Chem 102 1st Edition Lecture 18 Outline of Last Lecture I. Chapter 16: Lessons 5.12-5.17 : Pheromones and Medications, Isomerism for Carboxylic Acids and Esters, Physical Properties of Esters, Chemical Reactions of Esters, Sulfur Analogs of Esters, Acid Chlorides and Acid AnhydridesOutline of Current Lecture II. 6.1- Bonding Characteristics of Nitrogen Atoms in Organic CompoundsIII. 6.2- Structure and Classification of AminesIV. 6.3- Nomenclature for AminesV. 6.4 - Isomerism for AminesCurrent Lecture6.1 Bonding Characteristics of Nitrogen Atoms in Organic Compounds• Nitrogen is a member of Group VA of the periodic table • Nitrogen has five valence electrons • Nitrogen can form three covalent bonds to complete its octet of electrons 6.2 Structure and Classification of Amines• Amine: Organic derivative of ammonia (NH3) in which one or more alkyl, cycloalkyl, or aryl (R) groups have replaced ammonia hydrogen atoms • Classification: – Primary amines (1o): Nitrogen with one R group – Secondary amines (2o): Nitrogen with two R groups – Tertiary amines (3o): Nitrogen with three R groups Cyclic Amines • Cyclic amines are either secondary or tertiary amines • Cyclic amines are designated as heterocyclic compounds • Numerous heterocyclic amines are found in biochemical systems 6.3 Nomenclature for AminesIUPAC Rules for Naming Primary AminesRule 1: Select as the parent carbon chain the longest chain to which the nitrogen atom is attached. Rule 2: Name the parent chain by changing the -e ending of the corresponding alkane name to -amine. Rule 3: Number the parent chain from the end nearest the nitrogen atom. Rule 4: The position of attachment of the nitrogen atom is indicated by a number in front of the parent chain name. Rule 5: The identity and location of any substituents are appended to the front of the parent chain name. • Secondary and tertiary amines are named as N - substituted primary amines. – The largest carbon group bonded to the nitrogen is used as the parent amine name. – The names of the other groups attached to the nitrogen are appended to the front of the base name. – N- or N,N- prefixes are used to indicate that these groups are attached to the nitrogen atom Common Nomenclature of Amines • In the common system of nomenclature, amines are named by listing alkyl group or groups attached tothe nitrogen atom in alphabetical order followed by suffix –amine • All the alkyl groups and the suffix –amine appear as one word with no space. • Prefixes such as di- and -tri are added when identical groups are bonded to the nitrogen atoms • In amines where additional functional groups are present, the amine group is treated as a substituent, E.g., an —NH2 group is called an amino group. • The simplest aromatic amine, a benzene ring bearing an amino group, is called aniline and the other simple aromatic amines are named as derivatives of aniline. • In secondary and tertiary aromatic amines, the additional group or groups attached to the nitrogen atom are located using a capital N-. 6.4 Isomerism for Amines• Constitutional isomerism in amines can arise from several causes. Different carbon atom arrangementsproduce isomers • Different positioning of the nitrogen atom on a carbon chain is another cause for isomerism • In secondary and tertiary amines, different partitioning of carbon atoms among the carbon chains present produces constitutional isomers. – There are three C4 secondary amines– Carbon atom partitioning can be two ethyl groups, a propyl group and a methyl group, or an isopropyl group and a methyl