Benzopyran is a cyclic organic compound that results from the fusion of a benzene ring to a heterocyclic pyran ring. According to IUPAC nomenclature it is called chromene.
synthesis of hetero-cyclic drugs which act as anti-malarial drugs where you get all information about synthesis, preparation, properties, uses of drugs.
synthesis of hetero-cyclic drugs which act as anti-malarial drugs where you get all information about synthesis, preparation, properties, uses of drugs.
Protecting and Deprotecting groups in Organic ChemistryAshwani Dalal
It gives the concise and complete protecting and deprotecting groups. A protecting group or protective group is introduced into a molecule by chemical modification of a functional group to obtain chemoselectivity in a subsequent chemical reaction. It plays an important role in multistep organic synthesis
This is a brief introduction to the Baeyer-Villiger Oxidation/Rearrangement in the form of a micro-presentation.
The Baeyer-Villiger Oxidation is useful in the synthesis of esters and lactones. Consult the pdf file for more information.
You are encouraged to visit :
http://www.harinchem.com/named_organic_reactions.html to view a flash micro movie of the mechanism.
Please send feedback or questions through:
http://www.harinchem.com/contactpage.aspx.
The importance of lactone synthesis is underscored by its presence in diverse molecules of pharmacological significance, including statins (HMG CoA reductase inhibitors).
SMILES REARRANGEMENT [REACTION AND MECHANISM]Shikha Popali
THE SMILES REARRANGMENT IS THE PROCESS OF REARRANGING OF ELEMENTS OF THE STRUCTURE, WHERE IN THIS PRESENTATION HOW TO REARRANGE IS EXPLAIN WITH ITS MECHANISM
N-BROMOSUCCINAMIDE A REAGENT USED IN THE SYNTHESIS, IT IS ALSO A SYNTETIC REAGENT AND HERE IN THIS PRESENTATION THE MOLECULAR FORMULA ITS ALTERNATE NAME APLLICATION ARE DISCUSSED.
When there are two functional groups of unequal reactivity within a molecule, the more reactive group can be made to react alone, but it may not be possible to react the less reactive functional group selectively.
A group the use of which makes possible to react a less reactive functional group selectively in presence of a more reactive group is known as protecting group.
A protecting group blocks the reactivity of a functional group by converting it into a different group which is inert to the conditions of some reaction(s) that is to be carried out as part of a synthetic route
Retrosynthesis or The Disconnection approach has been discussed in this presentation. Useful Courseware for the Undergraduate and Postgraduate students of Pharmacy , and Chemical Sciences
Protecting and Deprotecting groups in Organic ChemistryAshwani Dalal
It gives the concise and complete protecting and deprotecting groups. A protecting group or protective group is introduced into a molecule by chemical modification of a functional group to obtain chemoselectivity in a subsequent chemical reaction. It plays an important role in multistep organic synthesis
This is a brief introduction to the Baeyer-Villiger Oxidation/Rearrangement in the form of a micro-presentation.
The Baeyer-Villiger Oxidation is useful in the synthesis of esters and lactones. Consult the pdf file for more information.
You are encouraged to visit :
http://www.harinchem.com/named_organic_reactions.html to view a flash micro movie of the mechanism.
Please send feedback or questions through:
http://www.harinchem.com/contactpage.aspx.
The importance of lactone synthesis is underscored by its presence in diverse molecules of pharmacological significance, including statins (HMG CoA reductase inhibitors).
SMILES REARRANGEMENT [REACTION AND MECHANISM]Shikha Popali
THE SMILES REARRANGMENT IS THE PROCESS OF REARRANGING OF ELEMENTS OF THE STRUCTURE, WHERE IN THIS PRESENTATION HOW TO REARRANGE IS EXPLAIN WITH ITS MECHANISM
N-BROMOSUCCINAMIDE A REAGENT USED IN THE SYNTHESIS, IT IS ALSO A SYNTETIC REAGENT AND HERE IN THIS PRESENTATION THE MOLECULAR FORMULA ITS ALTERNATE NAME APLLICATION ARE DISCUSSED.
When there are two functional groups of unequal reactivity within a molecule, the more reactive group can be made to react alone, but it may not be possible to react the less reactive functional group selectively.
