Synthesis of glycoconjugates containing a 1,2,3-triazole unit

Transcription

1 Synthesis of glycoconjugates containing a,2,3-triazole unit Sílvia Cunha, Sofia Pereira, Maria J. Malheiro, Lígia M. Rodrigues, Ana M. liveira-campos, Ana P. Esteves* Chemistry Centre, School of Sciences, University of Minho Abstract: The preparation of several alkynyl esters, derived from amino acids, coumarins and an alkynyl derivative of acetylated D-glucose is described. Eight new glycoconjugates containing the,2,3-triazole unit were obtained, by a click approach from the above referred alkynyl derivatives with tetracetyl- -D-glucosylazide, prepared in situ from - acetobromoglucose. Keywords: glycoconjugates, click chemistry, triazole, alkynyl esters Introduction The glycoconjugates have an enormous potential in drug design. Between them, glycopeptides are particularly important as they combine the structural features of amino acids and carbohydrates in the same molecule. Glycoconjugates containing the,2,3-triazole unit find application in medicinal chemistry, particularly in those cases where this unit acts as a bridge between an amino acid/peptide and the sugar moiety. 2 In this work the synthesis of several glycoconjugates containing the,2,3-triazole unit as a bridge between a sugar (D-glucose) moiety and an amino acid or heteroaromatic unit is described. The,2,3-triazole unit was formed by an azide-alkyne,3-dipolar cycloaddition, catalysed by a Cu(I) species, a chemical process usually known as click chemistry. 3,4 The azido component was prepared in situ from -acetobromoglucose. 4,5 Results and Discussion The starting alkynyl esters -5 (figure ) were prepared by reaction between N- protected glycine, tyrosine and phenylalanine, 7-hydroxycoumarin and 7-hydroxy-4- methylcoumarin and propargyl bromide with high yields. All these compounds showed

2 in the proton NMR spectra the coupling patterns for the alkynyl function, for instance for compound a triplet (J=2.4 z) at 3.58 and a doublet (J=2.4 z) at 4.73 ppm for C and C 2 C, respectively. The formation of the,2,3-triazole unit occurred by reaction between an azide component and acetylenic compounds. The azido component was prepared in situ from -acetobromoglucose, by a known method 4, as shown in scheme. Ac Ac Ac Ac Ac Br NaN 3 DMS RT; 20 min Ac Ac Ac N 3 Scheme. Preparation of glucosylazide Compounds -5 and also three commercial alcohols, prop-2-yn--ol (propargyl), racbut-3-yn--ol and but-3-yn-2-ol, were used as acetylenic components. The final compounds 6-2 (figure ), containing the,2,3-triazole unit, were obtained following the conditions described in scheme 2. Ac Ac Ac Ac N 3 C CC 2 R CuS M sodium ascorbate M DMS; RT Ac Ac Ac Ac N N N R Scheme 2. General method for click reactions. Compounds 6, 7 and 8 0 were obtained in low yields (47, 24 and 4, respectively), and compounds 9, 0, and 2 in good yields (74, 64, 7 and 74%). All the final compounds showed the NMR spectra consistent with the proposed structure, namely the signal for the proton of the triazole ring (a singlet ppm). Compounds 3 and 4 were prepared using as starting material the acetylenic derivative of glucose and but-3-yn--ol and propargyl alcohol, respectively (scheme 3). These compounds were isolated in 60-69% yields and were fully characterized. The NMR confirms their structures, it can be observed besides the typical glucosyl moiety signals the protons for the alkynyl function [2.48 (, t, J 2.4 z, -; 4.37 (2, d, J 2. z, -3)] for 4.

