Organic Compound Nomenclature PDF

Activity 3 Nomenclature of Organic Compounds: FUNCTIONAL GROUPS 1 Introduction Functional groups: Site of chemical reactivity or function Includes double and triple bond Learning Objectives: To name organic compounds with functional group systems, and To write the...

Activity 3 Nomenclature of Organic Compounds: FUNCTIONAL GROUPS 1 Introduction Functional groups: Site of chemical reactivity or function Includes double and triple bond Learning Objectives: To name organic compounds with functional group systems, and To write their structures. 2 Naming Rules are the same with the hydrocarbons except: 1.a The parent chain is the longest continuous chain that bears the functional group of highest priority. The parent chain is named using the generic root and the appropriate suffix for the functional group. Refer to Table 2.1 2 Naming 1.b For esters The substituent attached to oxygen(underlined) is named first followed by the parent chain. O O e.g.1 CH3COCH2CH3 CH3CH2COCH3 O e.g. 2 CH3 CH2 CH2 CH2 O CH3 2 Naming 1.c For ethers The smaller alkyl group containing the ether oxygen is named first: (suffix for this group is – oxy). This is then treated as a substituent on the parent chain. e.g. CH3 CH2 O CH3 e.g. CH3 CH2 O CH2 CH2 CH2 CH3 2 Naming 2. The parent chain is numbered such that: a. The functional group gets the lowest number possible. In the case of the aldehydes and carboxylic acids, where the functional groups are always located at the terminal position, numbering starts with the carbons of those functional groups b. The branching groups are on the lower-numbered carbon rather than the higher-numbered carbon atoms 3. When the substituent groups such as –OH and −𝑁𝐻! are present, these are named as hydroxy and amino, respectively. 2 Naming 4. When the carbon chain bears both a halogen and an alkyl substituent, the two substituents are considered of equal rank, and the chain is numbered so as to give the lower number to the substituent nearer the end of the chain. CH3CHCH2CH2CHCH2CH3 CH3CHCH2CH2CHCH2CH3 CH3 Cl Cl CH3 3 Examples O CH3 CH3 CH3 CH3 O A. D. NH2 CH2 CH2 CH2 C O HC CH3 CH CH CH CH2 C H CH3 O OH O B. E. CH3 CH2 C OH CH3 CH2 CH2 CH2 CH CH2 C OH O C. Cl CH2 CH2 C CH3 F. Br CH2 CH2 CH2 O CH3 3 Examples O CH3 F OH G. J. H2C CH3 CH2 CH CH2 CH CH CH CH3 CHCH2CH2CH2CH CH3 CH2 O O HCCHCH H CH3 H. K. C C HOCH2CH2CH2 CH3 CH3 O CH3 CH CH2 CH2 CH3 I. L. CH3CCH2CH2CH NH2 CH3 3 Examples HO C O OH M. CH3 CH CH2 CH CH3 P. NH2 OH NH2 Cl O CH C N. CH3 CH CH CH3 Q. OH NH2 Ocy O O. R. H 4 Structure Writing 1. Identify the parent chain from the name. 2. Setup the carbon chain. Assign the numbers consistent with the rules. 3. The name preceding the parent name describes the substituent and its position in the parent chain. Attach the substituents to the chain as indicated by the numbers. 4. Supply the necessary number of H atoms to each carbon consistent with the covalency of the atom. Each carbon atom must have four bonds. 5 Example 2,3,4,5-tetramethylhexanoic acid 1. Identify the parent chain from the name. 2. Setup the carbon chain. Assign the numbers consistent with the rules. 3. The name preceding the parent name describes the substituent and its position in the parent chain. Attach the substituents to the chain as indicated by the numbers. 4. Supply the necessary number of H atoms to each carbon consistent with the covalency of the atom. Each carbon atom must have four bonds. 5 Example 3,3-dichloro-2-butanone 1. Identify the parent chain from the name. 2. Setup the carbon chain. Assign the numbers consistent with the rules. 3. The name preceding the parent name describes the substituent and its position in the parent chain. Attach the substituents to the chain as indicated by the numbers. 4. Supply the necessary number of H atoms to each carbon consistent with the covalency of the atom. Each carbon atom must have four bonds. 