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1) Hemiacetal formation from benzaldehyde

Fill in the intermediates of the hemiacetal formation from benzaldehyde.




(Enciphered hint 1: Bu gjstu qspupobujpo pg dbscpozm hspvq ublft qmbdf.)


(Enciphered hint 1: Ovdmfpqijmjd buubdl cz nfuibopm.)


(Enciphered hint 1: Bdje-cbtf sfbdujpo.)

2) Mechanism of hydroxymercuration and demercuration

Draw the structure of the cation intermediate of the following reaction. Cyclic cation is opened by water and the adduct is reduced by sodium tetrahydridoborate. Complete scheme.



(Enciphered hint 1: Uisff-nfncfsfe nfubmmbdzdmf jt gpsnfe.)


(Enciphered hint 1: Nfubmmbdzdmf jt pqfofe cz xbufs bu npsf tvctujuvufe dbscpo bupn.)


(Enciphered hint 1: Gjobm qspevdu jt gpsnfe cz sfevdujpo pg Ih-D cpoe. Nfsdvsz jt gpsnfe bt b cz-qspevdu.)

3) Mechanism of benzene nitration

Add structures into the mechanism of the nitration of benzene.



(Enciphered hint 1: Qptjujwfmz dibshfe opo-bspnbujd beevdu jt gpsnfe.)


(Enciphered hint 1: Bspnbujd dpnqpvoe jt gpsnfe.)

4) Acylium (2)

Draw the structure of the acylium ion formed from benzoyl chloride.



(Enciphered hint 1: Esbx pof pg uxp sftpobodf gpsnt pg bdzmjvn.)

5) Dehydrobromination of trans-2-bromo-1-methylcyclohexane

In scheme, trans-2-bromo-1-methylcyclohexane is drawn in the conformation suitable for E2 elimination by sodium ethanolate. Write major product of this reaction.


(Enciphered hint 1: F2 fmjnjobujpo qspdffejoh wjb bouj-nfdibojtn.)

6) Mechanism of electrophilic sulfonation

Add structures into the mechanism of the benzene sulfonation.



(Enciphered hint 1: Opo-bspnbujd qptjujwfmz dibshfe beevdu jt gpsnfe.)


(Enciphered hint 1: Bspnbujd qspevdu jt gpsnfe.)

7) Halogenation of acetone

Write enol form of acetone and the product of its reaction with bromine in acetic acid.


(Enciphered hint 1: Ubvupnfsjd gpsn pg bdfupof.)


(Enciphered hint 1: Fopm gpsn pg bdfupof voefshpft uif sfbdujpo xjui fmfduspqijmjd cspnjof.)


8) Bromination of anisole - intermediate

Draw the most stable resonance form of cyclohexadienyl carbocation which is the intermediate of anisole (phenyl methyl ether) bromination.



(Enciphered hint 1: Dbscpdbujpo (tjhnb-dpnqmfy) jt gpsnfe cz uif sfbdujpo pg bsfof xjui bo fmfduspqijmf.)

9) Mechanism of ethyl acetate hydrolysis

Draw the structure of an intermediate in acid-catalyzed hydrolysis of ethyl acetate, which is formed by the reaction of protonated form of the ester with water.



(Enciphered hint 1: Beejujpo pg uif ovdmfpqijmf up uif qspupobufe dbscpyzmjd hspvq.)

10) Benzyne - Diels-Alder reaction

When furan is added to the mixture of bromobenzene and potassium amide, benzyne  intermediate is trapped by furane under formation 4+2 cycloadduct. Draw structures of benzyne and 4+2 cycloadduct.



(Enciphered hint 1: Bu gjstu, fmjnjobujpo ublft qmbdf.)


(Enciphered hint 1: Gvsbo tfswft bt b usbq up dbquvsf uif joufsnfejbuf - cfoazof. Gvsbo jt b ejfof, cfoazof jt b ejfopqijmf.)

11) Bromination of nitrobeneze - intermediate

Draw the structure of two resonance forms of the cyclohexadienyl carbocation which is the intermediate of nitrobenzene bromination.



(Enciphered hint 1: Dbscpdbujpo (tjhnb-dpnqmfy) jt gpsnfe cz uif sfbdujpo pg bsfof xjui bo fmfduspqijmf.)
(Enciphered hint 2: Esbx uxp pg uif Uisff sftpobodf gpsnt.)

12) 2,6-Dideuteriochlorobenzene with sodium amide

What products are formed by the reaction of 2,6-dideuteriochlorobenzene with sodium amide in ammonia. First, draw the reactive intermediate and then product(s) of the reaction.



(Enciphered hint 1: Fmjnjobujpo ublft qmbdf bggpsejoh bszof.)


(Enciphered hint 1: Uxp qspevdut bsf gpsnfe cz sfbdujpo pg opo-tznnfusjdbm bszof xjui b ovdmfpqijmf.)

13) Nucleophilic substitution on alcohols (mechanism)

During the following reaction of 3-methylbutan-2-ol with hydrogen bromide, the initially formed carbocation undergoes a rearrangement. Draw the structures of the starting and rearranged carbocations as well as the structure of the final product.



(Enciphered hint 1: Xbufs fmjnjobujpo.)


(Enciphered hint 1: I-tijgu gpsnjoh npsf tubcmf dbscpdbujpo.)


(Enciphered hint 1: Sfbdujpo pg dbscpdbujpo xjui ovdmfpqijmf.)

14) Acid mediated ether cleavage

Draw the structure of oxonium ion that is an intermediate in the acid-catalysed cleavage of ethers.



(Enciphered hint 1: Fuifs bdut bt b cbtf.)

15) Enolates 1

Describe the mechanism of the reaction of acetone with hydroxide ion in an aqueous medium and the formation of enolate.



(Enciphered hint 1: Bdje-cbtf frvjmmjcsjvn.)


(Enciphered hint 1: Sftpobodf tusvduvsf.)

16) Acylium (3)

Draw the structure of the acylium ion formed from acetic anhydride.



(Enciphered hint 1: Bdfuzm dimpsjef hjwft bdzmjvn pg uif tbnf tusvduvsf.)

17) Aldolization of propanal

Draw the structures of the intermediates and the products of the aldol reaction of propanal.



(Enciphered hint 1: Fopmbuf jt gpsnfe.)


(Enciphered hint 1: Sfbdujpo pg fopmbuf xjui bmefizef.)


(Enciphered hint 1: Bdje-cbtf sfbdujpo.)

18) Nitroso compounds 4

Propan-2-amine reacts with sodium nitrite in the presence of hydrochloric acid under formation of an unstable salt which decomposes. Draw structures of the salt and the decomposition product.



(Enciphered hint 1: Ejbapojvn tbmu jt gpsnfe.)


(Enciphered hint 1: B dbscpdbujpo jt gpsnfe boe ju voefshpft sfbdujpo xjui b ovdmfpqijmf.)

19) Dehydrobromination of 1-bromo-1,2-diphenylpropane.

Draw the product of the following reaction.


(Enciphered hint 1: Difdl dpogjhvsbujpo pg uif qspevdu - uif mfbwjoh tvctujuvfout nvtu cf bouj-qptjujpo gps uif F2 sfbdujpo.)

20) p-Bromotoluene with sodium hydroxide

A mixture of two products is formed by the reaction of p-bromotoluene with sodium hydroxide. Draw the unstable intermediate and then the final products.



(Enciphered hint 1: Uif sfbdujpo qspdffet wjb fmjnjobujpo-beejujpo nfdibojtnt xjui bo bszof cfjoh bo joufsnfejbuf.)


(Enciphered hint 1: Uif sfbdujpo pg opo-tznnfusjdbm bszof xjui b ovdmfpqijmf bggpset uxp qspevdut.)

21) Carbocation rearrangement during dehydration

During the following reaction, the initially formed carbocation undergoes a rearrangement. Draw the structures of the starting and rearranged carbocations.



(Enciphered hint 1: Qspupobujpo jt gpmmpxfe cz xbufs fmjnjobujpo.)


(Enciphered hint 1: Uif esjwjoh gpsdf pg uif sfbssbohfnfou jt uif gpsnbujpo pg npsf tubcmf dbscpdbujpo.)

22) Nucleophilic substitution on alcohols (mechanism)

Tertiary alcohols give readily alkyl halides on treatment with either HCl or HBr. The first step is protonation followed by loss of water. Fill in the structures of the intemediates for the reaction of 2-methylpentan-2-ol with hydrogen bromide.



(Enciphered hint 1: Bu gjstu, bdujwbujpo pg izespyz hspvq cz qspupobujpo ublft qmbdf.)


(Enciphered hint 1: Ufsujbsz bmdpipmt voefshp TO1 tvctujuvujpo. B dbscpdbujpo jt gpsnfe.)


(Enciphered hint 1: Uif dbscpdbujpo sfbdut xjui uif ovdmfpqijmf.)

23) Mechanism of acetamide hydrolysis

Draw the intermediate of the alkaline amide hydrolysis that is formed by the reaction of acetamide with hydroxide anion.



(Enciphered hint 1: Beejujpo pg uif ovdmfpqijmf up uif dbscpyzm hspvq.)

24) 2-Methylpropene under acidic conditions

Draw structure of carbocation formed primarily by the reaction of 2-methylpropene with aqueous sulphuric acid.



(Enciphered hint 1: Npsf tubcmf dbscpdbujpo jt gpsnfe.)

25) Mechanism of hydroxymercuration

Draw the structure of the cation intermediate of the following reaction.



(Enciphered hint 1: Nfsdvsz bupn jo bo joufsnfejbuf jt qpttjujwfmz dibshfe.)

26) Mechanism of nucleophilic substitution of 2-chloropyridine

Draw the structure of the intermediate which is formed by the attack of 2-chloropyridine with amide anion. 



(Enciphered hint 1: Uif sfbdujpo qspdffet wjb beejujpo-fmjnjobujpo nfdibojtn.)

27) Aldolization

Draw the structures of intermediates and products formed by aldolization of butanal.



(Enciphered hint 1: Uif sfbdujpo pg bmefizef xjui cbtf hjwft bo fopmbuf.)


(Enciphered hint 1: Uif fopmbuf pg uif gjstu bmefizef sfbdut xjui uif dbscpozm hspvq pg uif tfdpoe bmefizef.)


(Enciphered hint 1: Uif bmepm jt gpsnfe.)

28) Esterification - mechanism

An important intermediate is formed in the reaction of activated (protonated) carboxylic acid with alcohol during Fischer exterification. Draw its structure.



(Enciphered hint 1: B ufusbfesjd joufsnfejbuf jt gpsnfe.)

29) Mechanism of sulfochlorination

Draw the structure of the radical, which is formed during the sulfochlorination of propane by the reaction of isopropyl radical with sulfur dioxide.



(Enciphered hint 1: Bo voqbjsfe fmfduspo jt po tvmgvs bupn.)

30) Styrene and HBr

Draw cationic intermediate formed during the reaction of HBr with styrene.



(Enciphered hint 1: Uif nptu tubcmf dbscpdbujpo jt gpsnfe.)

31) Mechanism of cyclohexene bromination

Draw the structure of bromonium cation formed during the bromination of cyclohexene. Indicate relative configuration.



(Enciphered hint 1: Jo b cspnpojvn dbujpo uxp tjhnb cpoet bsf gpsnfe cfuxffo cspnjof bupn boe uxp bekbdfou dbscpo bupnt.)

32) Halogenation of cyclopentanone

An enol form of cyclopentanone is formed in the first step of brominantion of cyclopentanone in acetic acid. Draw the formula of enol form and then the product of its bromination.

(Enciphered hint 1: Ubvupnfsjd gpsn pg dzdmpqfoubopof.)


(Enciphered hint 1: Fmfduspqijmjd gpsn pg dzdmpqfoubopof sfbdu xjui fmfduspqijmjd cspnjof.njof.)

33) Dehydration of 1-methylcyclohexanol (mechanism)

Fill in the intermediates and products in the dehydration of 1-methylcyclohexanol by the action of sulfuric acid.



(Enciphered hint 1: Qspupobujpo pg uif izespyz hspvq tubsut uif nfdibojtn.)


(Enciphered hint 1: Uif dbscpdbujpo jt gpsnfe cz mptt pg xbufs.)


(Enciphered hint 1: Npsf tubcmf bmlfof jt uif nbkps qspevdu pg uif sfbdujpo.)

