Thallium nitrate, trihydrate

When O-alkylated or O-acylated D-glucals are heated in 9 1 acetonitrile-methanol with thallium nitrate trihydrate, ring contraction occurs to give compounds 117 in about 50% yield following, it may be assumed, addition of the metal ion at C-2 and methoxyl at C-l to lead to intermediates that ring contract to the 2,5-anhydro products.128... 

Preparation. The salt is prepared by dissolving 50 g. of thallium(IIl) oxide in 150 ml. of warm concentrated nitric acid and cooling the pale-yellow solution to 0°. Thallium(lll) nitrate trihydrate separates and is dried under vacuum over P2O,. The salt is stable if stored in tightly scaled bottles. 

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