The generally accepted nomenclature for organic substances is the IUPAC systematic nomenclature.

The name is based on the name of the main carbon chain of the molecule, which may not be the longest, but must necessarily include multiple bonds (or their maximum number) and the oldest functional group (or their maximum number) of the compound. To designate functional groups in the names, the appropriate prefixes (prefixes) or suffixes are used (see Appendix A, tables A.1 and A.2). The formulas and names of the main functional groups must be learned by heart.

In the name of an organic substance, as in any word, one can distinguish a prefix, a root, a suffix and an ending. Each part of the word carries its own semantic load (table 2.1).

Table 2.1 - Composing the name of an organic substance

Name of the organic matter
PREFIX	ROOT	SUFFIX	THE ENDING
Substituents (radicals, junior functional groups, senior functional groups not included in the main chain)	Number of main chain carbons	The degree of saturation of C-C bonds in the main chain	senior functional group
ü The order is alphabetical. ü With the help of Arabic numerals, the place of each group in the main chain is indicated. ü For identical substituents, multiplying prefixes are used di-, tri-, tetra-, penta- etc.	Met- At- Prop- Booth- Pent- Hex- Gept- Oct- Non- Dec- (dec-)	1 C 2 C 3 C 4 C 5 C 6 C 7 C 8 C 9 C 10 C	ü-an (only single bonds); ü-en (1 double bond); ü-diene (2 double bonds) ü-yne (1 triple bond), etc. ü For multiple bonds, the place in the chain is indicated.	ü Arabic numerals indicate the place of the functional group in the chain (except for the aldehyde and carboxyl groups). ü Multiplying prefixes are used for identical groups di-, tri-, tetra-, penta- etc.

· Root words corresponds to the name of the number of carbon atoms of the main carbon chain.

· Suffix indicates the degree of saturation of the main chain. Yes, suffix -en indicates the absence of multiple bonds in the main carbon chain. A double bond is indicated by the suffix -en, triple - suffix -in. Greek numerals are used to denote several of the same type of multiple bonds. di-, tri-, tetra-, penta-, etc.. For multiple bonds, their place in the main chain must be indicated, using Arabic numerals located after the suffix.

· The ending corresponds to the name of the senior functional group with an indication of its place in the main carbon chain. Greek numerals are used to denote several functional groups of the same type. di-, tri-, tetra-, etc..

· AT prefix (prefix) in alphabetical order, indicating the place in the main carbon chain, hydrocarbon radicals and functional groups not indicated at the end of the name are listed. Multiplying prefixes are used for identical radicals or functional groups di-, tri-, tetra-, etc..

Algorithm for compiling a systematic name

organic matter

1. We determine the highest functional group and the class of the compound. If a substance does not contain functional groups and consists only of carbon and hydrogen atoms, then it is a hydrocarbon. Functional groups in descending order of precedence are given in Appendix A (Table A.1).

2. By the presence or absence of multiple bonds between carbon atoms, we determine the degree of saturation of the carbon chain.

3. Choose the main carbon chain.

· The main carbon chain begins and ends with a primary carbon atom, i.e. a carbon atom that forms bonds with only one carbon neighbor.

· For saturated organic compounds, it should be the longest of all possible, and should also include the highest functional group (or their maximum number).

In saturated hydrocarbons, choose the longest carbon chain. If there are several such chains, then we choose the most branched chain containing radicals with a smaller volume.

· For unsaturated compounds, the main chain must necessarily include a multiple bond or their maximum number, as well as the highest functional group (or their maximum number).

· In unsaturated hydrocarbons, the main chain may not be the longest, but must include a multiple bond (or their maximum number).

In aromatic hydrocarbons with a branched side chain, we choose the main chain in the side branch, considering the aromatic ring as a radical.

· Carbocyclic and heterocyclic structures, as a rule, are included in the main chain.

4. We number the selected main carbon chain.

We start the numbering of carbon atoms from the end to which the highest functional group is closer (or their maximum number).

· If the functional group is equidistant from the ends of the chain, then the numbering direction is determined by the position of the multiple carbon-carbon bond.

· In saturated hydrocarbons, we begin the chain numbering from the end to which the structural radicals (or their maximum number) are closer, taking into account their seniority. The fewer carbon atoms are included in the radical and the less its branching, the older the radical.

