Proton‐ionizable crown compounds. 20. The synthesis of polyazatriazolo‐, polyazabistriazolo‐ and bispyridono‐crown ligands containing lipophilic hydrocarbon substituents

Abstract

Four new macrocyclic polyaza‐crown compounds containing a triazole subcyclic group and two to five lipophilic hydrocarbon substituents have been prepared from the appropriate polyamine and N‐THP‐protected 2,5‐triazoledimethyl dichloride. N,N,N',N'‐Tetrabenzyltetraazabistriazolo‐18‐crown‐6 was prepared from N,N'‐dibenzylethylenediamine and N‐THP‐protected 2,5‐triazoledimethyl dichloride. Biscyclohexano‐bispyridono‐18‐crown‐6 was prepared from trans‐ 1,2‐cyclohexanediol and THP‐protected 4‐hydroxy‐2,6‐pyridinedimethyl ditosylate.

Synthesis of proton-ionizable acyclic, macrocyclic and macrobicyclic compounds containing one or two triazole groups

“…Subsequently, reaction of 9 with 1 and sodium carbonate in acetonitrile followed by acid hydrolysis of the tetrahydropyranyl-protecting group provided macrocycle 10 in 5% overall yield from the 2 + 2 cyclization reaction. (Low yields for such 2 + 2 cyclization reactions have been reported previously by others [13].) The solid-state structure of 10•1.5Methanol is described in the next section.…”

“…Also, Bradshaw and coworkers have reported a series of diaza-18-crown-6 compounds with pendant phenol and hydroxyquinoline units [7]. Macrocycles with 4-hydroxypyridine [8][9][10][11][12][13] and triazole [13][14][15][16][17] heterocyclic subunits within the macroring have been developed by Brandshaw, Izatt and their coworkers, de Mendoza and Torres and their coworkers [18][19][20][21][22][23][24][25] and others [26][27][28]. Podands [23][24][25][26][27][28][29] and polyaza macrobicyclic cryptands [24] with triazole subunits have been prepared, as well.…”

Synthesis of new optically active bis-pyridino- and bis pyridono-18-crown-6 type ligands containing four lipophilic chains attached to the chiral centers by "two-to-two" type macrocyclization

“…These yields can be considered as satisfactory for template assisted "two-to-two" type cyclizations. 2,3,4,19 Preparation of the optically active diols (S,S)-16 20 and (R,R)-17, 21 and of the di-p-tosylates 18, 22 and 19 22 was performed as reported.…”

“…19 It was prepared by sodium ion template assisted "two-to-two" type cyclization from racemic trans-cyclohexane-1,2-diol and 4-(tetrahydro-2-pyranyloxy)-2,6-bis(tosyloxymethyl)pyridine using sodium hydride in tetrahydrofuran, followed by removal of the protecting group by acid. The overall yield was 8%.…”

Synthesis of norbornane bisether antibiotics via silver-mediated alkylation

“…Indeed, it has been shown that in some cases alkylation of alcohols using typical Williamson protocols gives lower than expected yields, or no desired product. 26,27 Indeed, in circumstances where a stabilized leaving group can be formed the basic conditions employed can lead to an elimination/fragmentation event. 28,29 An example of this competitive elimination was described by Hergueta et al (Scheme 2); alkoxide 7, derived from a norbornane fused to a quinoxaline, undergoes elimination to give a carbanion (8) which is stabilized by the aromatic heterocyclic.…”