Question

Answer the questions below regarding synthetic Scheme 1: (20 marks) Fe, HCI NO NO2 BU - DME NaoMe Meo NH2 HN Scheme a) Give the missing reagents for Step A. What kind of selectivity does this reaction have and why? (3 marks) b) Give the structure of product 3 obtained in step B and explain the type of selectivity observed. (4 marks) c) Explain why DMF is used as a solvent in step C. (4 marks) d) Show the mechanism of step D. (7 mark) e) What kind of reaction is Step E? Suggest reaction conditions for this step. (2 marks) Recovered 39 ch O e Ê BY W

Answer 1

a) step 1 reagent is t-butylCOCl , and it goes to para to F(o-,p-directing) and meta to NO2 (meta directng) avoiding the steric crowding by not chossing the inbetween position of groups.

b)Fe/HCl reduces the nitro(NO2) to NH2 selectively.

c)NH2 on benzene ring is the nucleophile which is not very strong and the halide also has electronwithdrawing group. So to make the reaction follow SN2 , polar aprotic solvent DMF is used.

d)aromatic nucleophilic substitution activated by the RCO(electronwithdrawing group at para position

e)hydrolysis of carbamate . 6M HCl at boiling tmperature.

fe, HCO t-Bu no HNB DM DMF NH2 2-t-Bu اگ NOON NHKへリサュー