Isolation of cyclocolorenone from the essential oil ofLedum palustre

Summary From a carbon dioxide extract and also from the essential oil of the leaves ofLedum palustre L. the sesquiterpene ketone cyclocolorenone, hitherto unreported for this medicinal plant, has been isolated. The structure proposed for it previously has been confirmed by NMR and mass spectroscopy and also by the production of hydrogenation products.All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 212–215, March–April, 1978.     

A study of the chemical composition of the essential oil ofLedum palustre

Eight substances have been isolated by preparative chromatography on silica gel from the essential oil ofLedum palustre L., collected in the Kostroma oblast in August. Six of them have been described previously for this essential oil (myrcene, palustrol, ledol, allocaromadendrene, 6-methyl-2-methyleneocta-5,7-dien-3-ol, and cyclocolorenone) and two are new substances not described in the literature: a colorless liquid with a pleasant smell having the composition C₁₀H₁₄O₂, mp 108–111°C/4 mm Hg, n _D ²⁰ 1.4925, d ₂₀ ²⁰ 1.002, []_D±0°C, which has been called lepalol, and a colorless liquid with a pleasant smell having the composition C₁₀H₁₂O, bp 91–93°C/4 mm Hg, n _D ²⁰ 1.5175, d ₂₀ ²⁰ 0.9444, []_D±0°C, which have been proposed for lepalin and lepalol on the basis of their IR, UV, and NMR spectra. The physical constants of all the substances isolated and the characteristics of their IR, NMR, and mass spectra are given.All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 322–325, May–June, 1979.     

Chemical composition of Ledum palustre

Summary Extraction of the herbLedum palustre with liquefied carbon dioxide and Khladon-11 has yielded 10 individual substances belonging to various classes and various groups of organic compounds: hydrocarbons, alcohols, ketones, monoterpenes, sesquiterpenes, and flavonoids.All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 127–130, January–February, 1978.     

Isolation of very volatile compounds from the leaves ofLedum palustre using the purge & trap technique

Summary A comparison of different isolation methods for volatile compounds from the leaves ofLedum palustre has been carried out. The aim of the investigation was not to identify all the isolated compounds, though some new compounds were found. Methods used were steam distillation, Soxhlet extraction with n-hexane and the purge & trap technique.The results obtained by the three methods of extraction were compared and it is was found that the very volatile compounds isolated by the purge & trap technique, could not be found by the more conventional methods. The very volatile compounds found by the purge & trap technique were mainly dienals.     

Terpenoids of the essential oil ofLedum hypoleucum

The chemical composition of the terpenoids of the essential oil ofLedum hypoleucum growing in the Far East has been studied. It differs fromL. palustre by a larger amount of compounds of the bisabolane series in the essential oil. Among the monoterpenoids, p-cymene, -phellandrene, and ascaridole predominate. The main components of the sesquiterpenoids are ar-curcumene and ar-turmerone, now found for the first time inLedum essential oils.Tomsk State Medical Institute. Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 104–107, January–February, 1987.     

Chemical constitution of 3d complexes and rate constants of ortho-para positronium conversion reactions

The positronium spin exchange (SE) reactions promoted by the 3d complexes Mn _aq ²⁺ , Co _aq ²⁺ , [Cr(NH₃)₆]³⁺, [Cr(NH₃)₅H₂O]³⁺, and [Cr(H₂O)₅Cl²⁺] were investigated at different temperatures in order to ascertain whether they were diffusion controlled like those promoted by Cr _aq ³⁺ , Fe _aq ²⁺ , Ni _aq ²⁺ and [Ni(NH₃)₆] _aq ²⁺ ions studied previously.It was found that the reactions are diffusion controlled and that the effective reaction radii deduced from the Smoluchowski equation are smaller than the compound radii calculated from bond lengths and angles. It was also found that the rate constants, and therefore the reaction radii, are correlated with the spin—orbit coupling of 3d unpaired electrons and ligand capabilities to cause expansion of the d-electron cloud (nephelauxetic effect). In particular the effective reaction radii of SE reactions promoted by 3d complexes increase as the electron delocalization from 3d atoms increases.Work supported by Ministero Università e Ricerca Scientifica e Tecnologica (M.U.R.S.T.) and by Consiglio Nazionale Ricerche (C.N.R.).     

New terpenoids of the essential oil of Ledum palustre

The structures of two new natural compounds isolated from the essential oil ofLedum palustre L. have been established on the basis of their spectral characteristics as p-mentha-1,8(10)-diene 3,9-epoxide (lepaloks) and 3,10-epoxygermacr-4(14)-en-8-one (lepakson). The chemical structure of ledene as a sesquiterpene hydrocarbon has been determined by chemical correlation.Tomsk State Medical Institute. Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR, Novosibirsk. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 24–29, January–February, 1991.     

Bicyclic monoterpenoids of the essential oil of Ledum palustre

The structure of a new natural compound has been established as 5-isopropylbicyclo[3.1.0]hex-3-en-2-one, which has been called lebaikon. Two bicyclic monoterpenoids (2-formyl-5-isopropylbicyclo[3.1.0]hex-2-ene and 4-isopropyl-1-methylbicyclo[3.1.0]hexan-2-one) have been detected in natural materials for the first time.     

Two new taraxerane-type triterpenes from Ledum palustre L.

Abstract

Two new compounds, namely 6α-hydroxy-14-taraxerene-3,16,21-trione and 6α,26-dihydroxy-14-taraxerene-3,16,21-trione were isolated from the Ledum palustre L. Their chemical structures were confirmed after a combined analysis of IR, HR-ESI-TOFMS, 1D-NMR, and 2D-NMR. The compounds were evaluated for cell growth inhibitory activity against two cancer cell lines.     

Bicyclic monoterpenoids of the essential oil of Ledum palustre

The structure of a new natural compound has been established as 5-isopropylbicyclo[3.1.0]hex-3-en-2-one, which has been called lebaikon. Two bicyclic monoterpenoids (2-formyl-5-isopropylbicyclo[3.1.0]hex-2-ene and 4-isopropyl-1-methylbicyclo[3.1.0]hexan-2-one) have been detected in natural materials for the first time.Tomsk State Medical Institute. Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR, Novosibirsk. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 627–629, September–October, 1990.     

反相高效相色谱法测定杜香嫩枝叶中的熊果酸

杜香（Ledum palustre L.）是杜鹃花科杜香属常绿小灌木,其挥发油具有明显的镇咳、祛痰作用,对皮肤瘙痒和脚气等有较好的疗效,因而受到广大研究者的关注。我们在研究杜香指纹图谱时发现杜香含有活性化合物熊果酸,其对应色谱峰与熊果酸对照品的保留时间及吸收谱图基本一致,峰纯度良好。本文报道了杜香中熊果酸的反相高效液相色谱（RP-HPLC）测定方法,方法准确、简便,能排除杂质干扰,重复性好。     

Intraspecies chemical variability of the essential oil of Ledum palustre

The compositions of the essential oils of marsh tea,Ledum palustre L., from the southern regions of Tomsk, Transbaikalia and Amur province, and also from the southern part of the island of Sakhalin have been analyzed in detail. The results obtained indicate the sharply pronounced intraspecies chemical variability of this plant. In addition to the chemotype of march tea with myrcene as a macrocomponent which is widely distributed in the European part of the USSR, another three chemotypes with the macrocomponents limonene, sabinen, and p-cymene have been revealed.Tomsk State Medical Institute. Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 472–480, July–August, 1990.