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Front Pages.Pmd

Contents

Preface (v) Acknowledgements (vii)

PPPART 11ART Chemical Methods used for Purification 21 Drying of Organic Compounds 21 BASICS IN ORGANIC CHEMISTRY Criteria of Purity 22 Probable Questions 24 1. Introduction to Organic Chemistry Origin of Organic Chemistry 1 3. Qualitative Analysis The Vital Force Theory “Essence of Life” 1 (Detection of Elements) Definition of Organic Chemistry 2 Introduction 25 Reasons for Treating Organic Chemistry as a Detection of Elements 25 Separate Branch of Chemistry 2 Detection of Carbon and 25 Rise of Organic Chemistry 5 Detection of Nitrogen 26 Need for Studying Organic Chemistry 5 Detection of Halogens 27 Classification of Organic Compounds 6 Detection of Sulphur 28 Organic Chemistry in the Service of Mankind 8 Detection of Phosphorous 28 Probable Questions 8 Detection of Metals 29 Probable Questions 29 2. Purification of Organic Compounds Introduction 9 4. Quantitative Analysis Extraction of Organic Compounds 9 Introduction 31 Estimation of Elements 31 Methods for Purification of Solids 10 Crystallization 10 Estimation of Carbon and Hydrogen 31 Fractional Crystallization 11 Estimation of Oxygen 34 Special Considerations in Crystallization 11 Estimation of Nitrogen 34 Sublimation 12 Estimation of Halogens 38 Methods for Purification of Liquids 13 Estimation of Sulphur 39 Simple Distillation 13 Estimation of Phosphorous 39 Fractional Distillation 14 Probable Questions 40 Distillation under Reduced Pressure 15 Steam Distillation 15 5. Determination of Molecular Mass Extraction with Solvent 15 Determination of Molecular Mass 41 Salting Out 16 Physical Methods 41 Counter Current Extraction 16 Victor- Meyer Method (for volatile substances) 41 Chromatography 17 Dumas Method (For non-volatile substances) 41 Adsorption Chromatography 17 Hoffman Method (For non-volatile substances) 41 Column Chromatography 17 Chemical Methods 41 Thin Layer Chromatography 18 Silver Salt Method for Acid 41 Partition Chromatography 18 Platinichloride Method for Bases 41 Paper Chromatography 19 Volumetric Method for Acids and Bases 41 Gas-Chromatography 19 Molecular Mass of Volatile Substance 41 High Performance Liquid Chromatography 20 Molecular Mass of Non-Volatile Substances 43 High-Performance Thin Layer Probable Questions 49 Chromatography (HPTLC) 21 xiv Contents

6. Nomenclature of Organic Compounds Hybridization 87 Introduction 51 Salient Features of Hybridization 87 IUPAC System of Nomenclature 51 Conditions for Hybridization 87 Steps Involved in Writing IUPAC Theory of Hybridization for the Formation of name of the Compound 58 Covalent Bond (Sidwick – Powell theory) 87 Writing the Structural Formula Source of Energy required for Hybridization 88 from the given IUPAC Name 60 Types of Hybridization 88 3 Probable Questions 61 sp Hybridization or Tetrahedral Hybridization 88 sp2 Hybridization or Trigonal Hybridization 89 7. Structure of Organic Molecules and their sp Hybridization or Diagonal Hybridization 90 Relative Properties Effectiveness of Overlap 91 Introduction to Atom/Molecule 63 Molecular Orbital Theory 91 Wave Nature of Electrons and Wave Equations 63 Bonding and Anti Bonding Orbitals 92 Quantum Mechanics 65 Relationship between Electronic Atomic Orbitals Involved in Organic Molecules 65 Configuration and Molecular Behaviour 95 Shells, Sub-Shells and Orbitals 66 Probable Questions 96 Quantum Numbers 66 8B. Influence of Structure on Shapes of Atomic Orbitals 68 Physical Properties Shape of s Orbital 68 Introduction 99 Shape of p Orbital 68 Modern Concepts of Acids and Bases 99 Rules for Distribution of Electrons into 104 Various Shells, Subshells and Orbitals 69 Solubility of Ionic Solutes 104 Probable Questions 70 Solubility of Non Ionic Solutes 104 8A. Covalent Bond Boiling Point 105 Introduction 73 106 The Nature of Bond between Atoms 73 Melting Point of Non-Ionic Compounds 106 Types of Bonds 73 Probable Questions 107 Ionic Bond or Electrovalent Bond 73 Covalent Bond 75 9. Factors Influencing a Chemical Reaction or Co-Ordinate Covalent Bond or Dative Bond 76 Electronic Displacements in Molecules Electronic Theory of Valency 77 Introduction 109 Characteristic Property of Covalent Bond 77 Inductive Effect 109 Bond Length 77 Types of Inductive Effect 110 Mesomeric and Resonance Effect 111 Bond Angle 78 Bond Energy 79 Electromeric Effect 113 Bond Breaking 80 Resonance 115 Bond Order 80 Hyperconjugation 117 Polarity of Bond and Dipole Moments 80 Probable Questions 119 Applications of Dipole Moment 83 10. Hydrogen Bonding Intramolecular Forces 84 Introduction 121 Inter molecular Forces 84 Types of Hydrogen Bonding 122 Types of Orbital Overlapping and their Intermolecular Hydrogen Bonding 122 Orbital Diagrams 85 Intramolecular Hydrogen Bonding 123 s-s Overlapping 85 Effect of Hydrogen Bonding 123 s-p Overlapping 85 Impact of Hydrogen Bonding in Biology 126 p-p Overlapping 86 Probable Questions 127 Contents xv

