Hexamethylenetetramine → 4-(2',6'-Dichlorobenzyl)oxazole

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Reaction Conditions

Reaction Steps

21.7 g of crude 2,6-dichlorobenzylglyoxal are dissolved in 50 ml of formamide. 7.0 g of hexamethylenetetramine and 30.8 g of ammonium acetate are added and the reaction mixture is stirred at 100° C. for 2 hours, then is evaporated to dryness in vacuo. 200 ml of water are added and the pH of the aqueous phase is adjusted, while stirring, to 2-3 with concentrate hydrochloric acid. The solution is washed with toluene (3×50 ml). The aqueous solution is made alkaline with sodium hydroxide (pH=8-9) and then extracted three times with chloroform (1×100 ml and 2×50 ml). The combined chloroform extracts are washed with water, dried with sodium sulfate and evaporated to dryness. The residue, which consisted of crude product, is used in step (c) below.

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