Pyrroles fused with aromatic rings (isoindole derivatives) have been readily prepared by the reaction of aromatic nitro compounds with ethyl isocyanoacetate in the presence of DBU. The ease of this reaction depends on the aromaticity of the starting nitro aromatics. Polycyclic aromatic nitro compounds such as 1-nitroacenaphthylene or 9-nitrophenanthrene are more reactive than simple nitro aromatics such as nitrobenzene or nitronaphthalenes and give the corresponding pyrroles in good yields. Pyrroles prepared by this method have been converted into porphyrins fused with various aromatic rings by the reduction with LiAlH4 followed by treatment with an acid catalyst and oxidation with chloranil or oxygen. Tetra-1,2-naphthoporphyrin has been prepared by the reaction of 2-nitro-3,4-dihydronaphthalene or 1-nitronaphthalene with ethyl isocyanoacetate followed by reduction, tetramerization and oxidation. Thus, highly conjugated porphyrins are readily prepared starting from aromatic nitro compounds, and their electronic and optical properties can be controlled by choice of the starting aromatic nitro compound.

Abstract Nucleophilic addition of some carbon nucleophiles to tricarbonyl(1- exo -isopropyl-5-methoxytetralin)-chromium ( 4 ), tricarbonyl(1- endo -isopropyl-5-methoxytetralin)chromium ( 5 ), and tricarbonyl(1-isopropyl-5-methoxy-3,4-dihydronaphthalene)chromium ( 8 ) has been investigated. The regioselectivity of the nucleophilic addition using 2-lithio-1,3-dithiane under kinetic control conditions is dependent on the conformation of the Cr(CO) 3 group for the arene ring. exo -Isopropyl complex 4 gives the meta -substituted compound with high regioselectivity in good yield, while the corresponding endo -isopropyl complex 5 yields predominantly the ortho -substituted arene. The crystal structure of the endo -complex 5 has been determined by X-ray crystallography, indicating that three CO ligands adopt the staggered conformation for the aromatic ring. On the other hand, the addition reaction with nitriles or cyanohydrin-stabilized carbanions under thermodynamics conditions provide the high meta -selectivity, regardless of the conformation of the Cr(CO) 3 moiety.

Abstract Das bekannte polycyclische Iodid (I) lagert sich bei Behandlung mit dem 18‐Kronenether‐6‐Komplex des Kaliumfluorids in das Methylendihydronaphthalin (II) um.

Polycyclic aromatic hydrocarbons (PAHs) are common throughout the universe and are expected to be present in dense interstellar clouds. In these environments, some P.4Hs may be present in the gas phase, but most should be frozen into ice mantles or adsorbed onto dust grains and their spectral features are expected to be seen in absorption. Here we extend our previous work on the infrared spectral properties of the small PAH naphthalene (C10H8) in several media to include the full mid-infrared laboratory spectra of 11 other PAHs and related aromatic species frozen in H2O ices. These include the molecules 1,2-dihydronaphthalene, anthracene, 9,1O-dihydroanthracene, phenanthrene, pyrene, benzo[e]pyrene, perylene, benzo(k)fluoranthene, pentacene, benzo[ghi]perylene, and coronene. These results demonstrate that PAHs and related molecules, as a class, show the same spectral behaviors as naphthalene when incorporated into H2O-rich matrices. When compared to the spectra of these same molecules isolated in inert matrices (e.g., Ar or N2), the absorption bands produced when they are frozen in H2O matrices are broader (factors of 3-10), show small position shifts in either direction (usually 125 Kj. Given the small observed band shifts cause by H2O, the current database of spectra from Ar matrix-isolated neutral PAHs and related molecules should be useful for the search for these species in dense clouds on the basis of observed absorption band positions. Furthermore, these data permit de