Organic Lab Reactions 276

Organic Lab Reactions 276 - with hydrochloric acid nuclear...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
ACID USED FOR DIAZOTIZATION 271 whereas benzidine is converted to biphenyl in 80% yield, 14 the desmina- tion of 3,3'-dimethoxybenzidine takes place in but 24% yield. 46 Acid Used for Diazotization In most of the recorded deaminations with ethanol, sulfuric acid has been used rather than hydrochloric or nitric acid. As a general practice this appears to be a good choice since, in certain cases, diazotization with hydrochloric acid involves a risk that the deamination product may contain chlorine in place of a bromine atom or a nitro group originally present in the aromatic amine.* In the deamination of polybromoamines, if the bromine atoms are ortho or para to the amino group and if the diazotization is carried out
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: with hydrochloric acid, nuclear bromine is exchanged for chlorine. Bromine atoms meta to the diazo group are not affected. 32-46 B N 2 +C1-N 2 +Br-Monobromodiazonium chlorides do not isomerize, but dibromodiazonium chlorides do so readily, even at low temperatures. Thus, in H^6 normal methanol solutions of 2,4-dibromo- and 2,6-dibromobenzenediazonium chlorides, after one hour at 0°, 6.2% and 21.4%, respectively, of the * It must be emphasized, however, that a number of satisfactory deaminations have been effected via the diazonium chlorides. 46 Starke, J. prakt. Chem., [2] 59, 221 (1899). "Hantzsch, Ber., 30, 2334 (1897)....
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online