Organic 2 Review Problem 155

Organic 2 Review Problem 155 - and dry The glucosazone is...

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PREPARATIONS '39 with a reflux condenser, then to add about 75 ml. of methylated spirit, and boil gently. The osazone dissolves slowly; filter the hot solution through a fluted filter-paper (or a preheated Buchner funnel), and allow the filtrate to cool slowly in order to ensure good crystal formation. Glucosazone (Fructosazone) (B) Maltosazone FIG. 63. (C) Lactosazone If it is desired to observe the crystalline form of the osazone, draw up in a glass tube a few drops of the cold filtrate containing the fine crystals, and transfer to a microscope slide. Cover the drops with a slip and examine under the microscope: unless the filtrate has been cooled very slowly and thus given moderately- sized crystals, the high power of the microscope will probably be required. Note the fine yellow needles aggregated in the form of sheaves. Compare with Fig. 63(A). Then filter the remainder of the product at the pump, drain
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Unformatted text preview: and dry. The glucosazone is thus obtained as bright yellow crystals, m.p. 204° with decomposition. Maltosazone (Phenyl-maltosazone). C 12 H 20 9 (N.NHC 6 H 5 ) 2 . Required: Maltose, 2 g.; acetic acid, 2 ml.; phenylhydrazine, 2 ml. Proceed as in the preparation of glucosazone, using for the first solution 2 g. of maltose in 10 ml. of water, and for the second solution 2 ml. of phenylhydrazine dissolved in a mixture of 2 ml. of glacial acetic acid and 5 ml. of water. Heat in a boiling water-bath for 30 minutes. Maltosazone is much more soluble than glucosazone in hot water, and therefore does not separate whilst the boiling-tube is still in the boiling water-bath. When the heating is complete, either turn out the gas and allow the tube to cool slowly while still in the bath, or alternatively place...
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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.

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