· In unsaturated hydrocarbons, the direction of numbering is determined by a multiple bond, and the double bond is older than the triple bond.

· In arenes, the benzene ring is numbered so that the substituents get as low numbers as possible. The beginning of the numbering determines the leading radical.

In a heterocycle, the start of numbering is determined by the heteroatom.

5. We compose the name of the organic substance.

Remember:

· After suffixes indicating the presence of multiple carbon-carbon bonds in the main chain, a hyphen is placed, and then Arabic numerals showing their position and separated by commas.

· The position of the senior functional groups is indicated by Arabic numerals, which are placed after the corresponding ending and separated from it by a hyphen.

・After graduation -al or -oic acid numbers are not needed, because the numbering of the main chain starts from the carbon atoms of the corresponding functional groups.

· The number of substituents indicated in the name must match the number of digits indicating their position in the chain.

Multiplying prefixes are used for identical substituents di-, tri-, tetra-, penta-, etc.

Naming examples

1) C - C - C - C - C - C - C - C

C - C - C C - C C C

Note. In this example, only the carbon skeleton of the molecule is shown. Before compiling the name of the compound, it is necessary to add H atoms to the above formula, taking into account the fact that the C atom in organic compounds is 4-valent.

CH 2 –CH 2 –CH–CH 2 –CH 2 –CH 2 –C–CH 3

CH 3 -CH-CH 3 CH 2 -CH 3 H 3 C CH 3

1. The substance whose structural formula is given above is a hydrocarbon.

2. Between carbon atoms, all bonds are single. Therefore, it is a saturated hydrocarbon - an alkane.

3. We choose the longest and most branched chain, starting and ending with its primary C atom.

4. We number the selected chain from the end to which the methyl radicals are closer (the methyl radical is older than the ethyl radical).

CH 2 –CH 2 –CH–CH 2 –CH 2 –CH 2 –C–CH 3

10 CH 3 - 9 CH- CH 3 CH 2 -CH 3 H 3 C CH 3

Methyl ethyl methyl methyl

radicals

5. Compose the name of the hydrocarbon:

2) CH 2 \u003d C - CH 2 -CH - CH 2 -CH 3

C 2 H 5 CH 3

1. This compound belongs to hydrocarbons.

2. There is 1 double bond in the molecule. Therefore, it is an alkene.

3. We choose the main chain so that a double bond gets into it, and the chain is as long as possible.

4. The chain numbering starts from the side closest to the multiple bond.

CH 2 \u003d C - CH 2 - CH - CH 2 - CH 3

Ethyl C 2 H 5 CH 3 methyl

The basis of the name of the compound is the root of the word, denoting a saturated hydrocarbon with the same number of atoms as the main chain (for example, met-, et-. pro p-, but-, pent-, hex-, etc.). This is followed by a suffix characterizing the degree of saturation, -an, if there are no multiple bonds in the molecule, -ene in the presence of double bonds and -ni for triple bonds, for example, pentane, pentene. If there are several multiple bonds in the molecule, then the number of such bonds is indicated in the suffix, for example: -diene, -triene, and after the suffix, the position of the multiple bond is necessarily indicated in Arabic numerals (for example, butene-1, butene-2, butadiene-1,3) :

CH 3 -CH 2 -CH \u003d CH 2 CH 3 -CH \u003d CH-CH 3 CH 2 \u003d CH-CH \u003d CH 2
butene-1 butene-2 ​​butadiene-1,3

Further, the name of the oldest characteristic group in the molecule is placed in the suffix, indicating its position with a number. Other substituents are designated by prefixes. However, they are not listed in order of seniority, but alphabetically. The position of the substituent is indicated by a number before the prefix, for example: 3-methyl; 2-chloro and the like. If there are several identical substituents in the molecule, then their number is indicated in front of the name of the corresponding group (for example, dimethyl-, trichloro-, etc.). All numbers in the names of molecules are separated from words by a hyphen, and from each other by commas. Hydrocarbon radicals have their own names.

