Synthesis of 5-O-methyl-d-galactofuranose
5-O-Methyl-d-galactofuranose (7) was synthesized, for the first time, in five steps from d-galactono-1,4-lactone (1) in good overall yield. Tritylation and further acetylation of 1 gave 2,3,5-tri-O-acetyl-6-O-trityl-d-galactono-1,4-lactone (2); prolonged acetylation caused elimination to form 2,5-di...
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| Autores principales: | , |
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| Publicado: |
1986
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00086215_v146_n2_p233_Sznaidman http://hdl.handle.net/20.500.12110/paper_00086215_v146_n2_p233_Sznaidman |
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| Sumario: | 5-O-Methyl-d-galactofuranose (7) was synthesized, for the first time, in five steps from d-galactono-1,4-lactone (1) in good overall yield. Tritylation and further acetylation of 1 gave 2,3,5-tri-O-acetyl-6-O-trityl-d-galactono-1,4-lactone (2); prolonged acetylation caused elimination to form 2,5-di-O-acetyl-3-deoxy-6-O-trityl-d-threo-hex-2-enono-1,4-lactone. Detritylation of 2 with BF3 · Et2O occurred with acetyl migration and afforded 2,3,6-tri-O-acetyl-d-galactono-1,4-lactone (4). Methylation of 4 with CH2N2BF3 · Et2O gave 5-O-methyl-2,3,6-tri-O-acetyl-d-galactono-1,4-lactone. Subsequent reduction by disiamylborane followed by controlled deacetylation gave crystalline 7. The 1H- and 13C-n.m.r. spectra of 7 indicated a 1:1.3 ratio of the α and β furanose anomers. © 1986. |
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