure provides a lightweight fiber reinforced plastic (FRP) module that can be rapidly installed as decking for floating structures or military causeways. The edge supported composite deck can span up to 3m×9m at a weight less than 100kg/m2 (20lb/ft2).Triangular elements are fabricated using a single, thick ply of 3D-braided fiberglass textile drawn through a pultrusion die. The triangular pultrusions are bonded together with face sheets, using Plexus adhesive, to form the deck modules. The assembly is optimum weight for a plate over a span because the triangles carry the load with truss action and the face sheets carry the load in beam (EI) bending.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The isolation of (+)-uleine (1) and (+)-demethoxyaspidospermine (2) from the bark of Plumeria lancifolia is reported along with 1H- and 13C-NMR data.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

In order to reduce the large loads that are developed in connecting semi-submersible platforms on a 5000ft long mobile offshore base (MOB), a compliant connector concept was developed. This concept employs the cable compliant technology developed by NASA-Goddard and is based upon the use of 3-D Through-the-Thickness® braid reinforced elastomeric tubes as the compliant element in the connector. By selectively placing and orienting the composite tubes, the connector can be designed to provide stiffness in degrees of freedom critical to maintaining runway smoothness (such as relative heave or roll) while permitting larger displacements in other degrees of freedom (such as relative pitch or surge). Two different connectors were designed: a four-degree-of-freedom (4 DOF) connector for the deck attachment and a 6 DOF connector for connecting at the pontoon level. The work presented includes material characterization testing, including some fatigue studies, and constitutive model development to fully understand the material behavior. The constitutive model for the material included both the material nonlinearity of the urethane elastomer matrix and geometric nonlinearities to include the fiber reorientation during loading.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Hydrolysis of secologanin ethylene acetal at pH 7 resulted in stereoselective aldol cyclisation to a cyclohexene aldehyde, which, on reductive amination and cyclisation with tryptamine afforded (-)-3-iso-19,20-dehydro-beta-yohimbine, converted into various normal and pseudo isomers of yohimbine. (C) 2000 Elsevier Science Ltd. All rights reserved.

Stereoselective, enantiospecific syntheses of 16-methoxycarbonyl-16,17-dehydro-antirhine, its 10-hydroxy and 10-glucosyloxy derivatives have been realised from the corresponding tryptamines and the ethylene acetal of the monoterpenoid glucoside secologanin via hydrolysis and selective reduction of the aglucone with baker's yeast.

Chiral polyfunctionalised cyclopentanes have been readily obtained in ~65% enantiomeric excess via a stereo-specific Wagner–Meerwein rearrangement induced by bromination of derivatives of the exo-cis Diels–Alder adduct of furan and maleic anhydride, combined with desymmetrisation of a meso intermediate by pig liver esterase.

A convenient two-step synthesis of morphine-3,6-di-β-d-glucuronide in fair yield from morphine and methyl 2,3,4-tri-O-isobutyryl-1-O-trichloroacetimidoyl-α-d-glucopyranuronate is reported.

A biogenetically patterned synthetic route to the monoterpenoid quinoline alkaloids 20-deoxycamptothecin and (±)-camptothecin from secologanin and tryptamine via vincoside/strictosidine lactams has now been realized, and hence afforded likely biosynthetic intermediates for testing in vivo.

Pure enantiomers of two diastereomeric Aspidosperma alkaloid analogues antipodal at the spiro and adjacent centres have been prepared, as kinetic and thermodynamic products, respectively, in a biomimetic sequence via a secodine-like intermediate from a secologanin derivative and Kuehne's indolo-azepine.

(−)-3-Iso-19,20-dehydro-β-yohimbine has been converted into epiallo-yohimbines and, via a novel regio- and stereoselective hydration, into the 18R-hydroxy derivative, an analogue of deserpidine. Its 11-methoxy derivative, also prepared from secologanin, is a potential precursor for a reserpine analogue.

A claim by Lounasmaa and Hanhinen to have synthesised a biogenetic intermediate to heteroyohimbine alkaloids, 3-iso-19-epicathenamine, isolated as the cyano adduct, 21-α-cyano-3-isorauniticine, is wrong; the product is now shown by n.O.e. difference spectra to be in reality the known 21-α-cyano-akuammigine. Their “correction” of the latter structure is thus proven to be totally invalid.

From Siphocampylus verticillatus, two novel piperidine alkaloids have been isolated, namely meso-8,10-di-n-propyllobelidiol[meso-2,6-bis(2'-hydroxypentyl)-N-methylpiperidine] and 8-ethyl-10-n-propyllobelidiol [6-(2'-hydroxybutyl-2-(2"-hydroxypentyl)-N-methylpiperidine]. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.