Limit hydrocarbon radicals:

methyl ethyl propyl isopropyl

Butyl sec-butyl

isobutyl tert-butyl

Unsaturated hydrocarbon radicals:

CH 2 \u003d CH- HC - C- CH 2 \u003d CH-CH 2 -

vinyl ethynyl allyl

Aromatic hydrocarbon radicals:

phenyl benzene

Let's take the following connection as an example:

The choice of the chain is unambiguous, therefore, the root of the word is pent, followed by the suffix -en, indicating the presence of a multiple bond; the numbering order gives the highest group (-OH) the lowest number; the full name of the compound ends with a suffix denoting the senior group (in this case, the suffix –o l indicates the presence of a hydroxyl group); the position of the double bond and the hydroxyl group is indicated by numbers.

Therefore, the given compound is called penten-4-ol-2.

The trivial nomenclature is a collection of non-systematic historically formed Names of organic compounds (for example: acetone, acetic acid, formaldehyde, etc.). The most important trivial names are introduced in the text when considering the corresponding classes of compounds.

Rational nomenclature allows you to build the name of a substance based on its structure with a simpler compound chosen as a prototype. The way of such construction is illustrated by the following examples:

trimethylmethane acetylacetone phenylacetic acid

Nomenclature - a set of names of individual chemicals, their groups and classes, as well as the rules for compiling their names. The name of a substance should reflect not only its qualitative and quantitative composition, but also clearly show its chemical structure, the name should correspond to a single structure formula. The scientific development of the nomenclature of organic compounds began in the middle of the 19th century, its further development led to the modern nomenclature developed by the international commission according to the nomenclature of organic compounds of the International Union of Pure and Applied Chemistry (IUPAC). The structure of the molecules of organic compounds is expressed using complex name words, including the following fragments:
a) the designation of carbon chains C n: C - "met", C 2 - "et", C 3 - "prop", C 4 - "but", C 5 and subsequent - the roots of Greek numerals - "pent", "hex ”, “hept”, “oct”, “non”, etc.
b) designations of side chains - hydrocarbon radicals - consist of the above names of carbon chains and the ending "yl" (methyl, ethyl, propyl, etc.).
c) designation of the nature of the bond between atoms - “an” - single, “en” - double, “in” - triple bond
d) the designation of characteristic groups, and the name of the same group differs depending on the method of constructing the name and on the seniority of the group - the older one is mentioned in the suffix, the younger one in the prefix.
e) multiplying prefixes - "di", "three", "tetra" and their modified forms - "bis", "tris", etc., showing the number of identical structural elements
f) locants - numbers or letters showing the order of articulation of the constituent parts of the molecule
g) separating characters - hyphens, commas, dots, brackets.
When compiling a name according to the IUPAC nomenclature (as well as when constructing a structural formula according to the name), the following rules are consistently followed:
1) Find the senior characteristic group and choose a designation for it in the suffix (table 1).
2) Identify and name the main chain or main ring structure to which the main characteristic group adjoins. At the same time, they are guided by the following precedence of structural fragments: characteristic groups in order of decreasing precedence (those for which mention is provided in the suffix), double bond, triple bond, other prefix substituents in alphabetical order.
3) Determine the multiplicity of bonds, using the suffixes "an", "en" and "in" to indicate it, and in the carbo- or heterocyclic series - the prefixes "dihydro", "tetrahydro", etc.
4) Determine the nature of the substituents (side chains and junior substituents) and arrange their designations in alphabetical order in the prefix part of the name.
5) Determine the multiplying prefixes, taking into account that they do not affect the alphabetical order of the prefixes.
6) Carry out the numbering of the main chain or the main cyclic structure, while the main characteristic group should have the smallest number. Lokants are placed before the name of the main structure (2-butanol, 3-hexanol), before prefixes (3-chlorobutanol-1), before or after the suffix to which they refer (3-hexen-2-one, 3-hexanone-2) .
7) Compose the name from the above components, using the necessary delimiters.

Table 1.

