- Stereoselective hydrogenation and ozonolysis of iridoids. Conversion into carbocyclic nucleoside analogues
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Stereoselective hydrogenation of the iridoids geniposide (9) and aucubin (19) was achieved by using the 1-methyl-1- methoxyethyl ether as a protecting group for the allylic alcohol, as it enhanced the stereoselectivity and prevented undesired hydrogenolysis. Ozonolysis of the hydrogenation product from 9, adoxoside (11), with reductive workup, afforded either a chiral lactone (25) or a chiral polyol (26), depending on the reduction conditions. Polyol 26 was subjected to protecting-group manipulation and subsequent oxidation and reductions to yield cyclopentane building blocks (29-34), which, by Mitsunobu couplings with purines, afforded carbocyclic nucleoside analogues (7, 8, and 35).
- Franzyk, Henrik,Stermitz, Frank R.
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p. 1646 - 1654
(2007/10/03)
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- Efficient conversion of aucubin into 6-epi-aucubin
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Selective deprotection of peracetylaucubin (3) by use of KCN led to 6- O-acetylaucubin (4), which was readily converted into 2',3',4',6',10-penta- O-benzoylaucubin (7). Configuration inversion performed on 7, using a modified Mitsunobu reaction, followed by deprotection, afforded 6-epi- aucubin (2).
- Cachet, Xavier,Deguin, Brigitte,Koch, Michel,Makhlouf, Kader,Tillequin, Francois
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p. 400 - 402
(2007/10/03)
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- Hair dyeing by iridoid glycosides and aglycons thereof
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A method of dyeing hair which comprises contacting hair with an iridoid glycoside or an aglycon thereof.
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- Chemistry and Stereochemistry of Iridoids, XIV. - Aucubin and Scandoside from Catalpol
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Aucubin (9), scandoside (10), and its methyl ester were obtained, in good yields, from catalpol (1).The absolute configurations of 9-11 were established by correlation to catalpol, whose X-ray structure has previously been determined.
- Weinges, Klaus,Ziegler, Hans Juergen
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p. 715 - 717
(2007/10/02)
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- A NEW IRIDOID ESTER: THE 2'-O-BENZOYLAUCUBIN
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A new aucubin-type iridoid (2) which contains a benzoyl group, has been isolated from Odontites verna ssp. serotina (Scrophulariaceae).Chemical and spectroscopic data demonstrate that 2 has the structure of 2'-benzoylaucubin.
- Bianco, Armandodoriano,Bolli, Daniela,Passacantilli, Pietro
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p. 479 - 482
(2007/10/02)
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