Carboxylic acids
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Carboxylic acids. 1 C: formic acid, methanoic acid 2 C’s: acetic acid, ethanoic acid 3 C’s: propionic acid, propanoic acid 4 C’s: butyric acid, butanoic acid. Aspirin : Should you take a daily dose?. (Prostaglandins F 2 a ).

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1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Carboxylic acids

  • 1 C: formic acid, methanoic acid

  • 2 C’s: acetic acid, ethanoic acid

  • 3 C’s: propionic acid, propanoic acid

  • 4 C’s: butyric acid, butanoic acid


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Aspirin : Should you take a daily dose?

(Prostaglandins F2a)

Prostaglandins are involved in the regulation of a variety of physiological

phenomena, including inflammation, blood clotting, and the induction of labor. Aspirin act by blocking the biosynthesis of prostaglandins in the cell.



1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Carboxylic Acid

Carboxylate ion


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Electron-withdrawing groups stabilize a conjugate base,

making a carboxylic acid more acidic.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Electron-donating groups destabilize a conjugate base,

making a carboxylic acid less acidic.









Amines

NH3 + H2O NH4+ + OH-

Amines

RNH2, ArNH2 Primary, 1o Amines

R2NH, Ar2NH Secondary, 2oAmines

R3N, Ar3N Tertiary, 3o Amines

N,N-dimethylethylamine

butylamine

N-methylpropylamine


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

สารประกอบเอมีนที่มีฤทธิ์เป็นยาสารประกอบเอมีนที่มีฤทธิ์เป็นยา


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

NaNOสารประกอบเอมีนที่มีฤทธิ์เป็นยา2 inhibits the growth of Clostridium botulinum.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Quoteสารประกอบเอมีนที่มีฤทธิ์เป็นยา of The Day

Think like a wise man

but express yourself like

an ordinary one.

จงคิดเหมือนปราชญ์

แต่แสดงออกเหมือนสามัญชน


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Stereochemistryสารประกอบเอมีนที่มีฤทธิ์เป็นยา

is the study of the three-dimensional structure of molecules.

Stereoisomers

Isomers : Different compounds that have the same

molecular formula.

Stereoisomers : Isomers that have the same bonding sequence

but differ in the orientation of their atoms in space.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Mirror morning sickness and used extensively in Europe and Canada despite strong warning that it not be used by pregnant women.

180° rotation


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

คู่ morning sickness and used extensively in Europe and Canada despite strong warning that it not be used by pregnant women. enantiomers


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

  • Each enantiomer of a stereoisomeric pair is optically active and has an equal but opposite-in-sign specific rotation.

  • One enantiomer will rotate polarized light in a clockwise direction, termed dextrorotatory (+), and its mirror-image partner in a counter-clockwise manner, termed levorotatory (–).

  • It is common practice to convert the observed rotation, α, to a specific rotation, [α].


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

(http://www.cem.msu.edu/~reusch/VirtualText/sterism2.htm#isom12)


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Specific rotation melting points, they rotate the plane of polarized light in opposite directions. , [a] = amount (degrees) that a substance rotates plane polarized light expressed in a standard form.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Carvone from caraway:   [ melting points, they rotate the plane of polarized light in opposite directions. α]D = +62.5º

Carvone from spearmint:   [α]D = –62.5º

Lactic acid from muscle tissue:   [α]D = +2.5º

Lactic acid from sour milk:   [α]D = –2.5º


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

How can one identify enantiomerism? melting points, they rotate the plane of polarized light in opposite directions.

All objects may be classified with respect to chirality (from the Greek cheir = hand):

Chiral = Objects that are different from theirs mirror image;

i.e. golf clubs, scissors; enantiomers are chiral.

Achiral = Objects that are identical with theirs mirror image;

i.e. a pencil, a T-shirt.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Chiral molecule : (R)-lactic acid melting points, they rotate the plane of polarized light in opposite directions.

Achiral molecule : water

Water (H2O)

  • Achiral molecules have either one or both of the following:

  • Plane of symmetry

  • Center of symmetry


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Chiral molecules have melting points, they rotate the plane of polarized light in opposite directions. chiral center (or stereo or stereogenic center):

an atom attached to 4 different atoms or groups.

(chiral carbon)


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Designating the Configuration of Stereogenic Centers melting points, they rotate the plane of polarized light in opposite directions.

The CIP system of nomenclature.

(R. S. Cahn, C. K. Ingold and V. Prelog)

  • Each stereogenic center in a molecule is assigned a prefix (R or S), according to whether its configuration is right- or left-handed.

