DAMIETTA UNIVERSITY CHEM-103: BASIC ORGANIC CHEMISTRY LECTURE 2 Dr Ali El-Agamey
Common Alkyl Groups 2
Write the IUPAC names of the following compounds 3-Ethyl-5-methylheptane 3-Ethyl-4-methylhexane When the number could begin from both ends of the chain, begin with the one that is alphabetically first. 3
Write the IUPAC names of the following compounds 2,2-Dimethylpropane 2,2,4-Trimethylpentane 3-Ethyl-4-methylheptane 5-Ethyl-2,4-dimethylheptane 3,7-Diethyl-2,2-dimethyl-4- propylnonane 4
Write the IUPAC names of the following compounds 3-Ethyl-5-methylheptane 4-Ethyl-2,3-dimethyloctane 6-Ethyl-3,3-dimethyloctane 5
Homework: Write the IUPAC names of the following compounds 6
Homework: Provide the IUPAC names for the following compounds 7
Write the structures for the following compounds (i) 3-Ethyl-4-methylhexane (ii) 3-Ethyl-5-isobutyl-3-methylnonane (iii) 4-tert-Butyl-2-methylheptane (iv) 5-Isopropyl-3,3,4-trimethyloctane (v) 4-Isopropyl-2,2,3,6-tetramethyloctane 8
Homework: Write the structures for the following compounds (i) 2,2-dimethylbutane (ii) 2,2-dimethylpropane (iii) 6-ethyl-3,3-dimethyloctane (iv) 5-Isopropyl-3,3,4-trimethyloctane (v) 3-methyl-5-propylnonane (vi) 5-(1,2,2-Trimethylpropyl)nonane (vii) 2,2,4-Trimethylpentane (viii) 5-tert-Butyldecane 9
Write the correct IUPAC name of the following compounds (i) 4-Ethylpentane (ii) 2-Ethylpentane (iii) 3-Isopropylpentane (iv) 2-Methyl-3-ethylpentane 10
Homework: Write the correct IUPAC name of the following compounds (i) 2-Ethyl-3-methylpentane (ii) 3,4-Dimethylpentane (iii) 2-Isopropylhexane (iv) 3-methyl-5-ethylheptane (v) Isobutane 11
Nomenclature of cycloalkanes 1-Ethyl-2-methylcyclobutane If there are two or more substituents, the ring carbons are numbered to give the lowest possible numbers. When the acyclic portion of the molecule contains more carbon atoms than the cyclic portion (or when it contains an important functional group) the cyclic portion is named as a cycloalkyl sunstituent. 12
Homework: Write the IUPAC name of the following compounds (a and b) and the structures of i and ii (i) 1-Ethyl-3-methylcycloheptane (ii) Isobutylcyclohexane 13
Nomenclature of alkenes IUPAC nomenclature (1) Parent name is alkene i.e. change the -ane to -ene. Choose the longest continuous chain containing the double bond as the basis for the parent name. The position of the double bond takes the lowest possible number. A compound with 2 double bonds is a diene. A triene has 3 double bonds, and a tetraene has 4.
IUPAC and New IUPAC Chapter 7 15
Ring Nomenclature In a ring, the double bond is assumed to be between Carbon 1 and Carbon 2. 3 2 1 1 2 1-methylcyclopentene 3-methylcyclopentene Chapter 7 16
Nomenclature of alkenes Write the IUPAC name of the following compounds but-1-ene 4-ethylhept-1-ene 4-ethyl-3-methylcyclohexene
cis-trans Nomenclature cis-but-2-ene trans-but-2-ene cis-1,2-dichloroethene (m.p. = -80 o C) trans-1,2-dichloroethene (m.p. = -50 o C) If two similar groups bonded to the carbons of the double bond are on the same side of the bond, the alkene is the cis isomer. If two similar groups are on opposite sides of the double bond, the alkene is the trans isomer.
E-Z Nomenclature 2-methylbut-2-ene propene (E)-1-bromo-1-chloropropene If it is not obvious which substituents are referred to as being cis or trans, we use the E-Z system, which uses the Cahn- Ingold-Prelog rules to assign the priorities of the groups. Priority depends on atomic number (greater atomic No. leads to higher priority) Assign the 1 st and 2 nd priorities of the groups at each end of the double bonds. If two 1 st priority groups are together on the same side of the double bond, you have the Z isomer. If two 1st priority groups are on opposite sides of the double bond, you have the E isomer.
Nomenclature of alkenes Write the IUPAC name of the following compounds (E)-pent-2-ene (Z)-pent-2-ene (E)-5-vinylnona-1,7-diene (3Z,5E)-3-bromoocta-3,5-diene
Nomenclature of alkynes IUPAC nomenclature (1) Parent name is alkyne i.e. change the -ane to -yne. Choose the longest continuous chain containing the triple bond as the basis for the parent name. The position of the triple bond takes the lowest possible number. If both double and triple bonds are present, the ending becomes enyne and numbering is such as to give the lowest possible numbers to the double and triple bonds, irrespective of whether ene or yne has the lower number. When either group can assigned the same number, -ene has the higher priority.
