Allopyranoside with sodium benzoate

Al-Radhi, A K, Brimacombe, J S, Tucker, L C N, Nucleophilic displacement reactions in carbohydrates. Part XIX. The reaction of methyl 6-deoxy-3-0-methyl-4-0-methylsulphonyl-2-0-p-tolylsulphonyl-a-D-allopyranoside with sodium benzoate in hexamethylphosphoric triamide a vicinal axial substituent effect, J. Chem. Soc. C., 2305-2310, 1971. 

A solution of methyl 4,6-0-benzylidene-3-chloro-3-deoxy-p-D-allopyranoside [29] (33, 12.6 g) in dry tetrahydrofuran (500 mL) containing sodium benzoate (12 g) was boiled for 2 h under reflux. The cooled suspension was filtered, and the filtrate was evaporated to dryness. The residue was extracted with chloroform, and the extract was washed with water, dried (MgS04), and evaporated to dryness. Crystallization of the product from chloroform-petroleum ether gave methyl 4,6-0-benzylidene-P-D-eryriiro-hex-3-enopyranoside 43, yield 8.8 g (85%), mp 134°-135°C, [ot]D -43° (c 1.58, CHC13). 

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