Química Orgânica 2 · Exam review
Substituição acílica, aminas e sais de diazônio: problemas de prática
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- Azo coupling of benzenediazonium with 2-naphthoxide
- Balz–Schiemann: 4-fluorotoluene from 4-methylbenzenediazonium tetrafluoroborate
- Boc protection of benzylamine with di-tert-butyl dicarbonate
- Phenol from benzenediazonium and warm water
- DMAP-catalysed acetylation of cyclohexanol
- Releasing benzylamine from N-benzylphthalimide with hydrazine
- Hinsberg test: propan-1-amine and benzenesulfonyl chloride
- Hofmann elimination opens the piperidine ring
- Acid-catalysed lactonisation of 2-(hydroxymethyl)benzoic acid
Desenhe o mecanismo 37
- Azo coupling of benzenediazonium with 2-naphthoxideDraw the attack of C1 of 2-naphthoxide on the terminal nitrogen of benzenediazonium and the deprotonation that restores aromaticity, and explain why coupling occurs at C1.
- Balz–Schiemann: 4-fluorotoluene from 4-methylbenzenediazonium tetrafluoroborateDraw the loss of N₂ from 4-methylbenzenediazonium and the transfer of fluoride from tetrafluoroborate to the aryl cation that gives 4-fluorotoluene.
- Boc protection of benzylamine with di-tert-butyl dicarbonateDraw the addition of benzylamine to di-tert-butyl dicarbonate, the loss of tert-butyl carbonate, the proton transfer that gives the Boc carbamate, and the breakdown of tert-butyl hydrogen carbonate to CO₂ and tert-butanol.
- Phenol from benzenediazonium and warm waterDraw the loss of N2 from the benzenediazonium ion, the capture of the aryl cation by water and the final deprotonation that gives phenol.
- DMAP-catalysed acetylation of cyclohexanolDraw how DMAP acts as a nucleophilic catalyst: it is acylated by acetic anhydride to an N-acetylpyridinium ion, which transfers the acetyl group to cyclohexanol and releases DMAP again.
- Releasing benzylamine from N-benzylphthalimide with hydrazineDraw the two acyl substitutions by hydrazine that free benzylamine from N-benzylphthalimide and trap both carbonyls in the six-membered ring of phthalhydrazide.
- Hinsberg test: propan-1-amine and benzenesulfonyl chlorideDraw the sulfonylation of a primary amine and the two deprotonations by hydroxide that leave the N-propylbenzenesulfonamide anion dissolved in aqueous base.
- Hofmann elimination opens the piperidine ringDraw the N-methylation of N-methylpiperidine and the Hofmann E2 elimination of the 1,1-dimethylpiperidinium ion that opens the six-membered ring to N,N-dimethylpent-4-en-1-amine.
- Acid-catalysed lactonisation of 2-(hydroxymethyl)benzoic acidDraw the acid-catalysed ring closure of 2-(hydroxymethyl)benzoic acid to the five-membered lactone phthalide, with hydronium and water as the only acid and base.
- Hydration of benzonitrile to benzamide in aqueous acidDraw the acid-catalysed addition of water to benzonitrile through the nitrilium ion and the imidic acid, and the tautomerisation that gives benzamide.
- Reductive amination of benzaldehyde with morpholineDraw how benzaldehyde and the secondary amine morpholine form an iminium ion through a carbinolamine, with acetic acid and acetate moving the protons, and how cyanoborohydride reduces it to 4-benzylmorpholine.
- Saponification of phenyl acetateDraw the hydroxide addition and phenoxide loss that cleave phenyl acetate, and the two proton transfers that leave acetate and phenoxide, consuming two equivalents of hydroxide.
- Phenyl benzoate by the Schotten–Baumann methodDraw how aqueous hydroxide turns phenol into phenoxide and how phenoxide adds to benzoyl chloride and expels chloride to give phenyl benzoate.
- Ring opening of succinic anhydride by ammoniaDraw how ammonia opens the five-membered ring of succinic anhydride by addition–elimination, with the second ammonia as the base, to give ammonium succinamate.
- Diazoaminobenzene from benzenediazonium and anilineDraw the attack of aniline's nitrogen on the terminal nitrogen of benzenediazonium and the deprotonation by acetate that give 1,3-diphenyltriazene.
- N-Acetilação do álcool 4-aminobenzílico com anidrido acéticoDesenhe a N-acetilação quimiosseletiva do álcool 4-aminobenzílico com anidrido acético, terminando com o acetato removendo o próton N–H.
- Hidrólise ácida da N-metilbenzamida a ácido benzoicoDesenhe a hidrólise da N-metilbenzamida a ácido benzoico catalisada por ácido, incluindo a protonação que transforma o grupo metilamino em grupo abandonador.
- Phenyl acetate by pyridine-catalysed acetylation of phenolDraw pyridine attacking acetyl chloride to form the N-acetylpyridinium ion, phenol acylation by that ion, and deprotonation that gives phenyl acetate.