11. Organic Reactions and Mechanism PART 2 Introduction 129 ALIPHATIC COMPOUNDS Bond Breaking (Homolysis and Heterolysis) 129 Homolysis 129 14. Heterolysis 130 Introduction 215 Organic Reagents Importance of Alkanes 215 (Nucleophiles and Electrophiles) 130 Nomenclature of Alkanes 216 Nucleophiles (Nucleous Loving Species or General Methods of Preparation 220 Electron Rich Species) 130 Electrophiles (Electron Loving Species or Summary of General Methods of Electron Deficient Species) 130 Preparation of Alkanes 223 Types of Organic Reactions 131 Physical Properties 224 Substitution Reactions 131 Structure 224 Addition Reactions 132 Chemical Properties 224 Elimination Reactions 133 Summary of Chemical Reactions 230 Rearrangement Reactions 133 Pyrolysis or Cracking of Alkanes 230 Reaction Mechanisms 134 Conformations of Alkanes 231 Kinetics of Reactions 134 Individual Members 232 Reaction Progress 135 or Marsh Gas 232 Reactive Intermediates or Reaction Intermediates 137 Probable Questions 234 Carbonium Ions or Carbocations 138 Reactions of Carbocations or 15. or Olefins Fate of Carbocations 143 Introduction 235 Carbanions 145 Importance of Alkenes 235 Carbon Free Radicals 146 Nomenclature 237 Carbenes 148 Isomerism 238 Nitrenes or Imidogens 149 General Methods of Preparation 238 Vinylamines or Enamines or Summary of Methods of Preparation 241 α,β-Unsaturated 151 Structure 241 Probable Question 152 Physical Properties 242 12. Isomerism Chemical Properties of Alkenes 242 Introduction 153 Summary of Reactions of Alkenes 259 Types of Isomerism 153 Individual Members 260 Ethylene 260 Structural Isomerism or Constitutional Isomerism 154 Probable Questions 261 Stereoisomerism 157 Geometrical Isomerism 158 16. or Acetylenes Optical Isomerism 162 Introduction 263 Nomenclature of Enantiomers or the Importance of Alkynes 263 R, S-System or Nomenclature or R and Nomenclature 264 S Notation of Optical Isomers 163 Isomersim 265 Measurement of Optical Activity 168 General Methods of Preparation 265 Racemic Modification 170 Summary of Methods of Preparation 267 Walden Inversion 171 Physical Properties 268 Resolution or Separation of Racemic Mixture 172 Structure 268 Asymmetric Synthesis 173 Acidity of Terminal Alkynes 268 Tautomerism 174 Chemical Properties 269 Probable Questions 176 Summary of Chemical Reactions 274 13. General Terms used in Organic Chemistry Individual Members 275 General Terms Like Homologues Series 179 Acetylene 275 xvi Contents

Physical Properties 276 Monohydric 319 Chemical Properties 276 Introduction 319 Probable Questions 279 Classification 319 Nomenclature 320 17. Alkadienes or Dienes or Diolefins General Methods of Preparation 321 Introduction 281 Summary of Methods of Preparation 327 Importance of Alkadienes 281 Physical Properties 328 Nomenclature 282 Chemical Properties 328 Butadiene 284 Structure 328 Summary of Methods of Preparation 285 Reactions Involving Replacement of Relative Stability of Dienes 285 Hydrogen of the Hydroxyl Group 329 Stability of Conjugated Dienes 286 Reactions Involving Replacement of Summary of Chemical Reactions 295 Hydroxyl Group 330 Theory of Resonance 295 Reactions Involving both Alkyl Group and Resonance Stabilisation of Hydroxyl Group 331 Allyl Radicals - Hyper Conjugation 297 Chemical Tests for Alcohols 332 Nucleophilic Substitution in Allylic Substrates: Distinction between Primary, S 1 Reactivity and Allylic Rearrangement 298 N Secondary and Tertiary Alcohols 333 Nucleophilic Substitution in Allylic Substrates 299 Summary of Chemical Reactions 335 Probable Questions 299 Individual Members of Monohydric Alcohols 336 Methanol or Wood 336 18. or Grain Alcohol 336 Introduction 301 Dihydric Alcohols (or) Diols 340 Importance of Cycloalkanes 301 Introduction 340 Nomenclature 302 Nomenclature 340 General Methods of Preparation 303 General Methods of Preparation of Physical Properties 305 Ethylene Glycol 341 Chemical Properties 305 Physical Properties 341 Summary of Chemical Reactions 307 Chemical Properties 341 Bayer’s Strain Theory or Stability of Trihydric Alcohols (or) Triols 344 Cycloalkanes or Ring Strain 308 Introduction 344 Molecular Orbital Theory of Cycloalkanes 309 General Methods of Preparation 345 Type of Strains 310 Physical Properties 346 Sache-Mohr Theory 310 Chemical Properties 346 Structure of Two Forms of Cyclohexane 310 Pharmaceutically Important Alcohols 349 Conformations of Cycloalkanes 311 Nitroglycerin 349 Drawing Chair Form of Cyclohexane Ring 311 Unsaturated Alcohols 350 Interconversion of Conformations of Vinyl Alcohol 350 Cyclohexane 313 Allyl Alcohol 350 Conformations of Mono Substituted Qualitative Tests for Alcohols 354 Cyclohexanes 313 Pharmaceutical Importance of Conformations of Disubstituted Cyclohexanes 314 Ethylalcohol 352 Coulson and Moffit’s Theory of Chlorobutanol 352 Maximum Overlapping of Carbon Orbitals 315 Cetosteryl Alcohol 352 Probable Questions 315 Benzyl Alcohol 352 19. Alcohols Glycerol 352 Propylene Glycol 353 Introduction 317 Probable Questions 354 Importance of Alcohols 317 Contents xvii