3 Ac Ac Ac Ac Ac. C C(C 2 )n BF 3.Et 2 DCM; 5h 2. K 2 C 3 30 min Ac Ac Ac Ac (C 2 )nc Scheme 3. Synthesis of acetylenic derivatives of D-Glucose. n= or 2 C Compound 5 was synthesised, under the conditions of click reaction, using glycosylazide and compound 3 as the acetylenic component in 80% yield. The NMR showed the triazole proton at 8.09 ppm, along with the signals expected for the two glucosyl moieties. N N 2 N 3 Ac Ac 4 5 Ac Ac 6 N N Ac N ' ' Ac Ac 7 N N Ac N ' Ac Ac Ac Ac 4' 6' Ac N N N ' 3' ' N N Ac Ac Ac N ' 8 9 2' 2'' 3'' 4'' ' Ph Ac Ac Ac Ac N N Ac N 5 0 N Ph Ac Ac N N Ac N 5 N Ph Ac Ac Ac N N Ac N 5 2 N Ph Ac Ac Ac Ac 3 Ac Ac Ac Ac Ac 4 4' Ac Ac N N Ac N 5 5 2'' ' Ac '' '' Ac Ac Ac Figure. Structures and numbering of the compounds prepared.

4 Conclusions Glyconjugates containing the,2,3-triazole unit were obtained by an azide-alkyne,3- dipolar cycloaddition, catalysed by Cu(I). The azide component, glycosylazide, was obtained in situ from -acetobromoglucose and the alkyne components were prepared by reaction of propargyl bromide with N-protected glycine, tyrosine and phenylalanine, 7-hydroxycoumarin and 7-hydroxy-4-methylcoumarin with high yields. The final glyconjugates were isolated with a wide range of yields, varying from low, 4% to as high as 80%. Experimental Melting points were determined on a Gallenkamp melting point apparatus and are uncorrected. NMR (300 Mz) and 3 C NMR (75.4 Mz) spectra were recorded on a Varian Unity Plus Spectrometer at 298 K or on a Bruker Avance III 400 spectrometer (400 Mz for and 00.6 Mz for 3 C). Chemical shifts are reported in ppm relative to solvent peak or TMS; coupling constants (J) are given in z; ap states for apparent and Cq for quaternary carbon. Double resonance, MQC (heteronuclear multiple quantum coherence) and MBC (heteronuclear multiple bond correlation) experiments were carried out for complete assignment of and 3 C signals in the NMR spectra. ighresolution mass spectra (ESI-TF) were obtained on a Bruker FTMS APEXIII spectrometer. Elemental analyses were obtained on a Leco CNS-932 instrument. TLC was carried out on plates coated with silica gel 60 F254. Column chromatography was performed on silica gel ( or mesh). Light petroleum refers to the fraction boiling in the range 40-60ºC. General method for the preparation of alkynyl esters- method A To a solution of appropriated substrate in DMS (5 ml) anhydrous K 2 C 3 (.0 equiv.) and propargyl bromide ( equiv.) were added and the reaction mixture was stirred at room temperature for 4 hours. Water was added, and the mixture extracted with ethyl acetate and the