Organic 2 Review Problem 158

Organic 2 Review Problem 158 - 142 P RACTICAL ORGANIC...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
142 PRACTICAL ORGANIC CHEMISTRY 7-5-8-0 g.). Recrystallise the product from rectified spirit until the y.-pentacetylglucose is obtained as colourless crystals melting sharply at 110-111°. Two recrystallisations are usually sufficient for this purpose. (B) fi-PENTACETYLGLUCOSE. Required: Anhydrous sodium acetate, 2*5 g.; acetic anhydride, 25 ml.; glucose, 5 g. Carry out this preparation precisely as described for the a- compound, but instead of zinc chloride add 2*5 g. of anhy- drous powdered sodium acetate (preparation, p. 116) to the acetic anhydride. When this mixture has been heated on the water- bath for 5 minutes, and the greater part of the acetate has dis- solved, add the 5 g. of powdered glucose. After heating for i hour, pour into cold water as before. The viscous oil crystal- lises more readily than that obtained in the preparation of the a-compound. Filter the solid material at the pump, breaking up any lumps as before, wash thoroughly with water and drain. (Yield of crude product, 10-0-10-5 £•)• Recrystallise from
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.

Ask a homework question - tutors are online