Concept explainers
Interpretation:
Given that to be
Concept introduction:
According to Huckel’s rule, a molecule orb an ion or bradical will be stable and aromatic if it is planar, cyclic and conjugated (4n+2) electrons. For a cyclic system to be aromatic both conditions are to be satisfied. If only one of the conditions is satisfied the specie will not be aromatic, becomes less stable and cannot be synthesized.
To explain:
The observation that cyclodecapentaene fulfills one of the criteria for aromaticity but not the other and has resisted all attempts at synthesis.
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Chapter 15 Solutions
Organic Chemistry
- Acridine is a heterocyclic aromatic compound obtained from coal tar that is used in the synthesis of dyes. The molecular formula of acridine is C13H9N, and its ring system is analogous to that of anthracene except that one CH group has been replaced by N. The two most stable resonance structures of acridine are equivalent to each other, and both contain a pyridine-like structural unit. Write a structural formula for acridine.arrow_forwardCompounds A and B are isomers having the molecular formula C4H8O3. Identify A and B on the basis of their 1H NMR spectra.Compound A: δ 1.3 (3H, triplet); 3.6 (2H, quartet); 4.1 (2H, singlet); 11.1 (1H, broad singlet)Compound B: δ 2.6 (2H, triplet); 3.4 (3H, singlet); 3.7 (2H triplet); 11.3 (1H, broad singlet)arrow_forwardGive reasons: (i) C—Cl bond length in chlorobenzene is shorter than C—Cl bond length in CH3—Cl.(ii) The dipole moment of chlorobenzene is lower than that of cyclohexyl chloride.(iii) SN1 reactions are accompanied by racemization in optically active alkyl halidesarrow_forward
- On being heated with a solution of sodium ethoxide in ethanol, compound A (C7H15Br) yielded a mixture of two alkenes B and C, each having the molecular formula C7H14. Catalytic hydrogenation of the major isomer B or the minor isomer C gave only 3-ethylpentane. Suggest structures for compounds A, B, and C consistent with these observations.arrow_forwardEvaluate each of the following processes applied to cyclooctatetraene, and decide whether the species formed is aromatic or not. (a) Addition of one more π electron, to give C8H8− (b) Addition of two more π electrons, to give C8H82− (c) Removal of one π electron, to give C8H8+ (d) Removal of two π electrons, to give C8H82+arrow_forwardUse the following spectroscopic data to work out the structure of an organic compound: Molecular formula: C3H7NO2, IR (cm): 3001, 2987, 1553 and 1387 cm*1; 1H NMR (5): 1.0 (t, 3H), 2.1 (m, 2H), and 4.4 (t, 2H); 13C NMR (5): 10, 21, and 78. MS: 89 (M+), 43 (Base peak), 41, and 29arrow_forward
- (3) HI does not undergo free radical addition with 1-butene, even in the presence of a peroxide. Please provide an explanation by analyzing the propagation steps if the same radical reaction occurred with HI. Besides the bond dissociation enthalpies in the appendix, the following approximate bond dissociate enthalpies might be useful to you: ~310 kJ/mol The component of C=C CH3CH₂CH₂CH₂-Br CH3CH₂CH₂CH2-I -290 kJ/mol (C-Br bond) ~235 kJ/mol (C-I bond)arrow_forwardCompounds B and C are isomers with molecular formula C5H9BrO2. The 1H NMR spectrum of compounds B and C are shown below. The IR spectrum corresponding to compound B showed strong absorption bands at 1739, 1225, and 1158 cm-1, while the spectrum corresponding to compound C have strong bands at 1735, 1237, and 1182 cm-1. 1.Based on the information provided, determine the structure of compounds B and C. 2.Assign all peaks in 1H NMR spectrum of compounds B and C.arrow_forwardCompound A, C9H₁6 reacts with 1 molar equivalent(s) of hydrogen upon catalytic hydrogenation. A undergoes reaction with ozone, followed by Zn treatment, to give: CHỊCHỊCH CH3CCH₂CH₂CH₂CH₂CH₂CCH3 || Propose a structure for A.arrow_forward
- (a) Account for the following :(i) Electrophilic substitution reactions in haloarenes occur slowly.(ii) Haloalkanes, though polar, are insoluble in water.(b) Arrange the following compounds in increasing order of reactivity towards SN2 displacement:2-Bromo-2-Methylbutane, 1-Bromopentane, 2-Bromopentanearrow_forwardCompound X, C,4H12Br2, is optically inactive. On treatment with strong base, X gives hydrocarbon Y, C14H10: Compound Y absorbs 2 equivalents of hydrogen when reduced over a palladium catalyst to give z (C14H14) and reacts with ozone to give one product, benzoic acid (C,Hg02). Draw the structure of compound Z. • Use the wedge/hash bond tools to indicate stereochemistry where it exists. • Ignore alkene stereochemistry. • If more than one structure fits the description, draw them all. • Draw one structure per sketcher. Add additional sketchers using the drop-down menu in the bottom right corner. • Separate structures with + signs from the drop-down menu. ChemDoodlearrow_forward3. (i) Give the criteria for a compound to be considered as aromatic. (ii) Identify, with explanation the compounds below as aromatic, antiaromatic, or nonaromaticarrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning