Cahn ingold-prelog nomenclature

absolute configuration ,E-Z notation, Cis - trans nomenclature

1. CAHN-INGOLD-PRELOG NOMENCLATURE GUIDED BY: Prof. Mrs. J.S. MESHRAM PRESENTED BY: BIJI SARO VARGHESE DATE: 4 OCT 2017 RASHTRSANT TUKDOJI MAHARAJ NAGPUR UNIVERSITY DEPARTMENT OF CHEMISTRY

2. I would like to thank Dr. M rs. J.S. Meshram mam for her constant guidance and support throughout the completion of my presentation. I would like to thank my seniors of their support. I would also like to thank my friends and colleague who helped me directly and indirectly. I would also like to thank my parents who provided me all the facilities for completion of my presentation . ACKNOWLEDGEMENT 2

3. The Cahn-Ingold-Prelog (CIP) Nomenclature The system that we use was devised by R. S. Cahn Sir Christopher Ingold Vladimir Prelog 3

4. RULE 1:If four atoms attached to the stereocenter are different ,priorities depend on atomic numbers. (S)-2-BROMOBUTANE 4

5. Higher atomic number outranks lower atomic number Br > F Cl > H ( Z )- 1-Bromo-2-chloro-1-fluoroethene higher lower Br F Cl H higher lower C C 5

6. RULE 2:If two atoms are isotopes of the same element, the atom of higher mass number has the higher priority F H C D CH 3 1 4 3 2 6

7. C bonded to 3 H’s C bonded to C and 2 H’s C bonded to O and 2 H’s C bonded to 2 C’s and one H RULE 3:If the relative positions of two groups cannot be determined as earlier, they are decided by a comparison of priority atom at the first point difference. 7

8. Evaluate substituents one by one. Don't add atomic numbers within groups. —C H 2 O H outranks —C (CH 3 ) 3 —C ( O ,H,H) —C (C,C,C) 8

9. RULE 4:If two carbon chains are attached to the stereogenic carbon the chain with a secondary carbon is of higher priority than the one with primary carbon. 2 3 4 1 9

10. RULE 5:In case of double or triple bond both the atoms are considered to be duplicated or triplicated. 10

11. C OH H 3 C H CH 3 CH 2 C HO CH 3 H CH 2 CH 3 ( S )-2-Butanol ( R )-2-Butanol RULE 6:To assign R and S configuration the molecule has to be viewed with the lowest priority group at the back. 11

12. Absolute Configuration Rank the 4 groups (atoms) bonded to the chirality center The R,S system of nomenclature 12

13. Naming Enantiomers - R,S System Assigning Priorities to Groups Oxygen (from CH 2 OH) = 16 Carbon (from CH 2 CH 3 ) = attached to carbon Carbon (from CH 3 ) = attached to hydrogen Hydrogen = 1 13

14. RULE 7:When the lowest priority group is towards eyes interchanging of the position of any two groups twice at stereocenter retains its configuration and also puts group of lowest priority away from the viewer. First interchange Second interchange H and CH3 CH3 and NH2 2 3 4 1 4 3 1 2 4 1 3 14

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16. R-RECTUS S-SINISTER 16

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19. CIS-TRANS NOMENCLATURE RULE 8:In case of compounds of the type abC=Cab, the isomer in which the identical groups are on the same side of the double bond is called cis and if they are on the opposite sides then they are called trans . Cis-2-bromobut-2-ene Trans-2-bromobut-2-ene 19

20. C C C C The E-Z Notational System E :higher ranked substituents on opposite sides Z :higher ranked substituents on same side Entgegen Zusammen higher higher lower lower lower higher lower higher 20

21. C has higher priority than H Cl has higher priority than F ( Z )-1-chloro-1-fluoro-1-propene RULE 9:If the highest priority groups are on the same side of double bond the configuration is Z, if they are on the opposite sides, the configuration is E. 21

22. This is the Z-stereoisomer. 22

23. S-enantiomer is teratogenic and R-enantiomer is sedative IMPORTANCE OF ENANTIOMER 23

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26. IBUPROFEN ONLY S-ENANTIOMER IS ANTI INFLAMATORY BUT R-ENANTIOMER IS NON TOXIC AND INACTIVE ONLY S-ENANTIOMER IS ANTI INFLAMATORY BUT R- ENANTIOMER IS NON TOXIC AND INACTIVE 26

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28. TARTARIC ACID 28

29. References Stereochemistry by P.S. KALSI, seventh edition,2008 Organic chemistry by Morrison and Boyd, sixth edition,2007 Structures drawn by CHEM4WORD software Web sources- https :// pubchem.ncbi.nlm.nih.gov/compound/ibuprofen , https :// pubchem.ncbi.nlm.nih.gov/compound/thalidomide , www.chemspider.com/Chemical-Structure.852.html , https:// chem4word.codeplex.com , 29

30. Thank you 30