Nomenclature

Question 1

What does IUPAC stand for?

Answer 1

International Union of Pure and Applied Chemistry

Question 2

What is the zeroth field?

Answer 2

Stereodescriptors (e.g. R, S, E, Z, anti, syn…)

Question 3

What is the 1st field?

Answer 3

substituents (e.g. FGs, side-chains)

prefixes = functional groups attached to the main carbon chain (substituents)

Question 4

What is the 2nd field?

Answer 4

root

carbon skeleton

Question 5

What is the 3rd field?

Answer 5

multiple-bond index

suffixes = highest priority family name ending

Question 6

What is the 4th field?

Answer 6

principle functional group

suffixes

Question 7

Rules of the 2nd field: the root?

Answer 7

• Identify the longest continuous carbon chain (ensuring it features the principle functional group)
• This will form the root of the name, and is based on alkane nomenclature that you are already familiar with (e.g., “but” for C4)

Question 8

Rules of the 4th field: the principle functional group?

Answer 8

• Identify the highest priority FG

- The suffix for this FG will form the end of the name.

Question 9

Rules of the lower priority functional groups:

Answer 9

• If lower priority FGs are present, their prefixes are included in the 1st field.
• Exceptions are double and triple bonds, for which the suffixes “en” and “yn” are used in the 3rd field.

Question 10

Rules when there are multiple functional groups:

Answer 10

If there are multiple FGs of the same type, add a modifier before the prefix/suffix to denote the number (i.e., “di-“, “tri-“, etc)

Question 11

List of priorities of functional groups (highest to lowest):

Answer 11

carboxylic acid, ester, acyl chloride, amide, nitrile, aldehyde, ketone, alcohol, thiol, amine, arene, alkene,
alkyne, alkane, ether, alkyl halide, nitro compound, azide

Question 12

Rules of Side-Chains:

Answer 12

• Identify any side-chains (i.e., carbon chains branched off from the main chain) and apply the necessary prefixes (e.g. methyl, propyl) in the 1st field.
  If there is more than one of the same type of side-chain, add a “di-“ or “tri-“ (etc.) modifier before it.

Question 13

Rules of Locants:

Answer 13

-Number the carbon atoms in the main chain and assign locants (number positions) to all FGs and side-chains, choosing the locants so that their numerical values are as low as possible (or rather that their numerical sum is as low as possible).
-Locants are positioned immediately before the associated prefix/suffix and are separated from it by a hyphen. A hyphen is also used before a locant, unless it is at the very beginning of the compound name or is grouped together with other locants, in which case the
locants are separated from one another by commas.
-If there are several substituents of the same type, either prefixed or suffixed, the locants are ordered numerically.
-ane-1,2-diol
rather than ethane-2,1-diol).
If there are several identical substituents attached to the same carbon of the main chain, the locant is repeated as necessary.

Question 14

Rules of the multiple bond index:

Answer 14

-Identify any double/triple bonds and number them with the number of the carbon atom at the head of the bond (i.e., the carbon atom
with the lower number). For example, a double bond between carbon atoms 3 and 4 is numbered as “3-ene”.
-For more than one of any multiple bond type, apply the usual “di-“ or “tri-“ (etc.) modifiers. If both types of bonds exist, then use “ene”
before “yne” [e.g., (E)-pent-2-en-4-ynoic acid].

Question 15

carboxylic acid: formula? prefix? suffix?

Answer 15

F= CO2H
P = carboxy-
S = -oic acid

Question 16

ester: formula? prefix? suffix?

Answer 16

F=CO2R
P=R-oxycarbonyl-
S= -R-oate

Question 17

acyl chloride: formula? prefix? suffix?

Answer 17

F= COCl 
P= halocarbonyl
S= -oyl chloride

Question 18

amide: formula? prefix? suffix?

Answer 18

F= CONR2
P= carbamoyl-
S= -amide

Question 19

nitrile: formula? prefix? suffix?

Answer 19

F= -CN
P= cyano-
S= -nitrile

Question 20

aldehyde: formula? prefix? suffix?

Answer 20

F=-CHO
P= formyl-
S= -al

Question 21

ketone: formula? prefix? suffix?

Answer 21

F= =O 
P= oxo-
S= -one

Question 22

thiol: formula? prefix? suffix?

Answer 22

F= -SH 
P= sulfanyl- 
S= -thiol

Question 23

amine: formula? prefix? suffix?

Answer 23

F= -NR2 
P=  amino-
S= -amine

Question 24

arene: suffix?

Answer 24

S= benzene

Question 25

alkene: prefix? suffix?

Answer 25

P=  alkenyl-
S= -ene

Question 26

alkyne: prefix? suffix?

Answer 26

P=  alkynyl- 
S= -yne

Question 27

ether: formula? prefix?

Answer 27

F= -OR 
P= alkoxy

Question 28

alkyl halide: formula? prefix?

Answer 28

F= -Hal 
P= halo-

Question 29

nitro compound: formula? prefix?

Answer 29

F= -NO2 
P= nitro-

Question 30

azide: formula? prefix?

Answer 30

F= -N3  
P= azido-

Question 31

What does the term ‘Substituent nomenclature’ mean?

Answer 31

Substituent nomenclature takes a parent compound and identifies substituents that replace hydrogens on it with either prefixes (e.g. chloro-, phenyl-) or suffixes (e.g., -ol, -one).
This system can be based on trivial names for the parent compound (e.g., chloroacetone) or on IUPAC names.
Such names are one word, except for certain FGs (notably acid derivatives like esters and acid chlorides) which retain their historical two-word salt names.

Question 32

What does the term ‘Salt nomenclature’ mean?

Answer 32

Salt nomenclature was adopted from inorganic chemistry. In such names, the “cation” and the “anion” are always separate words: first the “cation” (generally ending in “yl” or “ene”), then the anion (e.g., butyl bromide, allyl iodide). If the last word ends in “ate” or “ide”you are using salt nomenclature, and your name will be at least two words.