ORGANIC CHEMISTRY 1 Lecture 1 Different manners of writing and drawing structural formulas of organic molecules Systematic (IUPAC) and common names of hydrocarbons Systematic (IUPAC) and common names of compounds with single functional group.

Language of organic chemists

Types of organic compounds HYDROCARBON FRAMEWORK HYDROCARBON FRAMEWORK FUNCTIONAL GROUP

Drawing and naming of organic structures

Rules for drawing skeletal structures Carbon atoms are not shown. They assumed to be at each intersection of two lines (bonds) and at the end of each line. Occasionally, a carbon atom might be indicated for emphasis or clarity. Hydrogen atoms bonded to carbon are not shown. Since carbon has always valence of 4, we mentally supply the correct number of hydrogen atoms to fill the valence of each carbon. All atoms other than carbon and hydrogen (heteroatoms) are indicated.

ALKANES (saturated hydrocarbons, aliphatic hydrocarbons) Do not contain functional groups

Functional groups. With carbon-carbon multiple bonds (aromatic ring) Alkene Alkyne Arene (aromatic ring)

Types of functional groups. With carbon singly bonded to an electronegative atom Alkyl halide Alcohol Ether Amine Thiol (thioalcohol) Sulfide (thioether)

Functional groups. With carbon-oxygen double bond (carbonyl groups) Aldehyde Ketone Carboxylic acid Ester Amide Acid chloride

Naming alkanes according to IUPAC rules Prefix—Parent—Suffix What are substituents? How many carbons? What family?

Parent names of chain alkanes from C1 to C20 C1 methane C2 ethane C3 propane C4 butane C5 pentane C6 hexane C7 heptane C8 octane C9 nonane C10 decane C11 undecane C12 dodecane C13 tridecane C14 tetradecane C15 pentadecane C16 hexadecane C17 heptadecane C18 octadecane C19 nonadecane C20 eicosane

Naming alkanes according to IUPAC rules Step 1. Find the parent hydrocarbon – that means find the longest continuous carbon chain in the molecule: If 2 different chains are equal, choose the one with the larger number of branch points:

Naming alkanes according to IUPAC rules Step 2. Number the atoms in the main chain beginning at the end nearer the first branch point: If there is branching an equal distance away from both ends, begin numbering at the end nearer the second branch point:

Naming alkanes according to IUPAC rules Step 3. Identify and number the substituents: on C3, CH2CH3 (3-ethyl) on C2, CH3 (2-methyl) on C4, CH3 (4-methyl) on C4, CH3 (4-methyl) on C7, CH3 (7-methyl) on C4, CH2CH3 (4-ethyl) 3-ethyl-4,7-dimethylnonane 4-ethyl-2,4-dimethylhexane Step 4. Write the name as a single word using hyphen to separate different prefixes, and commas to separate numbers. Prefixes should appear in alphabetical order.

Naming alkanes according to IUPAC rules Step 5. When a substituent of the main chain has its own sub-branching. The name of complex substituent is formed applying the steps 1-4 just as if the substituent was a compound itself. Numbering in complex substituent starts always at the point of attachment to the main chain.

Common names of straight-chain and branched-chain alkyl substituents derived from C3 – C4 alkanes propane propyl isopropyl 1 March 2018 butane butyl sec-butyl

Common names of straight-chain and branched-chain alkyl substituents derived from C4 – C5 alkanes isobutane isobutyl tert-butyl pentane pentyl

Common names of straight-chain and branched-chain alkyl substituents derived from C5 alkanes isopentane isopentyl tert-pentyl neopentane neopentyl

Naming cycloalkanes according to IUPAC rules Step 1. Use the cycloalkane name as the parent name When alkyl substituent contains more carbons than ring, use alkane as parent name.

Naming cycloalkanes according to IUPAC rules Step 2. In substituted cycloalkanes number the atoms in the ring starting at the point of attachment so as to arrive at the lowest sum. When different substituents are present, they are numbered by alphabetical priority. correct wrong

Nomenclature of alkenes according to IUPAC rules Alkenes are named according to a series of rules similar to those developed for alkanes, with the suffix –ene used instead of -ane to identify the family. Step 1. Find the parent hydrocarbon – that means find the longest carbon chain containing the double bond:

