Introduction to Organic Chemistry Nomenclature All organic compounds are made up of at least carbon and hydrogen. Carbon is a special element because it . The IUPAC system of nomenclature was established at various functional classes organic compounds, as well as the relationship between compounds that . vide basic rules and examples for naming monofunctional compounds. However, students of more advanced organic chemistry courses and graduate students.
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Short Summary of IUPAC Nomenclature of Organic Compounds. Introduction. The purpose of the IUPAC system of nomenclature is to establish an international . organic nomenclature are based on the definitive rules published by I.U.P.A.C.1 ( the I.U.P.A.C. Nomenclature for Organic Chemistry, Sections A, B and C. Chemical nomenclature is at least as old as the pseudoscience of alchemy, ( IUPAC) and its Commission on Nomenclature of Organic Chemistry (CNOC).
Skip to main content. Log In Sign Up. Intro to Organic Chemistry Nomenclature. Margaret Wettergreen. Introduction to Organic Chemistry Nomenclature All organic compounds are made up of at least carbon and hydrogen.
Acid Halides 18 F. Amides 18 G. Nitriles 19 H. Aldehydes 19 I. Ketones 21 J. Amines and Ammonium Salts 22 Revised and updated 5. Side chains are not included in the carbon count.
It is important that organic compounds are corrrectly and unambiguously named so that there b Name all of the side chains carbon chains attached to the longest chain and list can be absolutely no confusion about what compounds are actually being reported or them in alphabetical order. There have been many conventions for naming organic compounds - some have 3 , "tetra-" 4 etc.
Also ignore "sec-" and "tert-" but not "iso".
The following guidelines for organic nomenclature are based on the definitive rules published by I. CH 3 CH3 2.
After this, there is a numerical term of Greek origin followed by the sec-butyl tert-butyl ending "-ane". The first twelve members are given in Table 1. CH3 B. More than one double bond Branched side chains are named by renumbering the alkyl group giving the carbon with the a Find and name the longest carbon chain containing the maximum number of free valence i. One double bond C. This nomenclature is still used in some older texts, c Number the carbon chain giving the double bond the lowest possible location however, the approved nomenclature for alkene stereoisomers involves the prefixes Z- or E-.
The d Name side chains in the usual way. For example, a chlorine 5 6 substituent would have a higher priority than a CH3- which in turn would have a higher priority CH3 CH3 Emethylpentene than a H-. If they are on opposite sides then the prefix is E Cl CH3 Echloromethylpentenol from 'entgegen' meaning 'opposite'.
The group priority is then assigned based location number. Zchlorobutene The "e" is omitted before a vowel or a "y". The prefixes are as follows: The name of every organic molecule containing a functional group whose name appears as Group Prefix a suffix may be thought of as made up of four parts: F- fluoro Numbers Prefixes Stem Suffix Cl- chloro Locates the Substituents in The name of the Identifes the Br- bromo substituents in alphabetical order pricipal longest principal I- iodo the molecule chain functional group NO2- nitro The Principal Functional Group PFG whose suffix name is used is selected from Table 2 The list is in order of decreasing priority.
Examples Table 2.
CCl4 CBr4 carbon tetrabromide 11 12 A. Ethers and Thioethers a The chain must contain the maximum number of principal functional group s ; In the naming of ethers as alkyloxy derivatives of alkanes, it is general practice to shorten then the names of compounds containing four or less carbons to alkoxy derivatives i. An alternative system for naming ethers or thioethers is to name the alkyl groups on oxygen sulfur and list them in alphabetical order as separate words before the name "ether" or B.
Naming the Principal Chain sulfide. Examples Table 3. Alternatively, the alcoholates may be named as alkyloxides dropping the "yl" syllable for the first four members as in ether naming. Acids, Salts of Acids and Acid Anhydrides succinic acid butanedioic acid HO C CH2 CH2 C OH Carboxylic acids are named by identifying the longest carbon chain containing the carboxylic acid functional group and using this carbon chain as the stem for the carboxylic acid name.
O O The ending "-anoic acid" is added to the stem to indicate that the compound is a carboxylic acid.
Acid Halides anhydride. When unsymmetrical, the two acid groups are named as separate words in Acid halides are maned by replacing the "-ic acid" ending of the parent carboxylic acid with alphabetical order and the word anhydride is added. CH3 When there are substituents on the N atom, these are named using N-alkyl or N,N-dialkyl as prefixes note N or N,N are italicised immediately before the main chain name. Esters O The alkyl alkenyl etc. Ketones J. Since an aldehyde carbonyl group must always lie at the end of a carbon chain, it is always is given the 1 location position in numbering and it is not necessary to include it in the name.
There are several simple carbonyl containing compounds which have common names which are retained by IUPAC. Also, there is a common method for naming aldehydes and ketones.
For aldehydes common parent chain names, similar to those used for carboxylic acids, are used and the suffix —aldehyde is added to the end. In common names of aldehydes, carbon atoms near the carbonyl group are often designated by Greek letters.
The atom adjacent to the carbonyl function is alpha, the next removed is beta and so on.
If the aldehyde moiety -CHO is attached to a ring the suffix —carbaldehyde is added to the name of the ring. The carbon attached to this moiety will get the 1 location number in naming the ring. Summary of Aldehyde Nomenclature rules Aldehydes take their name from their parent alkane chains. The -e is removed from the end and is replaced with -al.
The aldehyde funtional group is given the 1 numbering location and this number is not included in the name.
For the common name of aldehydes start with the common parent chain name and add the suffix -aldehyde. Substituent positions are shown with Greek letters. When the -CHO functional group is attached to a ring the suffix -carbaldehyde is added, and the carbon attached to that group is C1.
Aldehyde Common Names to Memorize There are some common names that are still used and need to be memorized. Recognizing the patterns can be helpful. A ketone carbonyl function may be located anywhere within a chain or ring, and its position is usually given by a location number.
Chain numbering normally starts from the end nearest the carbonyl group. Very simple ketones, such as propanone and phenylethanone do not require a locator number, since there is only one possible site for a ketone carbonyl function.