THE PERICYCLIC REACTION THE MOST COMMON TOPIC INCLUDE THE SYLLABUS OF MANY SCIENCE STUDY INCLUDING BSC, MSC , PHARMA STUDY, AND MORE HENCE WE ARE COVERED ALL THE DATA OF IT HOPE THIS WILL MAKE READER EASY.
THE PERICYCLIC REACTION THE MOST COMMON TOPIC INCLUDE THE SYLLABUS OF MANY SCIENCE STUDY INCLUDING BSC, MSC , PHARMA STUDY, AND MORE HENCE WE ARE COVERED ALL THE DATA OF IT HOPE THIS WILL MAKE READER EASY.
Hydrogenation- definition, catalytic hydrogenation, homogeneous and heterogeneous catalytic hydrogenation, mechanism of catalytic hydrogenation, advantages and disadvantages of catalytic hydrogenation, applications of catalytic hydrogenation
Rearrangement to Electron Deficient Carbon
Rearrangement to Electron Deficient Nitrogen
Rearrangement to Electron Deficient Oxygen
Rearrangement to Electron-Rich Carbon
Aromatic Rearrangements
Hydrogenation- definition, catalytic hydrogenation, homogeneous and heterogeneous catalytic hydrogenation, mechanism of catalytic hydrogenation, advantages and disadvantages of catalytic hydrogenation, applications of catalytic hydrogenation
Rearrangement to Electron Deficient Carbon
Rearrangement to Electron Deficient Nitrogen
Rearrangement to Electron Deficient Oxygen
Rearrangement to Electron-Rich Carbon
Aromatic Rearrangements
The combination of a carbonyl group and a hydroxyl on the same carbon atom is called a carboxyl group. Compounds containing the carboxyl group are called carboxylic acids. The carboxyl group is one of the most widely occurring functional groups in organic chemistry.
Aromatic Carboxylic acids: Carboxylic acids have an aryl group bound to the carboxyl group is known as aromatic carboxylic acids. The general formula of an aliphatic aromatic carboxylic acid is Ar-COOH.
Acidity of carboxylic acid:
A carboxylic acid may dissociate in water to give a proton and a carboxylate ion. Dissociation of a carboxylic acid involves breaking an O-H bond gives a carboxylate ion with the negative charge spread out equally over two oxygen atoms, compared with just one oxygen atom in an alkoxide ion. The delocalized charge makes the carboxylate ion more stable therefore; dissociation of a carboxylic acid to a carboxylate ion is less endothermic.
Preparation Methods:
1. Oxidation:
The oxidation of aldehyde with oxidizing agents such as CrO3 to forms carboxylic acids containing the same numbers of carbon atoms with a oxidizing agents like chromic acid, chromium trioxide. The silver oxide (Ag2O) in aqueous ammonia solution (Tollen’s reagent) is mild reagent give good yield at room temperature. E.g. Acetaldehyde reacts with CrO3 in aqueous acid to give acetic acid.
2. Grignard reagents (from CO2):
Carboxylic acid can be prepared by the reaction of Grignard reagent (alkyl magnesium halide) with carbon dioxide (CO2) in presence of dry ether. Grignard reagents react with carbon dioxide to forms a magnesium carboxylates which on hydrolysis by dilute HCl produces carboxylic acids.
3. Hydrolysis of nitrile:
The hydrolysis of nitrile or cyanide in presence of dilute acid to forms a carboxylic acid. In this reaction –CN group is converted to a –COOH group.
4. Hydrolysis Reactions:
All the carboxylic acid derivatives can be hydrolyzed into the carboxylic acid in the acidic or basic media; the hydrolysis reaction is fast and occurs in presence of water with no acid or base catalyst.
1. From Ester (Hydrolysis of ester): Ester can be hydrolyzed in either acidic or basic medium to yield carboxylic acid. The ester is heated with an excess of water contains strong acid or base catalyst.
Properties of Carboxylic Acids:
1. Low molecular weights carboxylic acids are colourless liquid at room temperature i.e. lower member ate liquid up to C9 and have characteristic odors whereas higher members are solid.
