Organic Nomenclature Part VII -- Writing Diagrams from Names

Organic Menu

239.
Write the diagram for 3-methyl pentane.
       First: The name pentane indicates a chain
       containing ________ carbon atoms. 


                                                                                                        five
       Second: Draw a five-carbon chain, with bonds,
       and number the atoms from either end. ______



       Third: Since the compound is 3-methyl pentane,
       there must be a ______ radical on the #3 ______ 
                                                                                                       methyl

                                                                                                       carbon atom
        Fourth: Write the diagram for a methyl radical. ______ 

      Fifth: Show the methyl radical attached
      to the third carbon.____ 

      Sixth: Draw all the necessary bond lines.
      Add the hydrogen symbols ifyou wish._____ 
240.

Draw the structure of 2,4-dimethyl heptane. 
        First: The name "heptane" indicates a

        carbon chain of (How many?) _______ atoms. 
                                                                                                      7

        Second:  "Dimethyl" indicates that there are
        (how many?) _______ methyl radicals. 
                                                                                                 two

        Third:  The radicals are attached
        to the carbon atoms numbered ______ and _______. 
                                                                                                2,4

       Fourth: Draw the diagram, showing the radicals
       attached to the correct carbon atoms._____ 

241.

Draw the structure of 3,5-dimethyl-4-ethyl octane. ______
       First: Draw a chain of eight single-bonded carbons,
       number for the left or the right. 

       Second: The compound contains
       (how many?) ______ methyl radicals
       and (how many?) _______ ethyl radicals? 


                                                                                                     2, 1
        Third: The methyl radicals will be attached
        to carbon (what number?) _____ and (what number?) _____ 
                                                                                                    3, 5

        Fourth: The ethyl radical is attached to
        the carbon atom numbered _____ 
                                                                                                   4

        Fifth: The complete structure is ______ 




242.
Draw the structural diagram for:
3,3,6-trimethyl-4,5-diethyl nonane._______ 

243.
Draw the structural diagram for:
2,4,6,8-tetramethyl-4,5-diethyl decane._______ 

244.
In this series of questions we have, for the sake of clarity
made a small change in the usual way of writing the
names of these compounds.

2-methyl hexane should be written 2-methylhexane,
with no space between "methyl" and "hexane."

2,3-dimethyl-4-ethyl octane should be written
2,3-dimethyl-4-ethyloctane.

2,3,5-trimethyl decane should be written as ______


245.                                                                                     2,3,5-trimethyldecane

Butane has a four carbon single bond chain.
Its molecular formula follows this pattern:
              CnH2n+2
Write the molecular formula for butane._______ 


                                                                                           C4H10
246.
The compound butene has a four-carbon chain,
but there is a double bond etween two of the carbons.
The molecular formula is CnH2n
Write the formula for butene._______ 
                                                                                           C4H8

247.
We can draw the diagram for butene in two different ways.
These structures are called isomers (eye' so mers.)
This shows one isomer of butene:

The double bond is between which two carbons?_______ 
                                                                                         carbons 2 and 3

This shows the other isomer of butene:

The double bond is between which two carbons? ________


                                                                                       carbons 1 and 2

Many other chemical compounds besides
butene have isomers.
Isomers of a compound have exactly the same
number of the same kinds of atoms,
but are arranged structurally a bit differently.
Isomers have chemical properties somewhat
different from each other. 


248.
The isomers of butene are described
according to the location of the double bond.
In this isomer:

the double bond is beween carbon atoms #1 and #2.
We always assign the smaller of carbon-chain numbers.
The name of this isomer is, therefore, 1-butene.
This is the other isomer of butene:

What is its name?______ 
                                                                                        2-butene

249.
Remember that we number a carbon chain from both ends,
and choose the smaller of the two numbers that each carbon atom will have.

Suppose that we had a long carbon chain like this:

The double bond connects the carbon atom numbered 2 and 8
with the carbon atom numbered 3 and 7

What number will you use? 


                                                                                                 2
250.
Now look at this chain:

The double bond connects the carbon atom
numbered 7 and 3 with the carbon atom
numbered 8 and 2.

What number will you use?______


                                                                                             2
251.
This isomer has six carbons atoms,
two of  which are joined by a double bond.
Therefore it is an isomer of hexene.

Write its full name. _________ 
                                                                                            2-hexene

252.
This isomer has six carbons atoms,
two of  which are joined by a double bond.
Therefore it is an isomer of hexene.

Write its full name._____ 
253.                                                                                           2-hexene

This isomer has six carbons atoms,
two of  which are joined by a double bond.
Therefore it is an isomer of hexene.

Write its full name._______ 
254.

Study this diagram:

There are five carbon atoms with one double bond.
Therefore this is some sort of ________ 
                                                                                                     pentene

The double bond begins on the carbon
atom numbered ________ 
                                                                                                   one

The full name of the pentene is therefore ________ 
                                                                                                  1-pentene

Attached to the chain is a ______ radical. 
                                                                                                  methyl

The radical is attached to carbon atom number ______ 
                                                                                                  3

The full name of the compound is _________ 
255.                                                                                          3-methyl-1-pentene

What is the name of this isomer?

                                                                                              2-methyl-3-hexene
256.
What is the name of this compound? ________

                                                                                          3,3-dimethyl-1-pentene
257.
A carbon chain can have two double bonds.
There is a word to describe that.
The word is alos used as a suffix, as we shall see.
The word is diene (dy' een).
The "di" part of diene means _____ 
                                                                                         2

The "ene" part of the word means_________ 
                                                                                        a double bond

Look at this diagram:

Does the diagram showthe correct number of hydrogen bonds?______ 
                                                                                                  yes

The double bonds begin on carbons
number _______ and number ______ 
                                                                                                 1,3

259.
With these clues:
the four-carbon butane chain;
the suffix diene;
the double-bonding at the 1,3 carbon atoms;
name the compound._____

                                                                                             1,3-butadiene
260.
Look at this diagram:

Since there are two double bonds,
the suffix of the name of the compound will be _______ 
                                                                                            diene

Since there is a main chain of five carbon atoms,
part of the name will be ______ 
                                                                                            penta

Double-bond attachments will be shown
by these numbers _________ 
                                                                                            1,3

There is a ________ radical
attached to the chain. 
                                                                                            methyl

Point of attachment of the methyl radical
is shown by the number _________ 
                                                                                            3

Name the compound ________ 
                                                                                      3-methyl-1,3-pentadiene
261.
Look at this diagram, which shows
a triple bond.

The four-carbon chain and the triple bond
show that it is some kind of ________ 
                                                                                                       butyne

The triple bond begins on carbon atom number _______ 
                                                                                                        2

The name of the compound is __________ 
                                                                                                   2-butyne

262.
Name this compound._______

                                                                                                1-pentyne
263.
Name this compound.________

                                                                                               2-pentyne
264.
Name this compound.__________

                                                                                          4-methyl-2-pentyne
Organic Menu