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Synthesis of para-substituted phenyl 1-thio-β-d -galactopyranosides
Carbdhydrate Research, 26 (1973) 227-229 0 Elsevier Scientific Publishing Company, Amsterdam - Printed in Belgium
Note
Synthesis
of para-substituted
M.YDEAND
C.K.DEBRUYNE
Laboratoriam (Belgium)
Algemene en Biologische
phenyl
Scheikunde,
1 -thio-j?-D-galactopyranosides
IT. I. K. W., Ledegancksrraat
35 B-9000 Cent
(Received July 1 Ith, 1972; accepted for publication, July 20th, 1972)
In Table I, a series of para-substituted phenyl tetra-O-acetyI-l-thio-&D-galactopyranosides are described. They were obtained by a modified Michael’V2 condensation (method l), or by the method of cerng et aZ.3 (method 2). Method 2 (reaction of tetra-O-acetyl-1-thio-p-D-galactopyranose with the appropriate diazonium salts) was originally developed for the synthesis of phenyl I-thio-j?-D-glucosides, but is also applicable to galactosides. The arenethiols were commercial products, except for the p-acetylbenzenethiol which was synthesized according to Riesz and Frankfurther4. Catalytic deacetylation’ (sodium methoxide) of the galactoside acetates yielded the corresponding phenyl I-thio-P-D-galactopyranosides (Table II). EXPERIMENTAL
A solution of freshly distilled arenethiol (33 mmoles) and tetra0-acetyl-a-D-galactopyranosyl bromide6 (30 mmoles) in acetone (60 ml) was mixed with a solution of potassium hydroxide (30 mmoles) in water (15 ml). The reaction mixture was kept for 24 h at room temperature and then evaporated in t-acuo. A soIution of the residue in chIoroform was thoroughly washed with coId 5% aqueous sodium hydroxide and water, dried (Na,S04), and evaporated in uacuo. The resulting syrup was then crystaIIized from the appropriate solvent. The melting points were determined with a MettIer FP2 instrument and are uncorrected. The optical rotations were measured on 0.5% soiutions in chloroform (acetates) or methanol (galactosides) with a Perkin-Elmer Model 141 photoeIectric poiarimeter. The purity of the products was tested by t.1.c. on Silica Gel G (Merck) in acetic acid-water-ethyl acetate (1:1:3) for the galactosides, and ethyl acetate-benzene (3:7) for the acetates. Detection was effected with 5% sulphuric acid in ethanol (IO min at 120”). Method
1. -
REFERENCES 1 2 3 4 5 6
F. G. LOONTIENS AND C. K. DE BRU~NE, Naturwissenschuften, 51 (1964) 359. C. K.DE BRUYNEAND F.VAN WIJNENDAELE, Carbohyd. Res.,4(1967) 102. M. TERNS, D. ZACHY~TALOVA AND J.PACAK, Coil.Czech. Chem. Common., 26 (1961) 2206. E. RIESZ AND W-FRANKFURTER, Monotsh. Chem., 50 (1928) 72. A. THOMPSON AND M. L. WOLFROM, Methods Carbohyd. Chem., 2 (1963) 221. M. BARCZAI-MARTOS AND F. K~R~sY, Nature (London), 165 (1950) 369.
94-95
168-169 159-I 60 139-140 16-18 139-141 168-170 212-213
-53.4 -41.2 -50.4 -50.0 -56.P -36.4 - 108.5 -92.1*
52.3 41.0 46.9 54.5 57.9 51.5 45.5 53.1
6.1 4,3 4.9 6.4 1.4 6.0 4.8 5.9
‘X!rystdlisations from A, methanol; B, acetone; C, butanone; D, water. “C0.5 (water).