20. Ethers and Chemical Properties 388 Introduction 357 Elimination Reaction 388 Importance of Ethers 357 Miscellaneous Reactions 389 Nomenclature 358 Summary of Chemical Reactions 398 General Methods of Preparation 358 Nucleophilic Substitution Reactions 398 Physical Properties 361 Individual Members 399 Chemical Properties 361 Methyl Iodide 399 Summary of Chemical Reactions 364 Ethyl Chloride or Chloro Ethane 399 Zeisel Method 364 Dihalogen Derivatives 400 Individual Members 365 General Methods of Preparation 400 365 Physical Properties 401 Crown Ethers 366 Chemical Properties 401 Epoxides 367 Individual Compounds 402 Introduction 367 Methylene Dichloride 402 Ethylene Oxide 367 Ethylene Dibromide 402 Summary of Methods of Preparation 368 Trihalogen Derivatives 403 Physical Properties 368 Individual Compounds 403 Summary of Chemical Reactions 368 Chloroform 403 Probable Questions 369 Iodoform or Triiodo Methane 406 Polyhalogen Derivatives 406 21. Thioalcoholos and Thioethers Carbon Tetrachloride 407 Introduction 371 Unsaturated Alkyl Halides 408 Nomenclature 371 Vinyl Chloride or Chloroethene 408 General Methods of Preparation 371 Allyl Halides 410 Summary of Methods of Preparation 372 Allyl Chloride 410 Physical Properties 372 Allyl Bromide 410 Chemical Properties 372 Allyl Iodide 410 Summary of Chemical Reactions 374 Probable Questions 412 Thioethers 375 Introduction 375 22B. Nucleophilic Substitution and Nomenclature 375 Elimination Reactions General Method of Preparation 375 Introduction 415 Summary of Method of Preparation 376 Components of Nucleophilic Substitution Physical Properties 376 Reaction 415 Chemical Properties 376 Mechanisms 415 The S 2 Mechanism 415 Summary of Chemical Reactions 377 N Stereochemistry of S 2 Reaction 417 Individual Members 378 N Factors Affecting S 2 Reactions 418 Mustard Gas or Sulphur Mustard 378 N Probable Questions 378 First Order Nucleophilic Substitution Reaction (S 1) or Unimolecular N 22A. Halogen Derivatives or Alkyl Halides Nucleophilic Substitution Reaction 426 Stereochemistry of S 1 Reactions 428 Introduction 379 N Factors Affecting S 1 Mechanism 429 Importance of Alkyl Halides 379 N Carbocation Rearrangement in S 1 Reaction 432 Classification 380 N Competition between S 2 and S 1 432 Nomenclature 381 N N Comparison between S 1and S 2 Reactions 433 General Methods of Preparation 382 N N Summary of Methods of Preparation 386 Elimination Reactions 434 Introduction 434 Structure 387 E Mechanism or β-elimination 434 Physical Properties 387 2 Zaitsev’s Rule 437 xviii Contents