5 Example 4-bromo-3-methylpentanal 1. Identify the parent chain from the name. 2. Setup the carbon chain. Assign the numbers consistent with the rules. 3. The name preceding the parent name describes the substituent and its position in the parent chain. Attach the substituents to the chain as indicated by the numbers. 4. Supply the necessary number of H atoms to each carbon consistent with the covalency of the atom. Each carbon atom must have four bonds. PRACTICE PROBLEMS. For items 1-5, write the complete IUPAC name. For items 6 and 7, draw the condensed structural formula. For items 8-10, draw the line angle structural formulas of the compounds. 1. 4. 6. 4-methylhexanoic acid 7. 5-chloro-4-methyl-3-heptanone 2. 5. 8. 2-methyl-2-propanol 9. 2-ethylpentanal 3. 10. isopropylamine  Activity 4 Nomenclature of Aromatic Compounds 1 Introduction Arenes are hydrocarbons based on the benzene ring as a structural unit. Arenes are also referred to as aromatic compound. Used in this sense, the word “aromatic” has nothing to do with odor. Benzene Toluene Naphthalene 1 Introduction Based on structure: H C H 3CH 2CH 2CH 2CH 2CH 3 Hexane H H C H 2 C H 2 C H 2 H H C H 2 C H 2 H C H 2 Benzene Cyclohexane 1 Introduction Comparing benzene with acyclohexene based on reaction: H + HCl + HCl No reaction C l C l + Cl2 + Cl2 No reaction C l H + H2O + H2O No reaction O H H + H2 + H2 No reaction H 2 Structure of Benzene Benzene is not an alkene 3 Monosubstituted Benzene Increasing order of priority 4 Disubstituted Benzene The prefix ortho signifies a 1,2-disubstituted benzene ring, meta signifies 1,3- disubstitution, and para signifies 1,4-disubstitution. The prefix o, m, and p can be used when a substance is named as a benzene derivative or when a specific base name(such as acetophenone) is used. 4 Disubstituted Benzene Parent: C l benzene Substituent: C l 1,2-dichloro IUPAC: 1,2-dichlorobenzene o-dichlorobenzene 4 Disubstituted Benzene Parent: NO2 toluene Substituent: 3-nitro IUPAC: CH3 3-nitrotoluene m-nitrotoluene 4 Disubstituted Benzene O Parent: C H 3 C acetophenone Substituent: 4-fluoro IUPAC: 4-fluoroacetophenone F p-fluoroacetophenone 4 Disubstituted Benzene Parent: C O OH Benzoic acid Substituent: 3-amino IUPAC: 3-aminobenzoic acid N H 2 m-aminobenzoic acid 4 Disubstituted Benzene Parent: Benzaldehyde Substituent: 2-methoxy O CH3 IUPAC: 2-methoxybenzaldehyde C HO o-methoxybenzaldehyde 4 Disubstituted Benzene Parent: HO Phenol Substituent: 3-methyl IUPAC: 3-methylphenol CH 3 m-methylphenol 5 Polysubstituted Benzene Polysubstituted benzene rings should be numbered starting from the carbon bearing the functional group of highest priority. The prefixes ortho-, meta-, and para- are no longer applicable for polysubstituted benzene rings. C H 3 Parent: Benzoic acid O H Substituent: 3-hydroxy,4-methyl IUPAC: 3-hydroxy-4-methylbenzoic acid C O O H 6 Benzene ring as Substituent In some cases, the benzene ring needs to be treated as a substituent. The term phenyl is used to designate the presence of 𝐶6 𝐻5 − as a substituent. One should be careful not to be mistaken with benzyl substituent (𝐶6 𝐻5 𝐶𝐻2 −). O H O H C H2 Cl phenylethene 2-phenylethanol benzyl chloride benzyl alcohol Examples N O 2 Parent: benzene Substituent: 1-chloro,4-nitro IUPAC: 1-chloro-4-nitrobenzene p-chloronitrobenzene C l Examples Parent: toluene CH3 Substituent: 2-bromo Br IUPAC: 2-bromotoluene o-bromotoluene Examples Parent: propane Substituent: C6H5CH2CH2CH2Cl 1-chloro,3-phenyl IUPAC: 1-chloro-3-phenylpropane Examples Parent: Br butane Substituent: C6H5CCH2CH3 2-bromo,2-phenyl IUPAC: CH3 2-bromo-2-phenylbutane Examples Parent: N H 2 aniline N O 2 Substituent: 2-nitro IUPAC: 2-nitroaniline o-nitroaniline Examples Parent: OH phenol C6H5 Substituent: 2-phenyl IUPAC: 2-phenylphenol o-phenylphenol Examples Parent: ethene C 6H 5 H Substituent: 1,2-diphenyl IUPAC: 1,2-diphenylethene H C 6H 5 Examples C H 3 Parent: toluene C l Substituent: 2,4-dichloro IUPAC: 2,4-dichlorotoluene C l p-methylphenol