JEE (MAIN+ADVANCED) OXIDATION & REDUCTION OF ORGANIC COMPOUNDS CONTENT S.No Pages 1. Oxidation of alkenes, Alcohols & Carbonyl compounds 02 – 07 2. Exercise-1 08 – 11 3. Reducing agents and their role 12 – 15 4. Exercise-2 16 – 18 5. Exercise-3 19 – 21 6. Answer Key 22 – 27 OXIDATION & REDUCTION OF ORGANIC COMPOUND OXIDATION OF ALKENES, ALCOHOLS & CARBONYL COMPOUNDS (I) OXIDATION OF ALKENES OsO4 R–CH=CR2 R–CH—CR2 H2O OH OH Cold dil. alkaline KMnO4 R–CH—CR2 OH OH * Cold dil. alkaline KMnO4 is called as Bayer’s reagent. * Overall syn addition * Given by alkenes & alkynes * Benzene & Cyclopropane can not give this reaction. If we use acidic KMnO4 or warm KMnO4 or too concentrated KMnO4 the oxidative cleavage of Glycol occurs resulting in mixture of Carboxylic acids & Ketones. H ,KMnO R–CH = CR2 4 RCOOH + R2C = O Hot acidic KMnO4, Hot acidic K2Cr2O7 & hot acidic NaIO4 gives same result with alkene. The effect is similar to that of oxidative ozonolysis on alkenes. Preilschaive reaction : Epoxidation of alkenes is reaction of alkenes with peroxyacids. O O || || CH2=CH2 + CH3 C O O H CH2–CH2 + CH 3 C OH O With the decrease in nucleophilicity of double bond, rate of reaction decreases. With the decrease in e withdrawing substituents in leaving group, rate decreases. R CH CH2 H O + R dil.H2SO4 CH R H2O–CH + CH2 + O–H R + –H HO–CH CH2–OH CH2–OH H2O RCO3H RCO3H H 3O HCO3H O OH R CH + OH CH2 OH 1 O Ag 2 2 R CH CH2 O OH BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 2 OXIDATION & REDUCTION OF ORGANIC COMPOUND (II) OXIDATION OFALCOHOLS Oxidising agents Different oxidisingagentsare used tooxidisealcohols in correspondingcarbonyl compounds and carboxylic acids. e.g. (I) (II) (III) (IV) mild oxidising R C H (Aldehyde) R CH 2 OH agent || 1alcohol O O OH || | mild oxidising R CH R ' R C R ' (Ketone) 2alcohol agent strong oxidising R C OH R CH 2 OH agent || 1alcohol O CH 3 | Cu 300C CH 3 C OH | CH3 CH 3 CH2 C Dehydration takes place. CH3 (1) Cu / 300°C (or Red hot Cu tube) It oxidises only 1° alcohol in aldehyde and 2° alcohol into ketones. It does not oxidises 3°alcohol. Dehydration of 3°alcohol takes place and alkene is formed. (2) H /KMnO4, (Strong oxidising agent) (i) It oxidises 1° alcohol into carboxylic acid (ii) It oxidises 2° alcohol into ketone (iii) It does not affect 3° alcohol (iv) It affects carbon-carbon multiple bond and gives carboxylic acid (3) H/K2Cr2O7, (Strong oxidising agent) (i) It oxidises 1° alcohol into carboxylic acid (ii) It oxidises 2° alcohol into ketone (iii) It does not affect 3° alcohol (iv) It affects carbon-carbon multiple bond and give carboxylic acid (4) PCC (Pyridinium chloro chromate) N CrO3 Cl or N CrO3 + HCl H PCC oxidises 1° alcohol into aldehyde, further oxidation is not possible. PCC oxidises 2° alcohol into ketone. It does not oxidises multiple bond and 3° alcohol. It oxidises allylic primary alcohol to corresponding aldehyde further oxidation is not