Stereochemistry of E Reaction 440 2 Mono Carboxylic Acids or Fatty Acids 524 E Reaction or Unimolecular General Methods of Preparation 524 1 Elimination Reaction 442 Summary of Methods of Preparation 528 Stereochemistry of E 443 1 Structure 529 Competition between Substitution and Physical Properties 529 Elimination Reactions 444 Chemical Properties 530 Conditions for S 2/ E 445 N 2 Acidity of Carboxylic Acids 533 Conditions for S 1/ E 445 N 1 Effect of Substituents on Acidity 534 Elimination Reactions from Cyclic Compounds 446 Determination of Acidity Constant or E Elimination from Cyclic Compounds 446 2 Acidity of Carboxylic Acids 535 E Elimination from Cyclic Compounds 446 1 Summary of Chemical Reactions 542 Consecutive E Elimination Reactions 447 2 Individual Members 543 Evidence of E Mechanism 447 2 Formic Acid 543 Phase Transfer Catalysis 449 Acetic Acid or Ethanoic Acid or Vinegar 546 Probable Questions 451 Higher Fatty Acids 547 Palmitic Acid 547 23. and Stearic Acid 547 Introduction 453 Unsaturated Monocarboxylic Acids 547 Importance of Aldehydes and Ketones 453 Oleic Acid 547 Industrial Importance of Aldehydes and Ketones 454 Pharmaceutical Importance of 547 Nomenclature of Aldehydes 456 Acetic Acid 547 Nomenclature of Ketones 456 Lactic Acid 547 General Methods of Preparation of Citric Acid 547 Aldehydes and Ketones 457 Succinic Acid 547 Summary of Methods of Preparation 466 Oxalic Acid 548 Physical Properties 468 Salicylic Acid 548 Chemical Properties 469 Aspirin 548 Some of the Reactions of Aldehydes Benzoic Acid 548 which are not given by Ketones 508 Benzyl Benzoate 548 Summary of Chemical Reactions 509 Dimethyl Phthalate 548 Chemical Reactions of Aldehydes 509 Methyl Aalicylate 548 Chemical Reactions of Ketones 509 Probable Questions 550 Individual Members 511 25. Dicarboxylic Acids Formaldehyde (or) Methanol 511 Introduction 553 Acetaldehyde or Ethanol 513 Chloral or Trichloro Acetaldehyde 515 Importance of Dicarboxylic Acids 553 Pharmaceutical Importance of 516 Nomenclature 554 Formaldehyde 516 General Methods of Preparation 554 Chloral Hydrate 516 Summary of Methods of Preparation 556 Paraldehyde 516 Physical Properties 556 Hexamine 516 Chemical Properties 557 Benzaldehyde 517 Individual Members 559 Vanilin Oxalic Acid (Ethanedioic Acid) 559 Cinnamaldehyde 517 Summary of Reactions of Oxalic Acid 563 Acetone or Dimethyl 517 Malonic Acid (Propanedioic Acid) 564 Probable Questions 518 Succinic Acid (Butanedioic Acid) 565 Unsaturated Dicarboxylic Acids 566 24. Carboxylic Acids Maleic Acid 567 Introduction 521 Fumaric Acid (trans-butenedioic acid) 569 Importance of Carboxylic Acids 521 General Methods of Preparation 569 Nomenclature of Carboxylic Acids 522 Probable Questions 570 Contents xix

26. Substituted Acids-I Reactions of 615 Introduction 571 Summary of Chemical Reactions 622 Substituted Acids of Acetic Acid 571 or Acid Amides (–CONH ) 622 2 Nomenclature 571 Introduction 622 Halogen – Substituted Acids (Haloacids) 572 Nomenclature 623 General Methods of Preparation 572 General Methods of Preparation 623 Properties 573 General Methods of Preparation of Amides 624 Physical Properties 573 Physical Properties 624 Chemical Properties 573 Chemical Properties 625 Amino Acids 576 Summary of Chemical Reactions 630 Introduction 576 Acid halides or Acyl halides 630 Nomenclature of Amino Acids 576 Introduction 630 Identification Tests for Amino Acids 576 Nomenclature 631 Classification of Amino Acids 577 General Methods for Synthesis General Methods of Preparation 631 of α-Amino Acids 578 General Methods of Preparation of Physical Properties of Amino Acids 582 Acid Chlorides 632 Physical Properties 632 Chemical Properties of Amino Acids 582 Chemical Properties 632 Hydroxy Acids 589 Acid Anhydrides 636 Common Examples of Hydroxy Acids 589 Nomenclature of Hydroxy Acids 589 Introduction 636 Individual Members 592 Nomenclature 637 Citric Acid 592 General Methods of Preparation 637 General Methods of Preparation 592 General Methods of Preparation of Acid Physical Properties 593 Anhydrides 638 Chemical Properties 593 Physical Properties 638 Lactic Acid 594 Chemical Properties 638 Tartaric Acid 597 Summary of Chemical Reactions 639 Malic Acid 599 Probable Questions 640 General Methods of Preparation 600 28. Fats and Oils Properties 600 General Methods of Preparation 601 Introduction 641 Glycollic Acid 601 Occurence of Lipids 641 Biological Functions of Lipids 641 Probable Questions 603 Classification of Lipids 641 27. Functional Derivatives of Carboxylic Acids Simple Lipids (Fats and Oils) 642 Introduction 605 Differences between Fats and Oils 642 Physical Properties 605 Nomenclature of Fats 643 Reactivity Considerations 606 Extraction of Fats 644 Glossary 609 Rendering 644 Relative Reactivities of Carboxylic Acids, Solvent Extraction 644 Acyl Halides, Acid Anhydrides, Refining 644 and Amides 609 Physical and Chemical Properties of Fats and Oils 644 Esters 611 Physical Properties 644 Introduction 611 Chemical Properties of Fats 644 Nomenclature 612 Analysis of Oils and Fats 646 General Methods of Preparation 613 Physical Constants 646 General Methods of Preparation of Esters 614 Chemical Constants 647 Physical Properties 615 Acid Value 647 Chemical Properties 615 Saponification Value 647 xx Contents