Write the IUPAC name of the following compounds ethyne but-2-yne 6-bromo-2-methylhept-3-yne propyne 4-methoxyhex-2-yne 2-methylpent-1-en-3-yne
Multifunctional Compounds The functional group with the highest priority determines the parent name. Naming Priority: acid > ester > amide > nitrile > aldehyde > ketone > alcohol > amine > alkene > alkyne Chapter 21 23
Nomenclature of aldehydes and ketones IUPAC nomenclature Functional group Name as substituent Nitriles Cyano Aldehydes Formyl Ketones Oxo Alcohols Hydroxy Amines Amino Ethers Alkoxy Halides Halo
Chapter 21 25
Nomenclature of alcohols IUPAC nomenclature (1) Parent name is alkanol Choose the longest continuous chain containing the hydroxy group. Numbering begins at one end so as to give the hydroxy group the lowest possible number. Alcohols with two OH groups are called diols and Alcohols with three OH groups are called triols.
Examples of Nomenclature C H 3 C H 3 C H C H 2 O H C H 3 C H C H 2 C H 3 3 2 1 1 2 3 4 2-Methyl-1-propanol 2-Methylpropan-1-ol O H 2-Butanol Butan-2-ol 1C H 3 2 C H 3 C O H 3C H 3 2-Methyl-2-propanol 2-Methylpropan-2-ol O H C H 2 C H C H 2 C H C H 3 5 4 3 2 1 4-penten-2-ol pent-4-en-2-ol Chapter 10 27
Write the IUPAC name of the following compounds pentan-1-ol 1-bromo-3,3-dimethylbutan-2-ol (E)-pent-2-en-1-ol cyclohex-2-enol 1-cyclohexylbutane-1,3-diol
Homework: Write the IUPAC name of the following compounds
Nomenclature of aldehydes and ketones IUPAC nomenclature (1) Ketones: Parent name is alkanone Choose the longest continuous chain containing the carbonyl group. In cyclic ketones the carbonyl carbon atom is assigned the number 1. (2) Aldehydes: Parent name is alkanal An aldehyde carbon is at the end of a chain, so it is number 1. For cycloalkanes with aldehyde substituent, the suffix - carbaldehyde is used.
Examples O O 1 3 4 1 3 4 C H 3 C C H C H 3 C H 3 C C H C H 2 O H 2 2 C H C H 3 3 3-methyl-2-butanone 4-hydroxy-3-methyl-2-butanone 1 O C H 3 5 2 C H 3 C H 2 C H C H 2 3 3-methylpentanal O C H 1 3 B r 3-bromocyclohexanone O C H 3 O C H 3 C C H C H 2 C H 4 3 1 3-methyl-4-oxopentanal 31
Write the IUPAC name of the following compounds 1-phenylpropan-1-one 4-bromo-3-methylheptanal (E)-pent-2-enal cyclohexanecarbaldehyde
Homework: Write the IUPAC name of the following compounds
Nomenclature of carboxylic acids IUPAC nomenclature Acids are named in IUPAC nomenclature as alkanoic acid. Cycloalkanes with -COOH substituents are generally named as cycloalkanecarboxylic acids. Methanoic acid Ethanoic acid 4-aminobutanoic acid 2-isopropyl-4-oxopentanoic acid
Nomenclature of carboxylic acids IUPAC nomenclature Aliphatic dicarboxylic acids are named in IUPAC nomenclature by adding the suffix dioic acid. Choose the longest continuous chain that contains both carboxyl groups. Numbering begins with the carboxyl group that is closer to the substituents. 3-bromohexanedioic acid cyclopentane-1,3-dicarboxylic acid
Homework: Write the IUPAC name of the following compounds
Nomenclature of Esters isopropyl methanoate Esters are named as alkyl carboxylates. The first word is derived from the alkyl group of the alcohol, and the second word is derived from the carboxylic acid by changing -ic acid to ate. Chapter 21 37
Nomenclature of Esters IUPAC nomenclature Ethyl butanoate Methyl 3-bromo-2-methylbutanoate
Nomenclature of Amides IUPAC: N-Ethylethanamide Common: N-Ethylacetamide For 1 amide, first name the corresponding acid. Drop -ic acid or -oic acid from the carboxylic acid name and add -amide. For 2 and 3 amides, treat the alkyl groups on nitrogen as substituents, and specify their position by the prefix N-. Chapter 21 IUPAC: N,N-Dimethylmethanamide Common: N,N-Dimethylformamide 39
Nomenclature of Amides IUPAC: N-Ethyl-N,2-dimethylpropanamide Common: N-Ethyl-N-methylisobutyramide IUPAC: Cyclopentanecarboxamide For cycloalkanes with amide substituent, the suffix -carboxamide is used. Chapter 21 40
Homework: Write the IUPAC name for each of the following compound