Introduction:
Chromone (or 1,4-benzopyrone) is the derivative of benzopyran having a substituted keto group on the pyran ring. The derivatives of Chromone are collectively termed as Chromones. Most, although not all, Chromones are as well phenylpropanoids.
General Chemical reactions of Chromones:
Chromones vary marginally in their chemistry from Coumarins (benzopyran-2-ones) as the carbonyl group is now conjugated by the oxygen atom through the double bond of the heterocycle. This conjugation doesn't involve the benzene ring (figure shown below).
Fig: Chromone Conjugation
As a result, the Chromones are instead more basic and strong acids readily protonate the carbonyl oxygen atoms, making crystalline benzopyrilium salts. Once protonated, the molecule must be resistant to further electrophilic attack, however by fuming nitric acid and concentrated sulphuric acid at between 0°C and room temperature, Chromone provides the 6-nitro derivative (figure shown below). Chromone as well undergoes a Mannish-type reaction (figure shown below) with dimethylamine and formaldehyde (methanal) in hydrogen chloride and ethanol; here the product is 3-(N-N-dimethylaminomethyl) Chromone.
Fig: Reaction of Chromones
Comparatively hard nucleophiles, like Grignard reagents, might attack at the carbonyl carbon, while softer nucleophiles, example: hydroxide ion, join at C-2 by conjugative addition, and this might then cause ring opening (figure shown below).
Fig: Reactions of Chromones with Nucleophiles
Tutorsglobe: A way to secure high grade in your curriculum (Online Tutoring)
Expand your confidence, grow study skills and improve your grades.
Since 2009, Tutorsglobe has proactively helped millions of students to get better grades in school, college or university and score well in competitive tests with live, one-on-one online tutoring.
Using an advanced developed tutoring system providing little or no wait time, the students are connected on-demand with an expert at www.tutorsglobe.com. Students work one-on-one, in real-time with a tutor, communicating and studying using a virtual whiteboard technology. Scientific and mathematical notation, symbols, geometric figures, graphing and freehand drawing can be rendered quickly and easily in the advanced whiteboard.
Free to know our price and packages for online chemistry tutoring. Chat with us or submit request at [email protected]
www.tutorsglobe.com offers formal method model homework help, assignment help, case study, writing homework help, online tutoring assistance by computer science tutors.
Learning-Communication and Social behavior tutorial all along with the key concepts of Habituation, Classical conditioning, Instrumental conditioning, Latent learning and Insight learning
let phd tutors from financial management essay writing assignment help complete your essay to secure a++ at reasonable rates.
We offer First-class Graph Theory Assignment Help service at most viable prices which always make you stand out from your peers.
tutorsglobe.com bacteria assignment help-homework help by online biodiversity tutors
tutorsglobe.com structure of sarcomere assignment help-homework help by online muscles tutors
tutorsglobe.com hemophilia assignment help-homework help by online inborn errors of metabolism tutors
tutorsglobe.com tissue transplantation assignment help-homework help by online immunology tutors
Diagrams and charts show information in an easy and effective way. They available the information looks impressive and attractive.
the computers of 1990s are known as fifth generation computers. the speed is very high in this generation.
tutorsglobe.com medical lab methods assignment help-homework help by online applied biology tutors
Types of Compounds Found in Plants tutorial all along with the key concepts of History-Background of Natural Products, Classification of Natural Products, Terpenoids and steroids, Alkaloids, Fatty acid and polyketides
tutorsglobe.com economic importance of bacteria assignment help-homework help by online bacteria tutors
tutorsglobe.com freshwater shortages assignment help-homework help by online fresh water crisis and management tutors
Maintenance generally contains regularly scheduled inspection, greasing, oiling and probably minor repairs.
1949718
Questions Asked
3689
Tutors
1495728
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!