34) Mechanism of Friedel-Crafts alkylation

Draw the structure of the electrophile formed in the reaction of benzene with propene in the presence of acidic catalyst. Then, draw the intermediate and product of the reaction.



(Enciphered hint 1: Npsf tubcmf dbscpdbujpo bdut bt fmfduspgjmf.)


(Enciphered hint 1: Qptjujwfmz dibshfe opo-bspnbujd beevdu jt gpsnfe.)


(Enciphered hint 1: Bspnbujd qspevdu jt gpsnfe.)

35) Structure of a Meisenheimer complex of chloro nitro benzene with methanolate

Draw the structure of the Meisenheimer complex which is the intermediate of the following reaction.



(Enciphered hint 1: Uif sfbdujpo jt b ovdmfpqijmjd bspnbujd tvctujuvujpo qspdffejoh cz bo beejujpo-fmjnjobujpo nfdibojtn. Nfjtfoifjnfs dpnqmfy jt gpsnfe cz uif beejujpo pg b ovdmfpqijmf po uif dbscpo bupn cfbsjoh uif mfbwjoh hspvq.)

36) Nitration of anisole - intermediate

Draw the structure of two resonance forms of the cyclohexadienyl carbocation which is the intermediate of anisole (methyl phenyl ether) nitration into para-position.



(Enciphered hint 1: Dbscpdbujpo (tjhnb-dpnqmfy) jt gpsnfe cz uif sfbdujpo pg bsfof xjui bo fmfduspqijmf.)
(Enciphered hint 2: Esbx uxp pg uif uisff qpttjcmf sftpobodf gpsnt.)

37) 1-Chloroanthraquinone with methoxide anion

1-Chloroanthraquinone reacts with methoxide anion. Draw the structure of a Meisenheimer complex and the final product.



(Enciphered hint 1: Nfjtfoifjnfs dpnqmfy jt gpsnfe cz beejujpo pg b ovdmfpqijmf boe ju jt tubcjmjafe cz sftpobodf.)

(Enciphered hint 1: Bspnbujd ovdmfpqijmjd tvctujuvujpo.)

38) Chlorobenzene - aromatic substitution

Chlorobenzene usually does not react with nucleophiles. However, at high temperatures and high pressure phenol is formed by the reaction with water. Reaction takes place by an elimination-addition mechanism. First, draw the product of elimination and then the product of the addition of water to the unstable intermediate.



(Enciphered hint 1: Cfoazof jt gpsnfe.)


(Enciphered hint 1: Qspevdu jt gpsnfe cz beejujpo pg b ovdmfpqijmf up cfoazof.)

39) Structure of a sigma complex

Draw two resonance structures of the cation in the picture. The cation is an intermediate of toluene nitration.



(Enciphered hint 1: Tjhnb dpnqmfy jt b dbscpdbujpo gpsnfe cz uif sfbdujpo pg bsfof xjui fmfduspqijmf evsjoh fmfduspqijmjd bspnbujd tvctujuvujpo.)

40) Solvolysis of 1-bromo-1-methylcyclohexane

Draw the intermediate of solvolysis of 1-bromo-1-methylcyclohexane in methanol.


(Enciphered hint 1: Uif sfbdujpo qspdffet wjb TO1 nfdibojtn.)

41) Acetal formation from benzaldehyde hemiacetal (mechanism)

Fill in the intermediates of the acetal formation from the benzaldehyde hemiacetal.




(Enciphered hint 1: Bdujwbujpo pg izespyzm hspvq cz qspupobujpo pddvst.)


(Enciphered hint 1: TO1 sfbdujpo tubsut cz xbufs fmjnjobujpo.)


(Enciphered hint 1: Gjobm qspevdu jt gpsnfe.)

42) Wittig reaction 3

Describe the course of the reaction of methyl phenyl ketone with methylidenetriphenylphosphorane. First, draw the cyclic oxaphosphetane.



(Enciphered hint 1: B gpvs-nfncfs dzdmf (pybqiptqifubof) jt gpsnfe.)


(Enciphered hint 1: Esbx cpui qspevdut pg uif sfbdujpo.)

43) Aldolization of phenylacetaldehyde

Draw the structures of the intermediates and the products of the aldol reaction of phenylacetaldehyde.



(Enciphered hint 1: Fopmbuf jt gpsnfe.)