organic extracts were combined, dried (MgS 4 ) and evaporated to dryness. General method for the cycloaddition reaction by click chemistry-method B To a solution of -acetobromoglucose in dry DMS dry NaN 3 (.2 equiv.) was added and the mixture stirred at room temperature for 20 mins, forming the glycosylazide in situ. The acetylenic substrate (.5 equiv. for the but-3-yn--ol, but-3-yn-2-ol and

5 propargyl alcohol;.05 equiv. for the others), sodium L-ascorbate (M aqueous solution, 2.5 ml/mmol azide) and CuS (M aqueous solution, 2.5 ml/mmol azide) were then added to the reaction mixture, that which was stirred at room temperature for the time indicated. After filtration water was added to the filtrate, and the mixture extracted with ethyl acetate and the organic extracts were combined, dried (MgS 4 ) and evaporated to dryness. Synthesis of Z-Gly-C 2 C C () The general procedure A, starting from Z-Gly, gave the ester as a greenish solid (89%), m.p ºC. max (Nujol) 732 and 749 (C=), 225 (C C), 2854 and 2924 (C), 358 (N), 3243 ( C) cm -. (300 Mz, DMS-d 6 ) 3.58 (, t, J 2.4 z, C); 3.8 (2, d, J 6.0 z, C 2 N); 4.73 (2, t, J 2.4 z, C 2 C ); 5.04 (2, s, C 2 Ar); (5, m, Ar); 7.73 (, t, J 6.3 z, N). C (75.4 Mz, DMS-d 6 ) (C 2 N); 52.7 (C 2 C ); (C 2 Ar); (C ); 78.9 ( C); 27.73, 27.88, (5 x CAr); 36.9 (CqAr); (CN); 66.9 (C=). Anal. Calcd for C 3 3 N 4 : C, 63,5;, 5,30; N,5.67. Found: C, 62,78;, 5.36; N, Synthesis of Z-Phe-C 2 C C (2) Following the general method A, and starting from Z-Phe, compound 2 was isolated as a pure brown solid (88%), m.p ºC. (300 Mz, DMS-d 6 ) 2.87 (, dd, J 3.8 and 0.2 z, a- C 2 ); 3.04 (, dd, J 4. and 5. z, b- C 2 ); 3.59 (, t, J 2.4 z, C); (, m, -C); 4.73 (2, t, J 2.4 z, C 2 C ); 4.97 (2, s, C 2 Ar); (0, m, 2x Ar); 7.87 (, d, J 8.4 z, N). Synthesis of Z-Tyr(Bn)-C 2 C C (3) Following the general method A, and starting from Z-Tyr(Bn), compound 3 was isolated as a pure brown solid (68%), m.p ºC. Recrystallization from a mixture of ethyl acetate, ethyl ether and light petroleum yielded a white solid. (300 Mz, DMS-d 6 ) 2.8 (, dd, J 3.8 and 9.9 z, a- C 2 -Tyr); 2.98 (, dd, J 3.8 and 4.8 z, b- C 2 -Tyr); 3.58 (, t, J 2.4 z, C); 4.54 (, m, -C); 4.73 (2, t, J 2.4 z, C 2 C ); 4.98 (2, s, C 2 Ar(Z) or (Bn)); 5.05 (2, s, C 2 Ar(Z) or (Bn)); 6.9 (2, d, J 8.4 z, o-tyr); 7.6 (2, d, J 8.7 z, m-tyr); (0, m, 2 x Ar); 7.84 (, d, J 7.8 z, N). C (75.4 Mz, DMS-d 6 ) (C 2 -Tyr); (C 2 C ); ( -C) 65.4 (C 2 Z or Bn)); 69.4 (C 2 Z or Bn)); (C ); ( C); 4.53 (2x Co-Tyr); (Ar), (Ar), (Ar), (Ar), (Ar), (Ar), (Cq-Tyr), (Cm-Tyr);36.88 ((Cq-Z (or Bz));