Ester Value 647 Tetra Alkyl Ammonium Hydroxides 679 Acetyl Value 647 General Method of Preparation 679 Iodine Value 648 Physical Properties 679 Reichert Meissl Value (or) RM Value 648 Chemical Properties 680 Polenski Value 648 Ascent and Descent of Series 680 Fatty Acids 648 Pharmaceutical Importance of 680 Nomenclature of Fatty Acids 648 Amphetamine 680 Classification of Fatty Acids 649 Ethanolamine 681 Isomerism in Unsaturated Fatty Acids 650 Ethyene Diamine 681 Reactions of Fatty Acids 651 Probable Questions 681 Probable Questions 652 30. or Cyanogen Compounds 29. Amines, Alkyl Nitrites and Alkyl Nitrates Introduction 683 Introduction 653 Hydrogen Cyanide or Hydrocyanic Acid Importance of Amines 653 or Prussic Acid 683 Nomenclature 656 Introduction 683 General Methods of Preparation 658 Preparation 683 Separation of Mixture of Amines 664 Physical Properties 684 Fractional Distillation 664 Chemical Properties 684 Hoffmann’s Method 665 Uses 684 Summary of Methods of Preparation 666 Alkyl Cyanides 684 Preparation of Primary Amines 666 Introduction 684 Preparation of Secondary Amines 667 Importance of Alkyl Nitriles 684 Preparation of Tertiary Amines 667 General Methods of Preparation 685 Structure 667 Properties 686 Physical Properties 668 Physical Properties 686 Basicity of Amines 668 Chemical Properties 686 Chemical Properties 670 Basicity or Basic Character of Nitriles 686 Summary of Chemical Reactions Summary of Chemical Reactions 690 of Primary Amines 674 Chemical Properties of Alkyl Cyanides 690 Alkyl Nitrites and Alkyl Nitrates 675 Alkyl Isonitriles or Alkylisocyanides Alkyl Nitrites 675 or Carbylamines 690 General Methods of Preparation 675 Introduction 690 Summary of Methods of General Methods of Preparation 691 Preparation of Alkyl Nitrites 675 General Methods of Physical Properties 675 Preparation of Alkyl Isocyanides 691 Chemical Properties 675 Properties 691 Nitroalkanes 676 Physical Properties 691 General Methods of Preparation 676 Chemical Properties 692 Summary of Chemical Reactions 693 General Methods of Preparation of Alkyl Nitroalkanes 677 Cyanogens (Ethane Dinitrile or Oxalo ) 694 General Methods of Preparation 694 Physical Properties 677 Physical Properties 694 Chemical Properties 677 Chemical Properties 694 Summary of Chemical Reactions of Nitroalkanes 678 Cyanogen Chloride 694 Quarternary Ammonium Compounds 679 General Method of Preparation 694 Tetra Alkyl Ammonium Halides 679 Cyanic Acid 695 Physical Properties 679 Physical Properties 695 Chemical Properties 679 Chemical Properties 695 Contents xxi

Alkyl Isocyanates 695 33. α, β–Unsaturated Carbonyl Compounds General Methods of Preparation 695 Introduction 733 Physical Properties 695 General Methods of Preparation 734 Summary of Methods of Preparation 696 Nucleophilic Addition to α,β–unsaturated Summary of Chemical Reactions 696 Aldehydes and Ketones 734 Probable Questions 696 Nucleophilic Addition to α,β-Unsaturated Carboxylic 31. Organometallic Compounds Acid Derivatives 736 Introduction 697 Quinones 737 Nomenclature 697 Acrolein 737 Method of Preparation 737 Grignard Reagent 698 Physical Properties 737 Introduction 698 Chemical Properties 737 Preparation 698 Uses 738 Experimental Procedure 699 Precautions 699 Probable Questions 738 Chemical Properties 699 34. Aliphatic Diazo Compounds Chemical Properties of Grignard Reagent 705 Introduction 739 Probable Questions 706 Diazomethane 739 32. Active Methylene Group Containing Preparation 739 Physical Properties 739 Compounds Chemical Properties 739 Introduction 707 Uses 741 Difference between Ethyl Acetate and Active Probable Questions 741 Methylene Group Containing Compounds 707 Acetoacetic ester or Ethyl Acetoacetate 708 Introduction 708 PART 3 Preparation 708 Physical Properties 709 AROMATIC COMPOUNDS Chemical Properties 709 Keto Enol Tautomerism in Ethyl Acetoacetate 35. Introduction to Aromatic Compounds (Acetoacetic Ester) 710 Introduction 743 Synthetic uses of Acetoacetic Ester or uses of Reasons for Separate Classification of Acetoacetic Ester in Organic Synthesis 712 Aromatic Compounds 743 Constitution of Acetoacetic Ester 717 Nomenclature of Aromatic Compounds 743 Dual behaviour of AAE or Tautomerism 718 Orientation 746 Summary of Chemical Reactions of Reactions of Substituted Benzene 749 Acetoacetic Ester 720 Effect of Substituents on Reactivity 749 Malonic Ester / Diethyl Malonate 721 Relative Reactivity of Substituted Benzene 751 Introduction 722 The Effect of Substituents on Orientation 757 Preparation 722 Summary 760 Physical Properties 722 Electrophilic Aromatic Substitution of Chemical Properties 722 Disubstituted Benzene 760 Synthetic Applications of Malonic Ester 723 Probable Questions 761 Summary of Chemical Reactions of Malonic Ester 728 36. Benzene and its Analogues (Arenes) Cyanoacetic Ester or Ethyl Cyano Acetate 729 Introduction 763 Preparation 729 Importance of Benzene 763 Synthetic Applications of Cyanoacetic Ester 729 The Great Discovery of Benzene Probable Questions 732 (A Shining Molecule) 764 xxii Contents

