Front Cover
Photochemistry of Heterocycles
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Contents
Preface
1 Photochemical synthesis of heterocyclic compounds
1.1 Introduction
1.2 Azetidines
1.2.1 Synthesis by aza Paternò–Buchi reaction
1.2.2 Synthesis by intramolecular closure of N-formil-α-oxoamides
1.2.3 Synthesis by Norris-Yang rearrangement
1.2.4 Reaction between fullerene and formamidines
1.2.5 Synthesis by ciclization of amino ketones
1.3 Aziridines
1.3.1 Synthesis by rearrangement of pyridinium salts
1.3.2 Synthesis by insertion of nitrene into double bonds
1.3.3 Synthesis from homoallylpyrroles
1.3.4 Synthesis by rearrangement of triazolines
1.3.5 Synthesis of aziridines by visible-light induced decarboxylative cyclization of N-aryl glycines and diazo compounds
1.3.6 Photoinduced aziridination of alkenes with N-sulfonyliminoiodinane
1.3.7 Photochemical aziridination of fullerenes
1.3.8 Synthesis from sugar derivatives and azides
1.3.9 Synthesis from azides by photocatalysis
1.3.10 Synthesis from azidoformates
1.4 Diazepines and benzodiazepines
1.4.1 Synthesis from 4-pyridyl azides
1.5 Furans
1.5.1 Furans from α-bromo-β-dicarbonyl compounds and alkynes
1.5.2 Benzofurans from 2-chlorophenols and alkynes
1.5.3 Dihydro and tetrahydrofurans from cyclopropane derivatives
1.5.4 Dihydrofuran from photodimerization of β-carbonyl ketones
1.5.5 Tetrasubstituted furans from silylenolethers and α-bromo diketones
1.5.6 Synthesis of 5H-furanones from substituted cyclobutenones
1.5.7 Photochemical catalytical synthesis of dihydrofurans from vinyl and aryl cyclopropanes
1.5.8 Tetrahydrofurans from cyclobutanones and nitrile compounds
1.5.9 Reaction of propargyl derivatives with alkenes
1.5.10 Tetrahydrofurans from α,β-unsaturated ketones
1.5.11 γ-Lactones from allylic alcohols and α,β-unsaturated keto ester
1.5.12 Synthesis from cinnamic acid and ketones
1.5.13 Synthesis from α-chloro alkyl ketones and styrenes
1.5.14 Synthesis by isomerization of alkenes
1.6 Imidazoles and derivatives
1.6.1 Synthesis of an imidazole intermediated by HCN
1.6.2 Synthesis of dihydroimidazoles from pyridinium salts and an alkene
1.6.3 Synthesis of an imidazolinone by cyclization of a linear compound
1.6.4 Synthesis of purines by irradiation of urea/acetylene
1.6.5 One pot synthesis from aldehydes, α-aminonitriles and isoxazoles
1.6.6 Reaction of N-(1-methylpyrimidin-2-one)pyridinium chloride. Contraction to an imidazolidinone
1.7 Synthesis of oxadiazoles
1.7.1 1,2,4 Oxadiazoles from 2H-azirines and nitrosoarenes
1.7.2 Photooxidation of N-acylhydrazones to 1,3,4-oxadiazoles
1.8 Synthesis of oxazoles and related systems
1.8.1 Synthesis of oxazoles by conversion of 1-acyl triazoles
1.8.2 Synthesis from α-bromoketones and benzylamines
1.8.3 Three components condensation of silylenolethers, fluoroalkyl halides and chiral aminoalcohols to obtain oxazolidines
1.8.4 Oxazolidinones from propargylic amines and CO2
1.8.5 Conversion of benzoil formamides to oxazolidin 4-ones
1.8.6 Synthesis of phosphonium substituted oxazoles from phosphonium-iodonium ylides
1.8.7 Synthesis from azirines and aldehydes
1.9 Oxetanes: the Paternò Büchi reaction
1.9.1 Exo-oxetanes from carbonyl compounds with vinylene carbonates
1.9.2 Photocycloaddition of N-acyl enamines to aldehydes
1.9.3 Oxetanes from carbonyl compounds and 2,5 dimethyl-4-isobutyl-oxazoles
1.9.4 Reaction of 2,3-dihydrofuran
1.9.5 Reaction of a silyl derivative of cinnamyl alcohol
1.9.6 Reaction of geraniol derivatives
1.9.7 Reaction with isoxazole derivatives
1.9.8 Synthesis of an elusive oxetane by photoaddition of benzophenone to thiophene in the presence of a Lewis acid
1.9.9 Reaction of 2-furylmethanol derivatives
1.9.10 Reaction of silyl enol ethers
1.10 Piperidines
1.10.1 Iodine catalyzed sp3-H amination
1.10.2 Synthesis from 2,6-diaminopimelic acid to piperidine-2,6-dicarboxylic acid
1.10.3 A photochemical reaction in the synthesis of azasugar derivatives
1.10.4 Piperidines from ring-contaction of N-chlorolactams
1.10.5 Synthesis of 2-piperidinone catalyzed from a hydrophobic analog of vitamin B12
1.11 Pyrazoles
1.11.1 Aromatization of 1,3,5 trisubstituted pyrazolines
1.11.2 Photochemical bromination for preparation of mono, bis and fused pyrazole derivatives
1.11.3 Pyrazoles from hydrazines and Michael acceptors
1.11.4 Synthesis of pyrazole derivatives via formal [4+1] annulation and aromatization
1.11.5 Reaction of hydrazones and α-bromoketones
1.11.6 One pot synthesis of pyrazoles from alkynes and hydrazines
1.11.7 Sunlight-promoted direct irradiation of N-centered anion: the photocatalyst-free synthesis of pyrazoles
1.11.8 Efficient photooxidation of aryl (hetaryl)pyrazolines by benzoquinone
1.11.9 Synthesis of pyrazoles via photochemical ring opening of pyridazine N-oxides
1.12 Pyridines
1.12.1 Pyridines from ring closure of acyloximes
1.12.2 Synthesis of naphthyl pyridines from heptadynes and nitriles
1.12.3 Synthesis of substituted pyridine from aryl ketone and benzylamines
1.12.4 Pyridines from trimerization of two alkenes and a nitrile
1.13 Pyrimidines
1.13.1 Synthesis of benzo-fused pyrimidines- 4-ones from 1,2,4 oxadiazoles
1.13.2 Fluoroalkylates pyrimidines from silyl enol ethers, amidines, and fluoroalkylhalides
1.13.3 Three component synthesis from active methylene compounds, perfluoroalkyl iodides and guanidines
1.13.4 Synthesis of pyrimidones from 4-allyl-tetrazolones
1.14 Pyrroles
1.14.1 Dehydrogenative aromatization and sulfonylation of pyrrolidines
1.14.2 Synthesis of nitrogen heterocycles generated from α-silyl secondary amines under visible light irradiation
1.14.3 Synthesis of substituted pyrroles by dimerization of acyl azirines
1.14.4 Photochemical isomerizations of N-substituted 2-halopyrroles: syntheses of N-substituted 3-halopyrroles
1.14.5 Synthesis of pentacycles incorporating a pyrrole unit
1.14.6 Synthesis of 1,3,4 trisubstituted pyrroles by condensation of aryl azides and aldheydes
1.15 Pyrrolidines
1.15.1 Pyrrolydinones from suitable amides and an iridium catalyst
1.15.2 [3 + 2] Cycloaddition between a cyclopropylketone and an imine
1.15.3 Synthesis of pyrrolidines from alkanes and nitrogen derivatives
1.15.4 Aroylchlorination of 1,6 dienes to obtain 2-pyrrolidinones
1.15.5 Synthesis of pyrrolidinones fused with a cyclobutane ring
1.16 Thiophenes and benzothiophenes
1.16.1 Cyclization of 2-alkynylanilines with disulfide to afford benzothiophenes
1.16.2 Cyclization of diethynil sulfide to thiophene
References
2 Photoisomerization of heterocyclic compounds
2.1 Photoisomerization of pentaatomic heterocycles
2.1.1 Isomerization of furan derivatives
2.1.1.1 Furan
2.1.1.2 Methylfurans
2.1.1.3 Alkylfurans
2.1.1.4 Trimethylsilyl-substituted furans
2.1.1.5 Furans bearing electron-donating or electron-withdrawing groups
2.1.2 Isomerization of pyrrole
2.1.3 Isomerization of thiophene
2.1.3.1 Alkylthiophenes
2.1.3.2 Arylthiophenes
2.1.3.3 Cyanothiophenes
2.1.3.4 Other thiophenes
