this video very useful for all chemistry related exam like
jee main+adwance
bsc
msc
iit jam
CSIR
gate
du
bhu
hcu
in this we discuss stereochemistry of substitute cyclohexane.
we discuss about
1,3 diaxal interaction
1,2 interaction
mono substitute cyclohexane
Conformation of Cyclohexane
Stereochemical configuration of cyclohexane
Newman projection of cyclohexane
Repulsion energy of substituent in cyclohexane
Crown ethers
NOMENCLATURE
GENERAL SYNTHESIS OF CROWN ETHER
AZA CROWN
CRYPTAND
APPLICATIONS
1. SYNTHETIC APPLICTION
Esterification
Saponification
Anhydride formation
Potassium permanganate oxidation
Aromatic substitution reactions
Elimination reactions
Displacement reaction
Generation of carbenes
Superoxide anion
Alkylations – 1. o-alkylations
2. c-alkylations
3. n-alkylations
2. ANALYTICAL APPLICATION
Determination of gold in geological samples
Super critical fluid extraction of trace metal from solid and liquid materials
Application of ionic liquids in analytical chemistry
Oxidation and determination of aldehydes
Crown ethers are used in the laboratory as phase transfer catalyst
OTHER APPLICATION
It is used in photocynation
Resolution of racemic mixture
Benzoin condensation
Hetrocyclisation
Synthesis of furanones
Acetylation of secondary amines in presence of primary amine
Cyclohexane exists in different conformations viz chair, boat, twist boat and half chair. These conformations possess different energies. Therefore they differ in energy.
Crown ethers
NOMENCLATURE
GENERAL SYNTHESIS OF CROWN ETHER
AZA CROWN
CRYPTAND
APPLICATIONS
1. SYNTHETIC APPLICTION
Esterification
Saponification
Anhydride formation
Potassium permanganate oxidation
Aromatic substitution reactions
Elimination reactions
Displacement reaction
Generation of carbenes
Superoxide anion
Alkylations – 1. o-alkylations
2. c-alkylations
3. n-alkylations
2. ANALYTICAL APPLICATION
Determination of gold in geological samples
Super critical fluid extraction of trace metal from solid and liquid materials
Application of ionic liquids in analytical chemistry
Oxidation and determination of aldehydes
Crown ethers are used in the laboratory as phase transfer catalyst
OTHER APPLICATION
It is used in photocynation
Resolution of racemic mixture
Benzoin condensation
Hetrocyclisation
Synthesis of furanones
Acetylation of secondary amines in presence of primary amine
Cyclohexane exists in different conformations viz chair, boat, twist boat and half chair. These conformations possess different energies. Therefore they differ in energy.
Dynamic Stereochemistry and What role does conformation plays on stereochemistry is being exemplified in this presentation. Useful for the Undergraduate and Postgraduates students of Pharmacy, Pharmaceutical Chemistry and Chemical Sciences
Molecular Rearrangements of Organic Reactions ppsOMPRAKASH1973
This PPT is usefull for aspirants of JEE-IIT, CSIR-NET and UPSC exams in CHEMISTRY section. It is also usefull for grduates and Post graduates students of Indian Universities.
An organic species which has a carbon atom bearing only six electrons in its outermost shell and has a positive charge is called carbocation.
The positively charged carbon of carbocation is sp2 hybridized.
The unhybridized p-orbital remains vacant.
They are highly reactive and act as reaction intermediate.
They are also called carbonium ion.
The presentation is prepared for lecture for the M. Sc Chemistry students studying under University of Madras (MER3A: Unit III). It is dealing with Aromaticity and Organic Photochemistry
Rearrangement to Electron Deficient Carbon
Rearrangement to Electron Deficient Nitrogen
Rearrangement to Electron Deficient Oxygen
Rearrangement to Electron-Rich Carbon
Aromatic Rearrangements
Dynamic Stereochemistry and What role does conformation plays on stereochemistry is being exemplified in this presentation. Useful for the Undergraduate and Postgraduates students of Pharmacy, Pharmaceutical Chemistry and Chemical Sciences
Molecular Rearrangements of Organic Reactions ppsOMPRAKASH1973
This PPT is usefull for aspirants of JEE-IIT, CSIR-NET and UPSC exams in CHEMISTRY section. It is also usefull for grduates and Post graduates students of Indian Universities.
