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Synlett 2011(13): 1905-1911  
DOI: 10.1055/s-0030-1260966
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Odorless Eco-Friendly Synthesis of Thio- and Selenoglycosides in Ionic Liquid

Abhijit Sau, Anup Kumar Misra*
Division of Molecular Medicine, Bose Institute, P-1/12, C. I. T. Scheme VII M, Kolkata 700054, India
Fax: +91(33)23553886; e-Mail: akmisra69@gmail.com;
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Publikationsverlauf

Received 1 April 2011
Publikationsdatum:
25. Juli 2011 (online)

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Abstract

An environmentally benign odorless methodology for the preparation of 1,2-trans-thio- and selenoglycosides is reported. In a one-pot condition, the reductive cleavage of disulfides and di­selenides using triethylsilane and borontrifluoride diethyletherate combination followed by the reaction of the in situ generated ­thiolate and selenoetes with glycosyl acetate derivatives in recyclable room-temperature ionic liquid, [BMIM]˙BF4 resulted in excellent yields of thio- and selenoglycosides avoiding the use of obnoxious thiols/selenols and metallic catalysts.

Key words

thioglycoside - selenoglycoside - disulfide - diselenide - triethylsilane - ionic liquid

29

Spectral data of products, which have not been reported earlier, are presented below.

