Question

1. For the following compounds, label each substituent as electron donating or electron withdrawing, and indicate whether this effect is achieved via induction or resonance. ŅO2 H2N SO3H 2. Predict the TH NMR of the above benzene derivatives. For chemical shift, indicate whether the peak would likely be downfield or upfield of benzene (7.2 ppm). (Hint: think about the resonance structures that can be drawn based on your responses from above) A B # of peaks chemical shift indicate: >7.2, -7.2, or <7.2 ppm List all splitting patterns expected for each expected peak 3. All electrophilic aromatic substitutions have the same basic mechanism. a. Below, please draw the mechanism for the bromination of benzene. Br2 cat. FeBr3 3b. Please briefly provide an explanation why only mono-bromination is observed. 4. Label each of the following compounds as aromatic or non-aromatic. what products would be formed through the reaction shown below O MBE AICI

Answer 1

1 AS, HA Hag Chemical Shift doubletta > 7. G ppm HB = 7.05 ppm Her 4 He > 7.3 ppm стİPl<L) HB Splitting pattern 7 7.2 ppm i doublet 27.2 ppm wdd cdoublet of double HE > 7.2 ppm li triplet HA BSN HB chemical Shifl (02 HA O=0=0 -OH HA En 6.7 ppm splitting pattern is doublet in doublel. 27.2. ppm HB HB = 7.3 ppm > 7.2 ppm Hc 743.4 ppm ū HAHAH chemical Shirt 10 HA =>u2.1 ppm HB > 41.7 ppm He =u7.2 ppm Hd 47.3 ppm i quaatet Tu Esiplek 77.2 ppm > 7.2 ppm He=doublet ing Hd = Triplet 9.3 draw the mechanism for the boomination of benzene B&2 Ba FEB73 (cat) Mechanism:. step-1; Formation of electrophile Bə B2: ва Fe Bag

step-11; attack of benzene ding Ring on elcetao phile Since Ba н Ba Step-111; Aromatization! Ba Fast Ba :Bad Fe Bag + Fe B33 + HBO Q.35:- Ans: u bromination of benzene gives bromobenzene, Bzomine is not so electrophilic to attack the benzene ding we first conveat boomincinto strong electrophile using Lecois acid catalyst Fe Bag Og Alc/8, which polarize the B2-B2 bond and electrophilie. Bo is produced, which is attacked by benzene sing 34 once the Boomine gets Substituted ľE with daaces the electrons by (-3) effect, making the ding election deficient for fuather boomination. Hence only monobromination occuas 9.4; Label each of the following compounds as aromatic or non-aromatic => Any System is said to be 920matic if it obeys Huckel Jule. Huckel Jule states that any cyclic, planez. Fully conjugated system which contain (40 +2) Teo is said to be aromatic Now wesec examples.

Not conjugated double bond . Therefoa non-aromatic 21 T: => planez, cyclic, conjugated contain (40 +2) e Therefore it is aromatic 3) => Not contain (40 +2 )Tee, TheZefon non-aromatic planez, cyclis, conjugated contain (40+ 2) Teo; Thedefodeilis aromatic 9. klhat products would be formed through the deaction Shocen beloce 1 •Ba Alolz + + Hg2+ Alcla The above deaction is Friedal craft alkylation deaction, in this deaction H-atom Is Substyted by aikui goup

9.1; Ans:- i Iodine is halogen it shows two Opposite effect → it withdraws electaon by (-1.) inductive effect and donates electron by (+R) Jesonance effect) (4) (-1).(+R) electrondonating 9204p HN דר isogh -NH, group is electron donating gooup. donates electron by Resonance effect LL >> - Sogh group is electron electron withdrawing group withdaacing, it with deews electron by C-R) Resonance electron effect weithdacicoing NO geoup -> electron => is staongly donating geoup electron withdrawing 9aoup, it withdraws 5-CH-CHy is electron electron by (-R) Resonance donating group.it donates effect election by (+1) inductive effect. 9.2 1 (B) (C) (A) chemical shift: