Synthesis of Isomeric Dinitro and Diamino Derivatives of Polycyclic Crown Ethers: Dibenzo-18-crown-6 and Dibenzo-24-crown-8

Exploring the reaction pathway involved in the dibenzo‐18‐crown‐6 synthesis from catechol and bis(2‐chloroethyl) ether in presence of base

“…Presence of these three products is already reported by the experimental groups during the synthesis of DB18C6. [ 32 ] We can consider these compounds as the side products in the X method and may compete with the formation of the final product ID. The first step involved in IB′ formation is basically the same as in Pathway I where IA is formed first; the ring closing second step is the one that can compete with the formation of the intermediate IB.…”

“…The exceptional property of these ethers to bind the alkali and alkaline earth metals had drawn considerable attention of the chemists, and since then, several crown ethers have been synthesized. [ 5–29 ] A significant number of these compounds have been synthesized by Charles Pedersen himself during that decade and after that. [ 1 ] One of the most important of these cyclic polyethers is the DB18C6.…”

“…Synthesis of DB18C6 has revealed the presence of benzo‐9‐crown‐3, 1,2‐bis[2‐(2‐chloroethoxy)ethoxy]‐benzene and the semicrown diol as the side products. [ 32 ]…”

Synthesis and Structural Analysis of a Nitrobenzofurazan Derivative of Dibenzo-18-Crown-6 Ether

“…The filtrate was washed with cold water and left to dry in the open air. The yields were almost quantitative [8,9]. Alternatively, the same products could be obtained following the procedure using a mixture of acetic acid and chloroform as the solvents, and isomers can be isolated by crystallization [8].…”

“…DA-DB18-C-6. A total of 2 g DN-DB18-C-6 was dissolved in 40 mL DMF at 100 • C; 2 g Raney Ni was then carefully added under stirring [9], followed by the dropwise addition of 3.5 mL hydrazine hydrate (at around 70 • C). After 30-60 min, the solution was filtered off, water was added, and the mixture was extracted several times with DCM.…”