possible. BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 3 OXIDATION & REDUCTION OF ORGANIC COMPOUND (5) Collin’s reagent ( (2 mol) + CrO3 + CH2Cl2) N (i) It oxidises 1° alcohol into aldehyde (ii) It oxidises 2° alcohol into ketone (iii) Multiple bond is not affected (iv) 3° alcohol is not affected (6) Jones reagent (H2CrO4 in Anhydrous acetone) or CrO3 + H2SO4 in acetone. Sufficiently mild so that it oxidises alcohols without oxidising or rearranging double bonds (8 or 9) (i) It oxidised 1° alcohol into carboxylic acid (ii) It oxidised 2° alcohol into ketone (iii) Multiple bond is not affected (iv) 3° alcohol is not affected (7) TsCl + DMSO + NaHCO3 TsCl RCH2OTs RCHO RCH2OH s DMSO NaHCO3 TsCl R2CH–OTs R2CO R2CHOH s DMSO NaHCO3 TsCl DMSO R3C–OTs R3COH s NaHCO3 (i) (ii) (iii) (iv) (8) × It oxidised 1° alcohol into aldehyde It oxidised 2° alcohol into ketone Multiple bond is not affected 3° alcohol is not affected MnO2-Oxidises onlyallylic or benzylic–OH.i.e. 1°Allylic or benzylic OH MnO 2 Aldehyde 2°Allylic or benzylic OH MnO 2 Ketone No effect on 3° ROH and on Carbon-carbon multiple bond. BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 4 OXIDATION & REDUCTION OF ORGANIC COMPOUND (9) Periodic cleavage Periodic cleavage : It is done by periodic acid (H5IO6 or HIO4. 2H2O). Characteristics property of periodic acid is the oxidative cleavage of the bonds with adjacent oxidizable groups such as 1,2-diols, a-hydroxy carbonyl compounds, 1,2-diketones. R – CHOH R – CHOH HO OH OH OH I HO O O R – CH – O R – CH – O OH I O O 2R – CHO + IO 3¯ + H2O (10) Openaur oxidation CH3 O Al O–C–CH3 CH3 3 R – CH – R OH O R–C–R CH3 –C – CH3 R2CH–OH + Al(OCMe3)3Me3COH + Al(OCHR2 )3 (R2CH–O)2 Al–O CR2 O H 3Me2C 3R2C=O + (Me2C–O)3 Al Oxidation of alcohol with aluminium tertiary butoxide is Openaur oxidation. OH O Al (OCMe3)3 acetone (11) NBS It oxidises 1° alcohol into aldehyde. It oxidises 2° alcohol into ketone. 3° alcohol is not affected In case of alkene allylic position is brominated. BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 5 OXIDATION & REDUCTION OF ORGANIC COMPOUND (III) OXIDATION OF CARBONYL COMPOUNDS. 1. RCHO + [Ag(NH3)2]OH RCOOH + NH3 + Ag Ї Aldehyde acts as reducing agent, they can reduce mild oxidizing agents like Tollen’s Reagent. Tollen’s test Gentle Heating for 20 to 25 mins. 2. Fehling’s Solutions Fehling’sA aq. CuSO4 COONa H OH Fehling’s B OH H Alk. solution of Roschelye salt (sodium potassium tartrate) COOK It acts a carrier for Cu2+ as it make reversible complex with Cu2+ This test is also used is Blood and Urine test. H 2O RCOOH Cu RCHO + Cu2+ RCOO – Cu 2 O ( red ppt.) 3. Benedict’s solution Sodium Citrate + NaOH + NaHCO3 + CuSO4 H 2O RCOOH Cu RCHO + Cu2+ RCOO – Cu 2 O ( red ppt.) 4. RCHO + HgCl2 + H2O RCOOH + 2HCl + Hg2Cl2 RCHO + Hg2Cl2 + H2O ® RCOOH + 2HCl + 2Hg grey ppt. 5. Schiff’s Reagent Schiff’s Reagent is aq. solution of following base decolourised by passing