Ch. 1 - A Review of General ChemistrySee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins

Solution: Basic red 1 is a tetracyclic compound (it has four rings) that shares many structural similarities with the dyes in the previous problem (Chem. Rev. 1993, 93, 381–433). This compound has many significant resonance structures, and the positive charge is highly delocalized. While resonance structures can be drawn in which the positive charge is spread throughout all four rings, nonetheless, one of the rings likely bears very little of the charge relative to the other rings. Identify the ring that is not participating as effectively in resonance and suggest an explanation. 

Problem

Basic red 1 is a tetracyclic compound (it has four rings) that shares many structural similarities with the dyes in the previous problem (Chem. Rev. 1993, 93, 381–433). This compound has many significant resonance structures, and the positive charge is highly delocalized. While resonance structures can be drawn in which the positive charge is spread throughout all four rings, nonetheless, one of the rings likely bears very little of the charge relative to the other rings. Identify the ring that is not participating as effectively in resonance and suggest an explanation.