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Otto Diels and his pupil Kurt Alder received the Nobel Prize in 1950 for their discovery and work on the reaction that bears their names. Its great usefulness lies in its high yield and high sterospecificity. The Diels-Alder reaction has been employed extensively in the synthesis of complex natural products because it is possible to exploit the formation of up to four asymmetric carbons in one reaction and at the same time it is also possible to control the regioselectivity of the reaction.
You are watching: 9,10-dihydroanthracene-9,10-α,β-succinic anhydride
Many chemical reactions are done under reflux. By refluxing a reaction in a particular solvent, the reaction is kept at a constant temperature in a constant state of mixing. The boiling point of the solvent determines the reaction temperature. The solvent is boiled out of the reaction solution but quickly condenses and returns to the flask once the solvent vapors enter the reflux condenser.
Anthracene, 2,5-furandione adduct, 17-oxapentacyclo<188.8.131.52~2,7~.0~9,14~.0~15,19~>nonadeca-2,4,6,9(14),10,12-hexaene-16,18-dione, 5443-16-3, Anthracene,maleic anhydride adduct, AGN-PC-00GKYN, AC1L3CY7
We will be performing the Diels Alder reaction with a very popular dieneophile – maleic anhydride. The diene we will be using is anthracene – a polycylic aromatic hydrocarbon (PAH) that can be found in coal, petroleum, and charcoal grilled hamburgers. The interesting aspect of anthracene is that it offers several different diene sites for the Diels Alder addition of maleic anhydride.
Place 3g of pure anthracene, 30 ml of dry xylene (See Note ) and 1.5 g of maleic anhydride in a 100 ml dry round bottomed flask. Attach a water condenser and reflux the contents on a water-bath for 25 min with frequent shaking.Cool the mixture and collect the solid on a Buchner funnel. Recrystallize the adduct from ethyl acetate. The yield is 3.3 g, m.p.
Add 1 g of maleic anhydride to the round bottom. Despite its benign appearance, solid maleic anhydride is toxic and should not be handled with bare hands.
Add 25 mL of xylene (dimethyl benzene) to the round bottom. Do not remove the xylene bottle from the fume hood. Do this operation in the hood!
Add three boiling chips to the round bottom. Swirl the reactants to mix. The solids will not totally dissolve at this time.
Attach the round bottom to a reflux condenser mounted on a ring stand. Attach water hoses as shown in the preceding diagram
Use a thermwell mounted on an iron ring to heat the solution. Heat the mixture to boiling, and then adjust the heat input so that the boiling is maintained at a steady rate.Reflux for 25 minutes. Note any changes in the reaction mixture. Complement your “hood mate” on how nice he/she looks today.
8.Turn off the heat source. Carefully transferring the hot contents to a 50 or 150 mL beaker at this time will make to easier to remove the crystals that form.
10.Vacuum filter the solid (crude) product in a vacuum (Buchner) funnel. You may wash it with a small amount of ice-cold xylene.
The Diels-Alder reactionis a cycloaddition reaction, a reaction in which two molecules undergo addition to yield a cyclic product. Various types of cycloaddition reaction are known. Because a Diels-Alder reaction involves two double bonds(four π electrons) of a conjugated diene and one double bond (two π electrons) of the other reactant, this type of reaction is called<4+2> cycloaddition. In a Diels-Alder reaction, theconjugated dieneis referred to as the diene; the other compound is called thedienopile.
This Diels-Alder reaction is carried out by boiling the reactants inxylene. Both reactants are soluble in xylene, and the reaction is rapid because of the high boilig point of the solvent, xylene. As the mixture cools, the product crystallizes. The product is isolated by filtration; if the starting anthracene was pure, it requires no further purification.
It is difficult to remove the high-boiling xylene by “air-drying” the crystals. In addition, exposure to the air results in the hydrolysis of anhydrides by atmospheric moisture.
For this reason, the product is dried under an inverted beaker along with some paraffin wax, which dissolves xylene vapors and thus acts as a “dessicant.”
1. Anthracene: 1.0g
2. Maleic anhydride: 0.5g
3. Xylene: 17.5mL
1. Place 1.0g anthracene in a 25mL round-bottomed bottle
2. Pour 17.5mL xylene into the bottle
3. Add 0.5g maleic anhydride in the solution
4. Reflux the mixture for 30 minutes.
5. After the round-bottomed bottle cools to room temperature, put the bottle in an ice bath.
It is still very hot now
6. Filter the solid by vacuum and wash the product with ice-cold petroleum ether.
7. Collect the solid in a sample bottle and put some wax films with the solid.
|Weight of anthracene||1.000g|
|Weight of 9,10-dihydroanthracene-9,10-endo-α,β-succinic anhydride||1.255g|
|Chemical shift (d) in ppm||multiplicity|
Molten naphthalene provides an excellent solubilizing medium for poorly soluble aromatic compounds. In many cases it is more efficient than other high-boiling solvent, such asdichlorobenzene,benzonitrile,nitrobenzeneanddurene. A reaction ofC60with an equimolar amount of anthracene in refluxing naphthalene gives the 1:1 Diels-Alder adduct in 67% yield.
