Conversion of wedge - dash to Fischer projection

The concepts deals with the conversion of the wedge dash representation of a given molecule in a Fischer projection

With the help of this animation user will be easily able to convert any molecule given in wedge dash representation to planer Fischer projection , hence will be able to study the stereochemistry of the given molecule

By Rachit AgarwalDepartment of chemistry

IIT Bombay

Master layout

Bond coming out of the plane

Bond on the plane

Bond going in the plane

R3

R2

R1R4

Carbon center

Here bond of C-R2 , C-R3 are in the plane , while of C-R1 is out of the plane and C-R4 inside the plane, the bond C-R4 is exactly behind the bond C-R1, but to show the C-R4 bond it is shown sidewaysR1 R2 R3 and R4 are general notation for the atom

wedge

dash

Wedge – dash representation

Beginner’s level

advance level

With two carbon center (red dots) H3C

CH3H2N

Cl

HO

H

H3C CH3

H H

HO

OH Cl

Cl

With three carbon center (red dots)

While looking the molecule from top or bottom the plane which is considered is of thickness T. In which the top layer passes through 2 carbon center and the lower layer through 1 carbon center

H3C CH3

H H

HO

OH Cl

Cl

T

Definition and rules for the users

There are certain rules that are to be followed while making the Fischer projection

Rule no 1) User should view the molecule from the same place while making the projection i.e. top right, top left, bottom right, bottom left

Rule no 2) In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

Rule no 3) While rotating the bonds about any atom (chiral) the stereochemistry of the molecule does not changes

H3C

CH3H2N

Cl

HO

H

H3C CH3

H H

HO

OH Cl

Cl

Molecule with 2 chiral center

Molecule with 3 chiral center

Analogy / Scenario / Action / Example

3-D view of the given wedge dash molecule

3-D view of the molecule from a different angle so as to show all the atoms

The first 3-D molecule is rotated about the bond joining red and black atoms , such that orange atom comes out of the plane, green goes inside the plane and blue comes on the plane and the corresponding wedge – dash on the right side

R3

R2

R1R4

wedge – dash representation of the given molecule

R1

R2

R4R3

The heading over the slides (for user to understand)

There are total 8 types of option to be followed each containing of three (3) steps

The hierarch is shown below

Step 1

Action Description of the action Audio narration

Selection of the level Allow the user to click on one of two boxes containing the image with (option1 / option 2)

Select the level you want to learn, by clicking on desired box

Actual slide to be displayed

H3C

CH3H2N

Cl

HO

H H3C CH3

H H

HO

OH Cl

Cl

Select the level

For beginnersMolecule with two

carbon atom

For advanceMolecule with three

carbon atom

Option 1 Option 2

Step 2A

Action Description of the action Audio narration

Selection of the view point Allow the user to click on one of four boxes containing the view points i.e. top left, top right, bottom left, bottom right

Select the view point from which you would like to view the molecule

Actual slide to be displayed (option 1 selected)

H3C

CH3H2N

Cl

HO

H

Option 1

Select the view pointTop left Top right

bottom rightbottom left

Step 3AA

Actual slide to be displayed (top left view in option 1 selected)

CH3

CH3

ClH

NH2HO

TL2

CH3

CH3

HCl

NH2HO

TL3

CH3

CH3

NH2OH

HCl

TL4

H3C CH3

OH

H2N

H

Cl

TL1

Top left view

H3C

CH3H2N

Cl

HO

H

Top left viewCH3

CH3

NH2OH

HCl

Instruction on next slides

Initial display of the page final display of the page

H3C

CH3H2N

Cl

HO

H

TL0

Action Description of the action Audio narration

From TL0 to TL1

Rotate the molecule TL0 about the red line (axis) by 90 degrees toward yourself from top

From TL1 to TL2

Rotation the molecule TL1 by 90 degrees anti clock wise about the red spot

From TL2 to TL3

Rotate the bonds of TL2 molecule around the red spot (carbon atom) about the red axis by 180 degrees, for reference see the analogy slide

While rotating the bonds about any atom (chiral) the stereochemistry of the molecule does not changes

From TL3 to TL4

replace all the wedge and dash of TL3 molecule by simple lines and adjust the inclined bonds to become horizontal, so as to get the final image

In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

Step 3AA

CH3

CH3

NH2HO

HCl

BL4

H3C

CH3H2N

Cl

HO

H

BL0

H3C CH3

H2N

HO

Cl

H

BL1

CH3

CH3

HCl

OHH2N

BL2

Step 3AB

Actual slide to be displayed (bottom left view in option 1 selected)

bottom left view

H3C

CH3H2N

Cl

HO

H

Bottom left viewCH3

CH3

NH2OH

HCl

Instruction on next slides

Initial display of the page final display of the page

CH3

CH3

HCl

NH2HO

BL3

Action Description of the action Audio narration

From BL0 to BL1

Rotate the molecule BL0 about the red line (axis) by 90 degrees away from you from top