Step 2. Number the atoms in the chain beginning at the end nearer the double bond. If the double bond is equidistant from the two ends, begin at the end nearer the first branch point. This rule assures that the double bond carbons receive the lowest possible numbers: 2-hexene 2-methyl-3-hexene Step 3. Write the full name numbering the substituents according to their position in the chain and listing them alphabetically. Indicate the position of the double bond by giving the number of the first alkene carbon. If more than one double bond is present indicate the position of each and use the suffixes -diene, -triene, -tetraene, and so on. 2-ethyl-1-pentene 2-methyl-1,3-butadiene

Common names of unsaturated substituents accepted by IUPAC methylene ethylidene vinyl allyl ethenyl 2-propenyl

Common and systematic names of some alkenes Systematic name Common name Ethene Ethylene Propene Propylene 2-Methylpropene Isobutylene 2-methyl-1,3-butadiene Isoprene

Naming cycloalkenes according to IUPAC rules Cycloalkenes are named in a similar way, but because there is no chain end to begin from, we number the cycloalkene so that the double bond is between C1 and C2 and the first substituent has as low number as possible. 1-methylcyclohexene 1,4-cyclohexadiene 1,5-dimethylcyclopentene

Nomenclature of alkynes according to IUPAC rules Alkynes follow the general rules of hydrocarbon nomenclature. The suffix –yne is used to denote an alkyne, and the position of the triple bond is indicated by its number in the chain. Numbering always begins at the chain end nearer the triple bond so that the triple bond receives as low a number as possible. 6-methyl-3-octyne

4-methyl-7-nonen-1-yne 1-hepten-6-yne Compounds with more than one triple bond are called diynes, triynes and so forth; compounds containing both double and triple bonds are called enynes (not ynenes). Numbering of an enyne chain always starts from the end nearer the first multiple bond, whether double or triple. When there is a choice in numbering, though, double bonds receive lower numbers than do triple bonds. 4-methyl-7-nonen-1-yne 1-hepten-6-yne 4-methylnon-7-en-1-yne hept-1-en-6-yne Names of alkynyl substituents: ethynyl 1-propynyl 1-butynyl

Nomenclature of arenes Benzene Ethylbenzene Bromobenzene Disubstituted benzene derivatives: ortho-dibromobenzene meta-dibromobenzene para-dibromobenzene o-dibromobenzene m-dibromobenzene p-dibromobenzene 1,2-dibromobenzene 1,3-dibromobenzene 1,4-dibromobenzene

and substituents are listed alphabetically In tri- and more substituted benzenes the lowest possible numbers are used, and substituents are listed alphabetically 1,2-dibromo-4-methylbenzene 1,3,5-trimethylbenzene 1,4-dibromo-2,5-dimethylbenzene

Aryl substituents Phenyl Benzyl C6H5- C6H5CH2- Ph- PhCH2- Bn

Common names of some alkylbenzenes p-Cymene o-Xylene m-Xylene p-Xylene 1-isopropyl-4-methylbenzene 1,2-dimethylbenzene 1,3-dimethylbenzene 1,4-dimethylbenzene Cumene Mesitylene Styrene Isopropylbenzene 1,3,5-trimethylbenzene Vinylbenzene Ethenylbenzene

Some aromatic hydrocarbons found in coal tar Benzene Toluene ortho-Xylene Indene Naphthalene Biphenyl Anthracene Fluorene Phenanthrene

Every organic compound consists of hydrocarbon framework (and some contain also functional group) Type of skeleton and functional group determine both - physical properties and chemical reactivity of compound. 7 March 2018

Reactivity of functional group essentially the same, Aliphatic aldehyde Aromatic aldehyde Reactivity of functional group essentially the same, reactivity of hydrocarbon part different

Reactivity of hydrocarbon part essentially the same, Aliphatic amine Aliphatic carboxylic acid Reactivity of hydrocarbon part essentially the same, reactivity of functional group totally different

Overview of functional groups in organic molecules

Families of organic compounds Family name Functional group structure Example Name ending -ane pentane Alkane -ene 2-pentene Alkene -yne 1-pentyne Alkyne None benzene Arene

None 3-chloropentane Halide -ol 2-pentanol Alcohol ether dipentyl ether Ether

-amine pentylamine Amine -nitrile pentanenitrile Nitrile None 3-nitropentane Nitro

-thiol 2-pentanthiol Thiol sulfide dipentyl sulfide Sulfide sulfoxide dipentyl sulfoxide Sulfoxide sulfone dipentyl sulfone Sulfone

-al pentanal Aldehyde -one 2-pentanone Ketone

-oic acid pentanoic acid Carboxylic acid -oate ethyl pentanoate Ester

Amide -amide pentanamide -amide N-methylpentanamide -amide N,N-dimethylpentanamide