SO2. Aldehyde restore pink colour of Schiff’s reagent. NH2 NH 2 SO2 C + NH Colourless RCHO solution (Schiff’s Reagent) Pink colour Cl 2 p-Rosaniline Hydrochloride Magenta colour (Fuschin) Ketons are not easy to oxidize so they do not give these 5 tests. These five tests can be used to distinguish aldehyde and ketones. Both gives 2,4 DNP test BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 6 OXIDATION & REDUCTION OF ORGANIC COMPOUND KETONES ARE DIFFICULT TO OXIDIZE Ketones can be oxidized from their enolic form at high temperature with very strong oxidizing agent. Oxidation of ketones is sometimes governed by Popoff’s rule. According to this rule carbonyl group remains with the smaller alkyl group. More electron rich alkene will be easy to oxidized. O Me – C – Me [O] MeCOOH + CO 2 + H 2O Oxidation by using SeO2 SeO2 is a selective oxidizing agent with converts –CH2– group adjacent to carbonyl group into carbonyl group. The reagent, in general, oxidises active methylene and methyl groups to ketonic and aldehydic groups respectively. O O O O O | | | | | | || || SeO 2 SeO2 C CHO CH 2 C C C ; C CH 3 BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 7 OXIDATION & REDUCTION OF ORGANIC COMPOUND EXERCISE-1 Q.1 H / KMnO CH2 = CH2 4 (i) / KMnO 4 H (iii) / KMnO4 H (v) / KMnO 4 H (iv) / KMnO 4 H (viii) / KMnO 4 H (ix) H / KMnO CH3–CH= CH2 4 / KMnO4 H (vi) (vii) (ii) / KMnO 4 H / KMnO 4 H (x) / KMnO4 H (xi) H / KMnO C10H10 4 HOOC CH 2 CH 2 CH 2 COOH | CH 2 COOH (xii) Q.2 A to F alkenes with minimum possible carbon. (i) H / KMnO A 4 MeCOOH as the only product (ii) H / KMnO B 4 (iii) H / KMnO C 4 MeCH2COOH as the only organic product O O H / KMnO D 4 (iv) O (v) O || H / KMnO E 4 HOOC C C C C C C C C COOH || O (vi) H / KMnO F 4 acetone + ethanoic acid Q.3 (i) 1% alkaline KMnO4 (A) (ii) mCPBA mCPBA\hydrolysis (B) BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 8 OXIDATION & REDUCTION OF ORGANIC COMPOUND Me (1) mCPBA (2) hydrolysis (iii) C=C (iv) H H Me H Me Me H (1) mCPBA C=C (v) Me (2) hydrolysis H Q.4 (i) Me C=C (vi) H Ph (1) mCPBA (2) hydrolysis 1 Ag2O or 2Ag + O2 2 KMnO / OH ¯, ? CH3– CH2 – CH2 – OH 4 or KMnO 4 / H , K2Cr2O 7 / H , ? or conc. HNO 3, (ii) OH | KMnO , H ? CH3 CH CH 2 CH 3 4 or K 2 Cr2O 7 , H OH HO Cu/300°C + P H /KMnO 4/ (iii) OH HO Q.5 Q PCC or Collin's reagent MnO2/ R S (i) CH2 = CH – (CH2)3 – CH2 – OH PCC (ii) C6H5 – CH = CH – CH2 –OH PCC (iii) OH | CH 3 CH CH 2 CH 2 CH 2 OH PCC (A) OH (iv) PCC (v) CH2 = CH – CH2–OH MnO 2 ? CH2OH OH (vi) CH3O MnO CH–CH2–CH2–OH 2 ? Acetone CH3O BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 9 OXIDATION & REDUCTION OF ORGANIC COMPOUND (vii) Q.6 Q.7 OH | (viii) C6 H 5 CH CH 3 MnO 2 ? CH 3 | MnO 2 ? CH C CH C CH 2 OH Acetone CCl 4 (ix) TsCl NaHCO3 C 6 H 5 CH CH CH 2 CH CH 2 OH DMSO ? | CH 3 (i) HO (ii) OH | Aluminium tert butoxide CH 2 CH CH 2 CH CH 3 Acetone tert butoxide Aluminium ? Acetone Which one of the following alcohols are