K. Komatsua, Y. Murataa, N. Sugitaa, K. Takeuchib, T.S.M. Wan (1993). “Use of naphthalene as a solvent for selective formation of the 1:1 diels-alder adduct ofC60with anthracene”.Tetrahedron Letter34(52): 8473–8476.doi:10.1016/S0040-4039(00)61362-X.
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DR ANTHONY MELVIN CRASTO, Born in Mumbai in 1964 and graduated from Mumbai University, Completed his Ph.D from ICT, 1991,Matunga, Mumbai, India, in Organic Chemistry, The thesis topic was Synthesis of Novel Pyrethroid Analogues, Currently he is working with GLENMARK PHARMACEUTICALS LTD, Research Centre as Principal Scientist, Process Research (bulk actives) at Mahape, Navi Mumbai, India. Total exp 29 plus yrs, Prior to joining Glenmark, he has worked with major multinationals like Hoechst Marion Roussel, now Sanofi, Searle India Ltd, now RPG lifesciences, etc. He has worked with notable scientists like Dr K Nagarajan, Dr Ralph Stapel, Prof S Seshadri etc, He did custom synthesis for major multinationals in his career like BASF, Novartis, Sanofi, etc., He has worked in Discovery, Natural products, Bulk drugs, Generics, Intermediates, Fine chemicals, Neutraceuticals, GMP, Scaleups, etc, he is now helping millions, has 9 million plus hits on Google on all Organic chemistry websites. His friends call him worlddrugtracker. His New Drug Approvals, Green Chemistry International, All about drugs, Eurekamoments, Organic spectroscopy international, etc in organic chemistry are some most read blogs He has hands on experience in initiation and developing novel routes for drug molecules and implementation them on commercial scale over a 28 year tenure till date nov 2015, Around 30 plus products in his career. He has good knowledge of IPM, GMP, Regulatory aspects, he has several International patents published worldwide . He has good proficiency in Technology transfer, Spectroscopy, Stereochemistry, Synthesis, Polymorphism etc. He suffered a paralytic stroke/ Acute Transverse mylitis in Dec 2007 and is 90 %Paralysed, He is bound to a wheelchair, this seems to have injected feul in him to help chemists all around the world, he is more active than before and is pushing boundaries, he has 9 million plus hits on Google, 2.5 lakh plus connections on all networking sites, 20 Lakh plus views on dozen plus blogs, He makes himself available to all, contact him on +91 9323115463, email amcrasto
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DR ANTHONY MELVIN CRASTO Ph.D , Born in Mumbai in 1964 and graduated from Mumbai University, Completed his PhD from ICT ,1991, Mumbai, India in Organic chemistry, The thesis topic was Synthesis of Novel Pyrethroid Analogues,
Currently he is working with GLENMARKPHARMA LTD, Research centre as Principal Scientist, Process Research (bulk actives) at Mahape, Navi Mumbai, India.
Prior to joining Glenmark, he worked with major multinationals like Hoechst Marion Roussel, now Sanofi Aventis, & Searle India ltd, now RPG lifesciences, etc. He has worked in Basic research, Neutraceuticals, Natural products, Flavors, Fragrances, Pheromones, Vet Drugs, Drugs, formulation, GMP etc. He has total 29 yrs exp in this field, he is now helping millions, has million hits on google on all organic chemistry websites.
His New Drug Approvals , Green Chemistry International,Eurekamoments in Organic Chemistry , Organic Chemistry by Dr Anthony, WIX BLOG , ALL ABOUT DRUGS, WORLD DRUG TRACKER,MEDICINAL CHEM INTERNATIONAL, DRUG SYN INTERNATIONAL,SCALEUP OF DRUGS, ALL FOR DRUGSON WEB, are some most read chemistry blogs
He has hands on experience in initiation and developing novel routes for drug molecules and implementation them on commercial scale over a 25 year tenure, good knowledge of IPM, GMP, Regulatory aspects, he has several international drug patents published worldwide .
He has good proficiency in Technology Transfer,Spectroscopy , Stereochemistry , Synthesis, Reactions in Org Chem , Polymorphism, Pharmaceuticals , Medicinal chemistry, Organic chemistry literature , Patent related site , Green chemistry , Reagents , R & D , Molecules , Heterocyclic chem ,Sourcing etc
He suffered a paralytic stroke in dec 2007 and is bound to a wheelchair, this seems to have injected feul in him to help chemists around the world, he is more active than before and is pushing boundaries, he has one lakh connections on all networking sites, He makes himself available to all, contact him on +91 9323115463, amcrasto
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