Explain how substitutions at the 5-position of phenobarbital increase the compound's lipophilicity.

Name an interesting derivative of barbituric acid, describing its structure.

Briefly describe the synthesis mechanism of barbituric acid from the condensation of urea with a β-diketone.

Given the hydrazones indicated, draw the structures of the enamines that can be formed. Indicate the most stable enamine (explain). C6H5 C6H5 H C6H5 H

4. Propose a Synthesis for the molecule below. You may use any starting materials containing 6 carbons or less (reagents that aren't incorporated into the final molecule such as PhзP do not count towards this total, and the starting material can have whatever non-carbon functional groups you want), and any of the reactions you have learned so far in organic chemistry I, II, and III. Your final answer should show each step separately, with intermediates and conditions clearly drawn.

Indicate the importance of the indole ring. Find a representative example and list 5 structures.

ΌΗ 1) V2 CO 3 or Nalt In منه

6. The equilibrium constant for the reaction 2 HBr (g) → H2(g) + Br2(g) Can be expressed by the empirical formula 11790 K In K-6.375 + 0.6415 In(T K-¹) - T Use this formula to determine A,H as a function of temperature. Calculate A,-H at 25 °C and at 100 °C.

3. Nitrosyl chloride, NOCI, decomposes according to 2 NOCI (g) → 2 NO(g) + Cl2(g) Assuming that we start with no moles of NOCl (g) and no NO(g) or Cl2(g), derive an expression for Kp in terms of the equilibrium value of the extent of reaction, Seq, and the pressure, P. Given that K₂ = 2.00 × 10-4, calculate Seq/ of 29/no when P = 0.080 bar. What is the new value по ƒª/ at equilibrium when P = 0.160 bar? Is this result in accord with Le Châtelier's Principle?