- Photocaged Hydrocarbons, Aldehydes, Ketones, Enones, and Carboxylic Acids and Esters that Release by the Norrish II Cleavage Protocol and Beyond: Controlled Photoinduced Fragrance Release
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Five families of caged fragrance compounds that allow the storage and release of the following small volatile organic molecules are described: terpene hydrocarbons, aldehydes, ketones, Michael-type α,β-unsaturated enones, and carboxylic acids and esters. These caged molecules are released by photoexcitation via carbonyl-directed hydrogen-transfer processes and subsequent C-C bond cleavage (Norrish Type II) or by didenitrogenation of diazirines.
- Griesbeck, Axel G.,Porschen, Bj?rn,Kropf, Christian,Landes, Agnieszka,Hinze, Olga,Huchel, Ursula,Gerke, Thomas
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p. 539 - 553
(2017/01/25)
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- Lipophilic constituents from aerial and root parts of Mercurialis perennis L
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Introduction - Dog's mercury (Mercurialis perennis L.) is a perennial herb used in remedies for medicinal purposes. The plant is supposed to contain potentially active substances but its constituents have only been rarely studied. Objective - Detailed studies on the phytochemical composition are of great interest to broaden the knowledge on the chemotaxonomy and pharmacognosy of M. perennis. Methodology - Chloroform and hexane extracts from roots and aerial parts were investigated using GC/MS and LC/MS. Results - The whole plant exhihited a broad spectrum of structurally diverse constituents, mainly alkaloids, terpenes, sterols and simple aromatic compounds. Closer inspection of the piperidine alkaloid hermidin revealed its inherent instability towards air oxygen. To obtain quantitative data on these alkaloids the synthesis of the more stable reference compound 4-methoxy-1-methylpyridine-2,6(1H,3H)-dione (MMPD) was required. In this study, MMPD was detected for the fi rst time as a genuine compound in Mercurialis. Hermidine quinone and hermidin dimers originating from hermidin via a free anionic radical reaction were also confi rmed by GC/MS. Moreover, volatile compounds such as benzylalcohol, 2-phenylethanol, 4-methoxy- and 3,4-dimethoxyphenol, (-)-cis- and (+)-trans-myrtanol, (-)-cis-myrtanal as well as squalene were predominantely present in Mercurialis roots. In contrast, aerial parts mainly contained phytol derivatives, sterols and tocopherols. By changing solvent polarity, lipid and wax-containing fractions were obtained. LC/MS-studies on hexane extracts showed the presence of several mixed triglycerides constituted by linolenic, linoleic, oleic, stearic and palmitic acids, as well as lutein, carotenes and pheophytins. Conclusions - The phytochemical data presented complement our knowledge on the rarely studied plant M. perennis and may broaden its use in future phytotherapy. Copyright
- Lorenz, Peter,Hradecky, Marc,Berger, Melanie,Bertrams, Julia,Meyer, Ulrich,Stintzing, Florian C.
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experimental part
p. 234 - 245
(2011/11/06)
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- Convenient preparation of carbonyl compounds from 1,2-diols utilizing Mitsunobu conditions
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1,1-Disubstituted 1,2-diols are efficiently converted into carbonyl compounds by reaction with triphenylphosphine and diethyl azodicarboxylate. (C) 2000 Elsevier Science Ltd.
- Barrero, Alejandro F.,Alvarez-Manzaneda, Enrique J.,Chahboun
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p. 1959 - 1962
(2007/10/03)
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- Selective aerobic oxidation of primary alcohols catalyzed by a Ru(PPh3)3Cl2/hydroquinone system
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Aerobic oxidation of primary alcohols to aldehydes was efficiently performed using a Ru(PPh3)3Cl2/hydroquinone system under atmospheric oxygen at 60 °C. A primary alcohol even in the presence of a secondary one was selectively oxidized to the corresponding aldehyde in high yield.
- Hanyu, Atsushi,Takezawa, Eiichiro,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 5557 - 5560
(2007/10/03)
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