240 PROCEEDINGS OF THE AMERICAN ACADEMY. 



We have found, in attempting to prepare the diacetate of dinitro- 

 bromresorcine, that dinitrobromresorcine would not react with acetyl 

 chloride when heated with it at 100° for six hours in a sealed tube. 

 Water does not react with dinitrobromresorcine in a sealed tube at 

 temperatures varying from 100° to 150°. At temperatures between 

 150° and 190° the body is entirely decomposed, leaving a residue in 

 the tube which seemed to be carbon, as it was insoluble in all solvents. 

 It is strange that this substance should be less affected by water than 

 the tribromresorcine, which is slowly acted on by water at its boiling 

 point. The dinitrobromresorcine reacts with sodic etbylate, but, as in 

 the case of the tribromresorcine, the resulting amorphous mass could 

 not be purified or crystallized. 



Behavior of Tribromresorcinediacetate. 



While the tribromresorcine itself reacts readily with boiiing water 

 and sodic ethylate, but gives unmanageable products, and the di- and 

 tribromresorcine diethyl ethers do not act with these reagents, it was 

 thought that possibly the diacetate of tribromresorcine miglit be better 

 to work with than either of the ethers or the free phenol, because it 

 holds an intermediate place between the acid tribromresorcine and its 

 neutral ethers. Instead of using Claassen's method* of boiling penta- 

 bromresorcine with acetic anhydride, then with glacial acetic acid, and 

 finally with water, the tribromresorcinediacetate was directly prepared 

 from tribromresorcine by treating it in a sealed tube for four or five 

 hours at 100° with either acetyl chloride or acetic anhydride, prefer- 

 ably the former. It is best to use a slight excess of acetyl chloride, 

 and after the heating is finished to decompose the excess by means 

 of water. The diacetate is easily recrystallized from alcohol, and was 

 identified by its melting point, 108°. 



After boiling tribromresorcinediacetate with water for twenty-four 

 hours, the water was slightly pink in color, and gave a feeble test for 

 bromides with argentic nitrate. This is due, no doubt, to the fact that 

 water at 100° saponifies a small part of the diacetate, yieldiug tribrom- 

 resorcine, which in its turn is acted upon by the boiling water, as 

 before noted. In the hope of avoiding this saponification, a sealed 

 tube containing the diacetate was heated over night at 157° with 

 ordinary acetic acid, but the saponification was not prevented, for the 

 result was the same as if the free tribromresorcine had been heated 

 with water alone to that temperature. Sodic ethylate in alcoholic 



* Ber. d. ch. G., XI. 1439. 