oxidised by MnO2? (A) C6H5 – CH2 – CH2–OH OH | (B) CH 2 CH CH 2 CH CH 3 OH | (C) CH3 CH CH CH CH 3 (D) CH3–CH2 – CH2 –OH HIO Me CH CH 2 OH 4 | OH HIO (ii) Me 2C — CH — Et 4 | | OH OH Q.8 (i) OH HIO 4 (iii) OH (v) CH 2 — CH CH 2 CH 3 HIO 4 | | OH OH (vii) CH 2 — CH CH CH 2 HIO 4 | | | | OH OH OH OH (ix) Me C C Me HIO 4 || || O O Q.9 Which will give the Tollen test. O (i) OH H O (ii) OMe CH 2 OH HIO 4 (iv) HO CH 2 CH 2 CH | OH (vi) CH 2 — CH CH CH 3 HIO 4 | | | OH OH OH (viii) Me C CH Me HIO 4 || | O OH O OH || | (iii) R C CH 2 HO (iv) BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 HO Page # 10 OXIDATION & REDUCTION OF ORGANIC COMPOUND O Q.10 (a) O (b) (d) Q.11 [O] Me2CH–C–Me O (c) [O] H3C – CH 2 – C – CH 3 [O] Me3C–C–Me O [O] (a) CH3–CHO (b) Me2CO SeO2 SeO2 Me – C – C – H O (c) (d) H3C – CH2 – C –C H3 SeO2 P1 mCPBA P2 LAH P3 O SeO 2 BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 11 OXIDATION & REDUCTION OF ORGANIC COMPOUND Reducing agents and their role Group Product –CHO –CH2OH + >C=O >CH–OH –CO2H LiAlH4 +AlCl3 – + + + + + – + + + + –CH2OH + – – + + + –CO2R –CH2OH + – – + + + –COCl –CH2OH + +* + + – + –CONH2 –CH2NH2 + – – + + + (RCO)2O RCH2OH + – – + + + –CN –CH2NH2 + – – + + + >C=NOH –CH2NH 2 + – – + – + >C=C< >CH–CH< – – – – + + –CC– –CH=CH– – – – + + + + – – + – + RH LiAlH(OCMe3)3 in THF B2H6 in THF H2+ ** catalyst NaBH4 in EtOH 1° RX LAH in ether * Product is RCHO ** Catalyst : Ni / Pd / Pt / Ru BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 12 OXIDATION & REDUCTION OF ORGANIC COMPOUND LiAlH4 as a reducing agent : From LAH H (i) (1) LiAlH C = O 4 ( 2 ) H 2O C–O H From Solvent Mechanism H Li C=O (ii) + H–Al–H H H H EtOH C — OLi C — OH (1) LiAlH R C NH 2 4 R – CH2 – NH2 ( 2 ) H 2O || O Mechanism H + Li R–C–NH2 O H–Al–H H –H2O, –AlH3 R–C–NH Li O R–C= NH O¯Li + H–Al–H H H R–C–O–AlH2 + NH Li R–CH=NH H + Li R–C–O – Al–H Li NH H H–Al–H H R–CH2–NH Li (iii) H H–OH (1) LAH R–CH2–OH + R'–OH R C OR ' || ( 2) H3O O BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 13 OXIDATION & REDUCTION OF ORGANIC COMPOUND Mechanism H Li + H–Al–H H H –AlH3 R–C–OR' R–C–OR' O O–Li R–C–H + R'–OLi O + H–OH R'–OH LAH H2O R–CH2–OH (iv) 1) LAH R – C N ( R–CH2–NH2 ( 2 ) H 2O Mechanism H R – C N + + H H–Al–H Li R–C=N Li + AlH2 H H R–CH2–NH2 R–CH2–N–Li AlH2 (v) 1) LAH R C OH ( R–CH2–OH ( 2 ) H 2O || O Mechanism H Li R–C–OH + H H–Al–H H –H2 O R–C–O¯Li + AlH3 R–C–O–Al–H Li O H O H R–CH2–OH (1) LiAlH4 (2) H2 O R–C–H O + Li O¯AlH 2 R–C–OAlH2 O Li BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 14 OXIDATION & REDUCTION OF ORGANIC COMPOUND Wolf Kischner reduction : NH 2 / OH ¯ C = O NH 2 CH2 + N2 Mechansim –H2O C = O + NH2 – NH2 C = N–NH2 –H2O OH H C – N=N–H HO–H C = N–NH –H2O OH H C–N=N H–OH CH2 + N2 Clemension reduction Zn ( Hg ) C=O HCl( conc.) CH2 Mechanism C=O H C = O–H Zn Zn + 2e 2+ C – OH H –H2O CH CH–OH2 H CH – OH 2e CH H CH2 BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 15 