A group the use of which makes possible to react a less reactive functional group selectively in presence of a more reactive group is known as protecting group.
A protecting group blocks the reactivity of a functional group by converting it into a different group which is inert to the conditions of some reaction(s) that is to be carried out as part of a synthetic route
Retrosynthesis or The Disconnection approach has been discussed in this presentation. Useful Courseware for the Undergraduate and Postgraduate students of Pharmacy , and Chemical Sciences
The IOSR Journal of Pharmacy (IOSRPHR) is an open access online & offline peer reviewed international journal, which publishes innovative research papers, reviews, mini-reviews, short communications and notes dealing with Pharmaceutical Sciences( Pharmaceutical Technology, Pharmaceutics, Biopharmaceutics, Pharmacokinetics, Pharmaceutical/Medicinal Chemistry, Computational Chemistry and Molecular Drug Design, Pharmacognosy & Phytochemistry, Pharmacology, Pharmaceutical Analysis, Pharmacy Practice, Clinical and Hospital Pharmacy, Cell Biology, Genomics and Proteomics, Pharmacogenomics, Bioinformatics and Biotechnology of Pharmaceutical Interest........more details on Aim & Scope).
All manuscripts are subject to rapid peer review. Those of high quality (not previously published and not under consideration for publication in another journal) will be published without delay.
Lecture "Phenols and amines" on Pharmaceutical Chemistry is devoted by synthesis, physico-chemical properties and analysis of medicinal substances, which are derivatives of phenols and aromatic amines.Also is included examples of tests "KROK-2".
Is the separation of medicinally active portions of plant (and animal) tissues using selective solvents through standard procedures.
The products so obtained from plants are relatively complex mixtures of metabolites, in liquid or semisolid state or in dry powder form (after removing the solvent), & are intended for oral or external use
The Medicinal plants constitute an effective source of both traditional and modern medicines, herbal medicine has been shown to have genuine utility and about 80% of rural population depends on it as primary health care. [WHO, (2005)]
the redistribution of the energy of orbitals of individual atoms to give new orbitals of equivalent energy and named the process as hybridisation. In this process, the new orbitals come into existence and named as the hybrid orbitals
Indole is an aromatic heterocyclic organic compound. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing pyrrole ring. Compounds that contain an indole ring are called indoles.
The delocalization of σ-electron in to adjacent π orbital or p-orbital is called hyperconjugation. The contributing structures involving sigma electrons of C - H bond do not show any covalent bond between C and H. Hyperconjugation, therefore, is also called as "no bond resonance" or "Baker-Nathan effect
Benzene has 6π electrons delocalized in 6p orbitals that overlap above and below the plane of the ring. Because benzene’s six pie electrons satisfy Huckel’s rule, benzene is especially stable. Reaction that keep the aromatic ring intact are therefore favoured
Pericyclic reactions are defined as reactions that occur by concerted cyclic shift of electrons. In concerted reaction, reactant bonds are broken and product bonds are formed at the same time.
More from Dr.Mohd Kamil Hussain, Department of Chemistry, Govt Raza PG College Rampur (10)
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
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.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
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.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
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.
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.
2. Benzopyran is a cyclic organic compound that results from the
fusion of a benzene ring to a heterocyclic pyran ring. According to
IUPAC nomenclature it is called chromene.
2H-chromene 4H-chromene1H-isochromene 3H-isochromene
O
R
R
2,2-dialkyl2H-chromene
2H-chromene are constituents of considerable number of natural phenolic compounds
including flavanoids, coumarins, rotenoids, stilbenoids, and chromene glycosides.
These compounds are widely distributed in nature and almost every class of natural
phenolic compounds include members that feature a 2,2-dialkylchromene ring system
2H-Chromens have been extensively as a consequence of their widespread natural
occurrence and extremely diverse biological property.
2H-chromenes,which are also known as 2H-1-benzoprans, are an important family of
oxygen hetrocycles that have a benzo-fused-2H-Pyran ring system.