2.1.4 Isomerization of isoxazole
2.1.4.1 Isoxazoles bearing electron-donating groups
2.1.4.2 Isoxazoles bearing electron-withdrawing groups
2.1.4.3 Benzisoxazoles
2.1.4.4 Isoxazolidones
2.1.5 Isomerization of oxazole
2.1.6 Isomerization of pyrazole
2.1.7 Isomerization of imidazole
2.1.8 Isomerization of thiazoles
2.1.8.1 Aryl-substituted thiazoles
2.1.8.2 Bithiazoles
2.1.8.3 Trithiazoles
2.1.8.4 Benzothiazole
2.1.9 Isomerization of isothiazoles
2.1.9.1 Benzoisothiazole
2.1.10 Isomerization of oxadiazoles
2.1.10.1 1,2,4-Oxadiazoles
2.1.10.2 1,2,5-Oxadiazoles
2.1.11 Other pentaatomic heterocycles
2.2 Photoisomerization of hexatomic heterocycles
2.2.1 Isomerization of pyridines
2.2.1.1 Pyridines
2.2.1.2 Dihydropyridine
2.2.1.3 Pyridinium salts
2.2.1.4 Pyridinium ylides
2.2.1.5 Pyridinium oxide
2.2.1.6 Quinolines and isoquinolines
2.2.2 Isomerization of diazines
2.2.2.1 Pyrazine
2.2.2.2 Pyridazine
2.2.2.3 Pyrimidine
2.2.2.4 Other compounds
References
3 Photochemical behavior of diheteroarylethenes and photochromism
3.1 Photochemistry of olefins: An overview
3.2 Photoinduced pericyclic reactions: Stilbene and its diheteroarylethenes derivatives
3.2.1 Some applications of the Mallory reaction
3.3 The [2+2] photocycloaddition reactions on heteroarylethenes
3.4 Photochromism of diheteroarylethenes
3.4.1 A brief historical overview and basic reaction mechanism
3.4.2 Photochromism: Tuning with ethene bridges
3.4.3 Photochromism: Tuning with funtionalised heteroaryl groups
3.4.4 Photocyclization reactions and solvent effect
3.4.5 Photochromism in chiral diheteroarylethenes
3.4.6 Ring closure processes induced by visible radiation and all-visible photochromism
3.5 Applications of photochromic molecules of diheteroarylethenes: Switches and optical memories
3.5.1 Switches
3.5.2 Switchable electric conduction
3.5.3 Switchable supramolecular systems
3.5.4 Switchable liquid crystals
3.5.5 Switchable chemical properties and bioactivity
3.5.6 Optical memories
References
4 Heterocyclic-based photoactive materials
4.1 Overview of photoactive materials
4.1.1 From natural to artificial photoactive systems
4.1.2 Explanation of photoactivity through the comprehension of the nature of light
4.1.3 Explanation of molecular photoactivity through light–matter interaction models
4.1.4 The molecular skeleton of photoactive molecules define the behavior of light absorption and emission in molecules
4.2 Main classes of heterocyclic photoactive compounds: synthesis and photochemical reactions
4.2.1 Three-membered heterocycles
4.2.1.1 Three-membered compounds with one heteroatom
4.2.1.1.1 Aziridines
Synthesis of aziridines
Thermal or photochemical reaction of azides with alkenes22
Intramolecular cyclization of ß-amino alcohols
Addition to imines (Johnson-Corey-Chaykovsky aziridation)
From oxiranes
Reactivity of aziridines
Photochemical reactions of aziridines
4.2.1.1.2 Azirines
Synthesis of azirines
Thermolysis of vinyl azides31,32
Elimination and oxidation reactions of aziridines
4.2.1.1.3 Oxirane
Reactivity of oxiranes
4.2.1.1.4 Thiirane
Synthesis of thiiranes
Cyclization of β-substituted thiols
Ring transformation of oxiranes
4.2.1.2 Three-membered compounds with two heteroatoms
4.2.1.2.1 Diaziridine
Synthesis of diaziridines
Oxidative ring closure of aminals
Condensation-cyclization reaction of ketones
Reactivity
Photochemical reaction of ketone imines
Photolysis of 1,4-disubstituted tetrazoline
4.2.1.2.2 Oxaziridine
Synthesis of oxaziridines