An organic species which has a carbon atom bearing only six electrons in its outermost shell and has a positive charge is called carbocation.
The positively charged carbon of carbocation is sp2 hybridized.
The unhybridized p-orbital remains vacant.
They are highly reactive and act as reaction intermediate.
They are also called carbonium ion.
The presentation is prepared for lecture for the M. Sc Chemistry students studying under University of Madras (MER3A: Unit III). It is dealing with Aromaticity and Organic Photochemistry
Rearrangement to Electron Deficient Carbon
Rearrangement to Electron Deficient Nitrogen
Rearrangement to Electron Deficient Oxygen
Rearrangement to Electron-Rich Carbon
Aromatic Rearrangements
This presentation describes the concept of Hyperconjugation in simple words, gives definition of hyperconjugation, explains why it is called as 'No bond Resonance' and gives the effects of hyperconjugation on the chemical properties of compounds: alkyl cations and their relative stability, alkyl radicals and their relative stability, alkenes and their relative stability, bond length, anomeric effect and Baker - Nathan effect.
Conformational isomerism
Conformations of Ethane:
Conformations of Cyclohexane
Representation of conformations:
Sawhorse projection:
Newman projection:
The conformational analysis of cyclohexane
CONFORMATION OF MONO SUBSTITUTED CYCLOHEXANE
for video go my YouTube channel science world
copy this link https://youtu.be/cKbQvOxtNbI and search in youtube
In this video we solve coordination quiz part 2
#inorganicChemistry
#CoordinationChemistry
#coordinationIsomers
#crystal_field_theory
#jahn_teller_distortion
#colour_theory
#coordination_Isomers
#spin_selection_rule
#coordination_quiz
#spinalcompound
#CFT
#inverse_spinal
#normal_spinal
#JTD
#hydration_energy
#colour_of_complex_compound
#crystal_field_diagram_of_octahedral_comples
#existence_of_Ag3+
#spinal
#quiz_dicussion
#inorganicChemistry
#CoordinationChemistry
tetrahedral complex
#hydrationenergy
#NiCO4
#OsO4
#NiCl4]2-
#metal_ion
link or playlist of crystal field theory
https://youtube.com/playlist?list=PLA1jCLnc0NdOm-zSIlEtyh067DSe6sOYX
link of playlist of main group compound
https://youtube.com/playlist?list=PLA1jCLnc0NdM5yfM3IwaSy65-drs307Kq
link of hydration energy of d block element
https://youtu.be/ULaE3qwT8tQ
link of concept of hydration energy
https://youtu.be/iJ9uGR6RkeA
https://youtu.be/fB2muVLc_0A
this video very useful for all #chemistry related exam like
#jee main+ #adwance
#bsc
#msc
#iit #jam
#CSIR
#gate
#du
#bhu
#hcu
link of playlist of crystal field theory
https://youtube.com/playlist?list=PLA1jCLnc0NdOm-zSIlEtyh067DSe6sOYX
link of playlist of color theory
https://youtube.com/playlist?list=PLA1jCLnc0NdOTROKOS0axGBQn0MkkVr9d
coordination quiz 1 ||crystal field theory MUKULsethi5
this is ppt of coordination quiz solve all question solution video available in youtube
link of solution video is
https://youtu.be/u-nPDRGexbQ
#crystal_field_theory
#jahn_teller_distortion
#colour_theory
#spin_selection_rule
#coordination_quiz
#CFT
#JTD
#colour_of_complex_compound
#crystal_field_diagram_of_octahedral_comples
#existence_of_Ag3+
#spinal
#quiz_dicussion
#inorganicChemistry
#CoordinationChemistry
property of Tris(acetylacetonato)manganese(III) MUKULsethi5
this presentation useful for discussing #chemical and #physical property and application of ..
#Manganese(III)acetylacetonate
#Manganicacetylacetonate
#3-Penten-2-one,4-hydroxy-,manganese(3+) salt
#Mangan(3+)tris[(2Z)-4-oxo-2-penten-2-olat]
#3-Penten-2-one,4-hydroxy-,manganese(3+)salt,(3Z)-(3:1)
in this I discuss chemical and physical property, #spectra, application, #harmness etc
sufficient method of hydrogen production by water gas shift reactions MUKULsethi5
today energy production in big race, because population and technology increasing rate is very fast,
we discussed hydrogen as good energy source and some synthesis method of hydrogen gas and major focus on water gas shift reaction
#water, #watergasshiftreaction,
#energy
#nanoparticle
#property_of_nanopartical
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
2. Simple representation
Conformation of Cyclohexane
1. Chair Conformation
2. Boat Conformation
3. Twist Conformation or Skew Boat Conformation
4. Half Chair Conformation
Cyclohexane is a cycloalkane with the molecular formula C6H12.
