Green Chemistry Greener Alternatives to Synthetic Organic Transformations V.K. Ahluwalia Alpha Science International Ltd. Oxford, U.K. Contents Preface v Parti 1. Introduction 1.1-1.10 1.1 Principles of Green Chemistry 1.1 1.2 How to Plan a Green Synthesis 1.2 Part II Green Alternatives to Synthesis Organic Transformations 2. Aqueous Phase Transformations 2.1-2.48 2.1 p-Acetylaminophenol (Tylenol) 2.1 2.2 3-Aminopyridine 2.2 2.2a Anthranilic Acid 2.3 2.3 Benzilic Acid 2.3 2.4 Benzoin 2.5 2.5 Benzotriazole 2.6 2.6 2-Benzoyl-3,5-dimethylbenzofuran 2.7 2.7 n-Butyl Bromide 2.8 2.8 Tert.Butylchloride 2.8 2.9 Chalcone (Benzalacetophenone) 2.9 2.10 Cycloheptanone 2.10 2.11 2,3-Dihydroxy Anisole (Pyrigallol Monomethyl-ether) 2.12 2.12 2,4-Dihydroxybenzoic acid (P-resorcylic Acid) 2.13 2.13 3,4-Dimethoxyphenol 2.14 2.14 2,3-Dimethyl-l-phenylpyrazol-5-one 2.15 2.15 3, 5-Dimethylpyrazole 2.16 2.16 5,5-Diphenylhydantoin 2.17 2.17 Endo-cis-1,4-endoxo-A5-cyclohexene-2,3-dicarboxylic Acid 2.18 2.18 p-Ethoxyacetanilide (Phenacetin) 2.19 2.19 6-Ethoxycarbonyl-3,5-diphenyI-2-cyclohexenone 2.20 2.20 HeteroDiels-AlderAdduct 2.22 2.21 Hippuric Acid (Benzoyl Glycine) 2.22 Viii Contents 2.22 Hydantion 2.23 2.25 3-Hydroxy-3-phenyl-2-methylene Proponamide 2.24 2.24 Iodoform 2.25 2.25 Inodole 2.26 2.26 3-(p-Methoxyphenyl)-2H-1,4-Benzoxazine 2.27 2.27 3-Methylcyclopent-2-enone 2.27 2.28 2-(2'-Methlindol-3yl)-1,4-benzoquinone 2.28 2.29 2-methyl-2-(3-oxobutyl)-1,3-cyclopentanedione 2.29 2.30 P-Naphthyl Acetate 2.30 2.31 (5-Naphthyl Methyl Ether (Nerolin) 2.31 2.32 Naphthaldehyde 2.31 2.33 2-Naphthoic Acid 2.33 2.34 Phenyl Acetate 2.34 2.35 Phenylacetic Acid 2.35 2.36 2-Phenyl p-benzoquinone 2.36 2.37 1 -phenyl-2, 2-dichlorocyclopropane 2.36 2.38 P-Phenylpropionic Acid 2.37 2.39 Pinacolone 2.38 2.40 Salicylic Acid 2.39 2.41 Stilbene (Trans) 2.41 2.42 2,3,4-Trimethoxyphenol 2.43 2.43 o-Toluamide 2.44 2.44 Vanillideneacetone 2.45 2.45 Miscellaneous Transformations in Water 2.46 Autocatalysis 2.46 2.46 Conclusion 2.48 Transformations in Solid Phase 3.1-3.28 3.1 2-Allyl Phenol 3.1 3.2 Anthraquinone 3.3 3.3 Benzanilide 3.4 3.4 Benzamide 3.5 3.5 Benzil 3.5 3.5a Benzonitrile 3.7 3.6 Benzyl Alcohol 3.8 3.7 Benzylidene Aniline 3.9 3.8 2-Carbethoxycyclopentanone 3.10 3.9 Catechol 3.11 3.10 l,4-Dihydro-quinoxaline-2,3-dione 3.12 Contents ix 3.11 5,5-Dimethyl Hydantoin 3.12 3.12 2,5-Dimethylpyrrole 3.13 3.13 Diphenylcarbinol 3.14 3.14 Flavone 3.15 3.15 Imidazo [1,2-a] Pyridines 3.16 3.16 3-Nitro-2-phenyl-2H-Chromenes 3.16 3.17 (o-Nitrostyrene 3.17 3.18 Sec-Phenethyl Alcohol 3.18 3.19 Phenyl Benzoate 3.20 3.20 2-Phenyl-l,2,3,4-tetrahydro-4-quinolone 3.20 3.21 Phthalic Anhydride 3.21 3.22 3-Pyridyl-4(3 H) Quinazolone 3.22 3.23 cis-1, 2, 3, 6-Tetrahydro-4, 5-dimethyl Phthalic Anhydride 3.23 3.24 Miscellaneous Applications of Solid