3. Tephrosin is a natural fish poison found in the
leaves and seeds of Tephrosia purpurea.it
shows anti cancer activity in human cancer
cell lines
Acronycine is an antineoplastic agent
isolated from Acronychia baueri
Anti-cancer chromenes
Anti-leukemia Calanone from Calophyllum
teysmannii var. inophylloide
4. Calanolide A is a new, experimental non-nucleoside
reverse transcriptase inhibitor (NNRTI) first acquired
from Calophyllum lanigerum
Inophyllum B is a potent non-nucleoside inhibitor of
reverse transcriptase human immunodeficiency virus
type 1(HIV-1 RT) from Calophyllum ionophyllum
Mallotochromene isolated from of Mallotus
japonicu. have been tested for their ability to
inhibit the activity of human immunodeficiency
virus (HIV)-reverse transcriptase
5. Daleformis, a phytoalexin from the roots fo
Dalea filiciformis: an inhibitor of endothelin
converting enzyme
O
O
O Me
Me
H
H
HO
HO
Pongapinone A inhibits the production of interleukin-1
(anti nflamatory) from pongamia pinnata
Seselin possesses both anti-inflammatory and
antinociceptive properties. Seselin from
Plumbago zeylanica
7. Selective protein kinase inhibitors
Protein kinases are enzymes catalyze phoshphorylation of protien or other organic
molecule, usually on the serine, threonine, or tyrosine amino acids.
Phosphorylation is a necessary step in some cancers and inflammatory diseases.
Inhibiting the protein kinases, and therefore the phosphorylation, can treat these
diseases.
A protein kinase inhibitor is a type of enzyme inhibitor that specifically blocks the
action of one or more protein kinases.Therefore, protein kinase inhibitors are used as
drugs.
O O O
OHO
O
Robustic acid and warangalone from the insecticidal plant Derris scandens is a
selective and potent inhibitor of rat liver cyclic AMP-dependent protein kinase
catalytic subunit
Phytochemistry. 1997 ,44,787-96
O O
OH O
warangaloneRobustic acid
8. Cannabichromene
Cannabichromene is a cannabinoid found in the
cannabis plant.play a role in the anti-inflammatory
and anti-viral effects.
Both were isolated from the fungus Daedalea quercina.
show antioxidative and anti-inflammatory
9. Cancer Res. 1997,57, 3429-3435 and references therein
Phytochemistry 1997, 44, 787-796.
Inhibitors of electron transport chain
10. J. Chem. Pharm. Bull. 1994, 42, 1056-1062
Phytochemistry 2000, 53, 981-985
Phytochemistry 1997, 45, 1297-1298.
Phytochemistry 1994, 36, 1073-1076
Miscellaneous biologicaly active chromene containing
natural products
O
OMe
O
HO
OH
OO
OH
HO
Robustic Acid
specific inhibitor of cyclic amp-dependent protein kinas O
O
O
OH
Shinflavanone
Inhibitors of OCL bone reabsorption
O
OMe
OO
OH
Clausenidin
Inhibitor on interferon-y-induced nitricoxide genration
Artocarbene
Inhibitor of tyrosinase
O
NH
Grinimbine
Inhibitor of Cyclooxygenase
11. Biosynthetic pathway of 2H-chrome
R
OH
R1
R2
OPP
R2
R1
OH
R
O
R1
R2
R+
The most widely accepted hypothesis involves the abstraction of a hydride ion from the
benzylic position of isoprenylated phenol by a quinone- like enzyme cofactor. The resultant
ortho-quinone methide undergoes An electrocyclization reaction to afford the 2H-Chromene.
OH
R1
R2
R
HH
O
R1
R2
HH
O
R1
R2
HH
-2e
R R
O
R1
R2
R
O
R1
R2
R
Abstraction of
a hydride ion
Electrocyclization
Ring Closure mechanism of 2H-chrome:
12. Mechanism of photochromism of 2H-Chromene
The 2H-Chromene undergoes a reversible ring opening reaction on irradiation with UV light that
lead to the open-form.the molecule then can revert to ring-closed form via a thermal pathway. this
mechanism was later Confirmed by the reduction of the open form with lithium aluminum hydride
at low temperature.
