POLYNUCLEAR HYDROCARBON : STRUCTURE AND USES OF NAPHTHELENE, ANTHRACENE,DI-PHENYLMETHANE , TRI-PHENYLMETHANE , PHENANTHRENE

Hello everyone, we the students of Gurunanak College of Pharmacy, Nagpur have created a presentation of subject pharmaceutical organic chemistry -2 of third semester, Unit 4 : polynuclear hydrocarbons . This presentation was made for the purpose of better understanding of the topic structure and medicinal uses of naphthelene , anthracene, diphenylmethane , triphenylmethane , phenanthrene and their derivatives . This portion covers topics like structure, properties , and medicinal uses of polynuclear hydrocarbons such as naphthelene , anthracene , di-phenylmethane, tri-phenylmethane , phenanthrene and their respective derivatives.

1. STRUCTURE AND MEDICINAL USES OF NAPHTHELENE , ANTHRACENE, DI-,TRI-PHENYLMETHANE, PHENANTHRENE AND THEIR DERIVATIVES GROUP- SOLUTION SQUAD MEMBERS- Shweta Dhongade Mansi Malewar Sakshi Nerkar Divyani Dahake Rishika Behere (group leader) Under the guidance of : Ms. Pradnya Gondane

2. NAPHTHALENE (C 10 H 8 ) Molecular formula : C 10 H 8 It is one of the largest constituents of coal tar. It is the simplest fused ring system. [2 aromatic rings sharing a pair of carbon atoms ]. The examples of monosubstituted naphthalene are α-Naphthol and ß-Naphthol whereas polysubstitued naphthalenes are 1-Methyl-4-nitronaphthalene and 1,8-Dibromonapthalene. IUPAC name for naphthalene is Bicyclo[4.4.0]deca-1,3,5,7,9-pentaene 2

3. STRUCTURE OF NAPHTHELENE 3 Naphthalene is an aromatic compound as it follows the postulates of Huckel’s rule  -First of all, a naphthalene molecule is a cyclic molecule which means it has a ring system. Hence, it is following the first criteria. -The molecule is having a total of 10 π electrons in the ring system. Hence, it is following the second criteria (4n+2 electrons, where n=2). All the π electrons are fully delocalized in the ring system of a naphthalene molecule. It is having a fully conjugated system with all the carbon atoms sp2 hybridized. Hence, it is also following the third criteria. The naphthalene molecule is fully planner which means all the atoms are in the same plane. Thus, it is following the fourth criteria as well . Above and below this plane there is a cloud of π electrons formed by overlap of p orbitals and shaped like a figure 8 .

4. Naphthalene is white crystalline or colourless crystalline solid. It is unusually stable . It’s heat of combustion is 61 kcal. It is insoluble in water but soluble in organic solvent like alcohol, ether and benzene. 4 PROPERTIES OF NAPHTHALENE

5. USES OF NAPHTHALENE AND THEIR DERIVATIVES 1. In production of phthalic anhydride and in the synthesis of many 920 dyes. 2. In household naphthalene is used as fumigant. 3. Nadoxolol drug is used as an beta-blocker. 4. Sulfonated naphthalene is used as surfactants. 5. Amino naphthalene sulfonic acid is used in synthesis of synthetic dyes. 6. Naphthalene drugs acts well in curing the cough, urine infection, eyes trouble and fever. 7. Naphthalene sulfonic acids are used to make plasticizers, dispersants in synthetic and natural rubbers, tanning agents in leather industries and in agricultural formulations. 5

6. ANTHRACENE {C 14 H 10 } 6 Tricyclo[8.4.0.0 3 ,8 ]tetradeca-1,3,5,7,9,11,13-heptaene Anthracene is also called paranaphthalene or green oil. It is a solid polycyclic aromatic hydrocarbon (PAH) consisting of three Benzene rings derived from coal tar, Molecular Formula : C 14 H 10 is the simplest tricyclic aromatic hydrocarbon. IUPAC Name of anthracene : C-H Bond are formed by overlapping of sp2 and s orbitals C-C bond are formed by overlapping of sp2 and sp2 orbitals Not all C-C bonds length are equal because C1-C2 have more double bond character than C2-C3

7. RESONANCE IN ANTHRACENE Kekule Type Formula 4 CANONICAL FORMS It is less aromatic less stable and more reactive than benzene 7 Resonance energy of anthracene is 84 kcal/mol, resonance energy of each ring of anthracene is 28kcal/mol < resonance energy of benzene is 36kcal/mol Aromatic character-it undergoes ESR (Halogenation,nitration,sulfonation)similar to benzene and napthalene Presence of 3 fused rings-upon oxidation with K2Cr2O7 and H2SO4 it gives 9,10 anthraquinone which indicates the presence of 3 benzene rings fused in ortho position Haworth synthesis-pthalic anhydride upon reaction with benzene gives anthracene