Criteria for Aromaticity 765 38. Aromatic Sulphonic Acids Structure of Benzene Introduction 839 (Kekule’s Structure of Benzene) 765 Importance of Aryl Sulphonic Acids 839 Bonding in Benzene 768 Nomenclature 839 Unusual Stability of Benzene or General Methods of Preparation 840 Resonance Energy of Benzene 769 General Mechanism 840 Resonance Energy 770 Effect of Temperature on Sulphonation 842 The Molecular Orbital Structure of Benzene 771 Isolation of Sulphonic Acids 843 Representation of Molecular Orbital Summary of Methods of Preparation 844 Structure of Benzene 771 Physical Properties 844 The Energy Diagram of Benzene 773 Chemical Properties 845 Huckel’s Rule or Concept of Mechanism 848 Aromatic Character (Aromaticity) 774 Summary of Chemical Reactions 852 Theoretical Criteria for Aromaticity 774 Individual Members 853 Relationship between Some Aromatic Benzene Sulphonic Acid 853 Compounds and their Similar Benzene Sulphonyl Chloride 853 Open Chained Molecule 776 Benzene Disulphonic Acids 856 General Methods of Preparation of General Methods of Preparation 856 Benzene and its Analogues 780 Toluene Sulphonic Acids 857 Summary of Methods of Preparation 784 Saccharin 859 Summary of Methods of Preparation of Sulphanilic Acid 860 Homologues of Benzene 785 Sulphanilamide 861 Physical Properties of Benzene 786 Chemical Reactions of Benzene 786 Probable Questions 864 Summary of Chemical Reactions 807 39. Aromatic Nitro Compounds Comparison of Nucleophilic Aliphatic vs Introduction 865 Nucleophilic Aromatic Substitution Reactions 811 Importance of Arylnitro Compounds 865 Annulenes 812 Classification 866 Probable Questions 813 Representation of Nitro Functional Group 867 37. Aryl Halides Nomenclature 867 Introduction 815 General Methods of Preparation 868 Importance of Aryl Halides 816 Summary of Methods of Preparation 871 Nomenclature 822 Physical Properties 871 General Methods of Preparation 822 Chemical Properties 872 Summary of Methods of Preparation 827 Summary of Chemical Reactions 880 Physical Properties 827 Characteristic Identification Tests for Chemical Properties of Aryl Halides 827 Nitro Compounds 881 Benzyne Mechanism 829 Individual Members 881 Summary of Chemical Reactions 833 meta-Dinitro Benzene 881 Low Reactivity of Aryl Halides 834 ortho-Dinitrobenzene 882 Evidence for the Low Reactivity 834 para-Dinitrobenzene 884 Individual Members 834 1,3,5-Trinitrobenzene (or) TNB 885 Bromobenzene 834 Nitro Toluenes 886 Iodobenzene 835 2,4,6-Trinitrotoluene (TNT) 889 Chlorotoluenes 836 Phenyl Nitromethane 891 Benzyl Chloride or Phenyl Methyl Chloride 836 General Methods of Preparation 891 Benzene Hexachloride (BHC) 837 Nitrobenzene (Oil of Mirbane) 893 Probable Questions 837 Probable Questions 897 Contents xxiii