6 37.6 (Cq-Z (or Bn)), 55.95(Cqp-Tyr); 57.2 (C= Z), 7.22 (C= Tyr). Anal. Calcd for C N 5 : C, 73.2;, 5.68; N, 3.6. Found: C, 72.65;, 5.69; N, propargyloxycoumarin (4) The titled compound was prepared by the general method A, starting from the 7- hydroxycoumarin, and was isolated as a pure brownish solid, 99%, m.p ºC. max (Nujol) 735 (C=), 233 (C C), 2854 and 2923 (C), 3320 ( C) cm -. (300 Mz, DMS-d 6 ) 3.64 (, br s, C); 4.92 (2, d, J.8 z, C 2 C ); 6.32 (, d, J 9.6 z, -3); 6.97 (, d, J 2. z, -8); 7.00 (, dd, J 8.7 and 2. z, -6); 7.65 (, d, J 8.7 z, -5); 7.99 (, d, J 9.8 z, -4). Anal. Calcd for C : C, 72.00;, Found: C, 72.3;, m/z (ESI) 20.7 (M+, 00%). 4-Methyl-7-propargyloxycoumarin (5) General method A, starting from 7-hydroxy-4-methylcoumarin, yielded compound 5 as a pure white solid (99%), m.p ºC. max (Nujol) 604 (C=C Ar), 700 (C=), 2854 and 2924 (C) cm -. (400 Mz, DMS-d 6 ) 2.4 (3, d, J.2 z, C 3 ); 2.58 (, t, J 2.4 z, C); 4.77 (2, d, J 2.4 z, C 2 C ); 6.7 (, dd, J 2.4 and.2 z, -8); 6.95 (, br s, - 3); 6.94 (, dd, J 9.2 and 2.4 z, -6); 7.53 (, dd, J 8.0 and.2 z, -5). Anal. Calcd for C : C, 72.89;, 4.7. Found: C, 72.70;, m/z (ESI) (M+, 00%). 2- [ -(2,3,4,6 -tetra--acetyl- -D-glucopyranosyl)-(-,2,3 -triazol-4 - yl)]ethanol (6) Following the general method B and using but-3-yn--ol as the acetylenic substrate and a reaction time of 60 min. Compound 6 was obtained as a greenish solid (47%) after recrystallization from a mixture of dichloromethane-ethyl acetate-light petroleum, m.p ºC. [ ] 25.5 D -4.4 (0.02, CCl 3 ). max (Nujol) 750 (C=), 233 (C C), 2854 and 2924 (C), 3390 () cm -. (300 Mz, DMS-d 6 ).78 (3, s, C 3 C-2 );.95 (3, s, C 3 C-3 );.99 (3, s, C 3 C-6 ); 2.02 (3, s, C 3 C-4 ); 2.75 (2, t, J 6.6 z, C 2 C 2 ); 3.60 (2, ap q, J 6.3 z, C 2 C 2 ); 4.04 (, dd, J 2.6 and 2. z, a-6 ); 4.2 (, dd, J 2.3 and 5. z, b-6 ); 4.34 (, ddd, J 9.6, 5. and 2. z, -5 ); 4.7 (, t, J 5.4 z, ); 5.5 (, t, J 9.6 z, -4 ); 5.53 (, t, J 9.3 z, -3 ); 5.6 (, ap t, J 9.6/8.7 z, -2 ); 6.28 (, d, J 8.7 z, - ); 8.3 (, s, -5 ). C (75.4 Mz, DMS-d 6 ) 9.84 (C 3-2 ); 20.8 (C 3-3 ); 20.3 (C 3-6 ); (C 3-4 ); (C 2 C 2 ); (C 2 ); 6.76 (C-6 ); (C-4 ); (C-2 ); 72.5 (C-3 ); 73.3 (C-5 );

7 83.63 (C- ); 2.64 (C-5 ); (C-4 ); 68.4 (C-2 ); (C-4 ); (C-3 ); (C-6 ). m/z (ESI) (M+Na, 00%). - [ -(2,3,4,6 -tetra--acetyl- -D-glucopyranosyl)-(-,2,3 -triazol-4 - yl)]methanol (7) Prepared as compound 6 with propargyl alcohol as the acetylenic substrate. An oil was obtained which after recrystallization from a mixture of dichloromethane-ethyl acetatelight petroleum yielded a white solid (24%), m.p ºC [Lit. 4 oil, 85%]. [ ] 25.5 D (0.02, CCl 3 ). max (Nujol) 