260 DERIVATIVES OF DIPHENOOUINONE. 



G. New substances, 

 (i) Dihrouiodicrcsol dihenzoate, 

 Br 



obtained by the Schotten-Baumann method, forms white 

 granules, insoh;ble in alcohol, fairly easily in ether, melting at 

 239°. Found Br r= 2y.7,%. 



C28H2o04Br2 requires Br = 27.6%. 



Owing to " protection," it can only be hydrolysed by fusion 

 with solid potash: the dibromodicresol recovered gave 44.1% 

 Br, and had therefore its bromine intact. 



(2) Dihromodicrcsoldiacetatc, which forms boat-shaped 

 needles m.p. 198°, yields on oxidation with excess of CrOa in 

 boiling acetic acid a benzenoid bromo-acid, which after hydro- 

 lysing off its acetyl group, was converted into (3) 5 bi'oino- 3 

 methyl- 4 oxybcnzoic acid. This is almost insoluble in water 

 and melts at 233°. Found 35.2% Br. 



Cs H7 O3 Br requires Br =: 34.6. 



It is curious that Beilstein's Supplement II. describes an 

 isomeric hro'uo.vytoluic acid, with the same properties and melt- 

 ing point : possibly these are identical instead of isomeric. 



(4) ^-bromo ^' nitrodicresol (5 bronw 5' iiiti'o-;^-2,' diuicthyl- 

 ■diplicnol) : bye-product in preparation of dibromodicresoquinone 

 by Magatti's method, also directly by treating dicresol in acetic 

 acid first with bromine and then with yellow nitric acid : deep 

 orange needles, m.p. over 260° : potassium salt brick-red and 

 ■almost insoluble. Found 22.7% and 23.0% iCuHiaOi N Br re- 

 quires Br = 23.7%. 



(5) 5-5' dinitrodicresol can be made in one step from toli- 

 dine in boiling acetic acid by adding strong nitric acid, boiling 

 in a capacious vessel, diluting, and hydrolysing the dinitrotoli- 

 dine with strong caustic soda. Very dark chesnut brown sub- 

 stance very sparingly soluble in all solvents and charring at 

 about 320". The attempt to make 5-5' diamino-dicresoquinone 

 from this failed : the insoluble product was amorphous and gave 

 a dirty-brown witli sulphuric acid. 



(6) DicrcsoJdisiiJphonic acid. \Mien dicresol is heated 

 with sulphuric acid at 100°, the main product appears to be a 

 monosidphonic acid : a small quantity was obtained in sparingly 

 soluble white needles, which swell up on heating but do not melt. 

 To obtaine the disulphonic acid dicresol is heated with 20 parts of 

 H2 SO4 to 200° for some time, and the product worked up with 

 barium carbonate in excess as usual. The barium salt is some- 

 what soluble, as is also the free disulphonic acid, so that the 

 -solution was induced to crvstallise bv adding barium acetate, the 



