PETER PAZMANY CATHOLIC UNIVERSITY Consortium members SEMMELWEIS UNIVERSITY, DIALOG CAMPUS PUBLISHER

Transcription

1 SEMMELWEIS UNIVERSITY PETER PAZMANY CATLIC UNIVERSITY Development of Complex Curricula for Molecular Bionics and Infobionics Programs within a consortial* framework** Consortium leader PETER PAZMANY CATLIC UNIVERSITY Consortium members SEMMELWEIS UNIVERSITY, DIALG CAMPUS PUBLISER The Project has been realised with the support of the European Union and has been co-financed by the European Social Fund *** **Molekuláris bionika és Infobionika Szakok tananyagának komplex fejlesztése konzorciumi keretben ***A projekt az Európai Unió támogatásával, az Európai Szociális Alap társfinanszírozásával valósul meg TÁMP /2/A/KMR

2 rganic and Biochemistry (Szerves és Biokémia ) Functional groups: their unique role (Funkciós csoportok: Különleges szerepben) Compiled by dr. Péter Mátyus with contribution by dr. Gábor Krajsovszky Formatted by dr. Balázs Balogh TÁMP /2/A/KMR

3 Table of Contents 1. Inductive effect Mesomeric effect Field effect Steric effect TÁMP /2/A/KMR

4 rganic and Biochemistry: Functional groups rganic compounds: - unreactive carbon chain - functional groups (e.g. heteroatoms, multiple bonds, aromatic rings, generally substituents of carbon skeleton) Effects of substituents: - electronic: 1. inductive effect 2. mezomeric effect 3. field effect - steric TÁMP /2/A/KMR

5 rganic and Biochemistry: Functional groups 1. Inductive effect: Bond-polarization by difference in electronegativity. Electronegativity is dependent on: δ+ δ- 3 C > Cl a) Position in the periodic table pl. C<N<<F pl. F>Cl>Br>I TÁMP /2/A/KMR

6 rganic and Biochemistry: Functional groups b) Charge on the atom(s) > > c) Type of hybridization C sp > C sp 2 > C sp 3 C C 2 C C 2 3 C C 3 pk a ~ 25 pk a ~ 43 pk a ~ TÁMP /2/A/KMR

7 rganic and Biochemistry: Functional groups Inductive effect: a) through - covalent bonds (σ és π) - field b) Designation: > (the arrow indicates its direction) c) Diminishing with distance δ+ δ+ δ- 3 C > 2 C> Cl TÁMP /2/A/KMR

8 rganic and Biochemistry: Functional groups d) Two directions: negative (-I): toward the more electronegative substituent; e.g. -, -X, -N 2,-C,etc; δ+ δ+ δ- 3 C > 2 C> Cl positive (+I): toward carbonatom e.g. alkyl group, metals, carboxilate group R < C R < M R < C TÁMP /2/A/KMR

9 rganic and Biochemistry: Functional groups 2. Mesomeric effect (conj., resonance): By a group attached to an unsaturated system and possessing an unshaired pair of electrons, resulting in a new electron distribution. More than one Lewis structures. Positive or negative Conditions required: - coplanarity of interacting groups - parallel arrangement of overlapping orbitals C C TÁMP /2/A/KMR

10 rganic and Biochemistry: Functional groups Types of conjugation: 1. π - π : - Generally M N N > C N > C N > C R > C > NR 2 C S TÁMP /2/A/KMR

11 rganic and Biochemistry: Functional groups Acyclic examples: 2 C C C 2 C C C 2 C C C 2 C C C C 2 2 C C C C 2 2 C C C C 2 Cyclic examples: δ+ δ TÁMP /2/A/KMR

12 rganic and Biochemistry: Functional groups 2. n-π : - Generally +M +K +K C > C > -I -I F > Cl > Br > I > ~ R > C R > N 2 ~ NR 2 N C R TÁMP /2/A/KMR

13 rganic and Biochemistry: Functional groups Acyclic examples: Cyclic examples: 2 C C C 2 2 C C C 2 2 C C N 2 C C N 2 C C 2 C C TÁMP /2/A/KMR

14 rganic and Biochemistry: Functional groups 3. σ - π : Particularly in case of carbocations C C C TÁMP /2/A/KMR

15 rganic and Biochemistry: Functional groups 3. Field effect: Through space Example 1. Cl Cl Cl Cl C C pk a = 6,07 pk a = 5,67 Example 2. pk a1 = 2,00 pk a1 = 3,03 pk a2 = 6,26 pk a2 = 4, TÁMP /2/A/KMR

16 rganic and Biochemistry: Functional groups Substituent I M - 0,00 0,00 -F -0,74 +0,60 -Cl -0,72 +0,24 -Br -0,72 +0,18 -I -0,65 +0,12 -C 3 +0,01 +0,41 -CF 3-0,64-0,76-0,25 +0, ,46 +1,89 -C 3-0,54 +1,68 -CC 3-0,70 +0, TÁMP /2/A/KMR

17 rganic and Biochemistry: Functional groups Substituent I M -N 2-0,38 +2,52 -N(C 3 ) 3-0,69 +3,81 -NCC 3-0,77 +1,43 -CC 3-0,50-0,90 -C, -CEt -0,44-0,66 -CN -0,90-0,71 -C - +0,27-0,40 -N 2-1,00-1, N N -2,36-2, N(C 3 ) 3-1,54 0, TÁMP /2/A/KMR

18 Aromatic electrophylic subst (S E Ar) : orientation rules rganic and Biochemistry: Functional groups Substituent Effect rientation - - +I, +M Activation -N 2, -NR, -NR 2 -, -R -I < +M -NCR -CR alkyl +I, aryl +M -F, -Cl, -Br, -I -I > +M rtho, para -CN 2, -CNR, -CNR 2 -C, -CR -C, -CR -S 3, -S 2 N 2, -S 3 R -C N -N 2 -I, -M meta -(N N) + -NR 3+, -N 3 + -I Deactivation TÁMP /2/A/KMR

19 rganic and Biochemistry: Functional groups Steric effect: Steric hindrance Example N C C 3 N C C 3 S 2 Cl S acetanilide 4-acetilamino-benzenesulfonic acid no ortho product was obtained TÁMP /2/A/KMR

20 rganic and Biochemistry: Functional groups Steric effect: Steric acceleration N 2 Example S 2 S 2 N C 2 S 2 reductive desulfonation N 2 S 2 N C 2 2 S no desulfonation was observed TÁMP /2/A/KMR