Sereochemistry ppt by Sattar

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  • Understanding Stereo Isomer
  • Sereochemistry ppt by Sattar

    1. 1. STEREOCHEMISTRY
    2. 2. W h a t isS t e r e o is o m e r ?
    3. 3. Identical (Same Compounds) Stereoisomers (Different Compounds)
    4. 4.  Isomers:Different compounds with same molecular formula Stereoisomers:isomers that have same molecular formula and connectivity but differ in the way the atoms are oriented in space - i.e. the difference between two stereoisomers lies only in the three dimensional arrangement of atoms. Stereochemistry:chemistry that studies the properties of stereo- isomers
    5. 5.  Two types of stereoisomers: ◦ enantiomers  two compounds that are nonsuperimposable mirror images of each other ◦ diastereomers  Two stereoisomers that are not mirror images of each other  Geometric isomers (cis-trans isomers) are one type of diastereomers.
    6. 6.  The Light whose electric fields oscillate in single plane.
    7. 7.  The ability of a compound to rotate the plane polarized light either clockwise or anti- clockwise. E.g. Tartaric Acid
    8. 8. Substances should be light sensitivity.They should have chiral carbonThey should rotate plane polarized light(PPL) in different ways.As a result, they should produce twodifferent configurations i.e. enantiomers
    9. 9.  An optically active compound that rotates plane polarized light in a clockwise direction e.g. (+)Epinephrine
    10. 10. An optically active compound that rotatesplane polarized light in anti-clockwisedirection. E.g. (-) Epinephrine
    11. 11. A carbon which is bonded with four differentgroups.
    12. 12.  Some molecules are chiral: Asymmetric (chiral) carbon
    13. 13.  Organic compounds that contain a chiral Carbon usually have two non superimposable structures. These two structures are mirror images of each other.
    14. 14.  Have identical molecular formula Have same physical properties Both rotate plane polarized light (PPL) but in opposite sense. One rotates PPL to clockwise and another to anti-clockwise.
    15. 15.  Equimolar mixture of left- and right-handed enantiomers of a chiral molecule. Properties Optically inactive i.e. zero (0) rotation Sometimes have different properties of either pure enantiomers Different in solubility, melting and boiling points.Example: Ibuprofen
    16. 16. A compound with two identical chirality centerhaving no optical sensitivity because-They have two identical chiral partsOne part is optically active and another partis inactive.Optically active parts is neutralizes byinactive parts.As a result they have no light sensitivity
    17. 17. Racemic mixture Meso compoundMixture of two Equimolar One compound having twoenantiomers identical chiral parts.Individually light sensitive Though chiral C is present,but the mixture s neutral the compound is not light sensitiveComponents of the one compound, so twomixture can be separated. chiral parts can’t be separated.Mixture of d-lactic acid and Tartaric acidl-lactic acid
    18. 18.  Stereoisomers are different compounds and often have different properties. Each stereoisomer must have a unique name. The Cahn-Ingold-Prelog convention is used to identify the configuration of each asymmetric carbon atom present in a stereoisomer. ◦ (R) and (S) configuration
    19. 19.  The two enantiomers of alanine are: CO2H CO2H C C H H CH3 H3C NH2 H2N Natural alanine Unnatural alanine (S)-alanine (R)-alanine
    20. 20.  Assign a numerical priority to each group bonded to the asymmetric carbon: ◦ group 1 = highest priority ◦ group 4 = lowest priority Rules for assigning priorities: ◦ Compare the first atom in each group (i.e. the atom directly bonded to the asymmetric carbon)  Atoms with higher atomic numbers have higher priority
    21. 21. Cl 1 3 CH3 3 C 2 C H4 H3C OCH2CH3 NH2 H 1 F 2 4Example priorities:I > Br > Cl > S > F > O > N > 13C > 12C > 3H > 2H > 1H
    22. 22.  In case of ties, use the next atoms along the chain as tiebreakers. 2 CH CH Br 2 2 C H4 3 CH3 2 CH CH(CH3)2 1 CH(CH3)2 > CH2CH2Br > CH3CH2
    23. 23. Y C Y C Y C Y C  Treat double and triple bonds as if both YC C O atoms in the Y Y were duplicated or Y C bond C CO C triplicated: H Y C Y C C Y Y OHH C Y C Y C Y C Y C CH2OH C Y C Y C Y C Y C O 2 H C C O Y C Y C C Y2 O C H Y 1 C C OH C 1 OH 4 H CH2OH C4 H Y CH2OH 3 C Y3 Y C
    24. 24.  Using a 3-D drawing or model, put the 4th priority group in back. Look at the molecule along the bond between the asymmetric carbon and the 4th priority group. Draw an arrow from the 1st priority group to the 2nd group to the 3rd group. ◦ Clockwise arrow (R) configuration ◦ Counterclockwise arrow (S) configuration
    25. 25.  Theenantiomer with most remote OH from the CHO to the right is called D(+) enantiomer E.g. D(+) glyceraldehyde Theenantiomer with most remote OH from the CHO to the left is called L(-) enantiomer E.g. L(-) glyceraldehyde
    26. 26.  Except for inorganic salts and a few low- molecular-weight organic substances, the molecules of living systems are chiral Although these molecules can exist as a number of stereoisomers, generally only one is produced and used in a given biological system amino acids, nucleosides, carbohydrates and phospholipids are chiral molecules
    27. 27.  Bindingof drugs with enzymes depend on chirality
    28. 28. 1.Ibuprofen S(+) Ibuprofen R(-) Ibuprofen
    29. 29. 2. Thalidomide
    30. 30. 3. Naproxen S(+) Naproxen R(-) Naproxen
    31. 31. 4. Fluoxetine
    32. 32. 5. EpinephrineS(+) Epinephrine R(-)Epinephrine
    33. 33. ROLL- 11 & 13 Semester: 5 th Batch: 8 thDepartment o Pharmacy Dhaka International University

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