40. Aromatic Amines Dihydric Phenols 964 Introduction 899 Catechol 964 Importance of Aryl Amines 900 Quinol 965 Nomenclature 902 Trihydric Phenols 966 Primary Amino Compounds 902 Pyrogallol 966 General Methods of Preparation 902 Hydroxyl Quinol 966 Summary of Methods of Preparation 907 Phloroglucinol 967 Physical Properties 907 Aromatic Alcohols 967 Chemical Properties 908 Benzyl Alcohol (Phenyl Methanol) 967 General Methods of Preparation 967 Summary of Chemical Reactions 917 Phenyl Ethanol 968 Individual Members 919 Amino Phenols 968 Aniline 919 Toluidines or Amino Toluenes 920 Aromatic Ethers 969 General Methods of Preparation 921 2-Methoxy Benzeneol or 2- Methoxy Phenol (Guaiacol) 970 Benzenediamine or Phenylene Diamine 921 Anisole or Methoxy Benzene 970 o-Phenylenediamine or 1,2-benzenediamine 922 Summary of Chemical Reactions 972 Secondary Aromatic Amino Compounds 923 Probable Questions 973 Diphenylamine 923 Tertiary Amino Compounds 924 43. Aromatic Aldehydes and Ketones Triphenylamine 924 Aromatic Aldehydes 975 Araliphatic Amines 925 Introduction 975 Benzylamine 925 Importance of Aryl Aldehydes and Ketones 975 Acetanilide or N-Phenyl Acetamide 927 Nomenclature of Aldehydes 976 Probable Questions 927 Benzaldehyde (Benzene Carbaldehyde) 977 41. Aryl Diazonium Salts Preparation 977 Introduction 929 Summary of Methods of Preparation 981 Preparation 929 Physical Properties 982 Physical Properties 929 Chemical Properties 982 Chemical Properties 930 Summary of Chemical Reactions 994 Summary of Chemical Reactions 938 Unsaturated Aromatic Aldehydes 996 Probable Questions 939 Cinnamaldehyde (or) 3-phenyl-2-propenal 996 Phenolic Aldehydes or Hydroxy Benzaldehyde 997 42. Phenols Salicylaldehyde 997 Introduction 941 Vanillin or 4-hydroxy-3-methoxy Benzaldehyde 998 Importance of Phenols 942 Anisaldehyde or p-methoxy Benzaldehyde 999 Phenol 943 Protocatechualdehyde or 3,4-dihydroxy Preparation 943 Benzaldehyde 1000 Summary of Methods of Preparation 945 Piperonal or 3,4-methylenedioxy Physical Properties 945 Benzaldehyde (or) Heliotropin 1001 Chemical Properties 946 Aromatic Ketones 1002 Acidity of Phenols 946 Introduction 1002 Summary of Chemical Reactions 958 General Methods of Preparation of Uses of Phenol 961 Aromatic Ketones 1003 Tests for Identification 962 Nomenclature of Ketones 1003 Individual Members 962 Acetophenone 1003 Picric Acid 962 Summary of Methods of Preparation 1004 Homologues of Phenol 963 Summary of Chemical Reactions 1009 Methyl Phenols (Cresols) 963 Benzophenone (Diphenyl Ketone) 1010 xxiv Contents

Aromatic Diketones 1011 46. Polynuclear Quinones 1012 Introduction 1047 Benzoquinones 1012 Types 1047 p-Benzoquinone or Quinone 1012 Naphthalene 1047 Probable Questions 1014 Manufacture of Naphthalene 1047 Synthesis 1048 44. Aromatic Carboxylic Acids and their Physical Properties 1049 Derivatives Chemical Properties 1049 Introduction 1017 Uses 1054 Importance of Aryl Carboxylic Acids 1017 Anthracene 1054 Nomenclature 1019 Preparation of Anthracene 1054 General Methods of Preparation 1019 Synthesis 1055 Monobasic Acids with Carboxyl Group Directly Physical Properties 1056 Attached to the Nucleus 1020 Chemical Properties 1056 General Methods of Preparation 1020 Uses 1058 Summary of Methods of Preparation 1022 Phenanthrene 1058 General Properties 1022 Preparation 1058 Individual Members 1022 Isolation 1058 Benzoic Acid 1022 Synthesis 1058 Summary of Chemical Reactions 1027 Physical Properties 1059 Aromatic Derivatives 1028 Chemical Properties 1059 Benzoyl Chloride 1028 Uses 1061 Summary of Methods of Preparation 1029 Diphenyl Methane 1061 Benzonitrile or Phenyl Cyanide or General Methods of Preparations 1062 Benzene Carbonitrile 1030 Chemical Properties 1062 General Methods of Preparation 1030 Triphenyl Methane or Tritane 1063 Summary of Methods of Preparation 1030 General Methods of preparations 1063 Substituted Benzoic Acids 1031 Physical Properties 1064 Chemical Properties 1064 Amino Benzoic Acids 1031 Uses 1064 Anthranilic Acid (o-Amino Benzoic Acid) 1031 General Methods of Preparation 1031 Probable Questions 1065 Salicylic Acid 1033 Monobasic Acids with Carboxyl PART 4 Group in the Side Chain 1037 Cinnamic Acid 1037 SPECIAL TOPICS IN ORGANIC CHEMISTRY Manufacturing of Cinnamic Acid 1038 Summary of Chemical Reactions 1039 47. Oxidation and Reduction Phenyl Acetic Acid 1039 Oxidation 1067 Benzene Dicarboxylic Acids 1040 Oxidation State 1067 Phthalic Acid 1041 Determination of Oxidation State 1067 General Methods of Preparation 1041 Determination of Oxidation State from Industrial Method of Preparation 1041 Lewis Structures 1067 Determination of Oxidation States Whether Probable Questions 1041 we Know Lewis Structure or Not 1068 45. Dyes Mechanism 1069 Introduction 1043 Classification of Oxidation 1071 Classification of Dyes 1043 Reduction 1080 Probable Questions 1045 Classification 1080 Contents xxv