64 36 33 19 60 15 a3 12
I-THI~-~.~~-OALACT~PYRANOSID~S
None p_Bromo p-Chloro p-Methyl p-terl-Butyl p_Methoxy p_Nitro p_Acctyl
P~NYL
TABLE II
52.9
41.0 46,9 5404 X5 .51,6 45.4 53.5
5.9
4.3 4.9 6.3 1.4 6.0 4.8 5.8
Note
Synthesis
of para-substituted
M.YDEAND
C.K.DEBRUYNE
Laboratoriam (Belgium)
Algemene en Biologische
phenyl
Scheikunde,
1 -thio-j?-D-galactopyranosides
IT. I. K. W., Ledegancksrraat
35 B-9000 Cent
(Received July 1 Ith, 1972; accepted for publication, July 20th, 1972)
In Table I, a series of para-substituted phenyl tetra-O-acetyI-l-thio-&D-galactopyranosides are described. They were obtained by a modified Michael’V2 condensation (method l), or by the method of cerng et aZ.3 (method 2). Method 2 (reaction of tetra-O-acetyl-1-thio-p-D-galactopyranose with the appropriate diazonium salts) was originally developed for the synthesis of phenyl I-thio-j?-D-glucosides, but is also applicable to galactosides. The arenethiols were commercial products, except for the p-acetylbenzenethiol which was synthesized according to Riesz and Frankfurther4. Catalytic deacetylation’ (sodium methoxide) of the galactoside acetates yielded the corresponding phenyl I-thio-P-D-galactopyranosides (Table II). EXPERIMENTAL
A solution of freshly distilled arenethiol (33 mmoles) and tetra0-acetyl-a-D-galactopyranosyl bromide6 (30 mmoles) in acetone (60 ml) was mixed with a solution of potassium hydroxide (30 mmoles) in water (15 ml). The reaction mixture was kept for 24 h at room temperature and then evaporated in t-acuo. A soIution of the residue in chIoroform was thoroughly washed with coId 5% aqueous sodium hydroxide and water, dried (Na,S04), and evaporated in uacuo. The resulting syrup was then crystaIIized from the appropriate solvent. The melting points were determined with a MettIer FP2 instrument and are uncorrected. The optical rotations were measured on 0.5% soiutions in chloroform (acetates) or methanol (galactosides) with a Perkin-Elmer Model 141 photoeIectric poiarimeter. The purity of the products was tested by t.1.c. on Silica Gel G (Merck) in acetic acid-water-ethyl acetate (1:1:3) for the galactosides, and ethyl acetate-benzene (3:7) for the acetates. Detection was effected with 5% sulphuric acid in ethanol (IO min at 120”). Method
1. -
REFERENCES 1 2 3 4 5 6
F. G. LOONTIENS AND C. K. DE BRU~NE, Naturwissenschuften, 51 (1964) 359. C. K.DE BRUYNEAND F.VAN WIJNENDAELE, Carbohyd. Res.,4(1967) 102. M. TERNS, D. ZACHY~TALOVA AND J.PACAK, Coil.Czech. Chem. Common., 26 (1961) 2206. E. RIESZ AND W-FRANKFURTER, Monotsh. Chem., 50 (1928) 72. A. THOMPSON AND M. L. WOLFROM, Methods Carbohyd. Chem., 2 (1963) 221. M. BARCZAI-MARTOS AND F. K~R~sY, Nature (London), 165 (1950) 369.
94-95
168-169 159-I 60 139-140 16-18 139-141 168-170 212-213
-53.4 -41.2 -50.4 -50.0 -56.P -36.4 - 108.5 -92.1*
52.3 41.0 46.9 54.5 57.9 51.5 45.5 53.1
6.1 4,3 4.9 6.4 1.4 6.0 4.8 5.9
‘X!rystdlisations from A, methanol; B, acetone; C, butanone; D, water. “C0.5 (water).
64 36 33 19 60 15 a3 12
I-THI~-~.~~-OALACT~PYRANOSID~S
None p_Bromo p-Chloro p-Methyl p-terl-Butyl p_Methoxy p_Nitro p_Acctyl
P~NYL
TABLE II
52.9
41.0 46,9 5404 X5 .51,6 45.4 53.5
5.9
4.3 4.9 6.3 1.4 6.0 4.8 5.8