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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5574_Библиотеки_им_академика_М_И_Перельмана.pdf
COC H
63
13.
Diphenyl methanone or diphenyl
ketone or benzophenone
14.
CH
3
COOH
2-Methyl benzoic acid o
r
o-toluic acid
15.
COOH
COOH
1,4-Benzene dicarboxylic acid
or terephthalic acid
16.
CH2–— C
–
–
–
N
Benzal cyanide or
phenyl acetonitrile
MEMORY FOCUS
c h A P T e r 2 u nomenclature of Organic compounds
121
1. Classification of organic compounds: The large number of organic compounds are mainly grouped
into two classes: (1) open-chain or acyclic or aliphatic compounds and (2) closed-chain or ring
compounds.
2. There are four types of carbon atoms:
a. Primary (1º) carbon atom, which is bonded to either one more carbon atom or to none.
b. Secondary (2º) carbon atom, which is bonded to two other carbon atoms.
c. Tertiary (3º) carbon atom, which is bonded to three other carbon atoms.
d. Quaternary (4º) carbon atom, which is bonded to four other carbon atoms.
The hydrogens attached to 1º, 2º and 3º carbon atoms are called 1º, 2º and 3º hydrogen atoms
respectively.
3. General rules of IUPAC system
a. The longest possible continuous chain of carbon atoms must include the carbon atom carrying the
functional group and the maximum number of double and triple bonds is located and the word root
corresponding to it is noted. This is called principal chain.
b. A primary suffix is added to the word root to designate the saturated or unsaturated nature of the
principal chain.
c. A secondary suffix is added after the primary suffix to indicate the nature of functional group present
in the given organic compound.
d. A primary prefix ‘cyclo’ is used before the word root in alicyclic (but not aromatic) compounds.
e. Secondary prefixes are added before the word root in alphabetical order to denote the side chains
or substituent groups.
122
PhArmAceuTicAl OrgAnic chemisTry
4. Nomenclature of saturated branched chain acyclic hydrocarbon
a. The longest possible continuous chain of carbon atoms is selected and the compound is
considered as the derivatives of the corresponding alkane.
b. If a molecule contains two or more continuous chains of equal length, which is highly substituted
is selected as the parent chain.
c. Lower number rule: The selected longest chain is numbered by arabic numerals 1, 2, 3, 4……and
so on from that end, which gives lower number to be carbon carrying substituent.
d. When series of alkyl radicals (locants) containing the same number of terms are compared term
by term, that series is lowest which contains the lowest number on the occasion of the first
difference.
e. When two or more different groups are present at equivalent positions on the parent chain, the
lower number is given to that which comes first in the alphabetical order.
f. In case the substituent of the parent chain has sub-branching, the substituent is named as alkyl
derivative of the longest chain present in the substituent.
g. The name of a complex alkyl radical is considered to begin with the first letter of its complete
name.
h. The presence of identical complex radicals each containing two or more identical radicals as side
chains in the same or different positions may be indicated by approximately multiplying prefix
‘bis-’, ‘tris-’, ‘tetrakis-’, ‘pentakis-’, etc.
i. The longest chain having maximum substituent is considered as the principal chain whose side
chains have the lowest numbered locants.
5. Nomenclature of unbranched unsaturated hydrocarbon
a. The double bond or the triple bonds should be given the lowest number in the principal chain.
b. When both double and the triple bonds are present, the numbering of the principal chain should
be done from that end which is near to the first multiple bond (double or triple).
c. When both double bond and triple bonds are equidistant from either of the two ends, double bond
should be given lower locant.
6. Nomenclature of branched unsaturated hydrocarbon
a. Maximum number of double and triple bonds should be present in the principal chain.
b. Maximum length of the principal chain.
c. Lowest positional numbers (locants) for the multiple bonds.
d. Maximum number of substituents should be there in the principal chain.
e. Lowest locants for all the substituents.