720 (C=), 2854 and 2924 (C), 3520 () cm -. (300 Mz, DMS-d 6 ).79 (3, s, C 3 C-2 );.95,.99, 2.02 (9, 3s, C 3 C- 3, C 3 C-4, C 3 C-6 ); 4.05 (, dd, J 2.3 and 2.4 z, a-6 ); 4.2 (, dd, J 2.6 and 5.4 z, b-6 ); 4.35 (, ddd, J 9.9, 5. and 2.4 z, -5 ); 4.50 (2, d, J 5.7 z, C 2 ); 5.7 (, t, J 9.7 z, -4 ); 5.26 (, t, J 5.7 z, ); 5.54 (, t, J 9.4 z, -3 ); 5.66 (, t, J 9.3 z, -2 ); 6.3 (, d, J 9.0 z, - ); 8.25 (, s, -5 ). m/z (ESI) (M+Na, 00%). Anal. Calcd for C 7 23 N 3 0 : C, 47.55;, 5.40; N, Found: C, 47.65;, 5.38; N, [ -(2,3,4,6 -tetra--acetyl- -D-glucopyranosyl)-(-,2,3 -triazol-4 - yl)]ethanol (8) Prepared as compound 6 with rac-but-3-yn-2-ol as the acetylenic substrate. An oil was obtained which after recrystallization from a mixture of dichloromethane-ethyl acetatelight petroleum yielded a white solid (4%), as a mixture of the two diastereoisomers (.5:), m.p ºC. [ ] 27 D (0.02, CCl 3 ). max (Nujol) 75 (C=), 2854, 2925 and 2952 (C), 3330 ( C) cm -. (300 Mz, DMS-d 6 ).36 (.8, d, J 6.6 z, C 3 );.38 (.2, d, J 6.2 z, C 3 );.78 (.8, s, C 3 C-2 );.79 (.2, s, C 3 C-2 );.96,.99, 2.02 (9, 3s, C 3 C- 3, C 3 C-4, C 3 C-6 ); 4.05 (, dd, J 2.3 and 2.4 z, a-6 ); 4.2 (, dd, J 2.3 and 5.4 z, b-6 ); 4.34 (, ddd, J 2.6, 5.4 and 2.4 z, -5 ); (, m, C); 5.6 (, t, J 9.7 z, -4 ); 5.3 (0.6, t, J 5. z, ); 5.32 (0.4, t, J 5. z, ); 5.53 (, t, J 9.4 z, -3 ); 5.66 (, t, J 9.3 z, -2 ); 6.29 (0.6, d, J 9.3 z, - ); 6.30 (0.4, d, J 9.3 z, - ); 8.8 (0.6, s, -5 ); ); 8.20 (0.4, s, -5 ). 7- {[ -(2,3,4,6 -tetra--acetyl- -D-glucopyranosyl)--,2,3 -triazol-4- yl)]methoxy}-4-methylcoumarin (9) Following method B, with the acetylenic substrate 5, and stirring the reaction mixture for 60 min., a white solid was obtained after recristalization from dichloromethane-ethyl 27 acetate-light petroleum (74%, m.p ºC). [ ] D (0.02, CCl 3 ). max (Nujol) 72 and 740 (C=), 2854, 2923 (C), 3096 ( C) cm -.

8 (300 Mz, DMS-d 6 ).75 (3, s, C 3 C-2 );.95,.99, 2.02 (9, 3s, C 3 C- 3, C 3 C-4, C 3 C-6 ); 2.39 (3, d, J 0.9 z, C 3 ); 4.06 (, dd, J 2.3 and 2.4 z, a-6 ); 4.3 (, dd, J 2.6 and 5.4 z, b-6 ); 4.37 (, ddd, J 9.9, 4.8 and 2.4 z, - 5 ); 5.7 (, ap t, J 9.9/9.3 z, -4 ); 5.29 (2, s, C 2 ); 5.55 (, ap t, J 9.3/9.4 z, -3 ); 5.67 (, t, J 9.3 z, -2 ); 6.2 (, d, J 0.9 z, -3); 6.38 (, d, J 9.0 z, - ); 7.02 (, dd, J 8.7 and 2.4 z, -6); 7. (, d, J 2.4 z, -8); 7.68 (, d, J 9.0 z, -5); 8.59 (, s, -5 ). C (75.4Mz, DMS-d 6 ) 8.2 (C 3-4 ); 9.83 (C 3-2 ); (C 3-3 ); (C 3-4 ); (C 3-6 ); 6.49 (C 2 ); 6.77 (C-6 ); (C-4 ); 70. (C-2 ); 72. (C-3 ); (C-5 ); (C- ); 0.65 (C-8);.36 (C-3); 2.67 (C-6); 3.45 (C-4); 23.9 (C-5 ); (C-5); 42.8 (C-4); (C-4a); (C-2); 