2. Carboxylic acids are polar organic compound. Low molecular weight carboxylic acids (first four members) are soluble in water whereas solubility in water decrease as molecular weight and chain lengthing increases.
3. Aromatic acids are insoluble in water.
4. Carboxylic acids have higher melting and boiling point due to their capacity to readily form stable hydrogen-bonded dimers.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
2. 2
• Epoxides are cyclic three member ethers containing
oxygen atom as member of ring. Epoxides are also
called oxiranes.
• The C—O—C bond angle for an epoxide must be near to
60°, a considerable deviation from the tetrahedral bond
angle of 109.5°.
• Thus, epoxides have angle strain, making them more
reactive than other ethers.
3. 3
• Epoxides can be named in three different ways — As
epoxyalkanes, oxiranes, or alkene oxides.
• To name an epoxide as an epoxyalkane, first name the
alkane chain or ring to which the O atom is attached, and
use the prefix “epoxy” to name the epoxide as a
substituent. Use two numbers to designate the location
of the carbon atoms to which the O’s is bonded.
Nomenclature of EpoxidesNomenclature of Epoxides
4. 4
• Epoxides can also be named as derivatives of oxirane,
the simplest epoxide having two carbons and one oxygen
atom in a ring.
• The oxirane ring is numbered to put the O atom at
position one, and the first substituent at position two.
• In most of cases, no number is used for a substituent in a
monosubstituted oxirane.
O O
CH3
oxirane
(epoxyethane)
2-methyloxirane
(epoxypropane)
O
CH3
O
CH3H3C
O
CH3
CH3
2-ethyloxirane
(1,2-epoxybutane)
2,3-dimethyloxirane
(2,3-epoxybutane) 2,2-dimethyloxirane
(1,2-epoxy-2-methy-
propane)
5. 5
• Epoxides are also named as alkene oxides, since they
are often prepared by adding an O atom to an alkene. To
name an epoxide in this way:
Mentally replace the epoxide oxygen with a double
bond.
Name the alkene.
Add the word oxide at the end.
H2C CH2
O
H2C
CH3
O
CH3
ethene
(ethylene)
oxirane
(ethylene oxide)
prop-1-ene
(propylene)
2-methyloxirane
(propylene oxide)
6. 6
Preparation of epoxidePreparation of epoxide
There are two main laboratory methods for the preparation of
epoxides:
Epoxidation of alkenes by reaction with peroxy acids.
Base-promoted ring closure of vicinal halohydrins.
7. 7
Epoxidation of alkenes – oxidationEpoxidation of alkenes – oxidation
Epoxides are very easy to prepare via the reaction of an alkene with a peroxy acid.
This process is known as epoxidation.
C C R O
O
O
H
O
R O
O
H+ +
alkene
peroxy acid
Epoxide
Carboxylic acid
oxidation
A commonly used peroxy acid is
-peroxyacetic acid (CH3CO2OH),
- peroxy trifluoroacetic acid, peroxy
- benzoic acid,
- peroxy m-chlorobenzoic acid, etc.
Also carried out by using hydrogen peroxide and NaOH.
8. 8
Epoxidation of alkenesEpoxidation of alkenes
Epoxidation of alkenes with peroxy acids is a syn addition to the double bond.
Substituents that are cis to each other in the alkene remain cis in the epoxide;
substituents that are trans in the alkene remain trans in the epoxide.
C
C
H
H
H3C O
O
O
H
O
H
H
H3C O
O
H+ +oxidation
Peracetic acid
acetic acid
(E)-1,2-diphenylethene
(2R,3R)-2,3-diphenyloxirane
O
H H
(2R,3S)-2,3-diphenyloxirane
Not forming isomeric -
9. 9
Epoxidation of alkenesEpoxidation of alkenes
Addition of an O atom from either side of the trigonal planar cis-alkene leads to the same
compound - an achiral meso compound that contains two stereogenic centers.
H3C O
O
H+
acetic acid
O
H
H3C CH3
H
C C
H
CH3H3C
H
(Z)-but-2-ene
H3C O
O
O
H+ oxidation
Peracetic acid O
H
CH3H3C
H
+
O is added
below the plane
O is added
above the plane
(2R,3S)-2,3-
dimethyloxirane
(2S,3R)-2,3-
dimethyloxirane
pair of achiral meso compounds are formed
Addition of an O atom from either side of the trigonal planar trans-alkene leads to the
same compound - an enantiomeric compounds.