8. PROPERTIES OF ANTHRACENE Resonance energy of anthracene is 84 kcal/mole . It is less aromatic , less stable and more reactive than benzene . Most of the chemical reactions are substitution but it shows addition reaction also due to less aromatic than benzene . Anthracene is a white to yellow solid with a weak aromatic odor. Insoluble in water . 8

9. USES OF ANTHRACENE Anthraquinone is a precursor in synthesis of dyes . eg. Red dye alizarin, benzanthrones As a additive(redox-catalyst) in wood pulping and as a hydrogen carrier in H 2 O 2 Production Skin disorders:Dithranol impairs DNA replication and decreases cell division and is effective for healing psoriatic plaques antifungal Anthracene derevatives act as good anti cancerous drugs eg:doxocrubicin, dithranol etc. 9 dithranol Oxidized anthracene is a basic component of aloe and has anti-immflammatory properties

10. USES OF ANTHRACENE Drugs like secnna,cascara and aloes contains anthraquinone as a glycine part for cathartic or laxative activity Many herbal drugs contain anthracene and its derevatives for antimalarial , anti-HIV,antiviral and diuretic effects Used as wood preservative Insectiside in agriculture Commonly used as UV tracer Used as scintillator for detectors for high energy photons, electrons and alpha particles 10

11. DI-PHENYLMETHANE { [C 6 H 5 ] 2 CH 2 } 11 Molecular formula : {C6H5}2CH2 Diphenylmethane is an organic compound consists of methane where in 2 hydrogen atoms are replaced by phenyl groups . IUPAC name of diphenylmethane is 1,1’-Methylenedibenzene It is a colourless oil .

12. PROPERTIES OF DIPHENYLMETHANE Its melting point is 22-24 ° C and boiling point is 264 ° C . On nitration it gives 4,4’-Dinitrophenylmethane . On bromination it gives product named diphenylmethylbromide which on using Zn / KOH reagent gives product benzhydrol . On oxidation with chromic acid gives benzophenone . 12

13. Uses of diphenylmethane and their derivatives Antispasmodic : Used to relieve spasm of involuntary muscles Antiulcer : Tending to prevent or treat ulcers and especially ulcers of the walls of stomach or duodenum Antihistamine : used to treat allergy 13 Antianxiety : Used to treat symptoms anxiety such as feeling of fear, dread, uneasiness , muscle tightness that may occur as a reaction of stress Various derivatives of of diphenylmethane are prepared and are successfully used as :

14. TRIPHENYLMETHANE { [C 6 H 5 ] 3 CH } Molecular formula : {[C6H5]3CH} It is a colourless solid organic compound containing methane group in which 3 hydrogen atoms are replaced by phenyl groups . The IUPAC name is = Benzhydrylbenzene 14

15. PROPERTIES OF TRIPHENYLMETHANE Its melting point is 92 – 94 ° C and boiling point is 359 ° C . It is a colourless solid . Soluble in non- polar organic solvents . It is the basic moiety of many synthetic dyes like malachite green , magenta , crystal violet , etc . Many of them are pH indicators . 15

16. USES OF TRIPHENYLMETHANE Mainly in the preparations of colouring dyes called triarylmethane dyes . They have poor resistance to light and to chemical bleaches and are used chiefly in  copying papers , in hectograph and printing inks, and in textile applications for which light fastness is not an important requirement. Some are used as pH indicators . Some display fluorescence. 16

17. PHENANTHRENE (C 14 H 10 ) Molecular formula : C 14 H 10 It is a colorless crystalline substance obtained from coal tar . It is isomeric with anthracene . It is a fused ring poly nuclear angular hydrocarbon. 17

18. PROPERTIES OF PHENANTHRENE Resonance energy of phenanthrene is 92 kcal/mole . It’s solution in benzene shows blue colour fluorescene . It is very reactive in the 9,10- positions. The carbons in phenanthrene are sp2 hybridised, having 14 π-electron delocalized system and is aromatic in nature . Key difference between anthracene and phenanthrene : Anthracene is less stable compared to phenanthrene . 18

19. USES OF PHENANTHRENE Phenanthrene is used to make dyes, plastics and pesticides, explosives and drugs. It has also been used to make bile acids, cholesterol and steroids. Phenanthrene occurs naturally as well as is a man-made chemical. Animal studies have shown that phenanthrene is a potential carcinogen { an agent with the capacity to cause cancer in humans }. Perhydrophenanthrene is used in production of jet fuel . Phenanthrene is also used for synthesizing alkalosis morphine and caffeine , dimethyl morphine . 19

20. THANK YOU! 20