Synthesis and transformations of 2-deoxy-2-iodo-pyranosyl isothiocyanates from glycals

Santoyo‐González, Francisco; Garcia‐Calvo‐Flores, F.; Isac‐García, Joaquín; Hernández-Matéo, Fernando; Garcia‐Mendoza, P.; Robles‐Diaz, R.

doi:10.1016/s0040-4020(01)87000-9

Cited by 22 publications

(9 citation statements)

References 32 publications

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“…Several years ago, we described36 a convenient one‐step synthesis of 2‐deoxy‐2‐iodoglycosyl isothiocyanates from glycal monosaccharides and disaccharides by treatment with silica‐supported potassium thiocyanate and iodine. By this procedure, the trans ‐diaxial 2‐deoxy‐2‐iodopyranosyl isothiocyanates are obtained as major products and the corresponding trans ‐diequatorial derivatives as the minor products.…”

Section: Resultsmentioning

confidence: 99%

“…Anhydrous solvents were prepared according to standard procedures and were freshly distilled prior to use. Compounds 1 , 3 , 6 and 9 were prepared from the corresponding glycals following the reported procedure by Santoyo‐González et al36 The per‐ O ‐acetylated‐glycopyranosyl isothiocyanates 11−15 and 21−24 31 were prepared from the corresponding glycopyranosyl halides by treatment with KSCN in MeCN under phase‐transfer conditions following the methodology of Camarasa et al49 or the method described by Lindhorst et al50…”

Section: Methodsmentioning

confidence: 99%

“…In the context of a project directed towards the study of the reactivity of 2‐deoxy‐2‐iodoglycosyl isothiocyanates,36 we now report a new method for the synthesis of glycosylamimes from glycosyl isothiocyanates by using bis(tributyltin) oxide.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Glycosylamines from Glycosyl Isothiocyanates and Bis(tributyltin) Oxide

et al. 2001

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Synthesis of Glycosylamines from Glycosyl Isothiocyanates and Bis(tributyltin) Oxide

et al. 2001

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“…In this domain we have described 20 the application of glycals as glycosyl isothiocyanate precursors and reported a very convenient route for the simultaneous introduction of the iodo and isothiocyanate functionalities in a sugar molecule. Electrophilic addition of iodine(I) thiocyanate, generated in situ from silica supported KSCN and iodine, to the double bond leads exclusively to trans-2-deoxy-2-iodoglycopyranosyl isothiocyanates.…”

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confidence: 99%

“…2-Deoxyglycopyranosyl thioureas 9-11 were then accessed in good to high yields by treatment of 6-8 with tributyltin hydride in the presence of a catalytic amount of AIBN. An alternative route starting from 2-deoxy-2-iodoglycopyranosyl isothiocyanates was previously described for the synthesis of compounds 9 and 10 20.…”

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Synthesis of 2-Deoxyglycopyranosyl Thioureas from Glycals

