Question

2. Nitration and the Hofmann Rearrangement Monk, K.A.; Mohan R.S. The Hofmann Rearrangement Using Househo Synthesis of 3-Nitroaniline). Chem. Educ. 1999,76,1717 and McElveen, vardinas, K.; Stamberger, J.A.: Mohan. R.S. The Discovery-Oriented Approach Organic Chemistry 1. Nitration of Unknown Organic Compounds.). Chem. 1999, 76,535-536.) Step 1. Preparation of 3-nitrobenzamide This step was performed in duplicate to ensure that enough material was available to proceed to Step 2. A 50 mL Erlenmeyer flask was charged with benzamide (1.0 g) and concentrated sulfuric acid (6 mL), and the resulting solution was chilled in an ice bath. Cold concentrated nitric acid (44 drops) were added dropwise over 20 min to the Erlenmeyer flask placed in the ice bath. After each 2-3 drop addition, the flask was swirled to mix. After addition of the nitric acid, the flask was left in the ice bath for an additional 10 min. The viscous liquid was poured into a 50 mL beaker containing 20 g of crushed ice. The mixture was stirred rapidly with a glass stirring rod, and the solution became cloudy and thick. The flask was returned to the ice bath for 5-10 min. The solid was collected with a Hirsch funnel and washed with cold water until the filtrate was neutral to pH paper. The resulting solid was air-dried to yield 3-nitrobenzamide, mp 141-144 "C (literature 140-143 "C). A Step 2. Hofmann Rearrangement A 125 mL Erlenmeyer flask was charged with 3-nitrobenzamide (1.5 ) and a magnetic stirring bar. A 1 M sodium hydroxide solution (18 mL) and household bleach (13.3 mL) are added to the flask with stirring. The mixture was heated in a ter bath at 80 °C for 30 min. The task was removed from the water bath and cooled to 50 °C. A 10% aqueous NaHSO, solution (10 mL) was added. The feel was cooled to room temperature and placed in an ice bath. The solid was collected hy filtration with a Hirsch funnel, crude mp 110-112 "C. Recrystallization for hanol gave yellow crystals, mp 112-114 C. The product was compared to an authentic sample of 3-nitroaniline using TLC. STUDENT NOTES: You may have to try several TLC solvents before you wives adequate movement of compounds on the plate. Start with some of the TLC solvents that you have used before. It may be necessary to a third time to have enough material to proceed to Step 2. Make sure before used before. It may be necessary to perform Step

I need to know the mechanism for step 1- it should be detailed showing all curved arrows and the correct molecular structures for reactants, intermediates, and products. thank you for your help!

Answer 1

EINEN preparation of 3-nitrobenzamide: Structure!. -NH2 NO, N2 . Conc. H₂504 Conc. HNO3 NO, Mechanism stepl. 4504 + HNOZ = H50,7 + H26-No Step2. Hök Rio, — 10+ 0 Step3. CA Ö-NEO - 2-N=0 CA NO NG product