p -Nitrophenyl 2,3,4,6-Tetra- O -acetyl-1-thio-β- d -glucopyranoside (16)
Yellow solid; mp 180-182 ˚C; [α]D -32.7 (c 1.2, CHCl3). IR (KBr): 2923, 2368, 1753, 1344, 1220, 1042, 770 cm-¹. ¹H NMR (200 MHz, CDCl3): δ = 8.16 (d, J = 8.9 Hz, 2 H), 7.59 (d, J = 8.8 Hz, 2 H), 5.28 (t, J = 9.2 Hz each, 1 H, H-3), 5.08 (t, J = 9.7 Hz each, 1 H, H-2), 5.04 (t, J = 9.6 Hz each, 1 H, H-4), 4.89 (d, J = 10.0 Hz, 1 H, H-1), 4.25-4.21 (m, 2 H, H-6a,b), 3.85-3.80 (m, 1 H, H-5), 2.10, 2.08, 2.04, 2.0 (4 s, 12 H, 4 COCH3). ¹³C NMR (50 MHz, CDCl3): δ = 170.2, 169.9, 169.2, 169.0, 147.6, 141.6, 131.7 (2 C), 124.1 (2 C), 84.6, 76.6, 74.0, 70.0, 68.3, 62.2, 21.0, 20.9, 20.8 (2 C). ESI-MS: m/z = 508.1 [M + Na]+. Anal. Calcd for C20H23NO11S (485.10): C, 49.48; H, 4.78. Found: C, 49.25; H, 5.0.
Benzyl 2,3,4,6-Tetra- O -acetyl-1-seleno-β- d -gluco-pyranoside (31)
Yellow oil; [α]D ²5 -30 (c 1.5, CHCl3). IR (neat): 2934, 1769, 1357, 1242, 1074, 764 cm-¹. ¹H NMR (300 MHz, CDCl3):
δ = 7.40-7.21 (m, 5 H, ArH), 5.88 (d, J = 8.5 Hz, 1 H), 5.27 (t, J = 9.5 Hz each, 1 H), 5.06-4.89 (m, 2 H), 4.34-4.19 (m, 2 H), 3.90 (d, J = 11.1 Hz, 1 H), 3.83-3.67 (ABq, J = 12.0 Hz, 2 H), 2.08, 2.02, 1.99 (3 s, 12 H, 4 COCH 3). ¹³C NMR (50 MHz, CDCl3): δ = 171.0, 170.8, 169.9 (2 C), 135.0-127.0 (ArC), 78.8, 76.3, 71.7, 71.2, 69.9, 68.6, 62.0, 26.6, 21.0, 20.9 (2 C). ESI-MS: m/z = 525.0 [M + Na]+. Anal. Calcd for C21H26O9Se (502.07): C, 50.31; H, 5.23. Found: C, 50.08; H, 5.50.
Benzyl 2,3,4,6-Tetra- O -acetyl-1-seleno-α- d -manno-pyranoside (33)
Yellow oil; [α]D ²5 +126.8 (c 1.0, CHCl3). IR (neat): 2972, 2362, 1742, 1598, 1373, 1246, 1107, 1050, 977, 756 cm-¹. ¹H NMR (200 MHz, CDCl3): δ = 7.28-7.09 (m, 5 H, ArH), 5.35 (br s, 1 H, H-2), 5.24 (br s, 1 H, H-1), 5.20-5.16 (m, 2 H, H-3 and H-4), 4.24-4.20 (m, 2 H, H-6ab), 3.91-3.85 (m, 1 H, H-5), 3.77-3.73 (ABq, J = 12.0 Hz, 2 H, CH2Ph), 2.07, 2.03, 1.98, 1.90 (4 s, 12 H, 4 COCH3). ¹³C NMR (50 MHz, CDCl3): δ = 170.2, 169.4 (2 C), 169.3, 137.6, 128.6 (2 C), 128.3 (2 C), 126.8, 77.6, 71.4, 70.6, 69.7, 65.8, 61.8, 27.4, 20.5, 20.4, 20.3, 20.2. ESI-MS: m/z = 525 [M + Na]+. ESI-MS: m/z = 525.0 [M + Na]+. Anal. Calcd for C21H26O9Se (502.07): C, 50.31; H, 5.23. Found: C, 50.09; H, 5.52.
Benzyl 2,3,4-Tri- O -acetyl-1-seleno-α- l -rhamno-pyranoside (36) Yellow oil; [α]D ²5 -114 (c 1.2, CHCl3). IR (neat): 2367, 1756, 1600, 1366, 1230, 955 cm-¹. ¹H NMR (200 MHz, CDCl3): δ = 7.28-7.14 (m, 5 H, ArH), 5.34 (br s, 1 H, H-1), 5.32-5.30 (m, 1 H, H-2), 5.18 (dd, J = 9.7, 3.0 Hz, 1 H, H-3), 5.04 (t, J = 9.7 Hz each, 1 H, H-4), 4.12-4.02 (m, 1 H, H-5), 3.83 (ABq, J = 12.2 Hz, 2 H, PhCH2), 2.08, 2.01, 1.93 (3 s, 9 H, 3 COCH3), 1.18 (d, J = 6.2 Hz, 1 H, CCH3). ESI-MS: m/z = 467.0 [M + Na]+. Anal. Calcd for C19H24O7Se (444.07): C, 51.47; H, 5.46. Found: C, 51.25; H, 5.70.
Benzyl 2,3,4,6-Tetra- O -acetyl-α- d -glucopyranosyl-(1→4)-2,3,6-tri- O -acetyl-1-seleno-β- d -glucopyranoside (39) Yellow oil; [α]D ²5 +51 (c 1.0, CHCl3). IR (neat): 3023, 1764, 1418, 1257, 1086, 769 cm-¹. ¹H NMR (400 MHz, CDCl3):
δ = 7.32-7.20 (m, 5 H, ArH), 5.40-5.23 (m, 2 H), 5.18-5.09 (m, 1 H), 5.06-4.88 (m, 2 H), 4.86-4.76 (m, 1 H), 4.54-4.49 (m, 1 H), 4.46-4.38 (m, 1 H), 4.26-4.16 (m, 2 H), 4.06-3.82 (m, 5 H), 3.58-3.49 (m, 1 H), 2.13, 2.07, 1.99, 1.96, 1.95, 1.94 (6 s, 21 H, 7 COCH3). ESI-MS: m/z = 813.1 [M + Na]+. Anal. Calcd for C33H42O17Se (790.16): C, 50.19; H, 5.36. Found: C, 50.0; H, 5.60.
Phenyl 2,3,4,6-Tetra- O -acetyl-β- d -galactopyranosyl-(1→4)-2,3,6-tri- O -acetyl-1-seleno-β- d -glucopyranoside (40)
Yellow oil; [α]D ²5 +9 (c 1.0, CHCl3). IR (neat): 3036, 1790, 1432, 1276, 1094, 766 cm-¹. ¹H NMR (400 MHz, CDCl3):
δ = 7.56-7.26 (m, 5 H, ArH), 5.30-5.28 (m, 1 H), 5.16 (t, J = 9.1 Hz each, 1 H), 5.05 (dd, J = 7.3 Hz each, 1 H), 4.94-4.82 (m, 3 H), 4.51-4.46 (m, 1 H), 4.42 (d, J = 7.9 Hz, 1 H), 4.12-4.02 (m, 3 H), 3.85-3.81 (m, 1 H), 3.70 (t, J = 9.1 Hz each, 1 H), 3.62-3.56 (m, 1 H), 2.13, 2.07, 2.05, 2.01, 2.0, 1.94 (6 s, 21 H, 7 COCH3). ESI-MS: m/z = 799.1 [M + Na]+. Anal. Calcd for C32H40O17Se (776.14): C, 49.55; H, 5.20. Found: C, 49.32; H, 5.50.

Benzyl 2,3,4,6-Tetra- O -acetyl-β- d -galactopyranosyl-(1→4)-2,3,6-tri- O -acetyl-1-seleno-β- d -glucopyranoside (41)
Yellow oil; [α]D ²5 +21 (c 1.0, CHCl3). IR (neat): 3023, 1767, 1424, 1281, 1089, 769 cm-¹. ¹H NMR (400 MHz, CDCl3):
δ = 7.30-7.27 (m, 5 H, ArH), 5.40-5.28 (m, 2 H), 5.20-4.88 (m, 4 H), 4.54-4.44 (m, 2 H), 4.22-4.06 (m, 4 H), 4.02-3.86 (m, 2 H), 3.82-3.70 (m, 1 H), 3.56-3.48 (m, 1 H), 2.17, 2.15, 2.14, 2.06, 2.03, 2.0, 1.97 (7 s, 21 H, 7 COCH3). ESI-MS: m/z = 813.1 [M + Na]+. Anal. Calcd for C33H42O17Se (790.16): C, 50.19; H, 5.36. Found: C, 50.0; H, 5.58.