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MedChem Midterm 2 > I WANT SOME MOORE > Flashcards

I WANT SOME MOORE Flashcards

1
Q

Racemic Switch = Chiral Switch

A

a drug that is already sold as a racemate is patented and sold as a single enantiomer

examples:

  • Levomoprolol/Levotensin
  • Dexfenfluramine/Isomeride
  • Levodropropizine/Levotuss
  • Ibuprofen/Serectil
  • Levofloxacin/Cravit
  • Barnidipine/Hypoca
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2
Q

Why is drug chirality an important concept for future pharmacists and pharmaceutical scientists?

A

Drug metabolism

Defferent stereoisomers maybe metabolized through:

DIFFERENT MECHANISMS

DIFFERENT ENZYMES

have DIFFERENT METABOLITES

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3
Q

Eutomer

A

More Potent enantiomer

with DESIRED ACTIVITY

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4
Q

Distomer

A

LESS POTENT ENANTIOMER

with UNDESIRED activity

  • an impurity (“isomeric ballast”)​*
  • (-)-thalidomide = a TERATOGEN*
  • chemical that can cause birth defects by adversely altering development of embryo or fetus without necessarily altering organism’s genetic structure.
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5
Q

Eudismic Ratio

A

Eutomer / Distomer

High eudismic ratio when antagonist has stereogenic center in pharmacophore

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6
Q

Why are receptors and drugs three-dimensional?

A
  1. Bond length:
  2. Bond angles:
  3. Conformation: (torsion angle)
  4. Hybridization:
  5. Charges:
  6. Size and nature of R group:
    * (hydrophobic, flexible, aromatic, polar)*
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7
Q

Structure

Methods to determine & Related Terms

A

Complete Arrangement of all atoms of a molecule in space.

Determined by X-ray / Cryo-Em

Constitution

Configuration

Confirmation

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8
Q

Constitution

A

Nature & Number of atoms

types of Bonds

manner at which they are linked = Connectivity

Formula SAME

Constitution Different

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9
Q

Configuration

&

Isomer

A

Spatial arrangement of atoms that distinguishes molecules of the same CONSTITITION

Isomer = Same constitution, Different Configuration

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10
Q

Conformation

A

Spatial Arrangement of atoms in a molecule of given

CONSTITUTION & CONFIGURATION

ROTATION about single bonds

&

Pyramidal Inversions at some atoms (ie. N)

>GIVE RISE TO DIFFERENT CONFORMATIONS

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11
Q

Pyramidal Inversions

A

Change in Conformation (same consitution/configuration)

RAPID INTERCONVERSION

ex. Pyrimadal molecule like H-N-R3

*Not considered a Chiral Center

Technically CHIRAL but the rapid interconversion makes it NOT ISOLABLE

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12
Q

Chirality

A

Object that is

NOT SUPERIMPOSABLE ON ITS MIRROR IMAGE

Chirality is Removed if it acquires:

plane or center of symmetry

Can be chiral w/ symmetry of axis and none of the above

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13
Q

Chiral Center

=

Asymmetric Center

=

Stereogenic Center

A

TETRAHYDRAL (sp3) atom

Four NON-equivalent atoms or groups attached to it

  • *Sulfur or Phosphate tetrahydrals count (lone pair can be a group)*
  • *Nitrogen groups without the pyramidial inversions too (ex. quiniquodine)*

Optically Active UNLESS:

Has Plane or Center of Symmetry

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14
Q

σ Plane of Symmetry

A

Divides molecules so that

Points of one side of plane = Points on other side

by reflection through plane

ALWAYS ACHIRAL

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15
Q

A-Chiral

A

IS SUPERIMPOSABLE ON ITS MIRROR IMAGE

Molecule w/ σ Plane of Symmetry = Achiral

Molecule w/ Center of Symmetry = Achiral

Molecule w/ Rotational Axis of Symmetry (Cn) MAY BE CHIRAL

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16
Q

Center of Symmetry

“Point of Inversion”

*will be pointed out on test

A

Point from which ANY line drawn through the molecule

encounters identical environment in either direction from the center of symmetry

always ACHIRAL

*has chiral center but is ACHIRAL because of the center of symmetry

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17
Q

AXIS of Symmetry

Cn

N-fold axis

A

Axis which rotates molecule around by 360* / n

such that the new position is indistinguishable from OG.

can be CHIRAL if:

