Thiophene is a five-membered aromatic heterocyclic compound with one sulfur atom, important in drugs, dyes, and conducting materials. Chemical Formula of Thiophene: C₄H₄S Physical Properties of Thiophene: Property Value Appearance Colorless to pale yellow liquid Odor Benzene-like Boiling Point 84 °C Melting Point -38 °C Solubility Soluble in organic solvents; poorly in water Density ~1.05 … Read more
Stereoselective Reactions are reactions where one stereoisomer is formed preferentially over others from the same reactant. Definition of Stereoselective Reactions: A stereoselective reaction is a chemical reaction in which a single reactant can produce two or more stereoisomeric products, but one is formed preferentially over the others. The preference arises due to factors like steric … Read more
Stereospecific Reactions are chemical reactions where a specific stereoisomer of the reactant always leads to a specific stereoisomer of the product. Definition of Stereospecific Reactions: A stereospecific reaction is one where the stereochemistry of the reactant completely determines the stereochemistry of the product. Each stereoisomeric reactant leads to a different stereoisomeric product. The reaction mechanism … Read more
Conditions for Optical Activity require the presence of a chiral center, absence of symmetry, and a non-superimposable mirror image. Conditions for Optical Activity To be optically active, a compound (including biphenyl atropisomers) must meet the following: Chirality Must be non-superimposable on its mirror image. Can arise from: Chiral centers Axial, planar, or helical chirality No … Read more
Stereoisomerism in Biphenyl Compounds (Atropisomerism) Stereoisomerism in Biphenyl Compounds (Atropisomerism) occurs when restricted rotation around the biphenyl bond creates stable, isolable isomers with distinct properties. What is Biphenyl? Biphenyl is a molecule made of two benzene rings joined by a single bond: The two rings can rotate around the central C–C bond. However, rotation can … Read more
Conformational Isomerism in Cyclohexane Conformational Isomerism in Cyclohexane (C₆H₁₂) involves chair, boat, twist, and half-chair forms, with the chair conformation being the most stable. Why Is Cyclohexane Special? Although cyclohexane forms a ring, it avoids angle strain (unlike smaller rings) by adopting non-planar conformations. The ideal bond angle (109.5°) is maintained through specific 3D shapes, … Read more
Conformational Isomerism in n-Butane (C₄H₁₀) Conformational Isomerism in n-Butane (C₄H₁₀) arises from C–C bond rotation, giving anti, gauche, and eclipsed forms with different stabilities. Rotation around the C₂–C₃ Bond n-Butane has a straight chain: CH₃–CH₂–CH₂–CH₃. Rotation about the C₂–C₃ bond generates multiple conformations. Key Conformations Anti Conformation (Staggered): The two methyl groups are 180° apart. … Read more
Conformational Isomerism in Ethane (C₂H₆) Conformational Isomerism in Ethane (C₂H₆) shows staggered and eclipsed forms from C–C bond rotation, with staggered being more stable. Structure and Rotation Ethane contains a C–C sigma bond that allows free rotation. Each carbon is bonded to three hydrogen atoms. The rotation around the C–C bond leads to different conformations. … Read more
Nomenclature of Geometrical Isomers is done using cis-trans or E-Z system, based on the relative positions or priority of substituents. Nomenclature of Geometrical Isomers There are three main systems used to name geometrical isomers: Cis-Trans Nomenclature When it is used: Simple alkenes or cycloalkanes with identical groups Basis of naming: Relative positioning of identical groups … Read more
E–Z Nomenclature System uses Cahn–Ingold–Prelog rules to name isomers based on priority groups around a double bond (E = opposite, Z = same side). Why Use E-Z Nomenclature System? When each carbon in the double bond has two different substituents, the cis-trans system is not sufficient. In such cases, the E-Z system provides a consistent … Read more