-oyl chloride pentanoyl chloride Carboxylic acid chloride Carboxylic acid anhydride -oic anhydride pentanoic anhydride

Naming of compounds containing single functional group

carbon atom of functional group In chain structures with functional group containing carbon, like: nitrile (-CN), aldehyde (-CHO), carboxylic acid (-COOH), ester (-COOR), amide (-CONH2), acid chloride (-COCl) carbon atom of functional group has to be number 1

When functional group containing carbon, like: nitrile (-CN), suffix -nitrile aldehyde (-CHO), suffix -al carboxylic (-COOH), suffix -oic acid ester (-COOR), suffix -oate amide (-CONH2), suffix -amide acid chloride (-COCl) suffix -oyl chloride is directly linked to the ring, the suffix in the IUPAC name is changed to: -carbonitrile, -carbaldehyde, -carboxylic acid, -carboxylate, -carbonamide, -carbonyl chloride

ring carbon bonded to functional group and ring carbon bonded to functional group is assign as number 1 !!!

EXAMPLES 1 1 Propanenitrile Cyclopropanecarbonitrile 1 1 Butanal Cyclobutanecarbaldehyde 1 1 Pentanoic acid Cyclopentanecarboxylic acid

EXAMPLES 1 1 Ethyl hexanoate Ethyl cyclohexanecarboxylate 1 1 Heptanamide Cycloheptanecarbonamide 1 1 Octanoyl chloride Cyclooctanecarbonyl chloride

EXAMPLES 1,2-Dimethylcyclopropanecarbonitrile 2-Isopropyl-4-nitrocyclobutanecarbaldehyde 2-Methoxy-4-methylcyclooctanecarbonyl chloride

When the following functional groups: sulfonic (-SO3H), hydroxyl (-OH), amino (-NH2), carbonyl (CO), are linked to non-terminal carbons The numbering of parent skeleton should be done in such a way as to assure the lowest possible number for the carbon linked to the functional group

5-Methylheptane-3-sulfonic acid 3-Chloro-4-methylbenzenesulfonic acid EXAMPLES 5-Methylheptane-3-sulfonic acid 3-Chloro-4-methylbenzenesulfonic acid

1-Cyclohexylbutan-2-ol 5-Isopropyl-2-methylphenol EXAMPLES 1-Cyclohexylbutan-2-ol 5-Isopropyl-2-methylphenol

EXAMPLES 7-Methyloct-7-ene-4-amine 7- Methyl-7-octene-4-amine 4-Ethyl-2-methylcyclohexylamine 4-Ethyl-2-methylcyclohexaneamine

2,2,5-trimethylcyclohexanone EXAMPLES Hepta-1,6-dien-3-one 2,2,5-trimethylcyclohexanone

All principal functional groups are of higher priority than C=C or C≡C bonds!!!

SUBORDINATE FUNCTIONAL GROUPS – EXCLUSIVELY AS PREFIXES -F fluoro- -Cl chloro- -Br bromo- -I iodo- -NO2 nitro- -R alkyl- (methyl-, ethyl-, cyclopentyl-….etc.) -OR alkyloxy- or alkoxy (methoxy-, cyclopentyloxy-…etc.) -Ar aryl- (phenyl-, naphthyl-, anthryl-…etc.) -OAr aryloxy- or aroxy- (phenoxy-, naphthyloxy-…etc.)

PRIORITY ORDER OF PRINCIPAL FUNCTIONAL GROUPS (from the highest to the lowest priority) R4N+Cl- quaternary ammonium chloride R-COOH carboxylic acid R-SO3H sulfonic acid

R-COO- Na+ carboxylate salt PRIORITY ORDER OF PRINCIPAL FUNCTIONAL GROUPS R-COO- Na+ carboxylate salt R-COOR’ ester R-COCl acid chloride

PRIORITY ORDER OF PRINCIPAL FUNCTIONAL GROUPS R-CONH2 amide R-CN nitrile R-CHO aldehyde

PRIORITY ORDER OF PRINCIPAL FUNCTIONAL GROUPS R-CO-R’ ketone R-OH alcohol Ar-OH phenol R-NH2 amine

Common names of some functional benzene derivatives Phenol Aniline Benzoic acid Benzaldehyde Phenylamine Benzenecarboxylic acid Benzenecarbaldehyde Acetophenone Benzonitrile Salicylic acid Nitrobenzene 1-Phenylethanone Benzenecarbonitrile 2-Hydroxybenzenecarboxylic acid