NO OTHER SYMMETRY PROPERTIES

WITHOUT Center or Plane of symmetry

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18
Q

Enantiomer

RR / SS

RS / SR

A

NON-Superimposable Mirror Images

type of stereoisomer

has to be CHIRAL

Enantiomers have EXACTLY the same energies

can’t be measured physically, EXCEPT by

OPTICAL ROTATION

(enantiomers rotate LIGHT in OPPOSITE directions)

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19
Q

Fischer Projection

A

to help represent TETRAHYDRAL carbon w/ its 4 substituents

as a 2-D projection

  1. Pretend there is a lightbulb on the left hand side
  2. Light is shining to make a shadow
  3. Pretend the shadow comes from the wedge projection

BADA BOOM A FISCHER PROJECTION

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20
Q

Fischer Projection of Carbohydrates

A

Two in VERTICLE = going INTO the plane

(Carbonyl CHO & R Group)

Two in HORIZONTAL = going OUT TOWARDS YOU

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21
Q

Newman Projection

A

for molecule with Two-Tetrahedral Centers

viewed along the C-C Axis

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22
Q

Enantiopure

A

containing ONLY ONE enantiomer

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23
Q

Racemate

=

Racemic Mixture

A

mixture that has EQUAL amounts of opposite enantiomers

50/50 mixture

*not meso (has single compound), racemate has mixture of enantiomers

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24
Q

levo-rotatory (-)

&

dextro-rotatory (+)

little d & little l

A

Optically Active Enantiomers

l = (-) = rotate plane of polarized light to the left

d = (+) = “ to the right

CAN NOT BE DETERMINED

25
Q

Enantiomerismic Properties

A

NOT distinguished by interactions with:

ACHIRAL molecules (like solvent)

Physical properties measured by techniques

(except polarized light)

Interact differently w/ other Entantiomeric molecules

ex. Biological receptors

26
Q

Hybrid Drugs

A

Different Therapeutic Activities

ex. Propanalol

d-(+)-enantiomer = Vasodilation

l-(-)-enantiomer = antihypertensive

27
Q

CAPITAL

L / D

for Carbohydrates

A

Look @ stereocenter FURTHEST away from the aldehyde / ketone of the carbohydrate at the TOP.

L = -OH GROUP ON LEFT

D = -OH GROUP ON RIGHT

originated from glyceraldehyde

*carbohydrates are TYPICALLY = D

28
Q

Erythrose

vs

Threose

A

Erythrose = Two High Priorites on the SAME SIDE

Threose = Two high priorities on Opposite Sides

29
Q

CAPITAL

L / D

for Amino Acids

A

Look @ stereocenter FURTHEST away from the Carboxylic acid of the AA at the TOP.

L = -NH2 GROUP ON LEFT

D = -NH2 GROUP ON RIGHT

*Amino acids are TYPICALLY = L

30
Q

Cahn-Ingold-Prelog (CIP) Rules

Clockwise = R

Counter Clockwise = S

A

Asign order by atomic MASS/NUMBER

Clockwise = R

  • Counter Clockwise = S*
  • If first “sphere” is the same go to the NEXT
  • Double Bonds = Multiple Atoms

=O > -O x 2

31
Q

Order of Atomic Masses

for presidence

A

C < N < O < F < Cl < (S) < Br

Lonepair < Hydrogen < D

32
Q

Double Bond Geometry

Z / E

A

Ze same side

E = opposite

Z / E= DIASTERIOMER

33
Q

Cyclic Compounds Geometry

Cis / Trans

A

Trans = priorities are on both on axial position

Ring flipped= Trans are both equitorial

Cis = priorites are axial / equatorial

Ring Flipped = Still on axial and equatorial

Cis / Trans = DIASTERIOMER

34
Q

Diastereomers

E vs Z

Cis vs Trans

RR/RS , SS/RS , SS/SR

A

stereoisomers that are not enantiomers​

can have:

two+ Chiral Centers, where not all chiral centers have opposite configuration ( ike RR/RS , SS/RS , SS/SR)

no chiral center(s) / non-chiral

just differ by spatial difference (not related to mirror reflection)

E / Z or Cis / Trans

35
Q

Meso Compounds

A

Have chiral (assymetric) centers but ARE NOT CHIRAL

ACHIRAL

b/c CONTAIN A PLANE OF SYMMETRY

(can have center of symmetry but not common)

ex. mesoTartaric Acid
* *not a racemate (mixture of compounds), meso is a single compound*

36
Q

Pseudo-Hybrid Drug

A

Multiple Isomeric Forms w/ different biologic activity

ex. Labetalol

RR = eutomer for Beta Blocker

S,R = eutomer for Alpha Blocker

S,S / R,S = Inactive (isomeric Ballast)

37
Q

EPIMER

A

Stereoisomers thet differ by ONLY ONE STEREOCENTER

still Diastereomers if 2> stereocenters

can be enantiomers & epimers if ONLY 1 stereocenter

38
Q

Number of Stereoisomers

A

Number of Stereoisomers = 2n

n = # of stereocenters

Z/E COUNT TOO!

