1.4- Diamino-2,5-dibromobenzene

The same procedure is useful for N-alkylation of aromatic amines.3 Thus N,N,N, N -tetraethyl-l,4-diamino-2,5-dibromobenzene (4) was obtained in this way from 1,4-diamino-2,5-dibromobenzene (3) in 49 % yield. 

Shimoishi and Toei [766] have described a gas chromatographic determination of selenium in non saline waters based on l,2-diamino-3,5-dibromobenzene with an extraction procedure that is specific for selenium (IV). Total selenium is determined by treatment of non saline water with titanium trichloride and with a bromine-bromide redox buffer to convert selenide, elemental selenium and selenate to selenious acid. After reaction, the 4,6-dibromopiazselenol formed from as little as lng of selenium can be extracted quantitatively into 1 ml of toluene from 500ml of natural water up to 2ng L 1 of selenium(IV) and total selenium can be determined. The percentage of selenium(IV) in the total selenium in river water varies from 35 to 70%. 

Uchida et al. [793] determined various selenium species in river water and sea water by electron capture detection gas chromatography after reaction with l,2-diamino-3,5-dibromobenzene. This reagent reacts with seleniumflV) to form 4,6-dibromopiazselenol which is extracted into toluene. After Se(-ll) and Se(0) has been reduced by a bromine-... 

Steric control. l,4-Diamino-2,6-dibromobenzene in pyridine added to 2-benzoyl-oxy-5,5-dimethyl-2-oxo-l,3,2-dioxaphosphorinan in the same solvent, and allowed to stand 2 hrs. at room temp. 4 -amino-3, 5 -dibromobenzanilide. Y 87%. -The less hindered amino group is benzoylated. F. N-acylations and limitations s. R. S. Edmundson, C. I. Forth, and T. A. Moran, Soc. (C) 1971, 2452. 

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