Posts

Unit-I (a) Study of following reactions with mechanism

Unit-I (a) Study of following reactions with mechanism: 1. Dieckmann  Condensation ( Dieckmann Reaction ): The base-catalyzed intramolecular condensation of a diester. The Dieckmann Condensation works well to produce 5- or 6-membered cyclic ß-keto esters, and is usually catalysed by sodium alkoxide in alcoholic solvent. Mechanism of Dieckmann Condensation 2. Benzoin Condensation (  Benzoin Reaction ): The Benzoin Condensation is a coupling reaction between two aldehydes that allows the preparation of α-hydroxyketones. Mechanism of Benzoin Condensation 3. Favorskii reaction: Favorskii Rearrangement is a base catalysed organic reaction which converts  α -halo ketones or cyclopropanones to carboxylic acid derivatives. If the reaction involves cyclic  α -halo ketones, then ring contraction will take place during rearrangement. This reaction is named after Russian chemist Alexey Yevgrafovich
1 comment
Read more

M. Sc. - I (Semester-II) Organic Chemistry-II

M. Sc. - I (Semester-II) Organic Chemistry-II Paper No. HCT - 202 Unit-I (a) Study of following reactions with mechanism:                                                                 (7) Dieckmann, Benzoin, Favorskii reaction, Reimer-Tieman, Stobbe, Diels-Alder, Robinson annulation, Chichibabin, Simon- Smith, Ullmann, Mc. Murry and Dakin. (b)Reagents in organic syntheses:                                                                                           (8) Complex metal hydrides, LDA, dicyclohexylcarbodiimide(DCC), PTC, crown ethers, Merrifield resin, Peterson’s synthesis, 1,3-dithiane, diazomethane, DDQ. Unit – II (a) Reduction:                                                                                                                            (7) Study of following reductions: Catalytic hydrogenation using homogeneous and heterogeneous catalysts. Study of following reactions: Wolff-Kishner, MeerweinPondorffVerley, Birch, Clemmensen, Sodium borohydride
Post a Comment
Read more

Addition to Carbon–Carbon Multiple Bonds

Introduction There are four types of reactions in  organic chemistry----------1. Addition reaction                                                                                                      2. Elimination reaction                                                                                                     3. Substitution reaction                                                                                                     4. Rearrangement reaction Let us know more about the Addition reactions, particularly addition to carbon-carbon multiple bonds. Basically addition to a double or triple bond can takes place in four different ways.                              1.Two-step processes, with initial attack by a nucleophile,                             2. Two-step processes, with initial attack upon an electrophile                             3.Two-step processes, with initial attack upon a free radical. The second step of the reacti
3 comments
Read more

M.Sc.I, Sem.I, Organic Chemistry(Paper II)

M. Sc.-I (Semester-I) Organic Chemistry-I (Paper-II) Unit –I (a) Reaction mechanism: Structure and reactivity (7) Types of reactions, strength of acids and bases. Generation, structure, stability and reactivity of reaction intermediates: Carbocations, carbanions, free radicals, carbenes, nitrenes, benzynes and ylides. Effect of structure on reactivity: resonance, steric, hyperconjugation effects. (b) Aliphatic Nucleophilic substitutions: (8) The SN2, SN1 and SNi with respect to mechanism and stereochemistry. Nucleophilic substitutions at an allylic, aliphatic trigonal, benzylic, aryl and vinylic carbons. Reactivity effect of substrate structure, effect of attacking nucleophiles, leaving groups and reaction medium. SN reactions at bridged head carbon, competition between SN1 and SN2, ambident nucleophiles, Neighbouring Group Participation. Unit - II (a) Aromatic Electrophilic Substitutions: (8) Introduction, the arenium ion mechanism, orientation and reactivit
Post a Comment
Read more