  • The symbol R comes from the Latin rectus for right, and S from the Latin sinister for left.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

The assignment of the prefixes depends on the melting points, they rotate the plane of polarized light in opposite directions.

application of two rules:

The Sequence Rule

The Viewing Rule

Right-Handed

Left-Handed


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

The Sequence Rule melting points, they rotate the plane of polarized light in opposite directions.

  • Assign sequence priorities to the four substituents by looking at the atoms attached directly to the chiral stereogenic carbon atom.

  • The higher the atomic number of the immediate substituent atom, the higher the priority; H–  <  C–  <  N–  <  O–  <  Cl–.

  • If two substituents have the same immediate substituent atom, evaluate atoms progressively further away from the chiral center until a difference is found. i.e. CH3–  <  C2H5–  <  ClCH2–  <  BrCH2–  <  CH3O–.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

The Viewing Rule melting points, they rotate the plane of polarized light in opposite directions.

  • The chiral center must be viewed from the side opposite the lowest priority group.

  • Numbering the substituent groups from 1 to 4, with 1 being the highest and 4 the lowest in priority sequence, and put a viewers eye on the side opposite substituent #4.

  • If the progression from 1 to 3is clockwise, the configuration at the stereocenter is R. Conversely the counterclockwised progression is assigned as S.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Assign Priorities melting points, they rotate the plane of polarized light in opposite directions.

Twist the lowest

priority to the

back

Rotate Priorities


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Priorities melting points, they rotate the plane of polarized light in opposite directions.

2-Bromobutane

View &

Assign

(S)-2-Bromobutane



1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Only two kinds of motions are allowed for Fischer projection.

1) Rotation on page 180˚ is allowed for Fischer projection.

2) One group can be held steady while the other three rotate in either

a clockwise or a clockwise direction.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Assigning projection.R, S configurations to Fischer projections.

  • Assign priorities to the four substituents in the usual way.

  • Perform one of the two allowed motions to place the group

    of lowest (4th) priority at the top or bottom of the Fischer

    projection if it is necessary.

  • Determine the direction of rotation in going from priority

    1 to 2 to 3, and assign R (clockwise) or

    S (counterclockwise).


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Compounds Having Two or More Stereogenic Centers projection.

Stereocenter 2

Stereocenter 1

adrenaline

(1R), (2S)-(-)-Ephedrine


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

(+)-Pseudoephedrine and (-)-Pseudoephedrine are projection.diastereomers of (+)-Ephedrine.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Diastereomers projection.

  • Stereoisomers that are not mirror images of each other.

  • Diastereomers have similar chemical properties.

  • Diastereomers have different physical properties:

    melting points, boiling points, solubities in solvent, etc.

  • Diastereomers can be separated by fractional distillation,

    or crystallization.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Diastereomers projection.

Diastereomers


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Enantiomers: projection. non-superimposable (different) mirror images; most of chemical and physical properties are identical.

Diastereomers: are stereoisomers that are not mirror images (all stereoisomers except enantiomers) and have different chemical and physical properties.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Relationships Between Stereoisomers projection.

Stereoisomers

Enantiomeric with

Diastereomeric with

(1R), (2S)-(-)-Ephedrine

(1S), (2R)-(+)-Ephedrine

(1S), (2S)-(+)-

Pseudoephedrine

and

(1R), (2R)-(-)-

Pseudoephedrine

Cahn-Ingold-Prelog R/S notation = Specifies absolute configuration of a chiral center;

there is no correspondence between R and + or S and –


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Meso Isomer: projection.

an achiral molecule with 2 or more chiral centers and

an internal plane of symmetry; the molecule is achiral.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Number projection. of stereoisomers = a molecule with n stereogenic centers (and for which a meso isomer isn’t possible) will have 2n stereoisomers.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Resolution of Racemic Mixtures projection.

  • There are two basic ways that one can separate the

  • enantiomers in a racemic mixture:

  • Biological Resolution : Using a microbe which metabolizes

    one specific enantiomer leaving the other alone.

  • Chemical Resolution:The racemate is converted to two

    diastereoisomers. Once separated the diasteriosomeric

    forms are converted back to enantiomers in separate

    containers.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Z projection. isomer

E isomer

  • A competely unambiguous system, based on a set of group priority rules, assigns a Z (German, zusammen for together) or

    E (German, entgegen for opposite) to designate the stereoisomers.

  • Z is equivalent to cis and E is equivalent to trans.


1 c formic acid methanoic acid 2 c s acetic acid ethanoic acid

Today’s Quote projection.

One learns one’s most valuable lessons through hardships.

ชีวิตจะได้รับบทเรียนที่มีค่ามากที่สุดท่ามกลางความทุกข์ยาก