H.B. Mereyala, S.R. Gurrala/Carbohydrate Research 307 (1998) 351±354
353
for solutions in deuteriochloroform. 13C NMR
spectra were taken with a Varian Gemini (50 MHz)
spectrometer with CDCl3 as internal standard (ꢂ c
77.0) for solutions in deuteriochloroform. Optical
rotations were measured with a JASCO DIP-370
instrument, and [ꢁ]d-values are in units of 10 1 deg
(dd, 1 H, J1,2 7.6 Hz, J2,3 9 Hz, H-2), 5.03 (dd, 1 H,
H-3), 4.72 (d, 1 H, H-1), 4.39 (d, 2 H, J1,3 2.0 Hz,
H-1), 4.25±4.5 (m, 2 H, H-6), 3.85±4.0 (m, 1 H, H-
5), 2.45 (t, 1 H, H-3), 2.17, 2.09, 2.07, and 2.01 (4 s,
12 H, OCOCH3); 13C NMR (CDCl3): ꢂ 170.1,
170.0, 169.8, 169.3 (OCOCH3), 98.5 (C-1), 70.8,
75.2, 2Â70.7, 68.3, 66.9 (C-2, 3, 4, 5, 2, 3),
61.0 (C-6), 55.7 (C-1), 20.5, 2Â20.4, 20.3
(OCOCH3). Anal. Calcd for C17H22O10: C, 52.85;
H, 5.74. Found: C, 52.78; H, 5.65.
1
cm2 g . Melting points were determined by using
a Fischer-John's melting point apparatus and are
uncorrected. IR spectra were taken with a Perkin-
Elmer 1310 spectrometer. Organic solutions were
dried over anhydrous Na2SO4 and concentrated
below 40 ꢀC in vacuo.
2-Propynyl
4-O-[2,3,4,6-tetra-O-acetyl-b-d-
glucopyranosyl] - 2,3,6 - tri - O - acetyl - b - d - galacto-
pyranoside (3c).ÐReaction of 3b (15 g, 2.21 mmol)
with propargyl alcohol (1.56 mL, 2.65 mmol) and
BF3±Et2O (4.17 mL, 3.31 mmol) in dichlor-
omethane (300 mL) as described for 1c gave 3c
(13.93 g, 93.5%) as a crystalline solid. m.p. 74±
76 ꢀC, [ꢁ]d 12.8 (c 1.0, CHCl3); IR (KBr): ꢃ 3274
2-Propynyl 2,3,4,6-tetra-O-acetyl-b-d-glucopyr-
anoside (1c).ÐTo a solution of ꢀ-d-glucopyranose
pentaacetate (1b) (10 g, 25.6 mmol) in dichlor-
omethane (200 mL) was added freshly distilled
propargyl alcohol (1.8 mL, 30.7 mmol) and BF3±
Et2O (4.8 mL, 38.4 mmol) at 0 ꢀC and the reaction
mixture was stirred at room temperature for 2 h.
After completion of the reaction anhydrous K2CO3
(4.8 g) was added and stirring was continued for
a further 30 min. and the reaction mixture was
®ltered and washed with dichloromethane.The ®l-
trate was washed with water (2Â150 mL), the aqu-
eous phase was separated and extracted with
dichloromethane (2Â50 mL) and the combined
organic phases were dried (Na2SO4) and con-
centrated to yield a solid which was crystallised
(dichloromethane-hexane) to obtain the title com-
pound 1c (9.10 g, 92%) as a crystalline solid. m.p.
