Naming Organic Molecules

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.













Preface Gener eneral ally ly stud studen ents ts have have smal smalll doub doubts ts reg regardi arding ng the the nom nomenc enclatu lature re of the the orga organ nic comp ompound ounds. s. This This book book is been written with the aim of needs and interests of students in orga organi nic c nome nomenc nclat latur ure. e. In this book every topic has been dealt prec recisely and to the point in a sample and underst rstandable lang langua uage ge.T .Thi hing ngs s have have been been expl explai aine ned d wher wherev ever er poss possib ible le.. A good good numb umber of illus llustr trat atiion examp xample les s with with answ answer ers s is also also prov provid ide ed in this this book book.T .Thi his s help helps s the the stude tudent nts s in dev develop elopiing thei theirr reas reaso onin ning skilills sk ls in nome nomenc ncla latu ture re.. As every organic compound has its own name name..This This book book is help helpfu full in deter eterm mini inining ning the the IUP IUPAC nam names of the the give given n orga organi nic c comp compou ound nds. s.Th This is book book adit aditio iona nall lly y prov provid ides es a smal smalll and and inte intere rest stin ing g topi topic, c, "Mol "Molec ecul ular ar form formul ula a to an indi indivi vidu dual al person". Hope this book meets the needs of the the stude tudent nts s,ch ,chemi emists who who want ant to lear learn n orga organi nic c chem hemistr istry y nome nomenc nclat latur ure e in deta detailil..















Index

Page No

1. Nomenclature

4 Trial Trial Versi Version on only only

2. Saturated Aliphatic Compounds

16

3. Unsaturated Aliphatic Compounds

- --

4. Cyclic compounds

-- -

5. Aromatic compounds

- --

6. Bicyclo Compounds

---

7. Alco Alcoho hols ls 8. Ethers

---

9. Aldehydes

- --

10.Ketones

---

11.Carboxylic Acids

---

12.Acid derivatives

-- -

13.Nitrogen containing compounds

---

14.Tricyclo Compounds

---

15.Bio molecules

- --















1.Nomenclature What is organic organic chemistry chemistry? ? Organic chemistry is a bran ranch of chemistry which deals with carbon compounds.Organic compounds mainly contains carbon and hydrogen as its main cons consti titu tuen ents ts.I .In n addit dditio ion n to this this it als also conta ontain ins s N,S N,S,P,C ,P,Cl, l,Br Br and and I.

Why is nomenclature necessary? Organic chemistry is a vast branch as millions of organic compounds are already known and thousands of new compounds are beign added to this list every year.In order to facilitate the study of such large number of compounds.Therefore it is necessary to classify the organic compounds.In order to classify this organic compounds the term "Nom "Nomen encl clat atur ure" e" come comes s into into pict pictur ure. e.

What is nomenclature? Nome Nomenc ncla latu ture re mean means s the the assi assign gnme ment nt of names to the organic componds.The naming of organic compounds is an important aspect in the study of organic chemistry as their number is very large and variety of molecular structures exist in their molecules.The field has become more















Trivial System In this system whenever a new compound is discovered it is given an individual name.These names are called Trivial names.These names are also called Common names.

Examples (a) Acetic acid derives its name from vinegar of which it is chief constituent. (b) Formic acid was named as it was obtained from red ants. (c)The name oxalic acid, malic acid and citric acid is derived from botani botanical cal source sources. s. (d)U (d)Ure rea a and and Uric Uric acid cid have ave bee been deri deriv ved from from anim animal al sourc ources es.. (e)The liqiud that is obtained by the destructive dstaillation of wood was named as wood spiri irit.Later on it was called led methyl alco lcohol. (f)M (f)Me ethane is calle lled as marsh gas because it is prod roduced in marshes.

IUPAC system IUPA IUPAC C stand tands s for for "In "Intern ternat atio ion nal Unio nion Of Pure Applied Chemistry".By using this IUPAC system one can name any complex organic compound easily.The name assigned to an organic compound on the basis of latest IUPAC rules is known as system systematic atic name. name.















