PowerPoint PresentationSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47Slide 48Slide 49Slide 50Slide 51Slide 52Slide 53Slide 54Slide 55Slide 56Slide 57Slide 58Slide 59Slide 60Slide 61Slide 62Slide 63Slide 64Slide 65Slide 66Slide 67Slide 68Slide 69Slide 70Slide 71Slide 72Slide 73Slide 74Slide 75Slide 76Slide 77Slide 78Slide 79Slide 80Slide 81Slide 82Slide 83Slide 841Carboxylic Acids and Their Derivatives—Nucleophilic Acyl SubstitutionCarboxylic Acid Derivatives:23Types of anhydrides:Types of amides:4Cyclic esters and amides:Nitriles:5Structure and Bonding The two most important features of the carbonyl group are:6•Three resonance structures stabilize carboxylic acid derivatives (RCOZ) by delocalizing electron density.•The more resonance structures 2 and 3 contribute to the resonance hybrid, the more stable RCOZ is.78•Because the basicity of Z determines the relative stability of the carboxylic acid derivatives, the following stability order results:•In summary, as the basicity of Z increases, the stability of RCOZ increases because of added resonance stabilization.9•The structure and bonding of nitriles is very different from that of other carboxylic acid derivatives, and resembles the C—C triple bond of alkynes.•The carbon atom on the CN group is sp hybridized, making it linear with a bond angle of 180°.•The triple bond consists of one  and two  bonds.10Nomenclature•For acyclic acid chlorides: change the suffix –ic acid of the parent carboxylic acid to the suffix –yl chloride; or•When the –COCl group is bonded to a ring: change the suffix –carboxylic acid to –carbonyl chloride.11•Symmetrical anhydrides are named by changing the acid ending of the carboxylic acid to the word anhydride.•Mixed anhydrides, which are derived from two different carboxylic acids, are named by alphabetizing the names for both acids and replacing the word acid with the word anhydride.1213•Name the R’ as an alkyl group. This becomes the first part of the name.•Name the acyl group by changing the ic acid ending of the parent carboxylic acid to the suffix –ate.•Esters are often written as ROOR’, where the alkyl group (R’) is written last. When the ester is named however, the R’ group appears first in the name.14•All 1° amides are named by replacing the -ic acid, -oic acid, or -ylic acid ending with the suffix amide.15•Name the alkyl group (or groups) bonded to the N atom of the amide. Use the prefix “N-” preceding the name of each alkyl group to show that it is bonded to a nitrogen atom. This becomes the first part of the name.•For 3° amides, use the prefix di- if the two alkyl groups on N are the same. If the two alkyl groups are different, alphabetize their names. One “N-” is needed for each alkyl group, even if both R groups are identical.•Name the acyl group by replacing the –ic acid, -oic acid, or –ylic acid ending by the suffix amide.16•In contrast to the carboxylic acid derivatives, nitriles are named as alkane derivatives.•Find the longest chain that contains the CN and add the word nitrile to the name of parent alkane. Number the chain to put CN at C1, but omit this number from the name.•Common names of nitriles are derived from the names of the carboxylic acid having the same number of carbon atoms by replacing the –ic acid ending of the carboxylic acid with the suffix –onitrile.•When the CN is named as a substituent it is called a cyano group.17•In naming a nitrile, the CN carbon is one carbon atom of the longest chain. CH3CH2CN is propanenitrile, not ethanenitrile.1819Spectroscopic Properties—IR •Like all carbonyl compounds, carboxylic acid derivatives have a strong C=O absorption between 1600 and 1850 cm-1.•Primary (1°) and 2° amides have two additional absorptions due to N—H bonds:1. one or two N—H stretching peaks at 3200-3400 cm-1.2. an N—H bending absorption at ~1640 cm-1.•As the carbonyl  bond becomes more delocalized, the C=O absorption shifts to lower frequency.•Conjugation shifts a carbonyl absorption to lower frequencies.•For cyclic carboxylic acid derivatives, decreasing ring size shifts a carbonyl absorption to higher frequencies.2021Spectroscopic Properties—NMR •Protons on the  carbon to the carbonyl absorb at 2-2.5 ppm.•The N—H protons of 1° and 2° amides absorb at 7.5-8.5 ppm.•In their 13C NMR spectra, carboxylic acid derivatives give a highly deshielded peak at 160-180 ppm due to the carbonyl carbon. This is somewhat upfield from the carbonyl absorption of aldehydes and ketones, which occurs at 190-215 ppm.•Nitriles give a peak at 115-120 ppm in their 13C NMR spectrum due to the sp hybridized carbon. This is further downfield than the signal due to the sp hybridized carbon of an alkyne which occurs at 65-100 ppm.22Introduction to Nucleophilic Acyl Substitution•Nucleophilic acyl substitutions is the characteristic reaction of carboxylic acid derivatives.•This reaction occurs with both negatively charged nucleophiles and neutral nucleophiles.23•Other nucleophiles that participate in this reaction include:24To draw any nucleophilic acyl product:[1] Find the sp2 hybridized carbon with the leaving group.[2] Identify the nucleophile.[3] Substitute the nucleophile for the leaving group. With a neutral nucleophile, the proton must be lost to obtain a neutral substitution product.25Based on this order of reactivity, more reactive compounds can be converted into less reactive ones. The reverse is not usually true.26Reactions of Acid Chlorides•Acid chlorides react readily with nucleophiles to formnucleophilic substitution products.•HCl is usually formed as a by-product.•A weak base like pyridine is added to the reaction mixture to remove the strong acid (HCl), forming an ammonium salt.27Acid chlorides react with oxygen nucleophiles to form anhydrides, carboxylic acids and