O
UV
O
Closed- form
colourless
Open-form
Coloured
O O
Ph
Ph
Ph
Ph
UV
OH
Ph
Ph
LiAlH4
13. O OR OR
OR
O OHR OR
R
R1
RMgI/ THF
H+
BMS
1.ArMgI/ THF
R
D
IB
A
L-H
,toluene
2. H+ toluene
Synthesis of chromene from Coumarin
14. General routes for the synthesis of chromenes
J.Chem.soc.perkin trans I 1994,653-657 Eur. J. Org. Chem. 2010, 1339–1344
R OH
OH
Br O
+
O
O
R OR
O
Br
R
O
O
R
R1
OR
R1
1.K2CO3/Acetone
2. PPA
1.NaBH4
2.H+
Ar-Br, Pd(OAc)2,tBu3P.HBF4
KHCO3
PBr3
1.NaBH4
2.H+
R OH
O
OH
O
O
R
+
OR
1.NaBH4
2.H+
PPA
OR
Br
PBr3
16. 2,3-di Aryl chromene as potential Selectivee Estrogen Receptor Modulators
(SERMs)
OHO
OH
O
N
O
OH
O
N
OHO
OH
O
N
OO
O
O
N
O
O
O
O
N
CDRI 85/287
EM-800 (SCH 57050)
Anti-estrogen- prodrug
Eli Lilly and Co.
(EM-652·HCl (SCH 57068·HCl, acolbifene)
pure Anti-Estrogen
Eli Lilly and Co.
potent antiestrogenic agent
CDRI
potent antiestrogenic agent
CDRI
a potent estrogen antagonist
17. A general route for the synthesis of 2,3-di Aryl chromene
a.piperidine (0.3 equiv.), benzene,reflux.b 1-(2-chloroethyl)piperidine monohydrochloride Cs2CO3,
Acetone. C. MeLi (3 equiv.),THF, d. 19:1 acetic acid–water, 90C, J Label Compd Radiopharm 2004; 47: 741–752
R
O
R1
OH
O H
OH
R
O
R1
OH
OH
O
O
OH
R
R1
+
+
O
O
O
R
R1
N
R
O
R1
OH
O
N
O
R1
R
O
N
a
b b
Resolution
c
R + S
18. A general route for the synthesis of 2,3-diaryl chromene
a.Piperidine, benzene,reflux.b NaBH4, EtoH,c Acetic acid d. 1-(2-chloroethyl)piperidine
monohydrochloride K2CO3, Acetone
R
O
R1
OH
O H
OH
R
O
R1
OH
OH
O
OH
R
R1
+
+
O
R1
R
OH
O
R1
R
O
N
O
R1
R
O
N
a
b-c b-c
Resolution
O
R1
R
O
N
d
O
19. Reaction of Phenols with α,β-unsaturated aldehydes
The base promoted chromenylation reaction of phenols with α,β-unsaturated has been a popular
Method to prepare a 2H-Chromene. This method has found widespread application in the synthesis
Of natural products, such as total synthesis of(+)-Leocarpin and (+)-lsohemileocarpin
OH
OHO O
Me Me O
OHO
Me
Me
Pyridine
+
4 Steps
O
Me
Me
O
O
O
O
O
Me
Me
O
O
(+)-Leocarpin (+)-lsohemieocarpin
Pyridine catalyzed chromenylation reaction:
Synth.commun 1993,23,3019.
Hetrocycles 1984, 22,1719
Tetrahedron 1990,46, 2031
20. Preparation of 2H-Chromene via Aromatic lithiation reaction
A series of 2,2-di alkyl-2H-1-benzopyrans have been synthesized using aromatic lithiation reaction as a key
step,followed by treatment of α, β- unsaturated aldehydes. Cruz-Almanza and Co workers have reported the
synthesis of 2H-Chromene by the 1,2-addition of reaction of an appropriately protected aryl lithium compound
to an α, β- unsaturated aldehydes,on subsequent deprotection and cyclization of α, β- unsaturated aldehydes.
Heterocycles,1994,37 ,759
LiRO
OR
O
R1 R2 OH
OH
R1
R2
RO
O
R1
R2
RO
+
R = MOM,MEM, MTM,THP,Bn,Me Carbinol
Two natural product related compounds O-methylcordeachromene, O-methyldectayochromenol as well as
tricyclic 2H-Chromene have been prepared by this methods.
O Me
MeO
O-methylcordeachromene
O
Me
MeO
O-methyldectayochromenol
O
Me
HO
MeMe
Tricyclic-2H-Chromene
21. Reaction of titanium or magnesium salts of phenols with α,β-unsaturated aldehydes
Titanium or magnesium salts of phenols have also been reacted with α,β-unsaturated
aldehydes. This method has provided a facile synthesis of naturally occurring 2H-
Chromenes, such as precocenes 1&2 as well as evodinol.