Cyclohexane is non-polar. Cyclohexane is a colourless, flammable liquid
with a distinctive detergent-like odour.
2
3. stability order: chair > twist-boat > boat> half-chair
Energy diagram of
Conformation of
cyclohexane
3
4. In Cyclohexane every carbon have 2 more groups which one is above
the plane and another one is below the plane
In chair form there are
3 axial-up group
3 axial-down group
3 Equatorial-Up group
3 Equatorial-down group
4
6. Most stable conformer of cyclohexane is chair form.
So generally cyclohexane exist as chair form
If cyclohexane have one or more than one group which larger than hydrogen
so they fell some repulsion which decrease stability
1
2
3
4
5
6
Generally this repulsion is 2 type
1,3-Diaxial Interactions
1, 2 repulsion
6
7. 1,3-Diaxial Interactions
A
H
H
H
H
When any group which larger then hydrogen place in axial position
then it feel interaction with 3ed position carbons axial hydrogen .
This is type gauche interactions in Newman projection.
7
9. Q
A
1 and 4 is 1,3 repulsion
2 is 1, 2 repulsion
This repulsion due to attraction of adjacent substituent
9
10. A
H
H
H
H
CH3
• When the cyclohexane ring bears a substituent, the two chair
conformers are not the same. In one conformer the substituent
is axial, in the other it is equatorial.
• Due to steric hindrance In the axial location, substituent
groups prefer to be equatorial and that chair conformer
predominates in the equilibrium.
1, 3 repulsion
10
11. Why Iodine bromine chlorine etc. have low repulsion energy
In mono-substituted cyclohexane, the energy difference between
axial and equatorial conformers with a given substituent is known
as its A-value.
A value useful to find repulsion energy of substitute cyclohexane
Generally A value is additive in nature
11
12. We know that conformational isomers normally interconvert
rapidly so both form exist together but one form is more
compare to other
A value
12
13. An ethyl group is one carbon larger than a methyl group, About double in
size. it must be produce twice steric hindrance, and the energy difference
would be twice as big.
But the observable value similar to methyl group because The ethyl group
can rotate such that the CH3 points away from the ring, where it does not
lead to any significant increase in strain
13
14. the isopropyl group represents a secondary carbon attached to the
cyclohexane. There is a relatively small but significant increase in strain
to 2.15 kcal/mol .
This is because the isopropyl group can still adopt a conformation where
the C-H bond lies over the cyclohexane ring, which does not bring it into
significant contact with the axial C-H bonds.
14
16. Given that oxygen has a larger atomic number than carbon,
it’s not unreasonable to think that the OH group might be
“bulkier” than carbon.
But A value of Hydroxyl group is less than CH3 because
less number of hydrogen
16
17. Along similar lines one could be forgiven for thinking that Br,
being such a heavy and large atom, might exert a large
destabilizing influence when in the axial position. However, the
difference is only 0.43 kcal/mol, less than that for OH.
Because there are no hydrogen atom
the A values for Cl, Br, and I are all roughly similar (about 0.43
or so). This is because the increased size is balanced by the
increased bond lengath – the halogens might be increasing in size
along Cl <Br < I – but they are also getting farther away.
17
20. Compounds with 1,2-ax,ax-substitutions are always trans.
Compounds with 1,2-eq,eq-substitutions are always trans as well.
Compounds with 1,2-ax,eq- or 1,2-eq,ax-bonds are always cis.
Compounds with 1,3-ax,ax-substitutions are always cis.
Compounds with 1,3-eq,eq-substitutions are always cis as well.
20
21. Compounds with 1,3-ax,eq- or 1,2-eq,ax-bonds are
always trans.
Compounds with 1,4-ax,ax-substitutions are always trans.
Compounds with 1,4-eq,eq-substitutions are always trans as
well.
