Synthetic Exploration of Oxacalix[2]arene[2]quinazolines

Abstract

Oxacalix[2]arene[2]quinazoline macrocycles were prepared in good yields, as mixtures of syn and anti isomers, through nucleophilic aromatic substitution cyclocondensation reactions of 2,4-dichloroquinazolines and m-dihydroxybenzenes. The macrocyclization conditions were optimized and the isomeric ratio was investigated by means of one-step and frag-

Synthesis and Functionalization of Inherently Chiral Tetraoxacalix[2]arene[2]pyridines

“…A number of type -3 and type- 1 inherently chiral hetaracalixaromatics have been synthesized by us, Katz, and Siri since then using a similar stepwise synthetic strategy with or without isolation of linear “trimeric” intermediates. It is interesting to note that whereas the reaction between 1,3-dihydroxybenzene and 2,4-dichloroquinazoline gives a regioisomeric mixture of tetraoxacalix[2]arene[2]quinazolines, the simple one-pot condensation reaction between 3-aminophenols or 4-substituted 1,3-phenylenediamine and 1,5-difluoro-2,4-dinitrobenzene regioselectively affords type -3 inherently chiral diazadioxa or tetraazacalix[4]arene products in moderate to good yields . The type -1 inherently chiral azacalix[2]arene[2]pyridines have also been obtained from a desymmetrical m- bromination reaction of the pyridine moiety of the parent symmetric macrocycle .…”

Odd-Numbered Oxacalix[n]arenes (n = 5, 7): Synthesis and Solid-State Structures

“…Heteracalixarenes, − emerging members of the [1 n ]metacyclophane family in which the classical methylene bridges are replaced by heteroatoms, currently rejuvenate conventional calixarene chemistry. The conformational behavior, size, and structure of the cavity of this novel generation of cyclooligomers may be fine-tuned by the bond lengths and bond angles of the bridging heteroatoms, enhancing their molecular recognition ability.…”

“…The conformational behavior, size, and structure of the cavity of this novel generation of cyclooligomers may be fine-tuned by the bond lengths and bond angles of the bridging heteroatoms, enhancing their molecular recognition ability. Nowadays, straightforward protocols toward heteracalixarenes (mostly S-, N-, , and O-bridged , ) and postmacrocyclization functionalizations of these macrocycles are frequently appearing in the literature.…”

“…The vast majority of oxacalix[ n ](het)arenes have been synthesized by nucleophilic aromatic substitution (S N Ar) reactions involving a nucleophilic m -dihydroxybenzene component and an electrophilic 1,3-dihalogenated (hetero)aromatic building block. Careful optimization of the S N Ar reaction conditions has usually afforded the oxacalix[4]arene predominantly over other cyclooligomers and noncyclic materials by thermodynamic control. , Recently, more kinetic conditions have been developed affording larger oxacalix[ n ]arenes ( n = 6, 8) or poly( m -phenylene oxides) selectively in good yields. , …”

Suzuki-Miyaura Cross-Coupling Reaction of Dichloro-Heteroaromatics: Synthesis of Functionalized Dinucleophilic Fragments

“…Dinucleophilic fragments along with dielectrophiles are important building blocks in the construction of hetero-atom bridged calixaromatics; a new generation macrocylic host molecules in supramolecular chemistry [1][2][3][4][5][6][7][8]. The size and electronic features of the cavity of such macrocycles is very crucial for their applications and both these factors are in turn directly related to these building blocks.…”