L-Rhamnono-1,5-lactone

A convenient synthesis of ascarylose in four steps starting from L-rhamnono-1,5-lactone (121) was reported.202 The deoxy group in C-3 was introduced through stereoselective hydrogenation of the 2-enonolactone 122 as reported for the preparation of 3-deoxy sugars (see Section III.2). A crystalline furanose derivative of ascarylose, 2,5-di-(3-benzoyl-3,6-dideoxy-a-L-arafo>m-hexofura-nose (125) was also obtained (Scheme 35).203... 

L-Ascarylose (3,6-dideoxy-L-xy/o-hexose) has been synthesized from L-rhamnono-1,5-lactone, Benzoylation of the lactone in pyridine resulted in elimination of the 3-substituent to give (24). Subsequent hydrogenation of (24) was highly stereoselective, giving the 3,6-dideoxy-lactone (25) in 90% yield from which L-ascarylose and several of its derivatives were prepared. ... 

Lactone, tribenzoyl 2,3,4-Tri-O-benzoyl-L-rhamnono-1,5-lactone C27H22O8 474.466... 

Trideoxy sugars have also been prepared from aldono- 1,4-lactones. Thus, 2-0-benzoyl-3,5,6-trideoxy-a-D,L-t/ira>hexofuranose was obtained (202) from L-rhamnono- 1,4-lactone via the furanone 155. L-Rhamnono-1,5-lac-... 

If the 2-0-tosylated L-rhamnono-1,4-lactone (88) was boiled in water-dioxane the 2,5-anhydride (89) was obtained in good yield. The reaction time was 16 h in this case, compared to 2-4 h in the examples in which a primary tosyloxy group was substituted. The 2,5-anhydro-carboxylic acid 89 was isolated as the methyl ester, and was shown to have the L-gZuco-configuration [117]. Thus, a clean inversion at C-2 had taken place. 

Lactone, 2,5-dibenzoyl 2,5-Di-O-benzoyl-L-rhamnono-1,4-lactone C20H,gO7 370.358... 

Partial benzoylation of L-rhamnono-1,4-lactone gave mainly the 2,5-dibenzoate (48%), while similar treatment of D-mannono-1,4-... 

The 2-deoxy-derivative was obtained from the known 2,6-dideoxy-L-arahi/to-hexono-l,4-lactone, while the 4-deoxy-derivative was obtained by radical reduction of an O-protected L-ifaamnose 4-xanthate derivative. The 3-deoxy-derivative (42) was obtained from L-rhamnose via a mixture of acetylated L-rhamnono-1,4-lactone (41) and its 1,5-lactone istnner, utilizing hydrogenolytic conditions that effect elimination of acetic acid and stereoselective reduction of the resulting 3-deoxy-hex-2-enonolactone (Scheme 7). 2- and 4-Deoxy-L-rhamnose exist mainly in the pyranose form in solution, whereas 3-deoxy-L-ifaamnose (38) forms a mixture of pyranose and furanose forms in the ratio 2 1. Similar reactions have been used to convert benzoylated... 

Starting from L-rhamnono-1,4- or 1,5-lactone, via p-elimination reactions, 3,5,6-trideoxy-a-DL-t/zra -hexose276 or 3,4,6-trideoxy-DL-t/zreo-hexose has been obtained.277... 

Lactone 6-Deoxy-D-mannono-l, 4-lactone. D-Rhamnono-1,4-lactone [106293-98-5]... 

Full details of a preliminary communication (S.J. Mantell et at., Vol. 26, p. 310) of the synthesis of epimeric 3-hydroxymuscarines from L-rhamnono-1,4- or 1,5-lactones have appeared. The synthesis of the anhydrothioalditol 13 as an analogue of deoxymannojirimycin has been reported. The anhydro linkage is introduced by treating the intermediate bromothioacetate derivative 14 with sodium methoxide to give bicyclic compound 15. Subsequent de-silylation, benzylation, acid hydrolysis, hydride reduction and catalytic hydrogenolysis furnished 13. 

Tosylation of the four D-pentono-1,4-lactones with 2.0-2.3 equiv. TsCl in pyridine gave as the main products, the 2,5-ditosylates. On similar treatment, the eight D-hexono-l,4-Iactones furnished mainly the 2,6-ditosylates, and D-g/ycero-D-gM/o-heptonolactone yielded the 2,7-ditosylate. Monotosylation of D-erythrono- and L-rhamnono-lactone took place at 0-2. ... 

Resorcinol, S-heptadecyl Seedling Resorcinol, 5 pentadecyl Seedling Resorcinol, 5-tridecyl Seedling Rhamnono l 4 lactone, L ppsois Rice antifungal protein 1 Seedling Sakuranetin Lf ° ° ° ... 

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