- 3-(Methylamino)propanenitrile by aza-Michael additionDraw the conjugate addition of methylamine to the β-carbon of acrylonitrile and the proton transfers through methanol that give 3-(methylamino)propanenitrile.
- Acoplamento azo do 4-nitrobenzenodiazônio com fenolDesenhe o acoplamento azo do fenóxido com o 4-nitrobenzenodiazônio na posição para e a rearomatização que fornece o (E)-4-[(4-nitrofenil)diazenil]fenol.
- Hidrólise básica da fenilacetonitrila a fenilacetatoDesenhe a hidrólise da fenilacetonitrila promovida por hidróxido, passando pela fenilacetamida, até fenilacetato e amônia.
- N,N-Diethylbenzamide from benzoyl chloride and diethylamineDraw the addition–elimination of diethylamine on benzoyl chloride and the proton transfer to a second equivalent of amine that gives N,N-diethylbenzamide.
- Aniline from benzoyl chloride by the Curtius rearrangementDraw benzoyl azide formation, its Curtius rearrangement to phenyl isocyanate with loss of N2, and the hydrolysis and decarboxylation that release aniline.
- Acoplamento com DCC do ácido 3-fenilpropanoico com morfolinaDesenhe como a DCC converte o ácido 3-fenilpropanoico em uma O-acilisoureia e como a morfolina então forma a 4-(3-fenilpropanoil)morfolina com perda de diciclo-hexilureia.
- Diazotação da 4-metoxianilina com ácido nitrosoDesenhe como o ácido nitroso e o HCl convertem a 4-metoxianilina em cloreto de 4-metoxibenzenodiazônio, passando pelo íon nitrosônio e por uma N-nitrosamina.
- Alquilação de Gabriel da ftalimida com bromoacetato de etilaDesenhe a desprotonação da ftalimida pelo carbonato e o ataque SN2 do ânion imideto ao bromoacetato de etila.
- Pent-1-ene by Hofmann elimination of pentan-2-amineExcess CH3I with NaOH first converts pentan-2-amine into N,N-dimethylpentan-2-amine. Draw the third SN2 methylation to the quaternary ammonium salt and the Hofmann E2 of the quaternary ammonium hydroxide that gives pent-1-ene, the less substituted alkene.
- Rearranjo de Hofmann da 3-metilbutanamida a isobutilaminaDesenhe o rearranjo de Hofmann da 3-metilbutanamida a 2-metilpropan-1-amina, da N-bromação, passando pelo isocianato, até a perda de CO2.
- Abertura do anel da N-metilsuccinimida por hidróxidoDesenhe como um equivalente de hidróxido abre a N-metilsuccinimida a 4-(metilamino)-4-oxobutanoato e explique por que a amida formada sobrevive.
- Redução da piperidin-2-ona a piperidina com LiAlH4Desenhe a redução da lactama piperidin-2-ona a piperidina com LiAlH4, mostrando por que é o oxigênio, e não o nitrogênio, que sai do intermediário tetraédrico.
- Benzamide by ammonolysis of methyl benzoateDraw ammonia adding to methyl benzoate, the proton transfer to a second ammonia, loss of methoxide, and proton return that gives benzamide.
- N-Acetylglycine from glycine and acetic anhydrideDraw the acetylation of glycine by acetic anhydride: amine addition to an anhydride carbonyl, loss of acetate, and deprotonation by acetate to give N-acetylglycine.
- 1-Propanoilpirrolidina a partir de cloreto de propanoílaDesenhe a adição–eliminação da pirrolidina ao cloreto de propanoíla e a desprotonação pela trietilamina que fornece a 1-propanoilpirrolidina.
- Aminação redutiva da acetofenona com metilaminaDesenhe a formação do íon imínio a partir da acetofenona e da metilamina em ácido acético e sua redução pelo cianoboro-hidreto a N-metil-1-feniletan-1-amina.
- N-Cyclohexylaniline by reductive amination of cyclohexanone with anilineDraw iminium formation from cyclohexanone and aniline under acetic acid catalysis and its reduction by cyanoborohydride to N-cyclohexylaniline.
- Saponificação da γ-butirolactona com hidróxido de sódioDesenhe a abertura do anel da γ-butirolactona pelo hidróxido e as transferências de próton que terminam no 4-hidroxibutanoato.
- Cloreto de butanoíla a partir de ácido butanoico e cloreto de tionilaDesenhe como o cloreto de tionila converte o ácido butanoico em cloreto de butanoíla por meio de um grupo abandonador clorossulfito que se decompõe em SO2 e cloreto.
Preveja o produto 8
- Acetylating 2-aminoethanolPredict which nucleophile of an amino alcohol is acylated first by an anhydride.
- Which conversion runs directly?Use the reactivity ladder to decide which acyl substitution occurs on simple mixing.
- Which group does mild base cleave?Predict which acyl group of an ester–amide is hydrolysed by mild aqueous base and in what protonation state the product exists.
