TASHKENT MEDICAL ACADEMY Department of Bioorganic and Biological Chemistry

Bioorganic chemistryFIRST COURSE

SUBJECT: Mutual influence of atoms in molecules of organic compounds, and methods of transmission. PAIRING. Aromaticity. Acidic and basic

organic compounds.LECTURE №2

LECTURER: PROFESSOR A.D.DZHURAEV

The purpose of the lecture

Generate knowledge of electronic effects as the main

mode of transmission of mutual influence of atoms and electronic structure of molecules with conjugated bonds as thermodynamically stable systems that are used in the construction of biologically important

compounds, as well as build knowledge of acidity and basicity of organic compounds as the most important

properties that determine most of the chemical reactions in living organisms .

The Questions of:

Types of systemsStability of conjugated systemsTypes of pairingAromaticity, the criteria of aromaticitySpatial effectsAcidity of organic compoundsMost of the organic compounds

Spatial structure of organic compounds (stereoisomers). CONFIGURATION

Configuration - This spatial arrangement of atoms or atomic groups WITHOUT possible conformations.

Ethane Aminoethanol

Conformation

Conformation - This different geometric shapes into each other and the resulting atomic groups Spin Around One or more - Communication.

Eclipsed Canted Inhibited

Energy different conformations

0o 60o 120o 180o 240o 300o

energy

kJ / mol

Torsion angle

Eclipsed Inhibited

canted

Conformation of cyclic compounds

"Chair" form "Bath" form "Twist" form

Mutual influence of atoms in the molecule and the way it

TRANSMISSION

Inductive effect

INDUCTIVE EFFECT - mutual influence of atoms SUBMITTED On - Communication

CHH

HCH

HC ClH

H 3 2 1 + + + -+++

123

Mesomeric effectMesomeric effects - electronic influence vice Submitted

On - Communication.

CH2 CH C O

H

N O-O

CH2 CH Cl ;

•ELECTRON-DONATING SUBSTITUENTS - DEPUTY SHIFTS THE ELECTRON DENSITY FROM THE SELF.

•TO TREAT THEM - NR2, - NHR, - NH2, - OH, - OR, - CH3 , -I, -BR, -CL, -F

• ELECTRON-WITHDRAWING SUBSTITUENTS - DEPUTY SHIFTS THE ELECTRON DENSITY TO THE ME.

•TO TREAT THEM-NO3, -CN, -SO3H, -COOR, -COOH, -CHO

Electron-donor and electron-withdrawing substituents

1. CUMULATED SYSTEMС = С = С = С = С – С = С = С =С

2. ISOLATED SYSTEMС = С - (СН 2 )N – С = С

3. CONJUGATE SYSTEMС = С - С = С - С = С - С = С

TYPES OF SYSTEMS

OPEN INTERFACE CIRCUITСН2 = СН - СН = СН2

BUTADIENE - 1,3

CONJUGATE SYSTEMS

HH

HC C H

HC C

H

H

H H

H H

H

Ñ Ñ Ñ Ñ

1 2

3 4

1 23 4

À

Á

Â

Conjugated systemsWith Closed Circuit CIRCUIT INTERFACE

P Z - AO

- µî âóð¶à

TYPES OF INTERFACE

, -pairing - when p - orbitals of all-chain atoms are involved in the formation of - electron cloud, and the formation

of - communication

HH

HC C H

HC C

H

H

H H

H H

H

Ñ Ñ Ñ Ñ

1 2

3 4

1 23 4

À

Á

Â

P Z - AO

- µî âóð¶à

TYPES OF INTERFACEр, - conjugation – when р- orbitals of the heteroatom involved only in education -electron cloud, but not in

education -communication

СН 2 = СН – CI VINYL CHLORIDE

1. THE SYSTEM SHOULD HAVE CLOSED FLAT - SKELETON

2. ALL ATOMS IN THE CHAIN MUST BE IN SP2-HYBRIDIZATION

3. RULE HUCKEL SYSTEM SHOULD CONTAIN 4 N + 2 ELECTRONS

Criteria for aromaticity

BRONSTED ACIDS - ARE NEUTRAL MOLECULES OR IONS, ARE ABLE TO GIVE PROTON (PROTON DONOR).

ACIDITY ORGANIC COMPOUNDS

А - Н + : В А- + В – НAcid basis conjugate conjugate base acid

СН3СООН + Н2О СН=СОО- + Н3О+ACETIC ACID BASE ACETATE ION HYDRONIUM ION . (СОПРЯЖЕННОЕ ОСНОВ) (СОПРЯЖЕННАЯ К-ТА)

FOR THE REACTION EQUILIBRIUM CONSTANT EQUAL:

Equilibrium constant

ΟΗCΟΟНCΗ

ΟΗCΟΟCΗΚ23

33

ACIDITY CONSTANT EQUAL VALUE:

Р КА = – LG КА

acidity constantProduct K * [H2O] is constant acidity (Ka)

Н

CC

CCKKa3

332*

О - Н ACID CARBOXYLIC ACIDS, ALCOHOLS, PHENOLS

S – H ACID THIOLS, THIOETHERS

N – H ACID AMIDES, AMINES, IMIDES

C – H ACID HYDROCARBONS AND THEIR DERIVATIVES

Bronsted acid:

1. ON THE ABILITY OF THE ATOMS ARE BONDED TO HYDROGEN, KEEP YOURSELF IN ELECTRON PAIR AFTER THE DEPARTURE OF THE PROTON (OT ITS ELECTRONEGATIVITY)

2. THE SIZE OF THE ATOM IS BONDED WITH HYDROGEN (ATOMIC POLARIZABILITY)

3. FROM POSSIBLE DELOCALIZATION (REDISTRIBUTION) OF NEGATIVE CHARGE ON THE OTHER ATOMS (ON THE PRESENCE OF CONJUGATED SYSTEMS)

4. ON THE ABILITY OF THE SOLVATED ANION

Stability anion depends on the following factors:

С2Н5ОН = С2Н5О- + Н+

С2Н5SН = С2Н5S- + Н+

С2Н5SН > С2Н5 ОН

acidic compounds

СН– ACID< NH – ACID< OH- ACID<SH- ACID

Increasing the power acidity among Bronsted acid

CH OH CCH3 OH C2H5 OH OH(CH3)2 (CH )3 3

HCOOH> 3 CH COOH>(CH 3)3 C - COOH

REASONS BRONSTED - THIS NEUTRAL MOLECULES OR IONS, WHICH TAKE PROTON (PROTON ACCEPTOR)

REASONS BRONSTED

Distinguish between two types of Bronsted Reasons: π- GROUNDS n-GROUNDS (onium)

THESE REASONS TO APPLY - ALKENES, ALKADIENES, ARENA.

CENTER OF MAIN, THAT IS THE POINT OF ATTACHMENT OF THE PROTON, IS THE ELECTRONIC π-COMMUNICATIONS.

π-ОСНОВАНИЯ

DEPENDING ON THE NATURE OF THE HETEROATOM, THAT IS BY CENTER MAINLY

DIFFER:

А) AMMONIUM Б) OXONIUM

В) SULFONIUM

n-GROUNDS (onium )