7. Nomenclature of cyclic (alicyclic) hydrocarbons
a. cyclo (a primary prefix) is used immediately before the word root in case of alicyclic
hydrocarbons.
b. If two or more alkyl groups or other substituent groups are present in the ring, their positions are
indicated by arabic numerals, i.e. 1, 2, 3, 4… and so on.
c h A P T e r 2 u nomenclature of Organic compounds
c. If the ring contains fewer carbon atoms than the alkyl group attached to it, the compound is
named as a derivative of alkane and the ring is treated as cycloalkyl substituent otherwise it is
named as a derivative of cycloalkane.
d. If however, the side chain contains a multiple bond or a functional group, the alicyclic ring is
treated as the substituent irrespective of the size of ring.
e. If a multiple (double or triple) bond and some other substituent are present in the ring numbering
is done in such a way that the multiple bond gets the lowest number.
f. If a compound contains an alicyclic ring and benzene ring it is named as a derivatives of
benzene.
8. IUPAC nomenclature of compounds containing one functional group, multiple bonds and a
substituent
a. The longest possible continuous chain of carbon atoms containing the functional group and the
maximum number of double or triple bonds (if any) are identified and word root corresponding to
it is noted.
b. Numbering the principal chain: Principal chain in a compound must be numbered in such a way
that functional group gets the lowest possible number followed by double bond, triple bond and
the substituents.
c. To name the principal chain, select the appropriate word root denoting the total number of carbon
atoms in the principal chain, attach the primary suffix and attach the secondary suffix.
d. When a chain terminating functional group is present, it is always given position at number 1.
f. The prefixes and other substituents should be placed in alphabetical order before the word root.
9. Some additional rules for solving complex compounds
123
a. Select that chain as the principal chain which contains maximum number radicals of secondary
suffix.
b. When the number of radicals of principal functional group are same in different chain, select the
longest possible chain.
c. All things being equal, the principal chain must contain maximum number of double bonds.
REVISION QUESTIONS
1. name at least one compound of each of the following classes, write its formula and iuPAc name:
(a) Aldehyde (b) Alcohol (c) Alkyne (d) carboxylic acid
2. What is meant by homologous series? What are its characteristics?
3. Point out the error and write the correct iuPAc names of the following:
(a) 1,5-Pentadiene (b) 2-ethyl-2-butene
(c) 2-Dimethyl-3-hexyne (d) 2-methyl-3-butanone
124
Me
Me
Me
Me
Me
PhArmAceuTicAl OrgAnic chemisTry
Ans: (a) CH
(b)
(c)
(d)
CH CH2 CH CH2 1,4-pentadiene
2
CH3 C CH CH
CH
2
CH
3
CH
3
CH3 C C C CH2 CH
CH
3
3
3
O
CH3 CH C CH
CH
3
3
4. give the iuPAc names of the following compounds:
(a) ch2 chch2ch2Oh
(b) (ch3)4c
(c) ch3 ch(ch3) ch
3
Ans: (a) But-3-en-1-ol (b) 2,2,-Dimethylpropane (c) 2-Methylpropane
5. give the iuPAc name of the following compound:
Ans: 5,6-Diethyl-3-methyl-dec-4-ene
Hint: ‘Me’ stands for methyl and formula may be rst written as
CH
3
CH3 CH2 C CH CH CH2 CH
CH3 CH2 CH CH2 CH2 CH2 CH
3
3
6. Write the iuPAc names of the following compounds:
(a) (ch3)2chch3ch
(b) (c2h5)2chch
3
3
c h A P T e r 2 u nomenclature of Organic compounds
CH3 —— CH —— COOH
CH
3
CH CH CCH CH
|
|
||
CH
3
CH
3
CH
3
Cl
33
CH2 CH2 C
CH
3
Cl CH
3
(c)
Ans: (a) 2-methylbutane (b) 3-methylpentane (c) 2-methylpropanoic acid
7. Write the structures of the following:
(a) 2-methyl-2-butanol
(b) 2,2,4-Trimethyl-3-chloropentane
(c) 4-chloro-2-methyl-2-butene
(d) 4-iodo-2-hexenoic acid
125
Ans: (a) CH
= CH – CH2 – CH = CH2 1,4-pentadiene
2
(b)
(c)
(d) CH
CH2 CH CH CH–COOH
3
I
8. Write iuPAc names of the following:
CH3 CH2 C CH2 CH2 CH
(a)
CH
2
CH2 CH CH CH
(b)
CH2 CH CH CHO
(c)
(CH3)2CH CHCOOH
(d)
2
3
(e)
Ans: (a) 2-Ethyl -1-pentene (b) 1,3-Butadiene (c) 2-Butenal
(d) 2-iodo-3-methylbutanoic acid (e) 3-chloro-2-butanone
I
CH3 CH C CH
OCl
3
126
PhArmAceuTicAl OrgAnic chemisTry
9. Assign iuPAc names to the following compounds:
2
CH
CH
3
3
3
2
(a)
CH3 C CH C CH
CH
3
CH
3
CH2 CH CH CH CH CH
(b)
(C2H5)2C C(C2H5)
(c)
(CH3)3C C CH
(d)
(e)
CH
3
Ans: (a) 2,2,4-Trimethyl-3-hexene (b) 1,3,5-hexatriene (c) 3,4-Diethyl-3-hexene
(d) 3,3-Dimethyl-1-butene (e) 3-methylcycopentene
10. Write the iuPAc names of the following compounds:
(a)
CH
3 CH CH2 CH CH2 CH2
OH
(b)
(c)
(d)
CH
2
CH
3
CH
3 CH2 CH2
O
CH
3 CH2 CH
CH
CH
3
CH CH CH
NH2CH
COCl
3
3
3
Ans: (a) 3,5- Dimethyl-1-heptanol (b) 2-methyl-3-hexanamine
(c) 2-methylcyclohexanone (d) 2-methylbutanoyl chloride
c h A P T e r 2 u nomenclature of Organic compounds
11. Write iuPAc names of the following compounds:
OHC COOH
(a)
127
(b)
(c)
(d)
(e)
CH
3 CH2 C CH2
CH
CH
3 C
CHCl
O
CH
3
CHBr
CH
Br
CH
2 CH C
CH
OH
2
CH CH2COOH
NH
2
C CONH
CH
3
CH CHO
OCH
3
3
2
Ans: (a) Oxoethanoic acid
(b) 2-ethylprop-2-en-1-ol
(c) 3-Amino-4-chloro-5-oxohexanoic acid
(d) 4-Bromo-2-methylpent-2-enamide
(e) 3-Bromo-2-methoxy-3-methylpent-4-enal
12. Draw the structures of the following compounds:
(a) 4-Bromo-2-ethanol (b) 5,5-Diethyl-3-nonanol
(c) 1-Bromo-3-chlorocyclohexene (d) 1,6-Heptadiene
Ans: (a) 3-methylhexane (b) cis-but-2-ene
(c) 2,3-Dimethylbuta-1,3-Diene (d) 3-methylhexa-1,3,5-triene
(e) 2- ethylbut-1-ene
13. Draw the structures of the following compounds:
(a) cyclohexylcyclohexane
(b) 4-cyclobutylbut-3-en-2-one
(c) 5-(1-methylethyl)-3-methyloctane
(d) ethyl-3-methoxy-4-nitrobutanoate
(e) 2-isopropyl-5-methylcyclohexanol
128
CH3 CH CH CH2 CH2 CH
3
CH
2
CH
3
CH
3
PhArmAceuTicAl OrgAnic chemisTry
14. Write the iuPAc names of the following compounds:
(a) (b)
(c) (d)
(e)
15. Draw the structures of the following compounds:
(a) 4-chloropent-2-ene (b) neohexane
(c) glyoxal (d) Tartaric acid
(e) isoprene (f) Picric acid
1. Which of the following statement is not applicable to a homologous series?
(a) They can be represented by a general formula.
(b) There is a regular gradation in their physical properties.
(c) most of the members of a series can be prepared by similar methods.
(d) Two successive members differ by a common difference of –CH2–.
