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Ribonolactone syntheses from

Synthesis from o-ribonolactone An efficient synthesis of 1-deoxygalactostatin... [Pg.149]

Synthesis from o-ribonolactone The required intermediates 164 and 165 for the synthesis of clavalanine (2) were prepared from D-ribonolactone (Scheme 17). ... [Pg.235]

S Synthesis from n-ribonolactone D-Ribonolactone has been converted to tre-hazolamine derivatives via the allylic alcohol 99, whose condensation with p-methoxybenzylisothiocyanate followed by anti-Markovnikov iodo cyclization with iodine afforded the iodo oxazolidinone 100 (82%) (Scheme 14). The latter was treated with a mixture of acetic anhydride and snlfnric acid followed by activated zinc to furnish the allylic acetate 101 (90%), which nnderwent inversion at C-2 nnder Mitsnnobu conditions and the resnlting alcohol was epoxidized to produce 102. Hydrolysis of the epoxide 102 followed by acetylation of the resulting triol 103 afforded 104, which was treated with CAN to furnish the triacetate 105. Finally, 105 was converted into hexaacetate 86 in three steps. [Pg.282]

Synthesis from o-ribose D-Ribose has been used for a facile synthesis of the pyrrolidine derivative 103, an intermediate for the preparation of 1 and some of its analogues (Scheme 14). Thus, D-ribonolactone could be converted to the benzylidene derivative... [Pg.329]

Aldonolactones are useful starting materials for the synthesis of modified sugars. They have also been used as chiral templates in synthesis of natural products. Some of them are inexpensive, commercially available products or they may be obtained readily from the respective monosaccharides. The purpose of this chapter is to survey the main reactions of aldonolactones. Previous reviews on the subject include articles on gulono-1,4-lactones (1) and D-ribonolactone (2). Methods of synthesis, conformational analysis, and biological properties are not discussed in this chapter. [Pg.125]

The borohydride reduction-periodate cleavage applied to 2,3-O-isopro-pylidene-D-ribono- 1,4-lactone (16a) led to L-erythrose (30). The method was also employed (31) for the synthesis of D-erythrose, starting from an Obenzylidene-D-ribonolactone. However, in this case, the structural assignments for the intermediate compounds must be revised, as the starting material formulated as 3,5-O-benzylidene-D-ribono-1,4-lactone (2) was, as discussed previously in this section, the 3,4-0-benzylidene-D-ribono-1,5-lactone (3a). Therefore, the correct structure for the product described as 3,5-O-benzylidene-D-ribitol (20, not isolated) would be 3,4-O-benzylidene-... [Pg.130]

Acyloxybutenolides obtained by / -elimination from ribonolactone (see Section IX.2) have served as appropriate chiral intermediates in several synthesis of antibiotics. Barrett and Sheth (205) reported a seven-step synthesis of racemic terI-butyl-8-0-ter/-butyldimethylsilylnonactate, a monomeric moiety of the antibiotic nonactin, from 157. Also, (4,S,6[Pg.189]

D-Ribonolactone is a convenient source of chiral cyclopentenones, acyclic structures, and oxacyclic systems, useful intermediates for the synthesis of biologically important molecules. Cyclopentenones derived from ribono-lactone have been employed for the synthesis of prostanoids and carbocyclic nucleosides. The cyclopentenone 280 was synthesized (265) from 2,3-0-cyclohexylidene-D-ribono-1,4-lactone (16b) by a threestep synthesis that involves successive periodate oxidation, glycosylation of the lactol with 2-propanol to give 279, and treatment of 279 with lithium dimethyl methyl-phosphonate. The enantiomer of 280 was prepared from D-mannose by converting it to the corresponding lactone, which was selectively protected at HO-2, HO-3 by acetalization. Likewise, the isopropylidene derivative 282 was obtained (266) via the intermediate unsaturated lactone 281, prepared from 16a. Reduction of 281 with di-tert-butoxy lithium aluminum hydride, followed by mesylation, gave 282. [Pg.192]

Asymmetric synthesis of the C-l -C-5 segment 298 of a bis-normaytasin-oid was developed by Barton and coworkers (273) from the ditosyl derivative (296) of ribonolactone. Compound 296 was transformed into the dibromide, benzylated, and reduced to the 5-bromoaldose 297. Compound 298 was obtained in five steps from the intermediate 297. [Pg.195]

Scheme 26 Synthesis of 4-thio-L-lyxono-1,4-lactone from 2,3-0-isopropylidene-5-0-tosyl-D-ribonolactone... Scheme 26 Synthesis of 4-thio-L-lyxono-1,4-lactone from 2,3-0-isopropylidene-5-0-tosyl-D-ribonolactone...
Alkenes from 1,2-diols (7, 385-386). An efficient synthesis of (S)-(—)-y-methoxymethyl-a, /J-butenolide (3) from (+)-5-0-methyl-D-ribonolactone (1) involves conversion to the cyclic orthoformate 2 followed by pyrolysis to give 3 in 66.5% overall yield.1 In this case, the Corey-Winter reaction and the Hanessian route (8,192) were... [Pg.620]

