(R,R)-Threoninol was prepared in one step from L-threonine in 86% isolated yield. The product was regioselectively transformed into 2,2-bis[(4R,5R)-4-(hydroxymethyl)-5-methyl-1,3-oxazolin-2-yl]propane in 42% isolated yield.

AbstractFor Abstract see ChemInform Abstract in Full Text.

This is the second of two papers [Drews, M., Doverskog, M., Ohman, L., Chapman, B.E., Jacobsson, U., Kuchel, P.W., Häggström, L., 2000. Pathways of glutamine metabolism in Spodoptera frugiperda (Sf9) insect cells: evidence for the presence of the nitrogen assimilation system, and a metabolic switch by 1H/15N NMR. J. Biotechnol. 78, 23-37]. where the general goal has been to determine and characterise the glutamine metabolism in Sf9 cells. The presence of glutamate synthase (GOGAT) activity was investigated in cell-free extracts of S. frugiperda (Sf9) insect cells by modified 1H/15N spin-echo and gradient enhanced multiple quantum coherence NMR spectroscopy techniques. Cell-free extracts were prepared from cells cultured in a serum-free medium. The assay conditions were based on conventional spectrophotometric and chromatographic methods. NMR data showed that nitrogen from [5-15N] glutamine was selectively incorporated into 2-oxoglutarate forming [2-15N] glutamate with a specific activity of 4.15 +/- 0.21 nmol [2-15N] glutamate min -1 (mg total protein)-1 in the cell-free extracts. The enzyme activity was exclusively dependent on NADH as coenzyme and was completely inhibited by 1 mM azaserine. From the results obtained, we conclude that Sf9 cells possess NADH-GOGAT activity. Furthermore, the high specificity of the NMR method enables distinction of competing reactions from glutaminase and glutamate dehydrogenase.

Two new sesquiterpenes 7α, 8α, 13, 14-tetrahydroxy-marasm-5-oic acid γ-lactone, and 10β-hydroxy-lactarorufin A as well as the known dipeptide cyclo-L-prolyl-L-leucyl were isolated by multiple chromatography of the ethanolic extract of Lactarius vellereus.

The enantioselectivity of pig liver esterase catalysed hydrolysis of cis-N-benzyl-2,5-bis(methoxy-carbonyl)pyrrolidine (1) has previously been shown to be very dependent on the reaction conditions.1,2 Hydrolysis performed in media buffered with tris(hydroxymethyl)aminomethane (Tris) afforded a monoester with much higher optical purity than hydrolysis in media without Tris. Detailed product studies in a Tris-buffered medium have been performed using NMR-techniques and a 13C-labelled ester. The NMR-studies revealed the presence of (2S,5R)-N-benzyl-2-methoxycarbonyl-5-[[[2-hydroxy-1,1-bis(hydroxymethyl) (4) as an intermediate, which together with the isolated product (2S,5R)-N-benzyl-2-carboxy-5-[[[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]amino]carbonyl]pyrrolidine (3) suggested Tris as a competitive nucleophile to water. The increased enantioselectivity seen in the produced (2R,5S)-N-benzyl-2-methoxy-carbonyl-5-carboxypyrrolidin (2) was explained by the preference of Tris to react faster with one of the diastereomeric acyl enzymes over the other.

An indole dimer from Murraya gleniei root timber has been shown to be a tetrohydrocarbazolylindole and have the structure, methyl 2-methyl-4-( N -2′'β-methyl-1′',2′',3′',4′'-tetrahydrocorbazol-1′'α-ylindol-3′-yl)butanoate (1).

The thoracic gland of the ant-lionEuroleon nostras was found to contain nerol oxide (1a) and (Z)-6-undecen-2-ol (nostrenol,3) while the speciesGrocus bore contained 10-homonerol oxide (1b) and nostrenol (3). Nerol (2a) and 10-homonerol (2b) were found in a third species,Myrmeleon formicarius. 10-Homonerol, racemic 10-homonerol oxide, and racemic as well as (R)- and (S)-nostrenol were synthesized. The nerol oxide ofE. nostras and the 10-homonerol oxide ofG. bore were found to be racemic, while both species contained optically pure (R)-nostrenol (28).