Peroxidation of imines
Amination of carbonyl compounds
Reactivity of oxaziridine
Isomerization to nitrones
Photoisomerization of nitrones
4.2.1.2.3 Dioxirane
Synthesis of dioxiranes
Photolytic oxidation of diaryl diazoalkanes
4.2.1.2.4 3H-Diazirine
Synthesis of 3H-diazirine
Oxidation reactions
Reactivity of 3H-diazirine
Dediazoniation
4.2.2 Four-membered heterocycles
4.2.2.1 Four-membered compounds with one heteroatom
4.2.2.1.1 Oxetane
Synthesis of oxetanes
Intramolecular cyclodehydrohalogenation of γ-substituted alcohols
Photochemical cycloaddition (Paterno-Büchi reaction)68
4.2.2.1.2 Thietane
Synthesis of thietanes
Cyclization of γ-halo thiols or their acetyl derivatives by bases
Action of sodium or potassium sulflde on 1,3-dihaloalkanes
Reactivity of thietane
4.2.2.1.3 Azete
Synthesis and reactivityof azetes
4.2.2.1.4 Azetidine
Synthesis of azetidines
Cyclization of γ-substituted amines
Action of p-toluenesulfonamide and bases on 1,3-dihaloalkanes
Reactivity of azetidines
Rearrangement reaction
4.2.2.2 Four-membered compounds with two heteroatoms
4.2.2.2.1 1,2-Dioxetane
4.2.2.2.2 Synthesis of 1,2-dioxetane
Dehydrohalogenation of β-halo hydroperoxides
Photooxygenation of alkenes
4.2.2.2.3 1,2-Dithietane
Synthesis of 1,2-dithietanes
4.2.2.2.4 1,2-Dithiete
Synthesis and reactivity of 1,2-dithietes
Valence isomerization of disubstituted 1,2-dithietes
4.2.2.2.5 l,2-Dihydro-l,2-diazete
Synthesis of l,2-dihydro-l,2-diazete
4.2.2.2.6 1,2-Diazetidine and 1,3-diazetidine
Synthesis of 1,2-diazetidine and 1,3-diazetidine
Reactivity of 1,2-diazetidine and 1,3-diazetidine
4.2.3 Five-membered heterocycles
4.2.3.1 Five-membered compounds with one heteroatom
4.2.3.1.1 Furan
Synthesis of furans
Reactivity of furan
4.2.3.1.2 Benzo[b]furan, benzo[c]furan, dibenzofuran
Synthesis of benzo[b]furans
Reactivity of benzo[b]furans
Synthesis of benzo[c]furans
Reactivity of benzo[c]furans
Synthesis of dibenzofurans
Reactivity of dibenzofurans
4.2.3.1.3 Thiophene
Synthesis of thiophene
Reactivity of thiophene
Photochemical oxidation and substitution
4.2.3.1.4 Benzo[b]thiophene, benzo[c]thiophene, dibenzo[b,d]Thiophene
Synthesis of benzo[b]thiophene
Dieckman-like condensation
Diels-Alder reaction
Synthesis of benzo[c]thiophene
Synthesis of dibenzo[b,d]thiophene
Reactivity of benzo[b]thiophene
Reactivity of benzo[c]thiophene
4.2.3.1.5 Pyrrole
Synthesis of pyrrole
Reactivity of pyrrole
4.2.3.1.6 Indole, isoindole, indolizine
Synthesis of isoindole
Synthesis of indolizine
Reactivity of indole
Reactivity of isoindole
4.2.3.1.7 Carbazole
Synthesis of carbazoles
4.2.3.2 Five-membered compounds with two heteroatoms
4.2.3.2.1 1,3-oxazole (oxazole)
Synthesis of oxazole
Oxazole reactivity
Reaction with singlet oxygen
4.2.3.2.2 1,2-oxazole (isoxazole)
Synthesis of isoxazoles
4.2.3.2.3 1,3-Thiazole (thiazole) and 1,2-thiazole (isothiazole)
Synthesis of thiazoles
4.2.3.2.4 Imidazole
Synthesis of imidazoles
Reactivity of imidazoles
Fluorination
Photooxidation
4.2.3.2.5 Pyrazole
Synthesis of pyrazoles
Reactivity of pyrazoles
4.2.3.3 Five-membered compounds with three heteroatoms
4.2.3.3.1 1,2,3-Oxadiazole
Photochemistry of 1,2,3-oxadiazoles
4.2.3.3.2 1,2,4-Oxadiazole
Synthesis of 1,2,4-oxadiazole
Reactivity of 1,2,4-oxadiazole
Photochemical reactions of 1,2,4-oxadiazoles
4.2.3.3.3 1,2,5-Oxadiazole
Synthesis of 1,2,5-oxadiazole
Photochemical ring cleavage of 1,2,5-oxadiazole
4.2.3.3.4 1,3,4-Oxadiazole
Photolysis of 1,3,4-oxadiazoles
4.2.3.3.5 1,2,3-Thiadiazole
