Hetero Diels-Alder synthesis of 3-hydroxypyridines: access to the nosiheptide core

The 1-azadiene hetero Diels-Alder reaction of silylated enol oximes with alkynes was investigated and was optimized to furnish 2,5,6-trisubstituted 3-hydroxypyridines in high yields in one simple operation. Importantly, monosubstituted alkynyl ketones were found to lead to the formation of the 6-isomer with exceptional regioselectivity (>95:5). This methodology was applied to a scaleable synthesis of the core structure of the potent antibiotic nosiheptide. Protecting groups were optimized, which led to a racemization-free seven-step synthesis of the key building block.     

Total synthesis of nosiheptide. Synthesis of thiazole fragments

The preparation of three new thiazole derivatives from natural products is described, as well as improvements in the synthesis of ethyl 2-aminomethyl-4-thiazolecarboxylate.     

Steps towards a practical synthesis of macrocyclic bisbenzylisoquinolines

There are more than 400‐reported bisbenzylisoquinoline alkaloids, many with interesting biological activity, but the reported syntheses are long and low yielding. As a result, there have been no systematic attempts at exploitation of the potential therapeutic applications. The concept of a sulfur ‘stitch’, restricting the conformational freedom of intermediates in the synthesis, will potentially allow analogues of the natural products to be prepared using relatively efficient routes. The synthesis of intermediate sulfur heterocycles is reported, based on 2,8‐dimethylphenoxathiin, leading via 2,8‐bis(bromomethyl)phenoxathiin‐10,10‐dioxide to a synthesis of 3,4,8,9‐tetrahydro‐13‐oxa‐6‐thia‐2,10‐diazapentacene, a key potential intermediate on the route to a variety of macrocyclic bisbenzylisoquinolines.     

Unusual hydrothermal synthesis of a heteroaromatic macrocyclic complex

Hydrothermal treatment of 2,3-bis(2′,6″-bipyridyl)quinoxaline, molybdenum trioxide, cupric acetate and water unexpectedly forms the Cu(II) complex of a planar, macrocyclic 2-acyl-6,2′-bipyridyl dimer, imbedded within a copper benzotrizolate-octamolybtate matrix. X-ray crystallographic characterization of this material, and scalar relativistic ZORA DFT modeling of the complex dication are presented.     

Total synthesis of a macrocyclic spermidine alkaloid,codonocarpine

Total synthesis of codonocarpine ($\text{5}$) and its regio-isomer ($\text{1}$$\text{5}$) utilizing a new cyclization procedure is described.     

Reactions of macrocyclic rhodium carbenoids: regioselective synthesis of indol-3-yl macrocyclic lactones and cryptands

A wide variety of new macrocyclic diazocarbonyl compounds with various spacers was synthesized. Macrocyclic rhodium(II) carbenoid insertion with various substituted indoles was performed to afford regioselectively, indol-3-yl macrocyclic di- or tetralactones (C3-alkylation). Double carbenoid insertion was also performed to afford indolyl cryptand molecules.     

Directed synthesis of macrocyclic phenylene sulfides

A method has been developed for the directed synthesis of macrocyclic phenylene sulfides with 4–8 phenylene sulfide fragments, by condensation of dihaloaromatic compounds of various types with sodium sulfide or dithiophenate. A combination of this method with high dilution techniques has afforded pure macrocycles in high yields, and the macrocycle with six phenylene sulfide fragments in yields as high as 73%.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 854–858, April, 1990.     

Synthesis of a new and versatile macrocyclic NADH model

A new macrocyclic NADH model 1 has been designed and synthesised. The new model consists of the same subunits as previously reported models. However, the present model is designed as such that the pyridine nitrogen of the nicotinamide units are not incorporated in the macrocyclic framework. Thus, properties such as solubility can easily be varied by alkylation with an appropriate agent. The macrocyclic framework was prepared in 7 steps. Methylation of the pyridine nitrogens followed by reduction gave the desired model. This model compound was found to reduce methyl benzoylformate stereoselectively in good yield with 48% enantiomeric excess.     

Tandem reactions of α-diazo ketones with macrocyclic olefins: diastereoselective synthesis of oxanorbornane fused macrocyclic lactones

Tandem cyclization-cycloaddition reactions of α-diazo ketones with macrocyclic olefins in the presence of rhodium(II) acetate catalyst led to the oxanorbornane fused macrocyclic di- or tetralactone ring systems in moderate yield. This forms the first example of 1,3-dipolar cycloaddition reactions with a macrocyclic olefin as a dipolarophile, affording a variety of new oxanorbornane fused macrocycles with diastereoselectivity.     