C C
H
CH3H
H3C
H3C O
O
O
H
O
H
H3C
CH3
H+ oxidation
Peracetic acid(E)-but-2-ene
O
H
CH3
H3C
H
+ + H3C O
O
H
acetic acid
O is added
below the plane
O is added
above the plane
(2R,3R)-2,3-
dimethyloxirane
(2S,3S)-2,3-
dimethyloxirane
pair of enantiomers are formed
12. 12
• Organic compounds that contain both a hydroxy group and a halogen atom on
adjacent carbons are called halohydrins. It was synthesized by the treatment of
halogen followed by hydrolysis.
• In halohydrins, an intramolecular version of the Williamson ether synthesis can
occur to form epoxides.
From vicinal halohydrinsFrom vicinal halohydrins
C C
Alkene
C C
O
Epoxide
X2
HOH
C C
XHO
HO-
vicinal halohydrin
13. 13
From vicinal halohydrins - stereochemistryFrom vicinal halohydrins - stereochemistry
Substituents that are cis to each other in the alkene remain cis in the epoxide.
This is because formation of the bromohydrin involves anti addition, and the
ensuing intramolecular nucleophilic substitution reaction takes place with
inversion of configuration at the carbon that bears the halide leaving group.
C C
HH
C C
HH
O
Br2
HOH
HO-
vicinal halohydrin
C C H
Br
HO
H
C C H
Br
-
O
H
-Br-
(Z)-but-2-ene
cis-2,3-epoxybutane
(2R,3S)-2,3-dimethyloxirane
C C
H
H
C C
H
H
O
trans-2,3-epoxybutane
Br2
HOH
HO-
vicinal halohydrin
C C
Br
HO
H
H
C C
Br
-
O
H
H
-Br-
(E)-but-2-ene
(2R,3R)-2,3-dimethyloxirane
15. 15
Reactions of EpoxidesReactions of Epoxides
• Recall that epoxides do not contain a good leaving group.
• Epoxides do contain a strained three-membered ring with two polar
bonds.
• Nucleophilic attack opens the strained three-membered ring, making it a
favorable process even with a poor leaving group.
16. 16
• The reaction occurs readily with strong nucleophiles and with acids like HZ,
where Z is a nucleophilic atom.
17. 17
• Virtually all strong nucleophiles open an epoxide ring by a two-step reaction
sequence:
• In step 1, the nucleophile attacks an electron-deficient carbon, thus cleaving the
C—O bond and relieving the strain of the three-membered ring.
• In step 2 the alkoxide is protonated with water to generate a neutral product with
two functional groups on adjacent atoms.
• Common nucleophiles that open the epoxide ring include ¯OH, ¯OR, ¯CN, ¯SR
and NH3. With these strong nucleophiles, the reaction occurs by an SN2
mechanism.
19. 19
Let’s now consider the stereochemical consequences of the reaction of 1,2-
epoxycyclohexane with ¯OCH3.
Nucleophilic attack of ¯OCH3 occurs from the backside at either C—O bond,
because both ends are similarly substituted. Since attack at either side occurs with
equal probability, an equal amount of the two enantiomers (i.e. a racemic mixture)
is formed.
21. 21
• Acids HZ that contain a nucleophile Z also open epoxide rings by a two-step
sequence.
• HCl, HBr and HI, as well as H2O and ROH in the presence of acid, all open an
epoxide ring in this manner.
23. 23
• Ring opening of an epoxide with either a strong nucleophile
or an acid HZ is regioselective because one constitutional
isomer is the major or exclusive product.
• Note that the site selectivity of these two reactions is exactly
opposite.
24. • Epoxides can be opened by many strong nucleophiles.
• Both regioselectivity and stereoselectivity must be
considered.
Ring-opening of Epoxides
25. Question
• What is the product isolated when the epoxide below reacts with
NaOCH3
in CH3
OH?
• A) B)
• C) D)