State Reactions 3.24 Oxidation of Alcohols to Carbonyl Compounds 3.24 Oxidation of Sulfides to Sulfoxides 3.25 Pinacol-Pinacolene Rearrangement 3.26 Beckmann Rearrangement 3.27 Crossed Cannizzaro Reaction 3.27 Benzimidazoles 3.27 Alkylation of Reactive Methylene Compounds 3.27 Aziridines 3.28 3.25 Conclusion 3.28 4. Photochemical Transformations 4.1-4.12 4.1 Cis-Azobenzene 4.1 4.2 Benzopinacol 4.2 4.3 Maleic Acid 4.3 4.4 Methyl a-naphthyl Acetate 4.4 4.5 1,4-Naphthaquinone Photodimer 4.6 4.6 9-phenylphenanthrene 4.6 4.7 Cis-Stilbene 4.8 4.8 Miscellaneous Applications of Photolysis 4.9 Photochemical Cycloaddition Reactions 4.9 Paterno-Buchi Reaction 4.9 Photochemical Cycloadditions in Water 4.9 Phoinduced Substitution 4.10 Photorearrangement 4.10 Photochemical Reaction in Solid State 4.11 Photochlorination 4.11 X Contents Photo Sulfochlorination 4.12 Photochemical Sulfoxidation 4.12 Photonitrosation 4.12 4.9 Conclusion 4.12 5. Transformations Using Phase Transfer Catalysts 5.1-5.26 5.1 Benzoic Acid 5.1 5.2 Benzonitrile 5.3 5.2a Benzyl Cyanide 5.4 5.3 n-Butyl Benzyl Ether 5.4 5.4 1-Cyanooctane 5.6 5.5 Dichloronorcarane [2,2-Dichlorobicycyo (4.1.0) heptane] 5.7 5.6 4,6-Dimethyl-3-phenylcoumarin 5.9 5.7 2,2 Dimethyl-3-phenyl Propion Aldehyde 5.10 5.8 3,4-Diphenyl-7-hydroxycoumarin 5.11 5.9 Flavone 5.12 5.10 1-fluorooctane 5.14 5.11 l-Oxaspiro-[2,5]-octane-2-carbonitrile 5.15 5.12 2-Phenylbutyronitrile 5.16 5.13 Phenylisocyanide (C6H5 N s C) 5.17 5.14 Salicyaldehyde 5.19 5.15 2,4,6- Trimethylbenzoic Acid 5.20 5.16 Miscellaneous Application of PTC 5.21 Benzoin Condensation 5.21 Darzen's Reaction 5.22 Michael Reaction 5.22 Welliamson Ether Synthesis 5.22 Witting Reaction 5.23 Wittig-Horner Reaction 5.23 3-Aryl-2H-l, 4-benzoxazines 5.23 2-Aroylbenzofurans 5.23 1,4-Benzoxazines 5.24 Oxidation 5.24 6. Transformations Using Sonication 6.1-6.19 6.1 Benzyl Cyanide 6.1 6.2 Biphenyl 6.2 6.3 Butyraldehyde 6.4 6.4 Cannizzaro Reaction 6.5 6.5 2-Carbethoxy Cyclopentanone 6.5 6.6 N-2-Chlorophenyl Anthranilic Acid 6.6 Contents Xi 6.7 Cinnamaldehyde 6.7 6.8 Cyclohexanone 6.7 6.9 7.7-Dibromobicyclo (4.1.0) Heptane 6.8 6.10 Ethyl 2-hydroxy-2-phenyl acetate 6.8 6.11 Ethyl Phenyl Ether (Phenetole) 6.9 6.12 Miscellaneous Applications of Ultrasound 6.10 Hydrosis of Nitriles 6.10 Solvolysis 6.10 Formation of Azides and Sulphocyanides 6.10 Cyclopropanation 6.10 Methylenation 6.11 N-Alkylation of Amines 6.11 Ethers 6.12 Oxidation 6.12 Reduction 6.13 Hydroboration 6.14 Coupling of Aryl Halides 6.14 Dichloro Carbene 6 15 Conversion of Aryl Halides into the Corresponding Aldehydes 6.15 Cannizzaro Reaction 6.16 Strecker Synthesis 6.16 Reformatsky Reaction 6.16 Barbier Reaction 6.17 Curtius Rearrangement 6.17 Oxymercuration of Olefins 6.17 Isotopic Labelling 6.18 Grignard Reagents 6.18 Isomerisation of Maleic Acid to