Tetraheron,1997,53,12621 Mutagenesis. 1989 May;4(3):216-20.,
OM
O
R1
R2 O
R1
R2
+
M = Ti(IV), Mg
R Toluene 110 0C
R = H,Me,OMe,Ph,OH,NMe2 COMe
R
O
Me
Me
O
O
HO
Evodinol
O
Me
Me
O
Precocene 1
O
Me
Me
O
Precocene 2
O
Anti-juvenile harmones
Ageratum houstonianum
22. Phenylboronic acid-promoted condensation of phenol with α,β-
unsaturated aldehydes
The Phenylboronic acid-promoted condensation of phenol with α,β-unsaturated aldehydes has
been found to Be a convenient and mild method that complements classical routs for the
synthesis of 2H-Chromenes.Reaction of 3-methoxy phenol with citral afforded the
cannabichromene analogue.
O OH
O R
OO
Me
R
Me
PhB(OH)2 Toluene
Reflux
O
B
O
Ph
Me
Me
R
O Me
Me R
-PhBO
Via
R = Me, CH2CH2CH=C(Me)2
OO
Me
Me
Me
Cannabichromene analogue
+
Synthesis 1998, 279 and ref. therein
23. Preparation of 2H-Chromene via rearrangement of
propargyl Ethers
R
OH
R1
R2
R3
X
R
O
R1
R2
R3
O
R2
R3
R1
R
K2CO3 / Acetone
reflux
PhNMe2
reflux
+
R
O
R1
R2
R3
O
R1
C R2
R3
R
O
R1
C R2
R3
R
H O
R2
R3
R1
R
Via
X = Cl,Br, R = H OMe, Me,Cl,CN,NO2
A particularly useful synthesis of 2H-Chromenes involves the thermal rearrangement of
propargyl Ethers in a solvents of high boiling point. the reaction is proposed to proceed via
claisen- like [3,3]-sigmatropic rearrangement,followed by a[1,5] sigmatropic shift.An
electrocyclization reaction then complete the process
Tetrahedron.lett,2001,42,1091
24. Ring-Closing Olefin Metathesis
Ring-Closing Olefin Metathesis has been developed into a practical and highly efficient procedure for
a diverse array of 2H-Chromene derivatives . A series of substituted 2H-Chromenes were prepare in
high yields by the ring closing metathesis using a ruthenium carbene catalyst.
J. Org. Chem. 1998, 63, 864-866
R2
OH
O
R1
R3
R4
O
R1
R2
R4
R3
X
O
R2
R3
R4
R1
1.K2CO3 / Acetone
2. MTPPB,NaH
[Cl2(PCy3)2Ru=CHPh]
RCM
R1
/ R2
/ R3
/ R4
= H /Alkyl /Cl/ or diffrent sibstituens
+
Ru
Ph
PCy3
PCy3
Cl
Cl
25. Simultaneous Synthesis of Both Rings of Chromenes via a Benzannulation/o-Quinone Methide
Formation/Electrocyclization Cascade.
A new route to the chromene ring system has been developed which involves the reaction of an a,ß-
unsaturated Fischer carbene complex of chromium with a propargyl ether bearing an alkenyl group on
the propargylic carbon.
This transformation involves a cascade of reactions that begins with a benzannulation reaction and is
followed by the formation of an o-quinone methide, and finally results in the emergence of a chromene upon
an electrocyclization
(CO)5Cr
OMe
H
R2
R1
PO R4
R7
R6
R5R3
C
R3
R1
R2
MeO
R7
R6
R5
R4
PO
O
H(OC)3Cr
Benzannulation
R3
R1
R2
MeO
R7
R6
R5
R4
O
(OC)3Cr
MeO
H
R2
R1
PO R4
R7
R6
R5
R3
C
O
-HOP
O-Quenone
methide
formation
O
R3
MeO
R2
R1
R4
R5
R6
R7
Electrocyclization
Oxidative workup
+
J. Am. Chem.Soc. 2012, 134, 1357-1362
27. 2H-Chromenes from Salicylaldehydes by a Catalytic Petasis Reaction
The Petasis condensation of vinylic or aromatic boronic acids, aromatic aldehydes, and amines is
assisted by a hydroxy group adjacent to the aldehyde moiety. The products derived from
salicylaldehydes and vinylboronic acids undergo cyclization to 2H-chromene compounds with ejection
of amine upon heating.
