Condensed hetero-cyclic compounds

Indole.— The second compound above, a condensed benzene and pyrrole compound, is known as indole and is a very important compound both physiologically and in its relation to indigo. While indigo itself is not a simple condensed hetero-cyclic compound it belongs here in our discussion because of its relation to indole. The constitution of indole is proven by several synthetic relationships. 

When phenyl glycine ortho-caxhoxyMc acid is fused with potassium hydroxide it first loses water yielding an acid, indoi llic acid, and this loses carbon dioxide yielding indoxyl. In indoxyl the hydroxyl group is in the 3-position while in the isomeric oxindole it is in the 2-position. All of these comp>ounds are thus condensed hetero-cyclic compounds of a benzene ring and a pyrrole ring. Indole is the mother substance and the others are hydroxy or ketone derivatives. 

Two of the five membered hetero-cyclic compounds form condensed rings with benzene, viz., furfuran and pyrrole. The resulting compounds are represented as follows ... 

Quite interestingly, the hydrazido(2-) Hgands derived from the ligating N2 in complexes 1 and 2 are transformed into N-hetero cyclic compounds by application of the condensation and related methods (Scheme 6). Thus, their reactions with 2,5-dimethoxytetrahydrofuran, pyrylium salts, and phthalaldehyde, followed by workup of the complexes containing N-heterocyclic ligands with LiAlH4 or KOH/alcohol, result in the formation of pyrroles [29], pyridines [30], and phthalimidines [31], respectively. 

Abstract Phthalocyanines represent a versatile class of functional dyes which have found applications in various disciplines ranging from materials science, catalysis, nanotechnology to medicine. The intrinsic properties of the macrocycles as well as their molecular arrangements, both in solution and in the condensed phase, can be altered through rational chemical modification. Conjugation of other functional units to phthalocyanines can also complement the characteristics of the macrocycles. All these approaches can improve the performance of these macro-cyclic compounds as advanced functional materials. The purpose of this article is to provide an up-to-date review of the current research status of phthalocyanine-containing supramolecular systems. The formation, structures, and properties of self-assembled phthalocyanines as well as the non-covalent hetero-arrays containing phthalocyanines and other functional units are reviewed herein. 

In this Diels-Alder reaction with inverse electron demand the overlap of the LUMO of the 1-oxa-l,3-butadiene with the HOMO of the dienophile is dominant. Since the electron-withdrawing group of the oxabutadiene at the 3-position lowers its LUMO dramatically, both the cycloaddition and the condensation usually take place at room temperature. The reaction can be performed as a two-, three- or four-component transformation. There is actually no restriction on the aldehydes thus, aromatic, hetero-aromatic, saturated aliphatic and unsaturated aliphatic aldehydes may be used. In addition, ketones such as a-oxocarbocylic esters can also be employed. As 1,3-dicarbonyl compounds cyclic substances such as Meldrum s acid, barbituric acid and derivates, coumarines, any type of cycloalkane-1,3-dione and / -ketoesters, as well as their phosphorus, nitrogen or sulfur analogues and acyclic... 

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