Of large ring compounds

This reaction is used in the synthesis of large-ring compounds. 

A. Zeolites and LDPEs as Hosts for the Preparation of Large-Ring Compounds... 

IV. Cyclization of Large Ring Compounds on Polymeric Supports. 145... 

IV. CYCLIZATION OF LARGE RING COMPOUNDS ON POLYMERIC SUPPORTS... 

Methods for the construction of large ring compounds and their application to macrolide synthesis continue to attract attention. The synthesis of pyrenophorin, a macrolide antibiotic, illustrates the effective use of protecting groups and functional group activation for construction of the sixteen-membered bis-lactone ring. ... 

A spectacular application of the acyloin ester condensation was the preparation of catenaries like 11. These were prepared by a statistical synthesis which means that an acyloin reaction of the diester 10 has been carried out in the presence of an excess of a large ring compound such as 9, with the hope that some diester molecules would be threaded through a ring, and would then undergo ring closure to give the catena compound ... 

Griesbeck et al. successfully transformed w-phthalimidoalkanoates via PET with concomitant decarboxylation and C,C combination leading to medium- and large-ring compounds with yields in the range 60-80%. Thereby, the solvent system acetone/water and K2CO3 employed for the deprotonation of the carboxylic acids were crucial (Scheme 45) [66]. 

Streptomyces nodosus produces natural products such as amphotericin A and B. These are macrocyclic (large-ring) compounds containing numerous (three to seven) double bonds and multiple hydroxyl groups which are usually located on one side of the molecule. Amphotericin B (9.103) and the very similar nystatin (9.104) are antifungal... 

Crown ethers are large-ring compounds containing several oxygen atoms, usually in a regular pattern. Examples are 12-crown-4 (10),61 dicyclohexano-18-crown-6 (11), and 15-crown-5 (12). These compounds have the property62 of forming complexes with positive ions, gen-... 

Electronic spectra of large-ring heterocyclic compounds... 

This interesting reaction is especially useful for the synthesis of medium- and large-ring compounds from dicarboxylic esters, and is effective for ring sizes that cannot be made by the Dieckmann condensation or decarboxylation (Section 18-1 OB). Radical anions formed by addition of sodium to the ester... 

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