506 CARBOXYLIC ACIDS 19.9(b) The 16-membered ring of 15-pentadecanolide is formed from 15-hydroxypentadecanoic Disconnect this bond COH 5-Pentadecanolide 15-Hydroxypentadecanoic (c) Vernolepin has two lactone rings, which can be related to two hydroxy acid combinations CHECH OH HOCH CH=CH H H, H,C OH COH Be sure to keep the relative stereochemistry unchanged. Remember, the carbon-oxygen bond of an alcohol remains intact when the alcohol reacts with a carboxylic acid to give an 19.10 Alkyl chlorides and bromides undergo nucleophilic substitution when treated with sodium iodide in acetone(Section8. 1). A reasonable approach is to brominate octadecanoic acid at its a-carbon atom, then replace the bromine substituent with iodine by nucleophilic substitution CHa(CH,)15CH,CO,H CH3(CH)15 CHCO acetone CH3(CH) CHCO2H 2- Bromooctadecanoic acid 2-lodooctadecanoic acid 19.11 (b) The starting material is a derivative of malonic acid. It undergoes efficient thermal decar- boxylation in the manner shown HO H CH,(CH2)CHO CH3(CH,)CH c O, CH3(CH2)CH, COH Back Forward Main Menu TOC Study Guide Toc Student OLC MHHE Website19.9 (b) The 16-membered ring of 15-pentadecanolide is formed from 15-hydroxypentadecanoic acid. (c) Vernolepin has two lactone rings, which can be related to two hydroxy acid combinations. Be sure to keep the relative stereochemistry unchanged. Remember, the carbon–oxygen bond of an alcohol remains intact when the alcohol reacts with a carboxylic acid to give an ester. 19.10 Alkyl chlorides and bromides undergo nucleophilic substitution when treated with sodium iodide in acetone (Section 8.1). A reasonable approach is to brominate octadecanoic acid at its -carbon atom, then replace the bromine substituent with iodine by nucleophilic substitution. 19.11 (b) The starting material is a derivative of malonic acid. It undergoes efficient thermal decar￾boxylation in the manner shown. heat CH3(CH2)6CH  C O H O C O HO 2-Heptylmalonic acid CO2 Carbon dioxide CH3(CH2)6CH C OH OH CH3(CH2)6CH2COH O Nonanoic acid Br2, PCl3 NaI acetone Octadecanoic acid CH3(CH2)15CH2CO2H 2-Bromooctadecanoic acid CH3(CH2)15CHCO2H Br 2-Iodooctadecanoic acid CH3(CH2)15CHCO2H I CH2 O O O OH O CH2 H2C CH CH2 OH CH2 HOCH2 HO2C H2C CO2H CH OH Disconnect this bond. O OH COH O O 15-Pentadecanolide 15-Hydroxypentadecanoic acid 506 CARBOXYLIC ACIDS __ __ __ Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website