(c) (c) This This sys yste tem m is help elpful ful in nam naming ing the the mult multif ifun unc ctio tional nal grou group ps. (d) This is a simple,systematic and scientific method for the nome nomenc ncla latu ture re of orga organic nic comp compou ound nds. s.

Rules for organic nomenclature For naming the organic compounds sytematically first we have to first study about the following three features (a) Root word (b)Pri (b)Primar mary y suffix suffix (c)Sec (c)Second ondary ary suffix suffix (d)Prefix

Root word The basic unit in orga rganic nomenclature is the root word.Chains containing one to four carbon atoms are known by special root words while chains from C5 onwards are known by greek numb number er root roots. s.

Chain length

Root Word

C1

Meth-

C2

Eth-

C3

Prop-

















Chain length

Root Word

C8

Oct-

C9

Non-

C10

Dec-

C11

Undec-

C12

Dodec-

C13

Tridec-

C20

Eicos-

C30

Triacont-

C40

Tetracont-

C50

Pentacont-

Primary Suffix The primary suffixes are added to the root word to show how satur aturat atio ion n or uns unsatu aturati ratio on in a carbo arbon n chain hain.. Name of Carbon Chain

Primary

IUPAC

















Name of Carbon Chain

Unsaturated with

Primary

IUPAC

Suffix

name

-yne

Alkyne

-adiene

Alkadiene

-atriene

Alkatriene

one triple bond (

HC

CH

)

Unsaturated with two double bonds (

CH H2C

)

CH2 CH

Unsaturated with three double bonds (

H 2C

CH CH

CH CH

) CH 2

The compounds that are given above in the brackets are the examples les of the carbon chain mentioned above.

Secondary Suffix i di

t th

Suffixes that are added after the primary suffixes to f ti l f ti l i b h i i

















Amine(-NH2)

-amine

Thioalcohol(-SH)

-thiol

Cyanide( -CN)

-nitrile

Esters(-COOR)

-oate

Amides(-CONH2 )

-amide

Acid halide( -COX)

-oyl halide

Now le let us us se see ho how th the IU IUPAC na names ar are fo formed from frome ed from from the the Root Root,P ,Pri rim mary ary and and the the Secon econd dary ary suffi uffix xes

Homologus Series Alcohols

Root

Primary

Secondary

IUPAC

Word

Suffix

Suffix

name

Alk

-ane

-ol

Alkanol

Alk

-ene

-ol

Alkenol

(saturated) Alcohols (unsaturated)

















Prefix It is always be kept in mind that alkyl groups forming branches of the parent chain are considered as side chains.Atoms or groups of atoms such as fluoro(-F), Chloro(-Cl) bromo(-Br), Ido(-I), Nitro(-No2) and Alkoxy(-OR) are reffered to as substitu ituents.Root words are profixed with the name of the substituent or the the side ide chain hain..

Arrangment of Prefixes,Root word and Suffixes These ar are ar arranged a a fo follows wh while wr writing th the name in such a manner. IUPAC name =

Prefixes+Root word+Primary Suffix+ Secondary suffix

Example1

Br

HO

3 CH

CH3 4

1C

CH2 2

















Hence the IUPAC name of thhe compound is

3-bromobutanoicacid

Exam Exampl ple e 2

1

CH2

CH

HO

CH 2

3

CH3 4CH

CH3

4-methylpent-2-en-1-ol

In the above give iven example

5



















Exam Exampl ple e 3 5 H3C

OH 3 C

4 CH

2 C

1 C

H3C

O 4-methylpent-2-ynoic acid

In the above given example 1.Pr 1.Pref efix ix = Meth Methyl yl 2.Root word = Pent 3. Primary suffix = yne 4. Secondary suffix = oic acid



















In the above example 1.Prefix

=

Methyl

2.Root Word = Prop 3.Pri .Prima mary ry Suffi uffix x = ane ane 4.Se .Secon condary dary Suff Suffix ix = ol 5.Number of Carbons = 3 Hence the name of the Organic Compound is

2-methylpropan-2-ol IUPAC Nomenclature of Organic compounds in Bond Line structures : 1. 1

2 Ethane

=

H3C

CH3



















4. 2

4

2,2-dimethylbutane

1 3

5. 2 2,2-dimethylpropane

3

1

6. 2

4 2-methylbut-2-ene

1

3



















10. 2

OH

1

propan-1-ol

3 OH

11.

propan-2-ol

2 1

3

12.