Reactions in which an Organic Substrate is Hydroxylation of Allylic Group 1121 both Oxidised and Reduced 1088 N-Bromo Succinimide (NBS) 1122 Probable Questions 1089 Method of Preparation 1122 Applications 1123 48. Pericyclic Reactions Dakin’s Reaction 1124 Introduction 1091 Mechanism 1124 Polar Reaction 1091 Applications 1125 Free Radical Reaction 1091 Schmidt Rearrangement 1125 Pericyclic Reaction 1091 Mechanism 1126 Types of Pericyclic Reactions 1092 Applications 1127 Common Features of Pericyclic Reactions 1093 Beckmann Rearrangement 1127 Photochemical Reaction 1093 Mechanism 1128 Thermal Reaction 1093 Applications 1128 Molecular Orbitals and Orbital Symmetry 1094 Claisen- Schmidt Condensation 1129 Molecular Orbital Description of Ethylene 1094 Mechanism 1129 Molecular Orbital Description of 1,3-Butadiene 1095 Applications 1129 Electrocyclic Reactions 1097 Michael Addition 1130 Prediction of Configuration of the Product Formed Components of Michael Addition 1130 in Electrocyclic Reaction 1099 Mechanism 1130 Woodward - Hoffmann Rules for Synthetic Applications 1132 Electrocyclic Reaction 1100 Probable Questions 1132 Cyclo Addition Reactions 1100 Sigmatropic Rearrangement 1103 50. Some Official Medicinal Compounds Numbering of Sigmatropic Rearrangement 1104 ( Pharm. D.) Types of Rearrangements 1105 Chlorbutol or Chlorbutanol B.P., Mechanism 1107 U.S.P or Chloretone 1133 Biological Reactions Involving Electrocyclic Preparation, Test for Purity, Uses 1133 Reaction and Sigmatropic Rearrangement 1110 Dimercaprol (Synonym: B.A.L. Synthesis of Vitamin D in Our Body 1111 British Antilewisite) 1133 Summary of Easy Way to Remember the Urea or Carbamide 1134 Selection Rule 1111 Vanillin 1134 Probable Questions 1111 Paraldehyde 1135 Ethylene Chloride 1135 49. Reactions and Reagents Lactic Acid 1136 Lithium (LiAlH ) 1113 4 Tartaric Acid 1137 Preparation 1113 Citric Acid 1138 Properties 1113 Salicylic Acid (o-Hydroxy Benzoic Acid) 1139 Advantages 1113 Aspirin (Emipirin, Bufferin) 1140 Applications 1114 Methyl Salicylate (Oil of Winter Green) 1140 Lead Tetraacetate (LTA), (Pb(OCOCH ) ) 1117 3 4 Ethyl Benzoate 1141 Method of Preparation 1117 Applications 1117 Benzyl Benzoate 1141 Sodium Boro Hydride (NaBH ) 1119 Dimethyl Phthalate 1142 4 Method of Preparation 1119 Sodium Lauryl Sulphate (SLS) 1143 Advantages 1119 Saccharin Sodium 1143 Selenium Dioxide (SeO ) 1120 Mephenesin 1144 2 Preparation 1120 Ethylene Diamine Dihydrate 1144 Uses 1121 Probable Questions 1145 Some of the Important Applications of SeO 1121 2 xxvi Contents

PART 5 Various Techniques of Microwave Assisted Organic Synthesis 1160 ADVANCES IN ORGANIC CHEMISTRY Applications of Microwaves in Organic Synthesis 1160 51. Green Chemistry Applications of Microwaves in Inorganic Synthesis 1160 What is Green Chemistry? 1147 Applications of Microwave in Importance of Green Chemistry 1147 Analytical Chemistry 1165 Principles of Green Chemistry 1147 Applications of Microwave Irradiation in Waste Management 1166 Advantages of Green Chemistry 1148 Development of Green Chemistry 1150 Advantages of Choice of Solvent 1150 Microwave Assisted Reactions 1166 Disadvantages 1166 Guidelines for Implementation of Green Chemistry 1150 Probable Questions 1166 Applications of Green Chemistry 1151 53. Nanochemistry I Synthesis of Chemicals 1151 Introduction 1167 II Pharmaceutical Applications 1152 Characterization of Nanomaterials 1168 III Other Applications 1154 Properties of Nanomaterials 1168 Probable Questions 1154 Comparison of Nanoparticles and 52. Microwave Assisted Synthesis Bulk Materials 1168 Introduction 1155 Classification of Nano Structure Materials 1169 Evolution of Microwave Chemistry 1156 Synthesis of Nanomaterials 1171 Theories behind Microwave Heating or Applications of Nanomaterial 1173 Principles of Microwave Heating 1156 Disadvantages of Nanomaterials 1175 Loss Angle 1157 Probable Questions 1175 Solvents in Microwave Synthesis 1158 Index 1177 Modes or Instrument of Microwave Reactor 1158

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