  • unless there are MESO compounds*
  • <2n *
39
Q

Torsion Angle

(or Dihedral)

A

The single parameter differentiated such conformers is the TORSION ANGLE

Angle between two planes

You look down the two atoms that are IN COMMON

*NEWMAN PROJECTION

40
Q

synperi-planar

(eclipsed)

A

-30° to +30°

sp

HIGH ENERGY

41
Q

synclinal

(gauche)

A

+30° to +90°

(+sc shown)

  • 90° to -30°
  • sc as well
42
Q

anticlinal

(also eclipsed)

A

+90° to +150°

+ac (as shown)

  • 150° to -90°
  • ac
43
Q

antiperi-planar

(trans/anti)

A

+150° to -150°

ap

lowest energy

44
Q

Conformer

A

One set of stereoisomers

each characterized by a Conformation corresponding to a potential energy

Interconversion of conformations = infinite number

45
Q

Staggered Conformations

A

180°/ 60° / -60°

Torsion angle = groups are AS FAR AWAY AS POSSIBLE

  • *typically have LOWEST potential energies*
  • local/global minimums*
46
Q

Eclipsed Conformations

A

-120°/ 120° / 0°

Torsion angle between the 3 bonds = ZERO

  • *typically have the HIGHER potential energy*
  • maximums*
47
Q

Amide Bond

E / Z

Conformation

A

C-N bond acts like the Double Bond

C-N bond is much shorter than a single bond

(trans) Z is PREFFERED, due to sterics

*=O is the higher presidence group

48
Q

Ester Bonds

Cis (E) / Trans (Z)

Conformation

A

C-O bond acts like the Double Bond

C-O bond is much shorter than a single bond

(trans) Z is PREFFERED, due to sterics

*=O is the higher presidence group

49
Q

Hydrogen Bonding

on Conforormers

A

H-bonding can have a LOCKING EFFECT

on conformation about C-C Bonds.

Can overide unfavorable interactions

*synclinal interactions

50
Q

Why are all cyclic compounds NONPLANAR?

(except for 3-mem & aromatics)

A

Baeyer Strain

Balance between valence bond angle strain

Wants to be 109* but to be flat it needs to be 120*

Torsional Strain

If eclipsed (~flat) = torsional strain

If staggered (chair form) = tortional strain is relieved

51
Q

6-Membered Ring Conformations

A

Chair -> Half Chair (least favorable) ->Twist -> Boat -> Chair Flip

52
Q

What does the rate & equilibrium of chair-chair transitions depend on?

(6-membered rings)

A

–Presence of heteroatoms(O,N,S,P) instead of carbon atoms

–Steric size of substituents

–Existence of interactions which stabilize one particular conformer

–Presence of local dipoles

–Stereoelectronic effects (e.g. gauche effect, anomeric effect)

53
Q

Larger Substituants want to be placed in the ______ position

Why?

A

EQUITORIAL

Because of SYNAXIAL REPULSION

& sterics

A-value (conformational energy) = energy difference between the axial & equitorial positions

54
Q

5-Membered Systems

A

Envelope

Half Chair (MOST PREFFERED) -substituant is in EQUITORIAL

Envelope (ring flip)

Ring Pseudorotation / Conformational flux

much less ring strain, ring is constantly changing unlike 6mem

55
Q

-30° to +30°

HIGH ENERGY

A

synperi-planar

(eclipsed)

56
Q

+30° to +90°

(shown)

-90° to -30°

A

synclinal

(gauche)

57
Q

+90° to +150°

(as shown)

-150° to -90°

A

anticlinal

(also eclipsed)

58
Q

+150° to -150°

lowest energy

“Global Minimum”

A

antiperi-planar

(trans/anti)

MedChem Midterm 2 (6 decks)

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