OXIDATION & REDUCTION OF ORGANIC COMPOUND EXERCISE-2 Q.1 How many alkene on catalytic reduction give normal butane as product. (i) (iii) (v) Q.2 2 / Pt (A) H n-butane 2 / Pt (C) H Neo-pentane (iv) 2 / Pt (B) H Iso-pentane 2 / Pt (D) H Cyclopentane H2 (E) Pt Give the expected major product for each reaction, including stereochemistry where applicable. (a) H2 CH3–CH2–CH=CH2 P1 Pt H 3C (c) (b) H C=C H CH3 P D2 Pt P2 Me D2 (e) Q.3 (ii) Ni 3 H2/Pt excess P5 H2/Pt 1 eq. P6 (d) (i) H / Pt CH2 = CH–CH2 – CH = O 2 P1 (ii) H 2 / Pt P2 CH2=CH–CH2–CN Me Ni / H2 P4 excess excess Q.4 Identify the product? (i) NaBH4 Me–CHO LiAlH 4 (ii) LiAlH 4 NaBH4 Me2CO (iii) NaBH4 Me–COCl LiAlH 4 (iv) LiAlH 4 NaBH4 Me–COOEt (v) LiAlH 4 NaBH4 Me–COOH (vi) NaBH4 Me–COOMe LiAlH 4 (vii) NaBH4 Me–CONH2 LiAlH 4 (viii) LiAlH 4 NaBH4 Me–CONH–Me (ix) (x) LiAlH 4 NaBH4 Me–CH=NH (xi) NaBH4 Me–CONMe2 LiAlH 4 NaBH4 CH3–CH = CH2 LiAlH 4 Q.5 Give product in following reactions. (i) NaBH4 LiAlH 4 O (ii) NaBH4 H–N (iii) NaBH4 LiAlH 4 O (iv) NaBH4 O LiAlH 4 (vi) NaBH4 (v) NaBH4 N O N LiAlH 4 O LiAlH 4 H O LiAlH 4 O O BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 16 OXIDATION & REDUCTION OF ORGANIC COMPOUND LiAlH 4 (vii) NaBH4 Me–CO–N (ix) LiAlH 4 NaBH4 Ph–CH=CH–CHO Q.6 (viii) LiAlH 4 NaBH4 CH2=CH–CHO (x) NaBH4 LiAlH 4 O Give product in following reactions. O O P HI H Re d (a) P HI Re d (b) OH CHO COCH3 (c) CH2OH HO Q.7 P HI Re d Give product in following reactions. (i) N (iii) O (ii) LAH H3CCOO LAH CH3– CH – CH2 O (iv) COOCH3 LiAlH 4 (A) + (B) + (C) LAH AlCl3 O (v) Q.8 O Give product in following reactions. CHO (i) NaBH4 O COOEt O (ii) LAH (A)NaOI (B) C—OEt BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 17 OXIDATION & REDUCTION OF ORGANIC COMPOUND (iii) LiAlH4, D 2O LiAlH4 H2 O Q.9 (a) Zn ( Hg ) . (A) NBS (D) (B) alc (C) HCl O=C—CH 3 HCl KOH O Zn ( Hg ) (b) (c) HCl, O Zn ( Hg ) (d) HCl, H 2O O Q.10 O || Zn ( Hg ) Ph C CH 3 HCl O (e) i ) H 2 NNH 2 ( (ii ) KOH , heat N2H4 KOH, heat O (f) R 2O 2 (excess) O Zn(Hg) HCl (excess) Suggest appropriate reagents for following conversion. OH A O O B OH C BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 18 OXIDATION & REDUCTION OF ORGANIC COMPOUND EXERCISE-3 OBJECTIVE Q.1 Which of the following will decolourise alkaline KMnO4 solution? (A) C3H8 (B) CH4 (C) CCl4 [JEE 1980] (D) C2H4 Q.2 The reagent with which both acetaldehyde and acetone react easily is (A) Tollen's reagent (B) Schiff's reagent (C) Grignard reagent [JEE 1981] (D) Fehling reagent Q.3 When acetaldehyde is treated with Fehling's solution, it gives a precipitate of [JEE 1982] (A) Cu (B) CuO (C) Cu2O (D) Cu + Cu2O + CuO Q.4 Baeyer's reagent is (A) alkaline permanganate solution (C) neutral permanganate solution [JEE 1984] (B) acidified permanganate solution (D) aqueous bromine solution Q.5 Hydrogenation of benzoyl chloride in the presence of Pd on BaSO4 gives (A) benzyl alcohol (B) benzaldehyde (C) benzoic acid (D) phenol [JEE 1992] Q.6 The appropriate reagent for the following transformation: [JEE 2000] O CH2CH3 CH3 HO (A) Zn(Hg), HCl HO (B) NH2NH2, OH¯ (C) H2 / Ni (D) NaBH4 Q.7 Statement-1: Dimethyl sulphide is commonly used for the reduction of an ozonide of an alkene to get the carbonyl compound. [JEE 2001] Statement-2: It reduces theozonide giving water soluble dimethyl sulpoxide and excess of it evaporates. (A) Statement-1 is true, statement-2 is true and statement-2 is correct explanation for statement-1. (B) Statement-1 is true, statement-2 is true and statement-2 is NOT the correct explanation for statement-1. (C) Statement-1 is true, statement-2 is false. (D) Statement-1 is false, statement-2 is true. Q.8 1-propanol and 2-propanol can be best distinguished by (A) Oxidation with alkaline KMnO4 followed by reaction with Fehling solution. (B) Oxidation with acidic dichromate followed by reaction with Fehling solution (C) Oxidation by heating with copper followed by reaction with Fehling solution (D) Oxidation with concentrated H2SO4 followed by reaction with Fehling solution. [JEE 2001] Q.9 Butan-2-one can be converted to propanoic acid by which of the following? (A) NaOH, NaI / H+ (B) Fehling solution (C) NaOH, I2 / H+ (D) Tollen's reagent [JEE 2006] BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 19 OXIDATION & REDUCTION OF ORGANIC COMPOUND COMPREHENSION : In the following sequence, product I, J and L are formed. K represents a reagent. ( i ) Mg / Ether Cl ( ii ) CO K i ) NaBH 4 J Hex-3-ynal ( I 2 H3C ( ii ) PBr3 Q.10 ( iii ) H 3O [JEE 2008] 2 H L Pb / BaSO 4 quinoline O The structure of the product I is (A) H C 3 (B) H3C Br Br (C) H C 3 Q.11 (D) Br H3C Br The structures of compound J and K, respectively, are (A) (C) H3C COOH and SOCl2 H3 C (B) H C 3 COOH & SOCl2 (D) H3C and SO2Cl2 COOH and CH3SO2Cl COOH Q.12 The structure of product L is (A) H3 C CHO (B) H C 3 CHO (D) H C 3 CHO H3 C (C) CHO Q.13 The most suitable reagent for the conversion of R–CH2 – OH R – CHO is :[JEE Main 2014] (A) K2Cr2O7 (B) CrO3 (C) PCC (Pyridinium Chlorochromate) (D) KMnO4 Q.14 Reagent(s) which can be used to bring about the following transformation is(are) [JEEAdvance 2016] O C O O O C OH H COOH (A) LiAlH4 in (C2H5)2O (C) NaBH4 in C2H5OH O COOH (B) BH3 in THF (D) Raney Ni/H2 in THF BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 20 OXIDATION & REDUCTION OF ORGANIC COMPOUND SUBJECTIVE Q.1 One mole of a hydrocarbon A reacts with 1 mol of bromine giving a dibromo compound, C5H10Br2. CompoundAon treatment with cold dilute alkaline potassium permanganate solution forms a compound, C5H12O2. On ozonolysis,Agives equimolar quantities of propanone and ethanal. Deduce the structural formula ofA. [JEE 1981] Q.2 Awhite precipitate was formed slowlywhen silver nitrate was added to compoundAwith the molecular formula C6H13Cl. CompoundAon treatment with hot alcoholic potassium hydroxide gave a mixture of two isomeric