In epoxidation of the conformationally biassed 5-t-butylcyclohex-2-enols by peroxybenzoic acid, higher cisstereoselectivity and faster rate are found for the pseudo-equatorial than for the pseudo-axial alcohol. Cyclo-oct-2-en-1 -01 is epoxidised with stereospecific introduction of the epoxy-group trans to hydroxy, and appropriate acyclic allylic alcohols show a preference for formation of the threo-epoxy-alcohol. A consistent interpretation of these results is advanced, based on the postulate that the preferred conformation of an allylic alcohol in the transition state for epoxidation is as in ( X x ) .IN 1957 Henbest and Wilson 1 reported their work on the epoxidation of cyclohexene derivatives possessing various allylic substituents. Although 3-methoxy-and 3-acetoxy-cyclohexene gave predominantly the trans-epoxide, cyclohex-2-en-1-01 was converted mainly into the cisepoxide, a t a significantly faster rate. The observation was reasonably explained in terms of a transition state involving hydrogen bonding between the hydroxygroup of the allylic alcohol and the peroxy-acid. Since then, numerous examples of the intramolecular facilitation of epoxidation by hydroxy-groups have been described by different workers, particularly in the steroid field,2 but little has been done to put the phenomenon on a more quantitative basis, and to define more closely the preferred geometry of the transition state.An apparently anomalous result has been obtained with medium ring allylic alcohols ; cis-cyclo-oct-2-en-1-01 is reported 3 to give the trans-epoxy-alcohol, and cyclohept-2-en-P-o14 to give a mixture of the cis-and tramepoxy-alcohols on epoxidation. Studies on the stereochemistry of the reaction of peroxy-acids with acyclic allylic alcohols have been published,596 some of which will be discussed later; however, the results were discussed in terms of the preferred conformation of the starting alcohol in violation of the Curtin-Hammett principle .7As a result of another investigation,* 5-t-butylcyclohex-Zen-l-one became readily available. We decided, therefore, to examine the kinetics and stereochemistry of epoxidation of the epimeric 5-t-butylcyclohex-2-enols by peroxy-acids to try to define more closely the optimum requirements for intramolecular catalysis by the hydroxy-group. In addition we planned to re-investigate cyclo-oct-2-enol to see if the apparent anomalies could be resolved. A study of acyclic allylic alcohols was also envisaged but this was curtailed when the work of The n.m.r. data agree with the observation of Jensen and Bushweller l1 that pseudo-axial and pseudo-equatorial allylic hydrogens have similar chemical shifts.
A detailed study of metabolites produced by the plant cell culture line of Tripterygium wilfordii, a Chinese herbal plant, is presented. Eighteen compounds within the diterpene and triterpene families have been isolated and fully characterized. Of these, five are novel compounds, and their structures were determined by a combination of spectral analysis, chemical correlation and single crystal X-ray diffraction. The interest of these compounds in the treatment of rheumatoid arthritis, skin allergies, and for male contraception is noted. On rapporte une etude dCtaillCe des metabolites produits par une IignCe de culture cellulaire du Tripterygium wilfordii, un plante galenique chinoise. On a isole et caractCrisC 18 composks des familles des di-et des triterpknes. Cinq de ces produits sont de nouveaux composCs; on a determine leur structure par une combinaison d'analyses spectrales, de corrClations chimiques et de diffraction des rayons X par des cristaux uniques. On a not6 l'intCr&t de ces composCs pour le traitement de l'arthrite rhumatismale, d'allergies de la peau et comme contraceptifs pour les males.[Traduit par la rkdaction]Tripterygium wilfordii Hook f is a perennial twining vine of the family Celastraceae, which is cultivated in many parts of southern China such as Zhejiang, Anhui, Jiangxi, Fujian, and Guangdong provinces and also in Taiwan. The herb is commonly known in China as Lei Gong Teng (Thunder God vine) or Mang Cao (rank grass). Its use in Chinese traditional medicine dates back many centuries, and it is first mentioned in the Saint Peasant's Scripture of Materia Medica (1), written about two thousand years ago, as being used for the treatment of fever, chills, oedema, and carbuncle. Chinese gardeners used the powdered root to protect their crops from chewing insects. Most recently, crude extracts and refined extracts (a so-called multi-glycoside extract, or GTW) have been used increasingly to treat such disorders as rheumatoid arthritis, ankylosing spondilitis, and a variety of dermatological disorders (2-4).In 1972, Morris Kupchan et al. first isolated the novel diterpenoid triepoxides, tripdiolide ( I ) , triptolide (2), and triptonide (2a) from the roots of Triptetygium wilfordii (5) and showed that 1 and 2 have significant antileukaemic activity. The biological properties of 1 and 2 stimulated studies in our laboratory directed at developing a plant cell culture line that would hopefully produce these compounds in higher yield and under laboratory controlled conditions. The earlier studies, with these objectives in mind, have been published (6, 7) and the stable cell line, coded as TRP4a, was shown to produce 1 in yields 40 times that of the living plant.As these studies were underway, we became aware of more recent research data from various laboratories in the People's Republic of China that revealed an increasing interest in the clinical use of extracts from T. wilfordii plants. Various disorders (rheumatoid arthritis, skin disorders) have been 'Author to whom correspondence may be address...
An extensive investigation of the petroleum ether extract of TRIPTERYGIUM WILFORDII plants have revealed the presence of four new compounds, triptonoterpene, neotriptonoterpene, triptonodiol, and neotriptonolide, in addition to the diterpenes isolated and characterized earlier. The structures of these novel natural products have been elucidated.
Studies with Tissue Cultures of the Chinese Herbal Plant, Tripterygium wilfordii. Isolation of Metabolites of Interest in Rheumatoid Arthritis, Immunosuppression, and Male Contraceptive Activity -(isolation and structure elucidation of 18 compounds, mainly triterpenes and diterpenes, of which compounds (I)-(IV) are new). -(KUTNEY, J. P.; HEWITT, G. M.; LEE, G.; PIOTROWSKA, K.; ROBERTS, M.; RETTIG, S.
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