10,11-Dibromohendecanoic acid

Finally, the solution of 10,11-dibromohendecanoic acid in absolute ether is added slowly from a separatory funnel to the reaction flask. The reaction mixture is then stirred for 6 hours. After an additional 1 hour (Note 4) of stirring, during which time the cold-finger condenser is removed from the system, an excess of solid ammonium chloride (40 g., 0.74 mole) is introduced slowly into the reaction mixture to destroy excess sodam-ide. The ammonia is allowed to evaporate, 400-500 ml. of water is added, and the mixture is stirred until all the solid is broken up and dissolved (Note 5). 

Dehydrobromination, of 2-bromo-dodecanoic add, 37, 29 of 10,11-dibromohendecanoic acid with sodium amide, 32, 104 of 9,10-dibromooctadecanoic acid with sodium amide, 37, 77 Dehydrochlorination, of add chlorides, 31, 68, 71... 

The sodamide for dehydrobromination of dibromohendecanoic acid is prepared according to the method of Khan et al.,2 with some modifications (Note 2). A 3-1. three-necked flask is equipped with a stirrer and a Dry Ice-acetone cold finger reflux condenser attached through a drying tube to a trap and a bubbler filled with a saturated ammonia solution. After the con-... 

Experiments in the submitter s laboratory have shown that the yield obtained on dehydrobromination of dibromohendecanoic acid with ethanolic potassium hydroxide 6 is very poor, usually lower than 30%. On the other hand, the dehydrobromination with sodamide in liquid ammonia is smooth and very satisfactory. The directions employed here represent a modification of those of Lauer and Gensler.6... 

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