alkenes B and C, having the formula C6H12. The mixture of b and C, on ozonolysis, furnished four compounds. [JEE 1986] (a) CH3CHO (b) C2H5CHO (c) CH3COCH3 (d) CH 3 CH CHO | CH 3 What are the structures of A, B and C? Q.3 Write the balanced chemical equations for the following: [JEE 1991] "Ethylene glycol is obtained by the reaction of ethylene with potassium permanganate". Q.4 When gas A is passed through dry KOH at low temperature, a deep-red coloured compound B and a gas C are obtained. Gas A, on reaction with but-2-ene, followed by treatment with Zn/H2O yields acetaldehyde. IdentifyA, B and C. [JEE 1994] Q.5 An organic compound E(C5H8) on hydrogenation gives compound F(C5H12). Compound E on ozonolysis gives formaldehyde and 2-ketopropanal. Deduce the structure of compound E. [JEE 1995] Q.6 HydrocarbonAadds 1 mol of hydrogen in the presence of a platnium catalyst to form n-hexane. When A is oxidised vigorouslywith KMnO4, a single carboxylic acid, containing three carbon atoms, is isolated. Give the structure ofAand explain. [JEE 1997] Q.7 Monomer Aof a polymer on ozonolysis yields 2 mol of HCHO and 1 mol of CH3COCHO. (a) Deduce the structure ofA. [JEE 2005] (b) Write the structure of all cis forms of polymer of compoundA. BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 21 OXIDATION & REDUCTION OF ORGANIC COMPOUND ANSWER KEY EXERCISE - 1 Q.1 (i) CO 2 (ii) O + CO2 + HOOC – CH2 – CH2 – CH2–COOH (iii) (iv) O + CH3–COOH COOH COOH (v) (vi) O (vii) (xi) Q.2 O COOH (viii) O (ix) CH3–COOH + CO2 COOH CH 2 COOH | + | COOH CH 2 COOH O COOH HOOC 2CH3–COOH CH 2 COOH + | O CH 2 COOH O (x) O (xii) CH C CH 2 CH CH 2 C CH | CH 2 | C CH (i) Me–CH=CH–CH3 (ii) (iii) Me–CH2–CH=CH2 (iv) (v) (vi) OH Q.3 OH OH (i) (A) O (ii) (B) OH OH Me OH (iii) Me OH Me (iv) (v) OH OH Me OH HO H H H HO Me OH Me H H Me H OH Me Me (vi) H C—C Ph H O BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 22 OXIDATION & REDUCTION OF ORGANIC COMPOUND Q.4 –COO (i) CH3–CH2 , CH3–CH2–COOH (ii) O || CH 3 C CH 2 CH 3 O (iii) OH O (P) (Q) O OH Q.5 O (S) O O O OH HO (R) CHO OH O O O COOH CHO OH O O HO (i) CH2 = CH – (CH2)3 – CHO (iii) O || (A) H 3C C CH 2 CH 2 CHO (ii) Ph – CH = CH – CHO (v) H2C = CH–CHO (vii) CH 3 | CH C CH C CHO O (iv) CHO O (vi) MeO C–CH2–CH2–OH MeO (viii) O || Ph C CH 3 (ix) O Q.6 (i) Q.8 (i) (iii) (ii) Ph CH CH CH 2 CH CHO | CH 3 O || CH 2 CH CH 2 C CH 3 Me–CHO + HCHO CHO CHO (ii) Q.7 C O + Et – CHO (iv) HO–CH2–CH2–CHO + HCHO (v) HCHO + CH3– CH2–CHO (vi) HCHO + HCOOH + CH3–CHO (vii) 2HCHO + 2HCOOH (viii) Me–COOH + Me–CHO (ix) 2 Me–COOH BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 23 OXIDATION & REDUCTION OF ORGANIC COMPOUND Q.9 (i); (iii) ; (iv) O Q.10 (a) 2CH3 – COOH Me CH–C–Me (b) Me2CO + MeCOOH O Me CH–C–Me (c) Me3C–COOH + CO2 + H2O (d) COOH COOH SeO (b) Me – C – C – H SeO (a) CH – CHO Q.11 CH –CHO O O O O O O O || || | | || SeO2 mCPBA LAH C C C C C – C – C – C CH3–CH2–OH C C O C C (c) C – C – C –C O O SeO (d) O O EXERCISE - 2 Q.1 (i) cis & trans 2-butene & 1-butene; (ii) C C C C C C C C C C C C || | | C C C (iii) zero (Neo-pentane can not be prepared by catalytic hyrogenation of alkene); (iv) One (v) Including optical = 4 , Excluding optical = 3 D Q.2 (a) (b) D CH3 (c) H D CH3 D H CH3 D H CH3 H D (d) H CH3 H CH3 * (e) 2 G.I. Q.3 (i) P1 Q.4 (i) CH3–CH2–CH2–CH2–OH (ii) P2 CH3–CH2–CH2–CH2–NH2 MeCH2–OH, Me–CH2OH (ii) Me2CH–OH, Me2CH–OH (iii) MeCH2–OH, Me–CH2OH (iv) No reaction , Me–CH2–OH + EtOH (v) No reduction, MeCH2–OH (vi) No reaction, MeCH2–OH + MeOH (vii) No reduction, MeCH2NH2 (viii) No reaction, Me–CH2–NH–Me BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 24 OXIDATION & REDUCTION OF ORGANIC COMPOUND Me Q.5 (ix) No reduction, MeCH2–N (xi) No reaction, No reaction (i) OH , Me–CH2–NH2 , Me–CH2–NH2 (ii) NH Me OH (iii) No reaction, (v) No reaction, (vii) No reaction, Me–CH2–N (ix) Ph–CH=CH–CH2–OH, Ph–CH2–CH2–CH2–OH (x) Q.6 (x) CH2OH OH , HO (a) (iv) NH OH , NH NH , OH NH CH2OH OH (vi) No reaction, (viii) CH2=CH–CH2–OH, CH2=CH–CH2–OH HO (b) (c) CH3 Q.7 (i) OH CH OH 2 (ii) N (iii) CH 3– CH – CH 3 , CH3–CH2– CH 2OH OH HO OH CH2OH (iv) + MeOH (B) + Et–OH (C) (v) CH 2OH (A) CHO CH2OH Q.8 (i) OH CH NaBH4 COOEt O CH2OH OH COOEt CH3 CH2OH + EtOH CH CH3 OD H (ii) CH2OH + EtOHNaOI +Iodoform test OH (iii) BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 25 OXIDATION & REDUCTION OF ORGANIC COMPOUND Q.9 O C—CH3 NBS Zn ( Hg ) (a) HCl (b) (c) O H CH2—CH3 CH=CH2 Br—C—CH3 HCl alc .KOH Ph–CH2–CH3 (d) Cl—CH–CH3 R 2O 2 (e) O (f) , Q.10 (A) Ni will reduce alkene, aldehyde and all it is not specific ;(B) NH2 – NH2 / H2O2 ;(C) LiAlH4 EXERCISE - 3 OBJECTIVE Q.1 D Q.2 Q.8 C Q.9 C C Q.3 Q.10 C D Q.4 Q.11 C = CH – CH3 Br2 A A Q.5 Q.12 B C Q.6 Q.13 B C Q.7 Q.14 A CD SUBJECTIVE CH3 CH3 Q.1 CH3 CH3 CH3 (i) (ii O3 )H 2O cold & /Z n dil. KMnO4 CH3 C = CH – CH3 CH3 CH3 OH OH C – CH – CH3 Br Br C = O + OHC – CH3 Propanone Ethanol CH3 – CH – CH – CH2 – CH3 CH3 Cl (A) Alc. KOH Q.2 CH3 – C = CH – CH2 – CH3 (B) CH 3 O3 CH3 CH3 C = O + OHC – C2H5 + CH3 – CH – CH = CH – CH3 (C) CH 3 O3 CH3 – CH – CHO + OHC – CH3 CH3 BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 26 OXIDATION & REDUCTION OF ORGANIC COMPOUND CH2 Q.3 Q.4 cold dil. KMnO4/H CH2 – OH + CH2 CH2 – OH O 3 Gas ( A ) KOH KO3(B) + O2(C) Pottasium ozonide (Deep Red Coloured) O3 ( A ) CH3 – CH = CH – CH3 ( ii ) Zn / H 2 O 2CH3 – CHO (A) O3 ; (B) KO3 ; (C) O3 CH2 Q.5 O CH3 – C – CHO CH3 – C – CH = CH2 (E) H2 + 2-Keto propanol CH2O Formaldehyde CH3 CH3 – CH – CH2 – CH3 Q.6 CH3 – CH2 – CH = CH – CH2– CH2 (A) CH3 – CH2 – CH2 – CH2 – CH2– CH2 KMnO4 / 2CH3 – CH2 – COOH CH3 Q.7 (a) O CH2 Ozonolysis CH2 H CH3 (b) + H C CH2 H O CH3 H CH2 CH2 C CH3 O CH3 H C C CH2 BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 27 OXIDATION & REDUCTION OF ORGANIC COMPOUND NOTES BANSAL CLASSES Private Ltd. ‘Bansal Tower’, A-10, Road No.-1, I.P.I.A., Kota-05 Page # 28