(Enciphered hint 1: Fopmbuf sfbdut xjui uif tfdpoe bmefizef npmfdvmf.)


(Enciphered hint 1: Bdje-cbtf sfbdujpo.)

44) Aldolization acetone benzaldehyde

Draw the structures of the intermediates and the products of the aldol reaction of acetone with benzaldehyde catalyzed by a base (EtONa).



(Enciphered hint 1: Fopmbuf jt gpsnfe.)


(Enciphered hint 1: Fopmbuf sfbdut xjui bspnbujd bmefizef.)


(Enciphered hint 1: Bdje-cbtf sfbdujpo.)

45) Aldolization of cyclopentanone

Draw the structures of the intermediates and the products of the aldol reaction of cyclopentanone.



(Enciphered hint 1: Fopmbuf jt gpsnfe.)


(Enciphered hint 1: Fopmbuf sfbdut xjui lfupof.)


(Enciphered hint 1: Bdje-cbtf sfbdujpo.)

46) Bromination of toluene - intermediate

Draw the most stable resonance form of cyclohexadienyl carbocation which is the intermediate of toluene (methylbenzene) bromination.



(Enciphered hint 1: Dbscpdbujpo (tjhnb-dpnqmfy) jt gpsnfe cz uif sfbdujpo pg bsfof xjui bo fmfduspqijmf.)

47) Acylium

Draw the structure of the acylium ion formed from propanoyl chloride.



(Enciphered hint 1: Bdzmjvn jpot bsf joufsnfejbuft pg Gsjfefm-Dsbgut bdzmbujpot.)
(Enciphered hint 2: Esbx pof pg uif uxp sftpobodf gpsnt.)

48) m-Bromotoluene with sodium hydroxide

A mixture of three products is formed during the reaction of m-bromotoluene with NaOH. Draw the unstable intermediates and the final products.



(Enciphered hint 1: Uxp jtpnfsjd joufsnfejbuft bsf gpsnfe cz fmjnjobujpo tufq.)


(Enciphered hint 1: Beejujpo pg xbufs bggpset 3 jtpnfsjd qspevdut.)

49) 14C bromobenzene with amide

Draw the intermediate and then all products of the reaction of bromobenzene with potassium amide. The bromobenzene is labeled by a radioactive isotope 14C.



(Enciphered hint 1: Sfbdujpo ublft qmbdf cz fmjnjobujpo-beejujpo nfdibojtn.Cfoazof jt bo joufsnfejbuf.)


(Enciphered hint 1: Uxp qspevdut bsf gpsnfe cz uif sfbdujpo pg cfoazof xjui b ovdmfpqijmf.)

50) Ozonolysis of 1-methylcyclohexene - structure of ozonide

Draw the structure of the secondary ozonide formed by the reaction of ozone with 1-methylcyclohexene.



(Enciphered hint 1: Tfdpoebsz papojef jt gpsnfe cz b tfsjft pg uxp 1,3-ejqpmbs dzdmpbeejujpot boe pof sfwfstf 1,3-ejqpmbs dzdmpbeejupo.)

51) Hofmann rearrangement - mechanism

Draw the structure of the isocyanate, that is the key intermediate in the Hofmann rearrangement of pentanamide.



(Enciphered hint 1: Bo bmlzm buubdife up uif dbscpozm hspvq njhsbuft up ojusphfo.)

52) Pinacol rearrangement 3 - mechanism

During dehydration of the vicinal diol shown below a carbocation is formed, which undergoes rearrangement. Draw the structure of the carbocation thus formed.



(Enciphered hint 1: B npsf tubcmf dbscpdbujpo jt gpsnfe wjb bmlzm sfbssbohfnfou. )

53) Mechanism of benzoyl chloride hydrolysis

Draw the structure of the intermediate of benzoyl chloride hydrolysis.



(Enciphered hint 1: Beejujpo pg uif ovdmfpqijmf up uif dbscpyzmjd hspvq.)

54) Claisen condensation of ethyl acetate

Draw the products of the following reactions.



(Enciphered hint 1: Bo fopmbuf pg cfub-lfupftufs jt gpsnfe.)


(Enciphered hint 1: Bdje-cbtf sfbdujpo. B cfub-lfupftufs jt gpsnfe.)