Concept explainers
Interpretation:
The structure of the given compound and the mechanism of the given reaction are to be determined.
Concept introduction:
To determine the actual structure of organic compounds, IR spectroscopy (Infrared spectroscopy) is an invaluable tool. The use of
Transesterification is a process in which the R group of an ester is exchanged with an R group of an alcohol. This process takes place in the presence of a base catalyst or an acid catalyst.
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ORGANIC CHEMISTRY-ETEXT REG ACCESS
- H₂C ཏཱཏི 1 ནི OH 1. Br2, PBг3 2. H₂O H3C OH Br The a-bromination of carbonyl compounds by Br2 in acetic acid is limited to aldehydes and ketones because acids, esters, and amides don't enolize to a sufficient extent. Carboxylic acids, however, can be a-brominated by first converting the carboxylic acid to an acid bromide by treatment with PBr3. Following enolization of the acid bromide, Br2 reacts in an a-substitution reaction. Hydrolysis of the acid bromide completes the reaction. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions :0: H3C Br Br + :::OH2 Br H₂O H3C Br заarrow_forwardIn sugar metabolism, the enzyme phosphoglucose isomerase converts glucose-6-phosphate into fructose-6-phosphate, as shown in the reaction below. The enzyme provides a protonated Glu and a neutral Lys. Propose a three-step acid/base mechanism for this reaction. Hint: the product of the first step is an ene-diol. -203POH₂C HO.... ...OH HO OH OPO3-² -2 HO OH OH OHarrow_forwardGamma(y)-amino butyric acid (GABA) is a neurotransmitter (a chemical that is used to send signals from one neuron to another) of the mammalian central nervous system. In order to understand how GABA works, conformationally restricted analogues, such as compound 1, have been made. During a synthesis of compound 1, compound 2 was subjected to allylic bromination using NBS and a radical initiator (AIBN) instead of light (Aust. J. Chem. 1981, 34, 2231-2236). H₂N. CH3 GABA CO₂H CH3 dddd CH3 H₂N Modify the structures given below to draw all eight possible allylic bromides that can be formed when compound 2 undergoes allylic bromination, considering all possible regiochemical and stereochemical outcomes. You can use the single bond tool to add/remove pi bonds. CH3 CO₂H CH3 solddd CH3 CH3 2 CH₂ CO₂Etarrow_forward
- The following substances can be prepared by a nucleophilic addition reaction between an aldehyde or ketoneand a nucleophile. Identify the reactants from which they were prepared. If the substance is an acetal, identifythe carbonyl compound and the alcohol; if it is an imine or enamine, identify the carbonyl compound and theamine. You do not have to consider stereochemistry. In cases where there is more than one answer, just giveone. Use Grignard reagents when an organometallic reagent is required. Draw the Grignard reagent as acovalent magnesium bromide.arrow_forwardFollowing is a synthesis for toremifene, a nonsteroidal estrogen antagonist whose structure is closely related to that of tamoxifen. (a) This synthesis makes use of two blocking groups, the benzyl (Bn) group and the tetrahydropyranyl (THP) group. Draw a structural formula of each group and describe the experimental conditions under which it is attached and removed. (b) Discuss the chemical logic behind the use of each blocking group in this synthesis. (c) Propose a mechanism for the conversion of D to E. (d) Propose a mechanism for the conversion of F to toremifene. (e) Is toremifene chiral? If so, which of the possible stereoisomers are formed in this synthesis?arrow_forwardThe following sequence of steps converts (R)-2-octanol to (S)-2-octanol. Propose structural formulas for intermediates A and B, specify the configuration of each, and account for the inversion of configuration in this sequence.arrow_forward
- The base-promoted rearrangement of an -haloketone to a carboxylic acid, known as the Favorskii rearrangement, is illustrated by the conversion of 2-chlorocyclohexanone to cyclopentanecarboxylic acid. It is proposed that NaOH first converts the a-haloketone to the substituted cyclopropanone shown in brackets and then to the sodium salt of cyclopentanecarboxylic acid. (a) Propose a mechanism for base-promoted conversion of 2-chlorocyclohexanone to the proposed intermediate. (b) Propose a mechanism for base-promoted conversion of the proposed intermediate to sodium cyclopentanecarboxylate.arrow_forwardSeveral sulfonylureas, a class of compounds containing RSO2NHCONHR, are useful drugs as orally active replacements for injected insulin in patients with adult-onset diabetes. These drugs decrease blood glucose concentrations by stimulating b cells of the pancreas to release insulin and by increasing the sensitivity of insulin receptors in peripheral tissues to insulin stimulation. Tolbutamide is synthesized by the reaction of the sodium salt of p-toluenesulfonamide and ethyl N-butylcarbamate . Propose a mechanism for this step.arrow_forwardWhat is the right answer?arrow_forward
- Write down an organic chemistry mechanism (use curly arrows) for the transformation of benzamide to benzoic acid, via its sodium salt.arrow_forward3 The 1H- and 13C-NMR data of an ester of molecular formula C6H10O2 are given below. Also shown are the COSY and HETCOR NMR spectra of the ester. Identify the ester, explaining how you reach your conclusion. 1H-NMR: 7.20-6.90 (1H), 5.85 (1H), 4.16 (2H), 1.88 (3H), 1.31 (3H) ppm 13C-NMR: 166.7, 144.5, 123.0 , 60.2, 18.0, 14.3 ppmarrow_forwardAmantadine is effective in preventing infections caused by the influenza A virus and in treating established illnesses. It is thought to block a late stage in the assembly of the virus. Amantadine is synthesized by treating 1-bromoadamantane with acetonitrile in sulfuric acid to give N-adamantylacetamide, which is then converted to amantadine. CH,C=N in H,SO, Br NHCCH3 NH2 1-Bromoadamantane Amantadine (a) Propose a mechanism for the transformation in Step 1. (b) Describe experimental conditions to bring about Step 2.arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage LearningIntroduction to General, Organic and BiochemistryChemistryISBN:9781285869759Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar TorresPublisher:Cengage Learning