Questions dealing with carboxylic acid and their derivatives

1. Propose a synthetic route for the following:
1. methyl benzoate ® 4-phenyl-4-heptanol

1) CH₃CH₂CH₂MgBr 2) H⁺/H₂O

2. 5-decene ® pentanoic acid

     KMnO₄/OH^-/D

2. Write the structure(s) of the organic product(s) of the following reactions:
1. propyl benzoate + i) LiAlH₄ ii) H₃O⁺

CH₃CH₂CH₂OH + PhCH₂OH

2. 5-hydroxypentanoic acid + D



3. acetic anhydride + 1-propanol



4. butanoyl chloride + lithium diphenylcuprate

 

3. Compound "A", C₆H₁₃NO, produces a gas on heating with aqueous NaOH. When the resulting solution is acidified and extracted with ether, compound "B" is isolated. "C" is formed when "B" is heated with acidic methanol. Reduction of "C" with LiAlH₄ yields methanol and 4-methyl-1-pentanol. What are the structures of "A", "B" and "C"?





  



 

4. Consider the reaction between OH^- and N,N-dimethylacetamide.
1. What is the structure of the initially formed tetrahedral intermediate?

 



2. Why does the intermediate revert to starting material rather than produce hydrolysis products?

   OH^- is a better leaving group than (CH₃)₂N^-

5. (S)-Ibuprofen is an anti-inflammatory drug. Racemic ibuprofen can be synthesized from benzene:

  Benzene + (CH₃)₂CHCOCl/AlCl₃ ® "A"



  "A" + Zn(Hg)/HCl ® "B"



"B" + CH₃COCl/AlCl₃ ® "C" (para substitution occurs)



  "C" + NaCN/H₂SO₄ ® "D"



  "D" + H₃O⁺ ® ibuprofin



6. Progesterone is a hormone, secreted by the corpus luteum. It is involved in the control of pregnancy. It can be synthesized from stigmasterol, obtained from soybean.



stigmasterol

stigmasterol (C₂₉H₄₈O) + acetic anhydride ® "A" (C₃₁H₅₀O₂)



  "A" + Br₂ ® "B" (C₃₁H₅₀O₂Br₂)



  "B" + O₃, then Ag₂O ® "C" (C₂₄H₃₆O₄Br₂)



  "C" + Zn/CH₃CO₂H ® "D" (C₂₄H₃₆O₄)



"D" + C₂H₅OH/H⁺ ® "E" (C₂₆H₄₀O₄)



  "E" + C₆H₅MgBr, then H₂O ® "F" (C₃₆H₄₆O₃)



  "F" + H₃PO₄ ® "G" (C₃₆H₄₄O₂)



  "G" + Br₂ then CrO₃/H⁺ ® "H" (C₂₃H₃₄O₃Br₂)

 

  "H" + Zn/CH₃CO₂H ® "I" (C₂₃H₃₄O₃)

 

"I" + H₃O⁺/D ® "J" (C₂₁H₃₂O₂) pregnenolone

 

 



  pregnenolone + Br₂ then CrO₃/H⁺ ® "K" (C₂₁H₃₀O₂Br₂)

"K" + Zn/CH₃CO₂H ® progesterone (C₂₁H₃₀O₂)



7. In clinical studies with atherosclerotic patients it was found that one of the metabolites of the hyperlipidemia drug (Z)-3-methyl-4-phenyl-3-butenamide is compound "A" which has the formula C₁₁H₁₅NO₂. When heated with aqueous acid, the following lactone is formed along with NH₄⁺:
1. What is the structure of metabolite "A"?
2. Write a mechanism for its transformation into the lactone.



 

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Updated August 23, 2002