CLASSES OF ORGANIC COMPOUNDS AND NAMES
CHARACTERISTIC GROUPS
(in descending order of precedence)

CLASS	FUNCTIONAL GROUP	TITLE
		in prefix	in suffix
Cations	-X+	they are about	ony
carboxylic acids	-COOH -(С)UN *	carboxy -	carboxylic acid oic acid
Sulfonic acids	-SO 3 H	sulfo	sulfonic acid
Amides	-CONH 2 -(C)ONH 2	carbamoyl -	carboxamide amide
Nitriles	-CN -(C)N	cyano -	carbonitrile nitrile
Aldehydes	-CHO -(C) BUT	formyl oxo	carbaldehyde al
Ketones	C=O	oxo	is he
Alcohols, phenols	-IS HE	hydroxy	ol
Thiols	-SH	mercapto	thiol
Amines	-NH2	amino	amine
double bond	=	-	en
triple bond		-	in
Ethers **	-OR	alkoxy, aroxy	-
Halogen derivatives	-F -Cl -Br -I	fluorine chlorine bromine iodine	- - - -
Nitroso compounds	-NO	nitroso	-
Nitro compounds	-NO 2	nitro	-
Diazo compounds	-N 2	diazo	-
Azides	-N 3	azido	-

* The carbon atom in brackets is included in the name of the parent compound
** Characteristic groups of ethers and subsequent classes are listed in prefixes alphabetically, not by seniority

Example 1

We determine the longest chain of carbon atoms (it will be the main one) and number the carbon atoms. This compound has a characteristic amino group and a side chain containing one carbon atom. The prefix part of the name, given that the amino group is older than the side chain: 2-methyl-3-amino- ... The main chain contains 5 carbon atoms, so the main part of the name "pent" (five): 2-methyl-3-aminopent ... The presence of a double bond indicated by the suffix "en": 2-methyl-3-aminopentene-... The double bond begins at the carbon atom of the main chain with serial number 1, so finally: 2-methyl-3-aminopentene-1.

Names of carbon chains

chain

The designation of the degree of saturation of connections

С-С С=С С≡С (here is a triple bond between atoms)

Names of characteristic groups of organic compounds

Compound Class Characteristic Prefix Suffix Group Carboxylic acids -COOH carboxycarboxylic acid Carboxylic acids -(C)OOH - oic acid Sulfonic acids -SO3H sulfosulfonic acid Aldehydes -CHO formyl carbaldehyde Aldehydes -(C)HO oxo al Ketones >(C)=O oxo one Alcohols -OH hydroxyol Phenols -OH hydroxyol Thiols -SH mercapto thiol Amines -NH2 amino amine Ethers -OR alkoxy, aroxy - Halogen derivatives -F, -Cl, -Br, -I fluorine, chlorine, bromine, iodine - Nitro compounds -NO2 nitro -

The carbon atom enclosed in brackets is part of the name of the main carbon chain.
The arrow shows the increase in the seniority of the characteristic groups.

Names of aromatic compounds

CH 3 -OH -COOH

C 6 H 6 C 6 H 5 CH 3 C 6 H 5 OH C 6 H 5 COOH

benzene toluene phenol benzoic acid

Names of some hydrocarbon radicals

(CH 3) 2 CH- CH 3 CH 2 (CH 3) CH- (CH 3) 2 CHCH 2 - (CH 3) 3 C-

isopropyl second-butyl isobutyl tert-butyl

CH 2 \u003d CH- CH 2 \u003d CH-CH 2 - HC≡C- (with a triple bond)

vinyl allyl ethynyl

phenyl benzyl

Numeric Prefixes

(indicate the number of identical structural elements)

1 mono monokis

3 three tris

4 tetratekis

5 penta pentakis

6 hexa hexakis

At naming substances according to its structural formula(and vice versa) you must perform the following steps in sequence:

1. Find the main one (by seniority) characteristic group and choose a designation for it in the suffix.

2. Find main carbon chain (cycle) including the main characteristic group, and number it from the end of the chain, closer to which the older group is located. If there are several such possibilities, then you need to consider the presence of:

a) other characteristic groups (by seniority);
b) double bond;
c) triple bond;
d) other substituents (in alphabetical order).

3. To the name of the main chain add suffix denoting the degree of saturation of connections. If there are several multiple bonds in the molecule, their number must be indicated in the suffix, and after the suffix - their position in the carbon chain in Arabic numerals. Further, the name of the senior characteristic group is included in the suffix, indicating its position in Arabic numerals.

4. Using prefixes (prefixes) designate deputies(side chains, minor characteristic groups) and arrange them alphabetically. The position of the substitute must be indicated by a number before the prefix.

5. Arrange digital set-top boxes, indicating the number of repeating structural elements (they are not taken into account when prefixing alphabetically).

6. Arrange punctuation marks: separate all numbers from words with a hyphen, and from each other with commas.