2. Which of the following contains only a set of homologues?
(a) c2h2, c2h4, c2h6, c2h5 (b) c2h2, c3h6, c4h6,c5h
(c) c6h6, c7h16, c8h10, c9h12 (d) ch4,c2h6, c3h8, c4h
3. According to iuPAc system, the correct name of the following structure is
MULTIPLE CHOICE QUESTIONS
10
10
c h A P T e r 2 u nomenclature of Organic compounds
CH3 æ CH æ CH æ CH2 æ CH2 æ CH
3
Ω Ω
CH
3 C2H5
CH3 æ CH2 æ CH2 æ CH æ CH æ CH
3
Ω Ω
CH
3 C2H5
CH3 æ CH æ CH æ CH2 æ CH2 æ CH
3
Ω Ω
C
2H5 CH3
(a) 2-ethyl-3-methyl hexane (b) 3-methyl octane
(c) 3,4-Dimethylheptane (d) 4,5-Dimethyl heptane
4. how many isomers of the alkyl group c4h9 are possible?
(a) 2 (b) 3 (c) 4 (d) 5
H
129
5. iuPAc name of the compound
H3C C CH2 CH
3
is
(a) 3-Phenyl butane (b) 3-cyclohexyl butane
(c) 2-cyclohexyl butane (d) 2-Phenyl butane
6. The structural formula of 3-ethyl-2-methylhexane is
(a)
(b)
(c)
(d) none of the above
7. iuPAc name of compound ch2=CH–CH (CH3)2 is
(a) 1,1-Dimethyl-2-propene (b) 3- methyl-1-butane
(c) 2-vinyl propane (d) 1-isopropyl ethylene
8. The compound which has one isopropyl group is
(a) 2,2,3,3-Tetramethylpentane (b) 2,2-Dimethylpentane
(c) 2,2,3-Trimethylpentane (d) 2-methylpentane
9. The correct iuPAc name of the compound with molecular formula (ch3)3C–CH3 is
(a) Pentane (b) 1,1,1-Trimethylethane
(c) 2,2-Dimethylpropane (d) neopentane
130
CH3–CH–CH –C–CH
23
|
OH
|
OH
|
CH
3
PhArmAceuTicAl OrgAnic chemisTry
10. The iuPAc name for
is
(a) 1-Dimethyl-1,3-butanediol
(b) 4-methyl-2, 4-pentanediol
(c) 2-methyl-2 4-pentanedial
(d) 1,3,3-Trimethyl-1,3-pentanediol
11. Alicyclic compounds are
(a) Aromatic compounds (b) Aliphatic cyclic compounds
(c) heterocyclic compounds (d) none of these
12. indicate the wrongly named compound
(a) (ch3)2CH–CH2–CH2–CHO (b) (CH3)2CH–C=C–COOH
(4-methyl-1-pentanal) (4-methyl-2-pentyn-1-oic acid)
(c) ch3ch2ch2ch(ch3)cOOh (d) ch3ch2ch=chcOch
(2-methyl-1-pentanoic acid) (3-hexene-5-one)
13. The iuPAc name of compound ch3Och2ch2ch2Och2ch
3
(a) 1-ethoxy-3-methoxypropane
(b) ethoxy pronanoxymethane
(c) 3-ethoxy-1-methoxypropane
(d) 2,5-Dioxyhexane
3
14. iuPAc name of the following compound is (ch3 = ch)2 CH – CH = CH
(a) 3,3-Divinyl-1-propene (b) Triethenylmethane
(c) Trivinylethane (d) 3-vinylpenta-1,4-diene
15. iuPAc name of ch3ch(Oh)cOOh is
(a) lactic acid (b) a-hydroxypropionic acid
(c) carboxypropanol (d) 2-hydroxypropanoic acid
16. Which of the following structure represents 2,2, 3-trimethylhexane?
(a) ch3c(ch3)2ch2ch2ch(ch3)
(b) ch3(ch3)ch ch(ch3)ch2ch
(c) ch3c(ch3)2ch(ch3)ch2ch2ch
(d) ch3c(ch3)2ch2c(ch3)2ch3
2
2
3
3