Heterocycles saturated, reactions

Heats of formation of three-membered heterocycles 89CRV1225. Saturated three-membered heterocycles, addition reactions leading to 5-membered 1,3-heterocycles 86MI4. 

Saturated and Partially Unsaturated Heterocyclic Compounds Reactions and Synthesis... 

Six-membered heterocycles Saturated as well as unsaturated nitrogen heterocycles have been prepared. The malononitrile derivative 139 underwent a ring-closure reaction with... 

Saturated and partially unsaturated heterocyclic compounds reactions and synthesis... 

Nucleophilic attack on ring atoms of large heterocycles is largely confined to saturated systems, saturated parts of partially unsaturated systems, and to carbonyl functions and the like. These reactions are not fundamentally different from those of corresponding acyclic systems, except for transannular reactions. 

Each section has the following structure synthesis of target structures, properties including spectral properties (meaning anomalous or confirming structure), reactions on ring atoms, reactions on substituents, partially saturated heterocycles, applications, and biological properties. 

Generation and reactions of nonstabilized a-aminocarbanions, derivatives of saturated N-heterocycles 98T2647. 

Heterocyclic amines are compounds that contain one or more nitrogen atoms as part of a ring. Saturated heterocyclic amines usually have the same chemistry as their open-chain analogs, but unsaturated heterocycles such as pyrrole, imidazole, pyridine, and pyrimidine are aromatic. All four are unusually stable, and all undergo aromatic substitution on reaction with electrophiles. Pyrrole is nonbasic because its nitrogen lone-pair electrons are part of the aromatic it system. Fused-ring heterocycles such as quinoline, isoquinoline, indole, and purine are also commonly found in biological molecules. 

Considering the formation of saturated five-membered heterocycles with two heteroatoms, it is worth to note the possibility to prepare 1,3-dioxolanes, dithiane, oxathianes 148 [93] and dioxolanones 149 [94] by condensation of the corresponding carbonyl compounds under microwave irradiation in acid medium (Scheme 52). The reaction, which is very useful for the protection of carbonyl compounds or for the preparation of useful synthetic intermediates, has also been carried out under batch conditions over Montmorillonite KIO clay in more than 150 g scale, using a 1 L quartz reactor [95]. 

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