- Diazotisation then potassium iodidePredict the product when an arenediazonium salt is treated with potassium iodide and keep the other ring substituent unchanged.
- Product of a Sandmeyer reaction with CuCNPredict the product of a Sandmeyer cyanation and place the new group at the former diazonium carbon.
- Anhydride + aminePredict both products when an acid anhydride acylates a primary amine.
- Hofmann elimination of pentan-2-aminePredict the major alkene from a Hofmann elimination.
- Open a lactone with hydroxidePredict the ring-opened product of saponifying a lactone.
Classificar 2
- What the Gabriel synthesis cannot makeRecognise that the Gabriel synthesis needs an SN2-capable alkyl halide.
- Which nitrogen of nicotine is protonated first?Identify the more basic nitrogen in a molecule with an sp³ amine and an sp² pyridine nitrogen.
Comparar 6
- Rank acetyl derivatives by reactivityOrder an amide, an ester, an anhydride and an acid chloride by their reactivity toward nucleophilic acyl substitution.
- Rank four nitrogen compounds by basicityOrder an amide, an arylamine, a benzylic amine and an alkylamine by basicity from where the nitrogen lone pair is.
- Rank para-substituted anilines by basicityOrder para-substituted anilines by basicity from the resonance and inductive effects of the substituent.
- Rank four nitrogen heterocycles by basicityRank pyrrole, pyridine, imidazole and piperidine by basicity.
- Ester or Weinreb amide for a ketone?Compare how an ester and a Weinreb amide react with one equivalent of a Grignard reagent.
- Thioester or ester: which acylates faster?Explain why a thioester is a better acyl donor than the corresponding oxoester.
Calcular 5
- Hydroxide consumed by 4-acetoxybenzoic acidCount every acidic proton and ester cleavage to find how much hydroxide a multifunctional compound consumes on saponification.
- pKb of methylamineConvert the pKa of an ammonium ion into the pKb of the amine.
- How much of an amine drug is protonated in blood?Use Henderson–Hasselbalch to find what percentage of an amine is protonated at a given pH.
- Neutral fraction of an amine at pH 7.8Calculate the percentage of an amine present as the neutral base at a given pH.
- Hydroxide for a triesterCount the hydroxide equivalents consumed by complete saponification of a triglyceride model.
Encontre o erro 1
- Find the error in an acid hydrolysis mechanismIdentify the step in a proposed acid-catalysed ester hydrolysis that is impossible in the stated medium.
Interprete as evidências 3
- Follow the labelled oxygen from waterUse acyl–oxygen cleavage to predict where an oxygen label from the solvent ends up after saponification.
- Use o IV para distinguir uma amida primária de um ésterAtribua um espectro de IV a uma amida primária usando a posição da C=O e o número de estiramentos N–H.
- Identifique o grupo responsável por uma banda fina em 2250 cm⁻¹ no IVAtribua uma banda fina de IV em 2250 cm⁻¹ a um grupo nitrila C≡N.
Trabalhe de trás para frente 1
- Choose partners for a reductive aminationWork backward from a secondary amine to the carbonyl compound and amine that give it by reductive amination.
Planeje uma síntese 5
- Choose the amide for a LiAlH₄ routeChoose the amide whose LiAlH₄ reduction gives a specified secondary amine, keeping track of which carbon becomes CH₂.
- Plan a route to 1,3,5-tribromobenzeneUse an amino group as a removable directing group in a multistep arene synthesis.
- Conditions to hydrolyze an amideChoose conditions that actually hydrolyze an unactivated amide.
- Route to 2-phenylethan-1-amineChoose a route to a primary amine that also adds one carbon.
- Escolha o reagente que forma um fluoreto de arilaEscolha a sequência de reagentes que substitui um grupo diazônio por flúor.
Explique por quê 9
- Why is an acid chloride so much more reactive than an amide?Explain the reactivity gap between an acid chloride and an amide from π donation and leaving-group ability.
- Why amides resist hydroxideExplain why a tertiary amide survives conditions that saponify an ester.
- Why aryl diazonium salts can be usedExplain why arenediazonium ions are useful intermediates while alkyldiazonium ions are not.
- Why DMAP is a much stronger base than pyridineExplain how resonance donation from a para amino group raises the basicity of a pyridine nitrogen.
- Why the Gabriel synthesis stops at one alkyl groupExplain how the phthalimide nitrogen prevents the over-alkylation seen with ammonia.
- Why trimethylamine breaks the trend in waterExplain the basicity order of the methylamines in water from solvation of their ammonium ions.
- Why saponification goes to completionExplain why ester hydrolysis in base is irreversible while acid-catalysed hydrolysis is an equilibrium.
- Por que a diazotação é feita a 0–5 °CExplique por que os sais de arenodiazônio são preparados e mantidos a 0–5 °C.
- Por que a aminação redutiva supera a alquilação no preparo de aminasExplique por que a aminação redutiva fornece uma amina secundária limpa, enquanto a alquilação direta com um haleto de alquila não fornece.
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