Racemic elacomine ((%)-2), a hemiterpene spiro oxindole alkaloid from Elueagnus commutata, was synthesized in five steps from 6-methoxytryptamine (19) in 16% overall yield (Scheme 3 ) . The final oxidative rearrangement of the corresponding 8-carboline precursor (%)-21 furnished isoelacomine ((%)-22) as a by-product (6% overall yield). A more elaborate route that started from L-tryptophan furnished (+)-2 and (-)-22 with optical purities of 76% (Scheme 4 ) and established the absolute configuration of these compounds. A reinvestigation of the alkaloidal content of the roots of E. cornmututu showed that both elacomine and isoelacomine occur naturally in racemic form. ( [ a ] , = +174.8) hemiterpene oxindole alkaloid3) from the roots of the shrub Elaeagnus commutata (Elaegnaceae) [ 11. Chemical degradation studies and spectroscopic evidence led to structure proposal 1 which, however, left open the exact position of the phenolic OH group and the relative configuration at the two asymmetric centres C(3) and C(4')4). These questions were addressed subsequently by James and Williams by means of an X-ray diffraction study that allowed them to established formula 2 for this compound which they had obtained from Locock and Slywka [2]. Curiously enough, the sample investigated by X-ray crystallography must have been racemic, since the crystal was composed of alternating layers of both optical antipodes of 2, a fact that is consistent with the reported space group P2,lc. Surprisingly, the evident conflict concerning the enantiomeric purity of 2 was not commented by James and Williams, and in the context of our interest in the chemo-and diastereoselective transformation of indole alkaloids into their oxindole (1,3-dihydro-2H-indol-2-one) or pseudoindoxyl (1,2-dihydro-3H-indo1-3-one) derivatives [4-81, we decided to synthesize (+)-elacomine ((+)-2) in a way that would allow to delineate its hitherto unknown absolute configuration. Introduction. ~ In 1968, Slywka reported the isolation of a novel, optically active

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The low degree of internal molecular mobility of stiff polysaccharide chains prevent any thermal transition in the temperature range of their chemical stability. Substituted starches were synthesised to find the structural range, i.e. the necessary amount and length of mobile side chains which support the molecule with high enough level of internal degrees of freedom. Esterification and transesterification with hydroxy alkanoates, their polymers and lactones were used. The reaction was best catalysed with strong delocalised bases. The thermal properties of these model substances were characterised.

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ChemInform 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.