60. (C-8a); (C-7); (C 3 C-2 ); (C 3 C-4 ); (C 3 C-3 ); 70,02 (C 3 C-6 ) ppm. -(2,3,4,6 -tetra--acetyl-β-d-glucopyranosyl)--,2,3-triazol-4-yl)methyl- (Bn)TyrZ (0) Prepared by method B, with the acetylenic substrate 3, and stirring the reaction mixture for 90 min., a white solid was obtained after recrystallization from ethyl acetate-light petroleum (64%, m.p ºC). max (Nujol) 690 and 720 (C=), 2855, 2925 (C), 324 (N) cm -. (300Mz, DMS-d 6 ).77 (3, s, C 3 C-2 );.95 (3, s, C 3 C-4 );.97 (3, s, C 3 C-6 ); 2.02 (3, s, C 3 C-3 ); 2.77 (, dd, J 3.8 and 0.5 z, C a Tyr); 2.95 (, dd, J 3.8 and 4.8 z, C b Tyr); 4.06 (, dd, J 2.3 and 2.4 z, a-6 ); 4.4 (, dd, J 2.6 and 5. z, b-6 ); (, m, α-c); 4.37 (, ddd, J 0.0, 5. and 2.4 z, -5 ); 4.96 (2, s, C 2 -Z); 5.04 (2, s, C 2 Ph); (3, m, C 2, and -3 ); 5.56 (, ap t, J 9.0/9.9 z, -4 ); 5.67 (, ap t, J 9.3/ 9.6 z, -2 ); 6.38 (, d, J 9.0 z, - ); 6.88 (2, d, J 8.7 z, Tyr); 7.2 (2, d, J 8.4 z, Tyr); (0, m, 2 C 6 5 ); 7.8 (, d, J 8. z, N); 8.45 (, s, -5) ppm. C (75.4Mz, DMS-d 6 ) 9.90 (C 3 C-2 ); (C 3 C-3 ); (C 3 C-4 ; (C 3 C- 6 ); (C 2 Phe); (α-c); (C 2 -); 6.76 (C-6 ); 65.4 (Z-C 2 ou C 2 Ph); (C-3 ); 69.2 (C 2 -Z ou C 2 Ph); (C-2 ); 72.3 (C-4 ); 73.3 (C-5 ); (C- ); 4.5 (2 C Tyr); (C-5); (Ar); (Ar); (Ar); (Ar); (Ar); (C 2 -CAr); 30.5 (2 C Tyr); and (Cq Z and C 2 Ph); (C-4 ); (C= (Z)); (CAr-C 2 Ph); 68.5 (C= (2 )); (C= (3 )); (C= (4 )); (C= (6 )); 7.6 (C=) ppm. Anal. Calcd for C 4 44 N 4 4. ½ 2 : C, 58.36;, 5.6; N, Found: C, 58.42;, 6.26; N, 6.29.

9 -(2,3,4,6 -tetra--acetyl-β-d-glucopyranosyl)--,2,3-triazol-4-yl)methyl- PheZ () Following method B, with the acetylenic substrate 2, and stirring the reaction mixture for 60 min., a greenish solid was obtained after recrystallization from ethyl acetate and 27 light petroleum (7%, m.p ºC). [ ] D -8.0 (0.02, CCl 3 ). (300Mz, DMS-d 6 ).77 (3, s, C 3 C-2 );.95 (3, s, C 3 C-4 );.97 (3, s, C 3 C-6 ); 2.02 (3, s, C 3 C-3 ); 2.85 (, dd, J 3.8 and 0.5 z, CPhe); 3.0 (, dd, J 3.8 and 4.8 z, CPhe); 4.07 (, d, J 2.0 z, a-6 ); 4.4 (, dd, J 2.6 and 5. z, b-6 ); (, m, α-c); 4.37 (, ddd, J 0.0, 5. and 2. z, -5 ); 4.96 (2, s, Z-C 2 ); (3, m, C 2 and -3 ); 5.56 (, ap t, J 9.6/9.3 z, -4 ); 5.66 (, ap t, J 9.0/9.3 z, -2 ); 6.37 (, d, J 8.7 z, - ); (0, m, 2 C 6 5 ); 7,86 (, d, J 8.4 z, N); 8.42 (, s, -5) ppm. C (75.4Mz, DMS-d 6 ) 9.88 (C 3 C-2 ); (C 3 C-3 ); (C 3 C-4 ); (C 3 C-6 ); 36.3 (C 2 Phe); (α-cphe); (C 2 -); 6.77 (C-6 ); 65.4 (Z- C 2 ); (C-3 ); (C-2 ); 72. (C-4 ); (C-5 ); (C- ); (C-5); 26.5 (Ar); (Ar); (Ar), 28,2 (Ar), (Ar), 29,07 (Ar), e (Cq Z and C 2 Ph), (C-4 ); (C= (Z)); (C= (2 )); (C= (3 )); (C= (4 )); (C= (6 )); 7.53 (C= (Phe)) ppm. -(2,3,4,6 -tetra--acetyl-β-d-glucopyranosyl)--,2,3-triazol-4-yl)methyl-glyz (2) Prepared by method B, with the acetylenic substrate, and stirring the reaction mixture for 60 min., an off-white solid was obtained after recrystallization from ethyl acetatelight petroleum (74%, m.p ºC). max (Nujol) 74 and 720 (C=), 2855, 2925 (C), 3242 (N) cm -. (300Mz, DMS-d 6 ).79 (3, s, C 3 C-2 );.96 (3, s, C 3 C-4 );.99 (3, s, C 3 C-6 ); 2.02 (3, s, C 3 C-3 ); 3.79 (2, d, J 6.3 z, C 2 Gly); 4.05 (, dd, J 2.3 and 2.4 z, a-6 ); 4.3 (, dd, J 2.6 and 5.4 z, b-6 ); 4.60 (, ddd, J 0.2, 5.4 and 2.4 z, -5 ); 5.03 (2, s, Z-C 2 ); 5.6 (, ap t, J 9.9/9.6 z, -4 ); 5.8 (2, s, C 2 ); 5.55 (, ap t, J 9.0/9.6 z, -3 ); 5.64 (, ap t, J 9.6/9.0 z, -4 ); 6.36 (, d, J 9.3 z, - ); (5, m, C 6 5 ); 7.72 (, t, J 6.0 z, N); 8.48 (, s, -5) ppm. C (75.4Mz, DMS-d 6 ) 9.92 (C 3 C-2 ); (C 3 C-3 ); (C 3 C-4 ); (C 3 C-6 ); 42.4 (C 2 Gly); (C 2 -); 6.80 (C-6 ); (Z- C 2 ); 67.5 (C-3 ); 70.2 (C-2 ); 72.7 (C-4 ); (C-5 ); (C- ); (C-5); (2xC-Ar); (Ar); 28.4 (Ar); 36.85(Cq-Z); 37.6 (Cq-Ph); 42,36 (C- 4 ); (C= (Z)); (C= (2 )); 69.4 (C= (3 )); (C= (4 )); 69.96

10 (C= (6 )); (C= (Ph)) ppm. Anal. Calcd for C N 4 3 : C, 52.26;, 5.20; N, Found: C, 52.0;, 5.2; N, (2,3,4,6 -tetra--acetyl-β-d-glucopyranosyloxy)but--yne (3) But-3-yn--ol (0.45 ml, 6.0 mmol) and BF 3 (Et) 2 (0.95 ml, 7.5 mmol) were added to a solution of commercial D-glucose -pentaacetate (.95 g, 5.0 mmol) in dichloromethane (40 ml). The mixture was stirred at room temperature for 5 hours and for further 30 mins after addition of K 2 C 3 (0.52 g,.. mmol). The solid was filtered off and the filtrate washed with water (2x30 ml) and the aqueous phase extracted with dichloromethane (2x 0 ml). The combined organic layers were dried over MgS 4 and concentrated to a solid product which was crystallized from dichloromethane-light petroleum yielding compound 3 (69%, m.p ºC). max (Nujol) 7 (C--C sym.), 223 and 259 (C--C asym.), 737 (C=), 220 (C C), 2855 and 2925 (C) cm -. (400Mz, CDCl 3 ).97 (, t, J 2.7 z, -); 2.00 (3, s, C 3 C-3 ); 2.02 (3, s, C 3 C-4 ); 2.05 (3, s, C 3 C-2 ); 2.08 (3, s, C 3 C-6 ); 2.47 (2, dt, J 2.7 and 7.0 z, -3); (2, m, -5 and -4); 3.94 (, dt, J 0.0 and 6.8 z, -4); 4.3 (, dd, J 2.4 and 2.4 z, a-6 ); 4.26 (, dd, J 2.4 and 4.8 z, b-6 ); 4.57 (, d, J 8. z, - ); 4.99 (, dd, J 9.6 and 7.6 z, -2 ); 5.08 (, t, J 9.6 z, -4 ); 5.20 (, ap t, J 9.2/9.6 z, -3 ) ppm. C (00.62Mz, CDCl 3 ) 9.80 (C-3); (C 3 C-3 ); (C 3 C-4 ); (C 3 C-2 ); (C 3 C-6 ); 6.86 (C-6 ); (C-4); (C-4 ); (C-); 7.08 (C-2 ); 7.8 (C-5 ); (C-3 ); (C-2); (C- ); (C= (2 )); (C= (4 )); (C= (3 )); (C= (6 )) ppm. Anal. Calcd for C : C, 53.87;, Found: C, 54.00;, (2,3,4,6 -tetra--acetyl-β-d-glucopyranosyloxy)prop--yne (4) This compound was prepared as 3, with propargyl alcohol, and isolated as a white solid (60.2%, m.p ºC). max (Nujol) 59 and 25 (C--C sym.), 22 and 236 (C--C asym.), 757 and 734 (C=), 29 (C C), 2855 and 2924 (C) cm -. (300Mz, CDCl 3 ) 2.0 (3, s, C 3 C-2 ); 2.03 (3, s, C 3 C-4 ); (3, s, C 3 C-3 ); 2.09 (3, s, C 3 C-6 ); 2.48 (, t, J 2.4 z, -); 3.73 (, ddd, J 0.0,4.5 and 2.4 z, -5 ); 4.4 (, dd, J 2.3 and 2.4 z, a-6 ); 4.28 (, dd, J 2.3 and 4.5 z, b-6 ); 4.37 (2, d, J 2. z, -3); 4.78 (, d, J 7.8 z, - ); 5.0 (, dd, J 9.3 and 7.8 z, -2 ); 5.0 (, t, J 9.6 z, -4 ); 5.24 (, ap t, J 9.9/9.3 z, - 3 ) ppm. C (00.62Mz, CDCl 3 ) 20.56, 20.58, and (4xC 3 C); (C-3); 6.70 (C-6 ); (C-4 ); (C-2 ); 7.87 (C-5 ); (C-3 ); (C-); (C-2); (C- ); (C= (4 )); (C= (2 )); (C= (3 ));

11 70.25 (C= (6 )) ppm. Anal. Calcd for C : C, 53.02;, Found: C, 52.85;, (2,3,4,6 -tetra--acetyl-β-d-glucopyranosyl)-4-[ -(2,3,4,6 -tetra-acetyl-β-d-glucopyranosyloxy)-ethyl]--,2,3-triazole (5) Following method B, with the acetylenic substrate 3, and stirring the reaction mixture for 2 h 45 min., a greenish solid was obtained after recrystallization from ethyl acetatelight petroleum (80%, m.p ºC). max (Nujol) 22 and 04 (C--C sym.), 225 (C--C asym.), 747 (C=), 2855 and 2925 (C) cm -. (300Mz, CDCl 3 ).78,.89,.9,.95,.96,.98, 2.00, 2.0 (24, 8 s, 8x C 3 C); 2.86 (2, ap t, J 6.9/6.3 z, -2 ); (, m,.5 ); (5, m, -6 and -6 ); 4.35 (, ddd, J 9.9, 5.4 and 2.4 z, -5 ); (3, m, -2, - 4, - ); 5.3 (, ap t, J 9.3/9.9 z, -4 ); (, m, -3 ); (2m, -2 and -3 ); 6.28 (, d, J 9.0 z, - ) ppm; 8.09 (, s, -5). Anal. Calcd for C N CuS 4 : C, 46.33;, 5.24; N, Found: C, 46.36;, 5.5; N, Acknowledgements To the Foundation for the Science and Technology (FCT, Portugal) for financial support to the NMR Portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho) and to FCT and FEDER (European Fund for Regional Development)-CMPETE- QREN-EU for financial support to the Research Centre, CQ/UM [PEst- C/QUI/UI0686/20 (FCMP FEDER-02276)] References. C. Böttcher, J. Spengler, S.A. Essawy, K. Burger, Monastshefte für Chemie, 2004, 35, B..M. Kuijpers, S. Groothuys, A.R. Keereweer, P.J.L.M. Quaedflieg, R.. Blaauw, F.L. van Delft, F.P.J.T. Rutjes, rg Lett. 2004, 6, F. imo, T. Lovell, R. ilgraf, V. V. Rostovtsev, L. Noodleman, K. B. Sharpless, V. V. Fokin, J. Am. Chem. Soc., 2005, 27, R. Kumar, P.R. Maulik, A.K. Misra, Glycoconj. J., 2008, 25, M. usen, D.A. Long, C.R. D Ardenne, A.L. Smith, Carbohydr. Res., 2005, 340, 2670.