Enantioselective synthesis of heterocyclic compounds using photochemical reactions

Abstract

Different methods for the direct enantioselective photochemical synthesis of heterocycles are presented. Currently, asymmetric catalysis with templates involving hydrogen bonds or metal complexes is intensively investigated. Enzyme catalysis can be simplified under photochemical conditions. For example, in multi enzyme systems, one or more enzyme catalytic steps can be replaced by simple photochemical reactions. Chiral induction in photochemical reactions performed with homochiral crystals is highly efficient. Such reactions can also be carried out with crystalline inclusion complexes. Inclusion of a photochemical substrate and an enantiopure compound in zeolites also leads to enantioselective compounds. In all these methods, the conformational mobility of the photochemical substrates is reduced or controlled. Memory of chirality is a particular case in which a chiral information is temporally lost but the rigid conformations stabilize the molecular structure which leads to the formation of enantiopure compounds. Such studies allows a profound understanding on how particular conformations determine the configuration of the final products.

املاح الفلزات الانتقالية الأولى للدايازونيوم المشتق من مركب حلقي غير متجانس للنيتروجين تحضيرو تشخيص و الفعالية الحيوية

“…The diazonium salt was synthesized by adding dropwise 10 mmole NaNO2 in distilled water to cold solution of 10 mmole 3-amino-2-chloro pyridine chloride in concentrated hydrochloride acid with continuous stirring. The resulting mixture was kept at 0-5C o for 1 hour to be used for complexes preparation 1 .…”

Photocatalytic Transformation of Biomass and Biomass Derived Compounds—Application to Organic Synthesis

“…In this context, photochemical reactions also became very interesting in the chemical or pharmaceutical industry [ 33 ]. Applications of photochemical reactions in heterocyclic chemistry are particularly interesting [ 34 , 35 , 36 ]. Heterocycles are the partial structure of numerous bioactive compounds and play an important role in material science, for example for organic semi-conducting materials.…”

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

“…UV-initiated reactions of heterocyclic systems are a significant part of organic photochemistry and there are numerous such transformations for various classes of heterocycles known in the literature [11][12][13][14][15]. Among them, photoreactions of compounds containing the 3-hydroxypyran-4-one (allomaltol) fragment attract considerable attention due to the unique photochemical properties of compounds of this class.…”