D. Liu and C. A. Caperelli, A new synthesis of D-ribonolactone from D-ribose by pyridinium chlorochromate oxidation, Synthesis, (1991) 933-934. [Pg.282]

This analysis turned out to be in excellent agreement with the experimental results 13). The required chiral building block for the synthesis of the herbarumins was prepared from D-ribonolactone as shown in Scheme 2. Thus,... [Pg.5]

M. Shiozaki, Y. Kobayashi, M. Arai, and H. Haruyama, Synthesis of 6-cpt-trehazolin from D-ribonolactone Evidence for the non-existence of a 5,6-ring fused structural isomer of 6-epi-trehazolin, Tetrahedron Lett., 35 (1994) 887-890. [Pg.113]

Kandil, A.A., and Slessor, K.N., A chiral synthesis of (+)-lincatin, the aggregation pheromone of Trypodendron lineatum (olivier), from D-ribonolactone, J. Org. Chem., 50, 5649, 1985. [Pg.294]

The full paper describing Mori s synthesis of lineatin (296) (Vol. 4, p. 489, Ref. 263) has been published. After converting the lactone 329 to ( )-lineatin using a [2 + 2] cycloaddition, Slessor et al. followed another route from the same lactone 329, which is readily available by the Lewis acid-catalyzed addition of ketene to mesityl oxide. The route is shown in Scheme 25. In this scheme, the mixture arising from the carbene addition is not separated because, at the stage of the epoxide formation, only the major (desired) isomer 330 was isolated, the other being thermally unstable. The exo alcohols obtained in small amounts after the borohydride reduction (step h) were not isolated. To obtain the natural isomer of lineatin [( + )-(l/ ,4S,5/ ,7R)-296] the alcohol 331 was resolved with (—)-(r)-l-(l-nephthyl)ethyl isocyanate/triethylamine. The first stereospecific chiral synthesis of (+)-lineatin (296) started from D-ribonolactone (332), and is illustrated (in somewhat abbreviated form) in Scheme 26 it proceeded in 2.7% overall yield. °... [Pg.332]

The azido aldehyde 91 as intermediate for the synthesis of (+)-hydantocidin was synthesized from ribonolactone (Scheme 10). The a- or 3-anomers 87 and 88 were readily obtained (76-80%) through the addition of 2-lithiothiazole to the ribonolactone and subsequent acetylation. Their reaction with TMSNj afforded the a- and 3-azides 89 and 90 in a 1 3 ratio and 84% overall yield. The cleavage of the thiazole ring in the major isomer 90 by using either mercury(ll) or copper(ll) ion assisted hydrolysis in the final step afforded the aldehyde 91 (57%). [Pg.83]

The first total synthesis of siastatin B (1) was achieved from L-ribose by protection of the 2,3-diol, followed by introduction of an azide group on C-5 and oxidation of the anomeric hydroxyl group to give 5-azido-5-deoxy-2,3-0-isopropylidene-L-ribonolactone... [Pg.193]

Xylopinine (1) is a naturally occurring compound and has been synthesized from the aldehyde 4, which was obtained by condensation of D-ribonolactone (2) and 3,4-dimethoxyphenethylamine (3) as mentioned before for the synthesis of calycotomine (Scheme 1). Treatment of 4 with a 5 M excess of 3,4-dimethoxyphenyllithium afforded 5 (71%), apparently as a result of the nucleophilic attack of the organolithium reagent on the aldehyde and the amide carbonyls. The synthesis of (5 )-(-)-xylopinine (1) was... [Pg.383]

A totally stereoselective synthesis of an optically pure carbacycline analog utilized the cycloaddition of the D-(+)-ribonolactone-derived substrate shown in Eq. (54). Initial attempts to achieve cyclization on an analogous substrate with a five-membered ring lactone in place of the seven-membered ring ketal failed, presumably due to the strain that would accompany generation of a trans ring fusion [122]. A number of reactions benefit from the addition of a phosphine oxide. Unfortunately, the effectiveness of this additive is neither general nor predictable, nor is its specific mode of action understood [99],... [Pg.162]


See other pages where Ribonolactone syntheses from is mentioned: [Pg.184]    [Pg.45]    [Pg.73]    [Pg.304]    [Pg.35]    [Pg.83]    [Pg.96]    [Pg.112]    [Pg.160]    [Pg.182]    [Pg.183]    [Pg.186]    [Pg.193]    [Pg.39]    [Pg.235]    [Pg.163]    [Pg.133]    [Pg.566]    [Pg.1971]    [Pg.1979]    [Pg.134]    [Pg.562]    [Pg.552]    [Pg.162]   
See also in sourсe #XX -- [ Pg.50 , Pg.192 , Pg.193 , Pg.194 ]




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