- Glycosylidene carbenes: Part 32: Reaction of glycosylidene diaziridines with acylating and sulfonylating agents
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Acylation and sulfonylation of the N,N'-unsubstituted glucosylidenespirodiaziridines 1A/1B 95:5 with Ac2O, BzCl, FmocCl, TsCl, (naphthalen-2-yl)sulfonyl, and (2,4,6-triisopropylphenyl)sulfonyl chloride, and concomitant rearrangement gave the ac
- Mangholz, Sissi E.,Briner, Karin,Bernet, Bruno,Vasella, Andrea
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p. 2490 - 2508
(2007/10/03)
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- Synthesis of [1-2H]- and [3-2H]-Guanosine
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Reliable methods are reported for the total synthesis of both [1-2H]- and [3-2H]-guanosine for use in studies of the stereochemistry and mechanism of two enzyme catalysed reactions.
- Baker, Stephen J.,Young, Douglas W.
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p. 1022 - 1032
(2007/10/03)
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- Chiral 1,4-dicarbonyl-2,3-O-isopropylidene derivatives. Rapid racemization on standing
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1,4-Dicarbonyl-2,3-chiral derivatives are useful synthetic precursors for the preparation of carbocyclic rings but, in many cases, losses of optical purity have been reported. 1-Deoxy-3,4-O-isopropylidene-6-O-trityl- D-erythro-hexo-2,5-diulose and 1-deoxy-3,4-O-isopropylidene-6-O-(tert- butyldiphenylsilyl)-D-erythro-hexo-2,5-diulose were synthesized from D- ribono-1,4-lactone. These compounds were selected to study the epimerizability of 2,3-O-isopropylidene-1,4-dicarbonyl derivatives. It was found that both compounds smoothly epimerize and partially racemize on standing.
- Rodriguez, Juan B.
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p. 2157 - 2170
(2007/10/03)
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- A new route to some enantiomerically pure substituted morpholines from D-ribono- and D-gulono-1,4-lactones
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D-Ribono-1,4-lactone, after acetalation, tritylation, and reduction, leads to a cyclization compound which gave with tosyl chloride 1,4-anhydro-2,3-O-isopropylidene-5-O-trityl-D-ribitol.The latter was transformed (acid hydrolysis, periodate oxidation, reduction, tritylation, and tosylation) into a ditosylated derivative 16, which was cyclized into morpholines by the action of primary amines.Acid hydrolysis, followed by acetylation, gives the (2S)-acetoxymethyl-4-isopropyltetrahydro-1,4-oxazine (21).A similar sequence has been applied to D-gulonolactone to give access to oxazines 33, 34, and 35. Keywords: Synthesis; D-Ribono-1,4-lactone; D-Gulono-1,4-lactone; Morpholine derivatives
- Bennis, Khalil,Calinaud, Pierre,Gelas, Jacques,Ghobsi, Mebrouk
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- Diastereoselective Diels-Alder Reactions with α-Chloronitroso Saccharides
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The α-chloronitroso reagent 2 obtained from ribose via the lactone oxime 3 reacts with the dienes 6-10 at low temperature to give the chiral dihydrooxazines 11-16 in 63-96percent yield and >/=96percent enantiomeric excess.The reagents 1 and 2 which are ap
- Braun, Heinz,Felber, Helena,Kresze, Guenter,Schmidtchen, Franz P.,Prewo, Roland,Vasella, Andrea
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p. 261 - 268
(2007/10/02)
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- EINFACHE, REGIOSPECIFISCHE SYNTHESE VON CYCLOALKENONEN AUS LACTONEN
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The reaction of lithiumalkylphosphonates with γ- or δ-lactones followed by oxidation leads to 2,5- or 2,6-dioxophosphonates, which can be cyclized to cyclopentanones or cyclohexanones, respectively, constituting an easy, regiospecific route to cycloalkanones from lactones.
- Altenbach, Hans-Josef,Holzapfel, Winfried,Smerat, Gerd,Finkler, Stefan H.
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p. 6329 - 6332
(2007/10/02)
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