From BL1 to BL2

Rotation the molecule BL1 by 90 degrees anti clock wise about the red spot

From BL2 to BL3

Rotate the bonds of BL2 molecule around the red spot (carbon atom) about the red axis by 180 degrees, for reference see the analogy slide

While rotating the bonds about any atom (chiral) the stereochemistry of the molecule does not changes

From BL3 to BL4

replace all the wedge and dash of BL3 molecule by simple lines and adjust the inclined bonds to become horizontal, so as to get the final image

In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

Step 3AB

H3C CH3

OH

H2N

H

Cl

TR1

CH3

CH3

HOH2N

HCl

TR2

CH3

CH3

HOH2N

ClH

TR3

CH3

CH3

ClH

OHH2N

TR4H3C

CH3H2N

Cl

HO

H

TR0

Step 3AC

Actual slide to be displayed (top right view in option 1 selected)

Top right view

H3C

CH3H2N

Cl

HO

H

Top right view

Instruction on next slides

Initial display of the page final display of the page

CH3

CH3

ClH

OHH2N

Action Description of the action Audio narration

From TR0 to TR1

Rotate the molecule TR0 about the red line (axis) by 90 degrees towards yourself from top

From TR1 to TR2

Rotation the molecule TR1 by 90 degrees clock wise about the red spot

From TR2 to TR3

Rotate the bonds of TR2 molecule around the red spot (carbon atom) about the red axis by 180 degrees, for reference see the analogy slide

While rotating the bonds about any atom (chiral) the stereochemistry of the molecule does not changes

From TR3 to TR4

replace all the wedge and dash of TR3 molecule by simple lines and adjust the inclined bonds to become horizontal, so as to get the final image

In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

Step 3AC

H3C CH3

H2N

HO

Cl

H

BR1

CH3

CH3

NH2HO

ClH

BR2

CH3

CH3

HOH2N

ClH

BR3

CH3

CH3

ClH

OHH2N

BR4

H3C

CH3H2N

Cl

HO

H

BR0

Step 3AD

Actual slide to be displayed (bottom right view in option 1 selected)

Bottom right view

H3C

CH3H2N

Cl

HO

H

bottom right view

Instruction on next slides

Initial display of the page final display of the page

CH3

CH3

ClH

OHH2N

Action Description of the action Audio narration

From BR0 to BR1

Rotate the molecule BR0 about the red line (axis) by 90 degrees away from you from top

From BR1 to BR2

Rotation the molecule BR1 by 90 degrees clock wise about the red spot

From BR2 to BR3

Rotate the bonds of BR2 molecule around the red spot (carbon atom) about the red axis by 180 degrees, for reference see the analogy slide

While rotating the bonds about any atom (chiral) the stereochemistry of the molecule does not changes

From BR3 to BR4

replace all the wedge and dash of BR3 molecule by simple lines and adjust the inclined bonds to become horizontal, so as to get the final image

In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

Step 3AD

Step 2B

Action Description of the action Audio narration

Selection of the view point Allow the user to click on one of four boxes containing the view points i.e. top left, top right, bottom left, bottom right

Select the view point from which you would like to view the molecule

Actual slide to be displayed (option 2 selected)

Option 2

Select the view pointTop left Top right

bottom rightbottom left

H3C CH3

H H

HO

OH Cl

Cl

Step 3BA

Actual slide to be displayed (top left view in option 2 selected)

Top left view Top left view

Initial display of the page final display of the page

H3C CH3

H H

HO

OH Cl

Cl

HO Cl

HO H

Cl H

Continued on the next page ….

Top left view

Intermediate step

TLd1

H3C CH3

H H

HO

OH Cl

Cl

TLo

Cl OH

HO H

Cl H

TLb

HO Cl

H OH

H Cl

TLc

HO H

Cl H

TLd2

TLd1

HO Cl

HO H

Cl H

TLd3

H3C CH3

H H

HO

OH Cl

Cl

TLo

Cl

OH

OH

H

Cl

H

TLa

Instruction on next slide

Step 3BA

Action Description of the action Audio narration

Intermediate step appears

The fig in the intermediate steps will appear The basic Fischer diagram will be this , now we have to place the respective atoms

From TLo to TLa

Rotate the molecule Tlo about the red line (axis) by 90 degrees toward yourself from topNote: the TLd1 will remain as it is

From TLa to TLb Rotation the molecule TLa by 90 degrees anti clock wise about the red spot Note: the TLd1 will remain as it is

TLd1 to TLd2 TLd1 changes to TLd2 by placing the respective atoms

In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

From TLb to TLc Rotate complete molecule about the red axis by 180 degreesNote: the TLd2 will remain as it is

By rotating the complete molecule about any axis the stereochemistry of the molecule does not changes

TLd2 to TLd3 TLd2 changes to TLd3 by placing the remaining respective atoms

In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

Step 3BA

Step 3BB

Actual slide to be displayed (bottom left view in option 2 selected)

bottom left view Bottom left view

Initial display of the page final display of the page

H3C CH3

H H

HO

OH Cl

Cl

HO Cl

HO H

Cl H

bottom left view

Intermediate step

H3C CH3

H H

HO

OH Cl

Cl

BLoBLd1

Continued on the next page ….