Fumaric Acid 6.18 Dieckmann Cyclisation 6.19 6.13 Conclusion 6.19 7. Transformations Using Microwave Irradiations 7.1-7.20 7.1 Anthracene-maleic Anhydride Adduct 7.1 7.2 Aspirin (Acetylsalicylic Acid) 7.2 7.3 Benzaldehyde 7.3 7.4 Benzimidazole 7.5 7.5 Benzophenone 7.6 7.6 Benzylideneaniline 7.7 7.7 2,3-Diphenylquinoxaline 7.8 7.8 Ethyl Benzoate 7.8 Xii Contents 7.9 Indole 7.9 7.10 4-Methylcarbostyril (2-Hydroxy 4-methyl quinoline 7.10 7.11 4-Methyl-7-hydroxycoumarin 7.10 7.12 3- methyl-7-methoxy Coumarin 7.11 7.13 3-Methyl-l-phenyl-5-pyrazolone 7.12 7.14 2-Phenylindole 7.13 7.15 Piperazine-2,5-dione (Diketopiperazine) 7.14 7.16 Phenylacetic Acid 7.15 7.17 Phenyl Propyl Thioether 7.15 7.18 1,2,3,4-Tetrahydrocarbazole 7.16 7.19 Miscellaneous Applications of Microwave Reactions 7.17 Deactylation of Benzaldehyde Diacetates 7.17 Deacetylation of Acetyl Derivatives of Phenols and Alcohols 7.17 Deportation of Benzyl Esters 7.17 Deportation of t-butyldimethylsily Ethers 7.18 Decarboxylation of Aromatic Carboxylic Acids 7.18 Sponification of Esters 7.18 Dethioacetalization of Thioacetals and Thioketals of Aldehydes and Ketones 7.18 Deprotection of Oximes 7.19 Cleavage of Semicarbazones and Phenylhydrazones 7.19 Witug Reaction 7.19 7.20 Conclusion 7.20 8. Enzymatic Transformations 8.1-8.13 8.1 Benzoin 8.1 8.2 Ethanol 8.3 8.3 (S) -(+)-Ethyl 3-hydroxybutanoate 8.4 8.4 l-Phenyl-(lS)ethan-l-ol 8.6 8.5 2-(Quinolin—8-yloxy)-naphtho [2, l-b]pyran-3-one 8.7 8.6 Reduction of Aldehyles and Ketones 8.7 8.7 Miscallanlous Enzymatic Transformations 8.8 Oxidation at Ethyl Alcohol to Acetic Acid 8.8 Baeyer-villiger Reaction 8.9 Oxidation Benzene to Trans, Trans Muconic Acid 8.9 Oxidation at Oleic Acid 8.9 Oxidation of Primary Alkyl Halides to Carboxylic Acids 8.10 Hydroxylation of a,|}-unsaturated Ketones 8.10 Oxidation of Aldehydes to Carboxylic Acids 8.10 Oxidation of Aromatic Side Charins to Carboxyl Group 8.11 Contents Xl\\ Oxidation of Primary Amines to Carboxylic Acids 8.11 Oxidation of Primaryamines to Nitro Compounds 8.11 Conversion of Penicillin into 6-APA 8.12 Miscellaneous Applications of Enzymes 8.12 Reductions 8.12 8.8 Conclusion 8.13 9. Transformations in Ionic Liquids 9.1-9.12 9.1 1-Acetylnaphthalene 9.1 9.2 4-Acetyl-l-methylcyclohexene 9.2 9.3 p-methylacetophenone 9.3 9.4 Oxidation of Benzylic Alcohols to Aldehydes 9.4 9.5 Miscelloneous Applications of Ionic Liquids 9.4 Alkylation of Active Methylene Compounds 9.4 Cyclopropanation 9.4 Synthesis of Ethers 9.5 Oxidations 9.5 Fridel Crafts Reaction 9.7 Diels-Alder Reaction 9.8 Knoevenagel Condensation 9.8 Aldol Condensation 9.8 Wittig Reaction 9.9 Suzuki Coupling Reaction 9.9 Still Coupling Reaction 9.10 Henry Reaction 9.10 Stetter Reaction 9.10 Esterification, Ether Formation and Pinacol-Pinacolone Rearrangement 9.11 Pechmann Condensation 9.12 10.