2

OH 2,2-dimethylpropan-1-ol

3

13.

1

O



















2. Satu turrated Aliphati tic c comp mpo ounds Nomenclature In order to study about the nomenclature of the saturated aliph liphat atic ic comp ompound ounds s one nedd edd to know now about bout the the "Lon "Longe gest st Chain hain Rule Rule"" This rule states that in naming an organic Longest Chain Rule : compound we have to selec lect the longest continuos chain of carbo rbon atoms which may or may not be horizontal.This continuos chain is called the "Par "Paren entt Chai Chain" n" or "Mai "Main n Cha Chain". in". Exam Exampl ples es : 1. 5 H3C

4

2

CH2

CH2

3 CH

CH3

3-methylpentane

1 CH3





















3. 3 H3C

1

7

CH2

CH3

CH2

5

2 CH

CH3

4 CH

H2C

CH2

6

5 6 CH3

4-ethyl-2-methylheptane





















In abov bove exam exampl ple e the the long longes estt chain hain cont ontain ains two poss possib ibil ilit itie ies s as shown in (a) and (b). In such a case the longest chain is choosen in such a way that it contains more number of substitu ituents. If we coside ider (a) it contains two substituents 2nd and 3rd position but if we consider (b) it contains ins one substitu ituent at 3rd position so the numbering as ind indica icated by the red numbers will be wrong in such that case and the name of the compou compound nd is 3-ethy 3-ethyl-2 l-2-me -methy thylpe lpenta ntane. ne. 5. 1 H3C

4

5

CH2

CH3

5

H3C

1 CH2

CH3





















6. Lowest Sum Rule CH3

2 1

H3C

5

4

4 3

2 3

5

Correct numbering 2,3-dimethylpentane (Correct)

CH3

1

Wrong numbering numbering 3,4-dimethylpentane (Wrong)

CH3

In th this ca case th the nu numbering of of ca carbon at atoms should be done in such a way that the sum of the positions of the bsti bstitu tu t at atta attach ched ed sh ld be mini mini





















8. CH3

7 CH2

8

2

H3C

H3C

CH3

6

4

C

1

3

CH2

5

CH2 H3C

1

4

5

3 CH2

6

8

2C 7

2,2,6,6-te 2,2,6,6-tetram tramethylo ethyloctane ctane (Correct) (Correct) 3,3,7,7-te 3,3,7,7-tetram tramethylo ethyloctane ctane (Wrong) (Wrong)

CH3

Sum of positions in correct numbering = 2+2+6+6 = 16 Sum of positions in wrong numbering = 3+3+7+7 = 20 Hence the name of the compound is





















10. H3C

7 H3C

6

CH3

5

4

3 CH3

2 CH3 H3C

1 CH3























12. H3C

6

CH3

2

3

4

CH3

5





















16.Tr 6.Triv ivia iall name ames for for some ome alk alkyl subst ubstiu iue ents nts : 3

( a)

H3C

2 CH

Q

Isopropyl





















17. H3C

3'

2

H3C

1 4

2'

3 5

1'

CH3





















18.

3' H3C

CH3

2'

1' 5

6





















Halo Haloge gena nate ted d Alip Alipha hatic tic Comp Compou ound nds s : Halogens are the molecules that are situated in 17th group roup (VII (VII A Gro Group) up) elem elemen ents ts in peri period odic ic tabl table. e.Th The ey are 1.Fluorine(F)







































































































































































































































































Naming Organic Molecules

Recommend Documents