OH

Cl

H

OH

H

Cl

BLa

HO Cl

H OH

H Cl

BLb

HO Cl

HO H

Cl H

BLd3

H3C CH3

H H

HO

OH Cl

Cl

BLo

HO Cl

BLd2

BLd1

Cl OH

HO H

Cl H

BLc Instruction on next slides

Step 3BB

Action` Description of the action Audio narration

Intermediate step appears

The fig in the intermediate steps will appear The basic Fischer diagram will be this , now we have to place the respective atoms

From BLo to BLa

Rotate the molecule BLo about the red line (axis) by 90 degrees away from you from topNote: the TLd1 will remain as it is

From BLa to BLb Rotation the molecule BLa by 90 degrees anti clock wise about the red spot Note: the TLd1 will remain as it is

BLd1 to BLd2 BLd1 changes to BLd2 by placing the respective atoms

In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

From BLb to BLc Rotate complete molecule about the red axis by 180 degreesNote: the BLd2 will remain as it is

By rotating the complete molecule about any axis the stereochemistry of the molecule does not changes

BLd2 to BLd3 BLd2 changes to BLd3 by placing the remaining respective atoms

In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

Step 3BB

TRd1

Step 3BC

Actual slide to be displayed (top right view in option 2 selected)

Top right view Top right view

Initial display of the page final display of the page

H3C CH3

H H

HO

OH Cl

Cl

H3C CH3

H H

HO

OH Cl

Cl

TRo

OHCl

OHH

ClH

Continued on the next page ….

Top right view

Intermediate step

Cl

OH

OH

H

Cl

H

TRa

ClHO

OHH

ClH

TRb

OHCl

HHO

HCl

TRc

OHCl

OHH

ClH

TRd3

Instruction on next slides

H3C CH3

H H

HO

OH Cl

Cl

TRo TRd1

OHH

ClH

TRd2

Step 3BC

Action` Description of the action Audio narration

Intermediate step appears

The fig in the intermediate steps will appear The basic Fischer diagram will be this , now we have to place the respective atoms

From TRo to TRa

Rotate the molecule TRo about the red line (axis) by 90 degrees towards yourself from topNote: the TRd1 will remain as it is

From TRa to TRb

Rotation the molecule TRa by 90 degrees clock wise about the red spot Note: the TRd1 will remain as it is

TRd1 to TRd2 TRd1 changes to TRd2 by placing the respective atoms

In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

From TRb to TRc

Rotate complete molecule about the red axis by 180 degreesNote: the BLd2 will remain as it is

By rotating the complete molecule about any axis the stereochemistry of the molecule does not changes

TRd2 to TRd3 TRd2 changes to TRd3 by placing the remaining respective atoms

In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

Step 3BC

Step 3BD

Actual slide to be displayed (bottom right view in option 2 selected)

Bottom right view bottom right view

Initial display of the page final display of the page

H3C CH3

H H

HO

OH Cl

Cl

OHCl

OHH

ClH

H3C CH3

H H

HO

OH Cl

Cl

BRoBRd1

Continued on the next page ….

Top right view

Intermediate step

OH

Cl

H

OH

H

Cl

BRa

ClHO

OHH

ClH

BRc

OHCl

OHH

ClH

BRd3

Instruction on next slides

H3C CH3

H H

HO

OH Cl

Cl

BRo

OHCl

HHO

HCl

BRb

BRd1

OHCl

OHH

ClH

BRd2

Step 3BD

Step 3BD

Action` Description of the action Audio narration

Intermediate step appears

The fig in the intermediate steps will appear The basic Fischer diagram will be this , now we have to place the respective atoms

From BRo to BRa

Rotate the molecule BRo about the red line (axis) by 90 degrees away from you from topNote: the BRd1 will remain as it is

From BRa to BRb

Rotate the molecule BRa by 90 degrees clock wise about the red spot Note: the BRd1 will remain as it is

BRd1 to BRd2 BRd1 changes to BRd2 by placing the respective atoms

In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

From BRb to BRc

Rotate complete molecule about the red axis by 180 degreesNote: the BRd2 will remain as it is

By rotating the complete molecule about any axis the stereochemistry of the molecule does not changes

BRd2 to BRd3 BRd2 changes to BRd3 by placing the remaining respective atoms

In Fischer projection the atoms/bonds which are in the horizontal line should come out of the plane while those are in vertical line should be going inside the plane

Links for further studies

Referencesbooks 1) Organic Chemistry Jonathan Clayden, Nick Greeves,

Stuart Warren, and Peter Wothers

2) Solomons, Fryhle: Organic Chemistry, 8th Edition

Websites 1) http://www.youtube.com/watch?v=KKOY1sdYEes

Questionnaire

Draw the Fischer of the following molecules

HO

H Cl

F OH

F I

Cl

HO

HF

H

A

C

B

D

Cl H

H

OHF

Answers

HO H

F H

D H

H Cl

HO F

HO F

Cl H

HO Cl

I F

A

C

B