Asymmetric synthesis of macrocyclic binaphthol dimers using a Sonogashira coupling reaction

Asymmetric synthesis of 24- and 26-membered macrocyclic binaphthol dimers was achieved by assembling a 3,3′-diethynyl-1,1′-bi-2-naphthol unit and 1,2- and 1,3-phenylene units with Sonogashira coupling reaction.     

The synthesis of macrocyclic polyether-diester compounds with a pyridine subcyclic unit

Two new series of macrocyclic polyether-diester ligands ( 4-15 ) containing a pyridine subcyclic unit have been prepared by treating various oligoethylene glycols and sulfur-containing oligo-ethylene glycols with 2,6- and 3,5-pyridine dicarbonyl chlorides. The compounds prepared from 2,6-pyridine dicarbonyl chloride were: 3,6,9,12-tetraoxa-18-azabicyclo[12.3.1 ]oetadeca-1(18), 14,16-triene-2,13-dione ( 4 ); 3,6,9,12,15-pentaoxa-21-azabieyclo[15.3.1]heneicosa-1(21),17,19-triene-2,16-dione ( 5 ); 3,6,12,15-tetraoxa-9-thia-21-azabicyclo[15.3.1 ]heneicosa-1(21),17,19-tri-ene-2,16-dione( 6 ); 3,9,15-trioxa-6,12-dithia-21-azabicyclo[15.3.1]heneicosa-1(21),17,19-triene-2,16-dione ( 7 ); 3,6,9,12,15,18-hexaoxa-24-azabicyclo[18.3.1 ]tetracosa-1(24),20,22-triene-2,19-dione ( 8 ); 3,6,9,12,15,18,21-heptaoxa-27-azabicyclo[21.3.1]heptacosa-1(27),23,25-triene-2,22-dione ( 9 ); and the corresponding analogues from 3,5-pyridine dicarbonyl chloride ( 10-15 ). The solid potassium thiocyanate complex of compound 5 was also prepared.     

Insertion reactions of macrocyclic rhodium carbenoids: a novel method for the synthesis of cryptands

Reaction of macrocyclic diazocarbonyl compounds and alcohols or diols in the presence of rhodium(II) acetate catalyst led to functionalized macrocyclic di- or tetralactones via O-H insertion. Interestingly, the double O-H insertion reaction with dihydroxy compounds gave cryptands of various ring sizes.     

Tetraaza macrocyclic complexes: synthesis,spectral and antimicrobial studies

A tetradentate nitrogen donor [N₄] macrocyclic ligand, 1,3,7,9-tetraaza-2,8-dithia-4,10-dimethyl-6,12-diphenylcyclododeca-4,6,10,12-tetraene has been synthesized by using thiourea and benzoylacetone. Complexes of Mn(II), Co(II), Ni(II), and Cu(II) have been synthesized with this ligand and characterized by element chemical analysis, molar conductance, magnetic susceptibility, mass, ¹H nuclear magnetic resonance, Fourier transform–infrared, electronic, and electron paramagnetic resonance spectral studies. The molar conductance measurements of Mn(II), Co(II), and Cu(II) complexes in dimethyformamide correspond to nonelectrolytes, whereas Ni(II) complex is a 1: 2 electrolyte. The complexes are high-spin except for Ni(II) which is diamagnetic. Octahedral geometry has been assigned for Mn(II) and Co(II) complexes, square planar for Ni(II) and tetragonal geometry for Cu(II). The ligand and its complexes were screened in vitro against two pathogenic fungi (Fusarium moniliformae and Rhizoctonia solani) and bacteria (Staphylococcus aureus and Pseudomonas aeruginosa) to assess their growth inhibiting potential.     

含二苯联恶二唑大环多胺及其配合物的合成

用2,5-双-(间甲酰基苯基)-1,3,4-恶二唑和相应的二胺，经[2+2]缩合环化反应，合成了三个含二苯联恶二唑的新型大环多胺4、5和7以及5的钡络合物。     

"ortho-Wurster's crowns": synthesis and properties of a novel phenylenediamine-based redox-active macrocyclic ligand

A hybrid, macrocyclic structure based on o-phenylenediamine and a crown ether promotes an intimate mutual interaction with a bound potassium ion in the form of chelation by the redox-active moiety. A general synthetic method and properties are described for the first member of a new class of redox-active, lariat-type macrocycles called the "o-Wurster's crowns".