Uriel¹,

Santoyo‐González

1999

Synthesis

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The reaction of glycals with phenylselenenyl chloride followed by treatment with KNCS lead to 2-deoxy-2-phenylselenoglycopyranosyl isotiocyanates which were further transformed into 2-deoxyglycopyranosyl thioureas.Sugar isothiocyanates are versatile synthetic intermediates in carbohydrate chemistry. By exploiting the strong electrophilic character of the NCS group, a wide variety of other functional groups can be accessed which, in turn, may be subjected to other transformations. The synthesis, chemistry and preparative applications of sugar isothiocyanates have been previously reviewed. 1,2 Glycals are also very versatile intermediates, especially in the synthesis of 2-deoxyglycosides, and different reports have exhaustively covered their synthetic applications. [3][4][5][6][7][8] In particular, the reactions of glycals with electrophilic sulfur and selenium reagents have been studied 9-17 and the factors controlling the stereoselectivity course of the reactions elucidated. 14 By application of these reactions, the introduction of nitrogen in the anomeric position was achieved using phenylselenenyl azide 18 or phenylselenenyl chloride followed by N-glycosidation with bis(trimethylsilyl)uracil 19 allowing the synthesis of 2-deoxyglycosyl azides and 2'-deoxypyranosyl nucleosides, respectively.In this domain we have described 20 the application of glycals as glycosyl isothiocyanate precursors and reported a very convenient route for the simultaneous introduction of the iodo and isothiocyanate functionalities in a sugar molecule. Electrophilic addition of iodine(I) thiocyanate, generated in situ from silica supported KSCN and iodine, to the double bond leads exclusively to trans-2-deoxy-2-iodoglycopyranosyl isothiocyanates. The methodology is relevant for its efficiency, good stereoselectivity and simplicity.We now report the synthesis of 2-deoxy-2-phenylselenoglycopyranosyl isothiocyanates and their transformation into 2-deoxyglycopyranosyl thioureas from glycals. Tri-O-acetyl-D-glucal (1) and -galactal (2) were chosen as starting materials. Reaction of 1 with phenylselenenyl chloride was followed by in situ addition of silica supported KSCN using ether as solvent. The trans addition compounds 3 (a-D-manno) and 4 (b-D-gluco) were isolated in 29 and 33% yield, respectively. However, when 2 was used only the stereoisomer with a-D-talo configuration 5 was obtained in 40% yield. The assignment of the product stereochemistry was based on vicinal proton 3 J H,H and geminal heteronuclear 1 J C1,H1 coupling constants (see Table 2 and 3). Typically, H-1 for the b-gluco product 4 appeared at d = 4.67 as a doublet (J 1,2 = 10.0 Hz), with H-2 appearing at d = 3.15 as a triplet (J 1,2 ªJ 2,3 ). In the case of the a-manno (3) and a-talo (5) isothiocyanates H-1 appeared at d = 5.82 and 5.88 as a doublet (J 1,2 = 1.7 and 1.3 Hz), respectively, and H-2 appeared at d = 3.98 and 3.60 as a doublet of doublets (J 2,3 = 4.4 Hz).In agreement with these assignations is the observed 1 J C1,H1 values that for the a-glycosylpyranosyl isothio...

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ChemInform Abstract: Synthesis and Transformations of 2‐Deoxy‐2‐iodo‐pyranosyl Isothiocyanates from Glycals.

et al. 1994

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Synthesis and Transformations of 2-Deoxy-2-iodo-pyranosyl Isothiocyanates from Glycals.-2-Deoxy-2-iodoglycosyl isocyanates, e.g. (III) and (VI), useful as intermediates in the synthesis of heterocyclic derivatives of sugars, are prepared in one step from mono-or disaccharidic glycals, e.g. (I) or (V), in good yields with high stereoselectivity. These compounds can easily be converted into 2-amino-2-thiazolines, thiazolidin-2-ones and 2-deoxyglycosyl thioureas. -(SANTOYO-GONZALEZ, F.; GARCIA-CALVO-FLORES, F.; ISAC-GARCIA, J.; HERNANDEZ-MATEO, F.; GARCIA-MENDOZA, P.; ROBLES-DIAZ, R.; Tetrahedron 50 (1994) 9, 2877-2894; Dep. Quim. Org.,

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Synthesis and transformations of 2-deoxy-2-iodo-pyranosyl isothiocyanates from glycals

Cited by 22 publications

References 32 publications

Synthesis of Glycosylamines from Glycosyl Isothiocyanates and Bis(tributyltin) Oxide

Synthesis of Glycosylamines from Glycosyl Isothiocyanates and Bis(tributyltin) Oxide

Synthesis of 2-Deoxyglycopyranosyl Thioureas from Glycals

ChemInform Abstract: Synthesis and Transformations of 2‐Deoxy‐2‐iodo‐pyranosyl Isothiocyanates from Glycals.

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