tailieunhanh - Ebook Study guide and solutions manual to accompany organic chemistry (11th edition): Part 2

(BQ) Part 2 book "Study guide and solutions manual to accompany organic chemistry" presents the following contents: Reactions of aromatic compounds, aldehydes and ketones; nucleophilic addition to the carbonyl group, condensation and conjugate addition reactions of carbonyl compounds-more chemistry of enolates; condensation and conjugate addition reactions of carbonyl compounds-more chemistry of enolates;. | REACTIONS OF AROMATIC COMPOUNDS SOLUTIONS TO PROBLEMS E A- E H A- -HA -HA The rate is dependent on the concentration of NO2 ion formed from protonated nitric acid. H O NO2 HA ------------- NO2 H3O A- H where HA HNO3 or HOSO3H Because H2SO4 HOSO3H is a stronger acid a mixture of it and HNO3 will contain a higher concentration of protonated nitric acid than will nitric acid alone. That is the reaction H O NO2 HOSO3H w H O NO2 HSO4- H Protonated nitric acid produces more protonated nitric acid than the reaction H O NO2 H O NO2 H O NO2 NO3- H 325 326 REACTIONS OF AROMATIC COMPOUNDS Step 1 F - Step 3 Step 2 s s H F OH BF3 H Rearrangement to the secondary carbocation occurs as the leaving group departs. H H O - BF3 hydride shift _ --------- HOBF2 F Both carbocations are then attacked by the ring. AlCl3 NH2NH2 KOH heat AlCl3 Zn Hg HCl reflux REACTIONS OF AROMATIC COMPOUNDS 327 C6H5 O AlCl3 NH2NH2 KOH heat O _______O AlCl3 AlCl3 Zn Hg HCl reflux If the methyl group had no directive effect on the incoming electrophile we would expect to obtain the products in purely statistical amounts. Since there are two ortho hydrogen atoms two meta hydrogen atoms and one para hydrogen we would expect to get 40 ortho 2 5 40 meta 2 5 and 20 para 1 5 . Thus we would expect that only 60 of the mixture of mononitrotoluenes would have the nitro group in the ortho or para position. And we would expect to obtain 40 of m-nitrotoluene. In actuality we get 96 of combined o- and j -nitrotoluenes and only 4 m-nitrotoluene. This shows the ortho-para directive effect of the methyl group. a SO3 H2SO4 CH3 SO3H O. OH b O kJ H2SO4 c Br2 FeBr3 .