2.5. Ionic Liquids Presented in This Review 2020 3. Cyclocondensation Reactions 2020 4. Synthesis of Three-Membered Heterocycles 2022 4.1. Aziridines 2022 5. Synthesis of Five-Membered Heterocycles 2022 5.1. Pyrroles 2022 5.2. Furans 2022 5.3. Thiophenes 2023 5.4. Pyrazoles 2024 5.5. Imidazoles 2025 5.6. Isoxazoles 2027 5.7. Oxazoles, Oxazolines, and Oxazolidinones 2027 5.8. Thiazoles and Thiazolidinones 2028 6. Synthesis of Six-Membered Heterocycles 2030 6.1. Pyridines 2030 6.2. Quinolines 2031 6.3. Acridines 2033 6.4. Pyrans 2033 6.5. Flavones 2035 6.6. Pyrimidines and Pyrimidinones 2035 6.7. Quinazolines 2037 6.8. -Carbolines 2038 6.9. Dioxanes 2039 6.10. Oxazines 2039 6.11. Benzothiazines 2040 6.12. Triazines 2040 7. Synthesis of Seven-Membered Heterocycles: Diazepines 2041

Ionic liquids in heterocyclic synthesis.

Isoquinoline and quinazoline urea derivatives were found to bind to human adenosine A3 receptors. Series of N-phenyl-N‘-quinazolin-4-ylurea derivatives and N-phenyl-N‘-isoquinolin-1-ylurea derivatives were synthesized and tested in radioligand binding assays on their adenosine receptor affinities. A structure−affinity analysis indicated that on the 2-position of the quinazoline ring or the equivalent 3-position of the isoquinoline ring a phenyl or heteroaryl substituent increased the adenosine A3 receptor affinity in comparison to unsubstituted or aliphatic derivatives. Furthermore, the structure−affinity relationship of substituted phenylurea analogues was investigated. Substituents such as electron-withdrawing or electron-donating groups were introduced at different positions of the benzene ring to probe electronic and positional effects of substitution. Substitution on the 3- or 4-position of the phenyl ring decreased the adenosine A3 receptor affinity. Substitution at position 2 with an electron-donat...

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Isoquinoline and quinazoline urea analogues as antagonists for the Human Adenosine A3 receptor

Update 1 of: Ionic liquids in heterocyclic synthesis.

The infrared spectra, as well as the integrated molar absorptivity (Ψ) and the molar extinction coefficient (ɛ) of each infrared transition of the hydrogenated fullerenes (known as fulleranes) C60H36, C60H18 and C70H38, and a mixture of fulleranes generally referred to as 77 per cent of C60Hx and 22 per cent C70Hy with x≈y > 30, are presented and discussed. These data are useful for the search, identification and quantitative determination of fulleranes in space after the recent discovery that their parent molecules, C60 and C70, are more abundant in space than initially thought, being present in a variety of H-rich circumstellar environments such as planetary nebulae and only mild H-deficient R Coronae Borealis stars, and in the interstellar medium. It is shown that the C–H stretching band of the fulleranes C60H36, C60H18 and C70H38, and their mixture may be most useful for the identification of these molecules because their Ψ and ɛ values are unique in terms of strength, overcoming by far the typical Ψ and ɛ values of reference molecules such as adamantane and docosane, as well as typical ɛ literature data for aliphatic molecules. In contrast to the rather simple infrared spectra of C60H36 and C60H38, the infrared spectra of two C60H18 isomers are reported as characterized by a rich number of bands which may allow an easier identification than the higher homologues. The dependence of the infrared bands of fulleranes on temperature was studied over a wide range of temperatures (from −180°C to +250°C) and extrapolated to 0 K.

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Infrared spectroscopy of hydrogenated fullerenes (fulleranes) at extreme temperatures

High resolution gas chromatography has greatly changed the field of polychlorinated biphenyl (PCB) analysis. From a rough estimation of the total PCB concentration on packed column GC, the development of commercially available fused silica capillary columns in the late 1970s and early 1980s has advanced the analysis of PCBs to a point where they can be accurately measured as separated congeners. The state-of-the-art of PCB analysis in the 1990s is routine isomer-specific analysis with multi-column techniques using long ( 0.25 mm) columns. A broad spectrum of commercially available stationary phases have been completely characterized with regard to their PCB elution profiles.

HRGC separation of PCB congeners

Hydroxide‐catalyzed synthesis of heterocyclic aromatic amine derivatives from nitriles

A new technique combining both mass spectrometry and infrared spectroscopy to analyse simultaneously the components from a single gas chromatographic injection has been applied to the quantitative and qualitative characterization (including distinguishing positional isomers) of polychlorinated biphenyl (PCB) mixtures. The sensitivity of vibrational spectroscopy to subtle differences in structure was shown to be highly complementary to gas chromatography–mass spectrometry (GC–MS) for qualitative identification of individual PCB isomers and congeners. A key feature of the infrared apparatus is the provision for low-temperature trapping (approximately 77 K) of the GC effluent for subsequent analysis. This technique produces infrared spectra that resemble normal room-temperature condensed-phase spectra (as opposed to the gas-phase spectra produced by light-pipe gas chromatography—Fourier transform infrared spectroscopy) and leads to lower detection limits (500 pg for 3,3′,4,5-tetrachlorobiphenyl). The GC–MS portion of the instrument provides superior quantitative capabilities with sub-picogram detection limits possible using selective ion monitoring.

Isomeric characterization of polychlorinated biphenyls using gas chromatography–Fourier transform infrared/gas chromatography–mass spectrometry

Infrared Absorption Spectroscopy

The use of remote-sensing diffuse-reflectance optics to obtain Fourier-transform mid-infrared spectra from sand-blasted gold, aluminum, and steel surfaces as a function of position in order to monitor the spatial distribution of oil over the surface is described, and used to map the spread of an 0.85 μg safflower oil droplet with time, to calibrate the spectra for film thickness near 1 μm, and to monitor the oil oxidation that limited the extent of the stain.

Norman R. Smyrl

Papers

Hydroxide‐catalyzed synthesis of heterocyclic aromatic amine derivatives from nitriles

Isomeric characterization of polychlorinated biphenyls using gas chromatography–Fourier transform infrared/gas chromatography–mass spectrometry

Infrared Absorption Spectroscopy

Oil Analysis on Metal Surfaces by Using DR-FT-IR Mapping Techniques