3.3.7 - Optical Isomerism + naming Flashcards by reyhana r

aldehyydes functional group prefix and suffix

. O
||
—- C — H

suffix -al
prefix formyl

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if 2 aldehyde groups then how is naming different

If two aldehyde groups
then di is put before –al
and an e is added to
the stem.
eg pentanedial

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ketones func group prefix and suffix

. O
||
—-C—–
suffix* -one
prefix oxo

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When ketones have 5C’s or more in a chain how is naming different

When ketones have 5C’s or more
in a chain then it needs a number
to show the position of the double
bond. E.g. pentan-2-one

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if 2 ketone groups how is naming different

If two ketone groups then
di is put before –one and
an e is added to the stem
eg pentanedione

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prefix oxo should be used for compounds…

The prefix oxo- should be
used for compounds that
contain a ketone group in
addition to a carboxylic acid
or aldehyde
2-oxopropanoic acid

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carboxylic acid func group and suffix

. O
||
—-C—-OH
suffix -oic acid

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If there are carboxylic acid groups on both ends of the
chain then it is called a …

dioic acid with an e after stem eg ethanedioic acid

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nitriles func group, suffix and prefix

—C triple bond N
suffix -nitrile
prefix cyano

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how to name nitrile w 4 carbons

butanenitrile
C from CN is included in the name

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amines func group, suffix and prefix

. |
|
—–C—-NH2
|
|
suffix* - -yl - amine
prefix amino

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2 ways of naming amine w 3 carbons for example

The exam board tend to use the common
version where the name stem ends in -yl
propylamine.
Another version of the same chemical is
propan-1-amine. (

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when is the prefix amino used when naming amines

If there is another priority
functional group as well
as the amine group then
the prefix amino is used.

. H2N O
\ //
CH—C
/ \
H3C O - H

2-aminopropanoic acid.

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if amine is secondary how is naming different

If the amine is secondary and has two alkyl
groups attached to the nitrogen, then each chain
is named and the smaller alkyl group is preceded
by an –N which plays the same role as a number
in positioning a side alkyl chain
eg
CH3CH2CH2NHCH3 N-methylpropylamine (common name)
N-methylpropan-1-amine (other name)

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if amine is tertiary how is naming different

If a tertiary amine similar rules apply, and
each alkyl side group is given an N
eg CH3CH2CH2 -N- CH3
|
CH3

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if 2 amine groups how is naming different

diamine is suffix
eg hexane-1,6-diamine

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esters func group, suffix and prefix + example

. ||
—C—O—-
-yl –oate
methyl ethanoate

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Esters have two parts to their names
The bit ending in –yl comes from the _______ that has formed it and is
next to the single bonded ________. The bit ending in –anoate comes
from the _______. (This is the chain including the C=O bond)

Esters have two parts to their names
The bit ending in –yl comes from the alcohol that has formed it and is
next to the single bonded oxygen The bit ending in –anoate comes
from the carboxylic acid. (This is the chain including the C=O bond)

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acyl chloride func group suffix and example

. O
//
— C -oyl chloride
\
Cl eg ethanoylchloride

amide func group, suffix and example

. O
//
— C -amide
\
NH2 ethanamide

how are secondary and tertiary amides named differently

Secondary and tertiary amides
are named differently to show the two (or three) carbon chains.
The smaller alkyl group is
preceded by an –N which plays the same role as a number in positioning a side alkyl chain

name this
O
||
H3C—CH2—C—NH—CH3

N-methylpropanamide

name this

                  O  CH3
                  ||   | H3C---CH2---C---N---CH3

N,N-dimethylpropanamide

acid anhydrides func group, suffix and example

. O
//
R — C
\
O
/
R — C

O
-oic anhydride
Ethanoic anhydride

why is ethanoic anhydride named the way it is

It is ethanoic because it is two ethanoate groups joined together. . O // CH3--C \ O / CH3 -- C \\ O

if the alkyl groups are different how is the acid anhydride named

If the alkyl groups are of different lengths then each one is named e.g. ethanoic propanoic anhydride . O // CH3-- C \ O / CH3--CH2 -- C \\ O

order of priority when multiple func groups

Carboxylic acids >carboxylic acid derivative>nitriles>aldehydes>ketones>alcohols>amines>alkenes>halogenoalkanes

when compounds have more than one func group ______ priority takes _____ with all others taking _____ form

when compounds have more than one func group *highest* priority takes *suffix* with all others taking *prefix* form

structural isomers def

same molecular formula different structures (or structural formulae)

Structural isomerism can arise from

*Chain isomerism *Position isomerism *Functional group isomerism

what kind of isomers would aldehydes and ketones be classed as

functional group isomers

define stereoisomerism

stereoisomers have the same structural formula with different arrangment of atoms

2 types of steroisomerism

e-z isomerism optical isomerism

optical isomerism is a type of of stereoisomerism where....

optical isomerism is a type of of stereoisomerism where molecules have the same molecular formula but a different spatial arrangment of atoms in space

optical isomerism occurs in ...

Optical isomerism occurs in carbon compounds with 4 different groups of atoms attached to a carbon (called an asymmetric carbon).

what is a chiral carbon

A carbon atom that has four different groups attached is called a chiral (asymmetric) carbon atom

4 groups are arranged _____ around carbon atom

These four groups are arranged *tetrahedrally* around the carbon.

presense of chiral centre leads to the presense of 2 ....

presense of chiral centre leads to the presense of 2 possible isomers that are mirror images of eachother (optical isomers)

An ________ carbon atom is _________ and gives rise to ______ ______ (________), which exist as ___ ______ __________ mirror images and differ in their effect on _______ ________ _____. A mixture of ________ amounts of enantiomers is called a ______ _______ (racemate).

An *asymmetric* carbon atom is *chiral* and gives rise to *optical* *isomers*(enantiomers), which exist as *non super-imposable* mirror images and differ in their effect on *plane polarised light*. A mixture of *equal* amounts of enantiomers is called a *racemic* *mixture* (racemate).

Two compounds that are optical isomers of each other are called...

enantiomers

Optical isomers have similar .....

physical and chemical properties

enantiomers are unique due to their effect...

enantiomers are unique due to thier effect on plane polarised light. each entantiomers causes the rotation of plane polarised lightby 90 degrees in opposite diretions

enantiomers exist as

non super-imposable mirror images and differ in their effect on plane polarised light

what is a racemate/racemic mixture ?

A mixture containing a 50/50 mixture of the two isomers (enantiomers) is described as being a racemate or racemic mixture.

how is a racemate formed

A racemate will be formed in a reaction mechanism when a reactant or intermediate has a trigonal planar group in the molecule is approached from both sides by an attacking species

why does a racemate form

There is an equal chance of either enantiomer forming so a racemate forms. No optical activity is seen