114±115 ꢀC, lit. 114±116 ꢀC [27], [ꢁ]d 39 (c 1.0,
CHCl3), lit. 37.4 [27]; IR (KBr): ꢃ 3260 (ꢁC±H),
1
1
(ꢁC±H), 2118 (CꢁC) and 1752 cm (C=O); H
NMR (CDCl3): ꢂ 5.4±4.8 (m, 5 H, H-2;,2,3,3,4),
4.72, 4.50 (2d, 2 H, J1,2/J1,2 8, 8.2 Hz, H-1,1), 4.45±
4.55 merged (m, 1 H, H-4), 4.4±4.24 (d, 2 H, J1,3
2.1 Hz, H-1), 4.2±3.55 (m, 6 H, H-5,5,6,6), 2.44 (t, 1
H, H-3), 2.19, 2.14, 2Â2.09, 2Â2.06, 1.98 (5 s, 21
H, OCOCH3); 13C NMR (CDCl3): ꢂ 2Â170.2,
2Â170.0, 2Â169.6, 169.0 (OCOCH3), 100.6, 97.8
(C-1, 1), 78.0, 75.9, 75.4, 2Â72.6, 71.2, 70.8, 70.6,
69.0, 66.5 (C-2,-2,-3,-3,-4,-4,-5,-5,-2,-3), 61.7, 60.7
(C-6, 6OCOCH3). Anal. Calcd for C29H38O18: C,
51.63; H, 5.68. Found: C, 51.52; H, 5.51.
2-Propenyl
2,3,4,6-tetra-O-acetyl-b-d-gluco-
pyranoside (1a).Ð1c (5 g, 12.9 mmol) was dis-
solved in methanol (100 mL), and 5% Pd±CaCO3
(250 mg) followed by quinoline (2.5 mL) were
added and the contents were stirred at room tem-
perature for 8 h under hydrogen atmosphere. When
TLC indicated the formation of a faster moving
spot and disappearence of starting material, the
reaction mixture was ®ltered and concentrated to a
residue, diluted with dichloromethane (50 mL)
washed with chilled 2% aqueous hydrochloric acid
(2Â50 mL) and water. The organic phase was
separated, dried (Na2SO4), concentrated to yield
the title compound 1a (4.9 g, 98%) as a solid. m.p.
1
1
2128 (CꢁC), and 1744 cm
(C=O); H NMR
(CDCl3): 5.32±4.9 (m, 3 H, H-2,3,4), 4.66 (d, 1 H,
J1,2 9.1 Hz, H-1), 4.39 (d, 2 H, J1,3 2.3 Hz, H-1),
4.5±4.05 (m, 4 H, H-1,6), 3.80±3.6 (m, 1 H, H-5),
2.45 (t, 1 H, H-3), 2.12, 2.09, 2.06, and 2.03 (4s, 12
H, OCOCH3); 13C NMR (CDCl3): ꢂ 170.4, 170.0,
2Â169.3 (OCOCH3), 98.1 (C-1), 78.1, 75.5, 72.7,
71.9, 70.9, 68.3 (C-2, -3, -4, -5, -2, -3), 61.7 (C-6),
55.8 (C-1), 2Â20.5, 2Â20.4 (OCOCH3). Anal.
Calcd for C17H22O10: C, 52.85; H, 5.74. Found: C,
52.77; H, 5.62.
2-Propynyl 2,3,4,6-tetra-O-acetyl-b-d-galactopyr-
anoside (2c).ÐReaction of 2b (15 g, 38.4 mmol)
with propargyl alcohol (2.72 mL, 46.1 mmol) and
BF3±Et2O (7.2 mL, 57.6 mmol) in dichloromethane
(300 mL) as described for 1c gave 2c (14.06 g, 95%)
as a syrup which solidi®ed on standing m.p. 55±
57 ꢀC, [ꢁ]d 23 (c 1.0, CHCl3); IR (KBr): ꢃ 3267
86±88 ꢀC, lit. 89±90 ꢀC [12], [ꢁ]d
CHCl3), lit. 11.7 (c 1.0, CHCl3) [12].
11 (c 1.0,
2-Propenyl 2,3,4,6-tetra-O-acetyl-b-d-galactopyr-
anoside (2a).Ð2c (6.4 g, 16.5 mmol) was hydro-
genated in presence of 5% Pd±CaCO3 (320 mg)
and quinoline (3.2 mL) as described for 1a to
obtain 2a (6.35 g, 98.8%) as a syrup. [ꢁ]d 8 (c 1.0,
CHCl3).
1
1
(ꢁC-H), 2096 (CꢁC), and 1744 cm (C=O); H
NMR (CDCl3): ꢂ 5.37 (d, 1 H, J3,4 3 Hz, H-4), 5.16