Compounds with 1,4-ax,eq- or 1,4-eq,ax-bonds are always cis
21
22. Stereo of 1,2 substitute cyclohexane
cis
trans
R
2
R
1
R
2
R
1
R
1
R
2
R
2
R
1
22
25. 1,1-dimethylcyclohexane: Both ring flip isomers identical: +1.8
kcal/mol.
cis-1,2-dimethylcyclohexane: Both ring flip isomers identical: one axial
methyl group = +1.8 kcal/mol. There is a gauche interaction between the
two methyl groups that raises this by 0.9 kcal/mol
Both energy is 1.8kcal/mol
Both energy is 2.7kcal/mol
25
26. trans-1,2-dimethylcyclohexane: Diaxial form would be 2*(+1.8)
kcal/mol = +3.6 kcal/mol, but the diequatorial form would be 0.
However, we should add a little bit back because the two methyl groups
are gauche to each other (this is about +0.9 kcal/mol
cis-1,3-dimethylcyclohexane: The diaxial form would be more than 2 x
1.8 kcal/mol, because the two methyl groups would run into each other
(rather than just into an axial hydrogen). The diequatorial form would
have no steric interactions, so it would have a strain energy of 0.
+3.6 kcal/mol
Some about 0 kcal/mol
more than 3.6 kcal/mol
0 kcal/mol
26
27. trans-1,3-dimethylcyclohexane: Both forms identical, with one
axial methyl group. +1.8 kcal/mol.
trans-1,4-dimethylcyclohexane: The diaxial form would be 2 x
1.8 kcal/mol = +3.6 kcal/mol; the diequatorial form would have
no interactions and be 0.
cis-1,4-dimethylcyclohexane: Both ring flip isomers identical:
one axial methyl group = +1.8 kcal/mol.
3.6 kcal/mol 0kcal/mol
27
30. There 2 different energy's conformers
Ax- ax conformer which hydroxy group in
axial position and have four 1,3diaxial
intrection
Newman presentation of stable form of trans 1,2 dicyclohexanol
30
31. There 2 different energy's conformers
Ax-ax conformer which hydroxy group
in axial position and have two 1,3 diaxial
intrection and one hydrogen bond.
Newman presentation of Cis 1,3 dicyclohexanol
31
41. Substitute cyclohexane exist as different conformer with different
interaction, orientation, and energy.
So they so different reaction in different conformation or some time only
one conformer is reactive and another is inactive.
This is because some time substituent is an axial position and
some time equatorial position
41
42. SN1 reaction is 2 and more than 2 step reaction
RDS step is first step in which carbocation is form duiring removing groups
In 1st reaction repulsion between
Ots group and axial hydrogen so
Ots group remove easily to
remove repulsion fources
There ots group in equitorial
position so there are no 1,3
repulsion so Ots can’t remove
easily
42
43. In this reaction Nearby groups can evidently increase the rate
of substitution reactions significantly
43
47. E1 and E2 are
mechanism path way of
elimination reaction
Reaction goes to which
path way decide strio
and orientation of
substituent cyclohexane
47
48. If removing group is
axial position it remove
easily because 1,3
repulsion
48
49. E2 mechanism have
single step
This occurs only anti
elimination
If L.G. and Hydrogen
are axial and anti
position then it remove
easily
49
56. In trans isomer there are no
1,3 diaxial intrection between
hydroxyl and hydrogen atom
so this reaction rate is slow
In cis isomer hydroxy group
faces 1,3 diaxial interaction
56
58. Path A 1,3 repulsions
occurs between ester
group and axial
hydrogen. So OH- ion
cant join easily so RDS
step is slow
Path B there are no 1, 3
interaction so RDS step
is fast
RDS step Base catalyze hydrolysis of ester is attacking of OH- ion on
C=O bond and attach there
58
65. The effect of conformation on E2 reactions is demonstrated by the difference
in rates of the dehydrobromination of cis- and trans-1-bromo-4-tert-
butylcyclohexane. The axial bromine atom of the cis isomer is eliminated
about 500 times faster than the equatorial atom of the trans isomer.
65
67. Which of the following compounds will react faster in an E2
reaction; trans-1-bromo-2-isopropylcyclohexane or cis-1-bromo-
2-isopropylcyclohexane?
Answer
The cis isomer will react faster than
the trans. The cis isomer has two possible
perpendicular hydrogen in which it can eliminate
from.
67