Thermal and Photochemical Reactions
4.2.3.3.6 1H-1,2,3-triazole
Reactivity of 1H-1,2,3-triazole
4.2.3.4 Five-membered compounds with four heteroatoms
4.2.3.4.1 Tetrazole
Synthesis of tetrazole
Reactivity of Tetrazole
4.2.4 Six-membered heterocycles
4.2.4.1 Six-membered compounds with one heteroatom
4.2.4.1.1 Pyridine
Synthesis of pyridine
Reactivity of pyridine
Photolysis of pyridine
4.2.4.2 Six-membered compounds with two heteroatoms
4.2.4.2.1 Pyridazine, pyrimidine, pyrazine
Thermal and photochemical reaction
4.2.4.3 Six-membered compounds with three heteroatoms
4.2.4.3.1 Triazines: 1,2,3-triazine, 1,2,4-triazine, 1,3,5-triazine
4.2.4.4 Six-membered compounds with four heteroatoms
4.2.4.4.1 Tetrazines: 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, 1,2,4,5-tetrazine
Photochemical reaction
4.3 Applications and technology of the main classes of heterocyclic photoactive compounds
4.3.1 Heterocyclic conjugated backbones for efficient emerging organic photovoltaics
4.3.1.1 Organic solar cell device’ major architectures: planar heterojunction (PHJ) vs bulk heterojunction
4.3.1.2 Principles of organic solar cells operation
4.3.1.3 Evaluate the performances of a bulk heterojunction organic solar cells
4.3.1.4 In principle the most widely used photoactive acceptors: fullerene acceptors (FA)
4.3.1.5 A novel concept of photoactive electron-acceptors: non fullerene acceptors (NFAs)
4.3.2 Light stability of non-fullerene acceptors: photo-oxidation and photophysical degradations
4.3.2.1 Chemical stability: water and oxygen resistance
4.3.2.2 Chemical resistance
4.3.3 Major classes of non-fullerene acceptors: rylene diimides
4.3.4 Major classes of non-fullerene acceptors: perylene diimide small molecules
4.3.5 Major classes of non-fullerene acceptors: fused-ring electron acceptors
4.3.6 Polymers and small-molecule donors
4.3.7 Nonlinear optical materials
4.3.7.1 Second-order nonlinear optical materials: molecules, bulk materials and poled polymers
4.3.7.2 Photorefractive heterocyclic materials: composite materials, liquid crystals and polymers
4.3.7.3 Photochromic heterocyclic materials
References
5 Photodegradation of drugs and crop protection products
5.1 Introduction
5.2 General mechanisms of photodegradation of drugs
5.3 Anti-inflammatory, analgesic, and immunosuppressant drugs
5.3.1 Nonsteroidal anti-inflammatory drugs
5.3.2 Pyrazolone analgesic and antipyretic drugs
5.3.3 Immunosuppressant and anti-histamic drugs
5.4 Drugs acting on the central nervous system
5.4.1 Barbituric acid derivatives
5.4.2 Benzodiazepines
5.4.3 Thioxanthene and phenothiazine psychotherapeutic agents
5.5 Cardiovascular drugs
5.5.1 Cardiac agents
5.5.2 Blood pressure-regulating drugs
5.5.3 Adrenergics
5.5.4 Diuretics
5.6 Chemotherapeutic agents
5.6.1 Antibacterial drugs
5.6.2 Antibacterials and antivirals: aromatic derivatives
5.6.3 β-Lactam antibiotics
5.6.4 Antiprotozoal, anti-amebic, antimycotic drugs
5.6.5 Antineoplastic drugs
5.6.6 Furocoumarins
5.7 General mechanisms of photodegradation of crop protection products
5.7.1 Azole fungicides
5.7.2 Dicarboximide fungicides
5.7.3 Imidazolinone herbicides
5.7.4 Macrocyclic lactone insecticide
5.7.5 N-Methyl carbamate insecticides
5.7.6 Neonicotinoid insecticides
5.7.7 Organophosphate insecticides
5.7.8 Triazine herbicides
5.7.9 Triazinone herbicides
5.7.10 Triazolopyrimidine herbicide
5.7.11 Unclassified pesticides
References
Index
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