1,2,3-Thiadiazoles are a group of heterocycles whose derivatives are important in industry, medicine, and agriculture. This volume provides a complete treatment of this group of heterocycles with an emphasis on syntheses, structural data, properties, reactions, and applications.

Autorentext

Wim Dehaen is Professor in the Department of Chemistry at the University of Leuven. Vasiliy Bakulev is Professor in the Department of Technology for Organic Synthesis?at The Urals State Technical University.

Inhalt
1 Synthesis of 1,2,3-thiadiazoles 1

1.1 Cyclization of Hydrazones with Thionyl Chloride (HurdMori Synthesis) 1

1.1.1 Scope and Limitations 2

1.1.2 Mechanism of the HurdMori Reaction 4

1.1.3 Application of the HurdMori Reaction in Organic Synthesis 5

1.2 Cycloaddition of Diazoalkanes onto a C=S bond (Pechmann Synthesis) 17

1.3 Heterocyclization of -diazo Thiocarbonyl Compounds (Wolff Synthesis) 22

1.3.1 Introduction of a Diazo Function into Compounds Containing a C=S Bond 23

1.3.2 Introduction of a C=S Bond in the -position to a Diazo Group 27

1.3.3 Simultaneous Introduction of Diazo and Thiocarbonyl Functions 29

1.4 Transformations of other Sulfur-containing Heterocyclic Compounds 30

1.5 Elaboration of Preformed 1,2,3-Thiadiazoles 33

1.5.1 Carboxylic Acids 33

1.5.2 Functional Derivatives of Carboxylic Acids 35

1.5.3 Aldehydes 36

1.5.4 Amino-1,2,3-Thiadiazoles 37

1.5.5 Halo Derivatives 39

1.5.6 5-Hydrazino-, 5-Mercapto-1,2,3-Thiadiazoles and 5-Sulfide Derivatives 40

1.5.7 2-(1,2,3-Thiadiazol-5-yl)acetic Acid Derivatives 41

1.5.8 Alkenyl-1,2,3-Thiadiazoles 42

1.5.9 5-Hydroxyiminomethyl- and 5-Diazomethyl-1,2,3-Thiadiazoles 42

1.5.10 4-Hydroxymethyl-1,2,3-Thiadiazoles 43

1.6 Tables 44

1.7 Selected Procedures 79

1.7.1 1,2,3-Thiadiazole-4-Carbaldehyde 79

1.7.2 4-Phenyl-1,2,3-Thiadiazole 80

1.7.3 4-Phenyl-1,2,3-Thiadiazole-5-Carbaldehyde 81

1.7.4 4-Phenyl-5-Oxyiminomethyl-1,2,3-Thiadiazole 82

1.7.5 5-Phenyl-1,2,3-Thiadiazole-4-Carbaldehyde 82

1.7.6 5-Chloro-1,2,3-Thiadiazole-4-Carbaldehyde 83

1.7.7 Ethyl 5-amino-1,2,3-Thiadiazole-4-Carboxylate 84

1.7.7.1 Pechmann Method 84

1.7.7.2 Wolff Method 85

1.7.8 Ethyl 5-chloro-1,2,3-Thiadiazole-4-Carboxylate 86

1.7.9 4-Phenyl-2-(2,4,6-Trichlorophenyl)-1,2,3-Thiadiazolium Chloride 86

1.7.10 5-Amino-4-ethoxycarbonyl-2-phenyl-1,2,3-thiadiazolium bromide 87

References 88

2 Structure of 1,2,3-Thiadiazoles 93

2.1 Theoretical Methods 93

2.2 Experimental Structural Methods 97

2.2.1 X-ray Analysis 97

2.2.2 Nuclear Magnetic Resonance Spectroscopy 103

2.2.2.1 Proton NMR Spectroscopy 103

2.2.2.2 Carbon-13 NMR Spectroscopy 103

2.2.2.3 Nitrogen-14 NMR Spectroscopy 106

2.2.2.4 Nitrogen-15 NMR Spectroscopy 106

2.2.3 Mass Spectrometry 107

2.2.4 Other Spectroscopic Data 110

References 110

3 Chemical Properties of 1,2,3-Thiadiazoles 113

3.1 Reactions due to the Reactivity of Ring Atoms 113

3.1.1 Reactions with Electrophiles 113

3.1.1.1 Protonation 113

3.1.1.2 Complexation 114

3.1.1.3 Alkylation 115

3.1.1.4 Acylation 116

3.1.1.5 Oxidation 116

3.1.1.6 Electrophilic Substitution of Hydrogen 117

3.1.2 Reactions with Nucleophiles 117

3.1.2.1 Attack at the Sulfur Atom 117

3.1.2.2 Attack at the C5 Atom 118

3.1.2.3 Attacks at H4 and H5 120

3.1.2.4 Cycloaddition Reactions 121

3.2 Reactions of Substituents 122

3.2.1 5-Alkyl-1,2,3-thiadiazoles 122

3.2.2 1,2,3-Thiadiazole-4-carbaldehyde 123

3.2.3 5-Amino-1,2,3-thiadiazole-4-carbothioamide 124

3.2.4 Mercapto-1,2,3-thiadiazoles 124

3.3 Rearrangements 124

3.3.1 Dimroth-type Rearrangements 125

3.3.2 Cornforth-type Rearrangements 129

3.3.2.1 Rearrangements of 4-(iminomethyl)- substituted-1,2,3-Thiadiazoles 129

3.3.2.2 Degenerate Rearrangements of 4-Thiocarbamoyl-1,2,3-Thiadiazoles 133

3.3.2.3 Rearrangements of 1,2,3-Thiadiazoles Bearing Diazo, Azido and Hydrazono Groups in the 5-`Position 133

3.3.2.4 Tandem Rearrangements 136

3.4 Ring Cleavage of 1,2,3-Thiadiazoles 137 3.4.1 Thermal Decomposition 137&l...