CHO
R
R2
R1
B
HO
HOOH
+
O R1
R2
R
R2NH
Dioxane
O
O
O
OH
O
O
O O O
O
Examples
Org. Lett. 2000 ,2,4063-4065
R1 = alkyl, phenyl, R2 = Alkyl, phenyl
28. Synthesis of ‘‘4-aryl-4H-chromene’’ as Anti-angiogenic /proliferative agent
‘‘4-aryl-4H-chromene compounnds were synthesized by the condensation of 3-(dimethylamino)phenol
Benzaldehyde and malonitrile in ethanol in the presence of piperidine
N OH
CHO
CN
CN O
CN
NH2N
R
R
Piperidine
EtOH
+
+
O
CN
NH2N
O
O
CN
NH2N
NO2
O
CN
NH2N
CF3
Anti-angiogenic/proliferativeAgents on blood vessel’s endothelial cells
Med Chem Res. 2011, 20, 920–929
29. Synthesis Of a Thieno-2H-chromene -Amino Acid Derivative
S
HO
Br
OH
O
O
S
Br
O
O
O
Al2O3 Ac
Toluene
+
NH2S
(Boc)2N
MeO2C
SO
O
O
HN
S
N(Boc)2
MeO2C
Pd(OAc)2
BINAP
Cs2CO3
A new photochromic thieno-2H-chromene r-amino acid derivative was prepared by C-N palladium-
catalyzed cross- oupling of a bromothieno2H-chromene with the aminated aromatic side chain of the
methyl ester of a N,N-diprotected amino acid.
Its good photochromic properties demonstrated by flash photolysis and continuous irradiation indicate a
possible application in ophthalmic lenses. It may also be inserted into peptides to give photoinduced
reversible structural changes
Org. Lett.2005,7, 4811-4814
30. Iron-Catalyzed Synthesis of Functionalized 2H-Chromenes via Intramolecular
Alkyne Carbonyl Metathesis
An iron-catalyzed intramolecular alkynealdehyde metathesis strategy of the alkynyl ether of salicylaldehyde
derivatives has been developed which works under mild reaction conditions to produce the functionalized 2H-
chromene derivatives
This protocol is compatible toward a wide range of functional groups, such as methoxy, fluoro, chloro,bromo,
and phenyl group
This method provides an atom-economical and environmentally friendly approach for the synthesis of a series
of substituted 2H-chromenes.
H
O
O
R2
R1
R1
O
R2
O
H
O
O
R2
R1
FeCl3
R1
O
R2
O
FeCl3
R1
O
R2O
Iron Salt Catalyzed Intramolecular Alkyne-
Aldehyde Metathesis
nucleophilic attack
cyclization by intramolecular
nucleophilic
oxetene intermediate
( 2+2) cycloreversion
FeCl3
MeCN
R1
= Cl,Br,Ph,OMe
R2
= Alkyl,Aryl
J. Org. Chem. 2011, 76, 3539–3544
31. Gold(III)-Catalyzed Efficient and Highly Selective Synthesis
of Functionalized 4H-Chromenes
O
H
O
H H
O
H O
+ 2H2O
AuCl3 / AgOTf
DCE
Tandem annulation
Highly Chemo Selective water being the only side product
O O
O
O
O
J. Org. Chem. 2010, 75,1309-1312
32. Ormeloxifene
Ormeloxifene (also known as centchroman) is one of the selective estrogen receptor modulators, or SERMs, a
class of medication which acts on the estrogen receptor. It is best known as a non-hormonal, non-steroidal oral
contraceptive which is taken once per week. In India, ormeloxifene has been available as birth control since the
early 1990s, and it is currently marketed there under the trade name Saheli.Ormeloxifene has also been licensed
under the trade names Novex-DS, Centron and Sevista.
Developed by CDRI
Ormeloxifene is primarily used as a contraceptive but may also be effective for
dysfunctional uterine bleeding and advanced breast cancer.
O
O
O
N