Oxidative Addition of Hexafluoroacetone,Perfluorinated 1,2-Diketones and Tetrachloro-O-Benzoquinone to Compounds of Low-Valent Phosphorus-New Modes of Addition and Unusual Products

Abstract

The reaction of hexafluoroacetone (HFA) with the benzoxazaphosphorinone 1 leads to the λ⁵-oxazaphosphepinone 2. In several cases unusual products, 3, 8 - 14, 16, and 17, were isolated in the reactions of 1, 4 - 7, and 15 with HFA, tetrachloroorthobenzoquinone (TOB) and perfluorinated 1,2-diketones. X-Ray crystal structure analyses were carried out for the derivatives 2, 3, and 8 - 10.     

The intercalation of bicyclic and tricyclic carboxylates into layered double hydroxides

Twenty-four nanocomposites built from layered double hydroxides and bicyclic and tricyclic carboxylates have been synthesised for the first time. Eight carboxylates were successfully intercalated into [LiAl₂(OH)₆]Cl·yH₂O, [Ca₂Al(OH)₆]NO₃·yH₂O, and [Mg₂Al(OH)₆]NO₃·yH₂O, and the products fully characterised. Guest species incorporated include 1-adamantane carboxylate (1-AC) and 5-norbornene-2-endo-3-exo-dicarboxylate. In some cases, carbonate anions were co-intercalated with the organic guest, and in others poorly crystalline aluminium hydroxides formed as by-products. Sharper resonances were observed in the ¹³C solid-state NMR spectra of the 1-AC intercalates than in the spectrum of pure 1-AC, suggesting increased order in the arrangement of the cyclic cages in the intercalates. Where possible, time-resolved in situ X-ray diffraction was employed to study the nanoscopic steps involved in the intercalation reactions. These investigations showed that the reactions are one-step processes, proceeding directly to the fully exchanged intercalate with no intermediate phases. The intercalation processes were found to be nucleation controlled.     

Cobalt(II), nickel(II) and copper(II) compounds derived from template reactions of enantiomerically pure 2-amino-thiazoles

Herein we report the syntheses and structural analyses of three coordination compounds Co(L)₂ (3), Ni(L)₂, (4) and Cu(L)₂ (5) (L = bis[(4R,5R)-4-methyl-5-phenyl-4,5-dihydro-thiazol-2-yl]-amine) prepared by template reactions from the optically active ligand (4R,5R)-4-methyl-5-phenyl-4,5-dihydro-thiazol-2-yl-amine (1) and CoCl₂·6H₂O, NiBr₂·3H₂O or Cu(OAc)₂·H₂O The template reactions involve the condensation of two molecules of thiazol-2-yl-amine and elimination of one NH₃. The resulting bidentate ligand coordinates to the metal ion through the imine nitrogen atoms forming a six-membered ring, presenting an electronic delocalization which averages the four M–N bond lengths. The distorted tetrahedral geometry of the metal atoms gives place to complex electronic spectra for compounds 3–5. A mixed ionic compound (6) formed by three cations (4S,5S)-3,4-dimethyl-5-phenyl-thiazolidin-2-ylidene ammonium, one dianion tris-(thiocyano)bromide cobaltate and one bromide, obtained from reaction of (4S,5S)-3,4-dimethyl-5-phenyl-thiazolidin-2-ylidene ammonium thiocyanate (2) and CoBr₂ is also described. Compounds 3–6 were characterized in the solid state by UV–Vis–NIR and IR spectroscopy, mass spectrometry and X-ray diffraction analyses. Metal···H–C, S···H–C interactions were observed in 3–6, whereas in 6, also Br···H–N, Br···H–C and Br···S, S···S short contacts were found.     

Facile One-Pot Synthesis of Novel Tricyclic Dibenzoheterocycles via the Dianion Protocol of Ditopic Ligands

In our ongoing studies on the synthesis of new heterocyclic ring systems via a dianion intermediate, we herein describe the preparation of novel dibenzoazadioxoninone, dibenzoazadioxoninethione, dibenzoazadioxocine, dibenzoazadioxacycloundecine, dibenzoazadioxacyclododecine, dibenzoaza-2-oxodioxaphosphonine, and dibenzoaza-2-oxo-1,3-thioxaphosphonine in good yields.     

Versatile Synthesis of Fused Tricyclic 1,2,4-Triazole Derivatives

ABSTRACT

A rapid and general method for the synthesis of symmetrical disulfides involves reaction of sulfur with sodium hydroxide under PTC-microwave irradiation condition to give sodium disulfide, which reacts with alkyl halides to afford the disulfides in good to excellent isolated yields.     

PdO-Catalyzed Synthesis of Tricyclic Compounds Using Biginelli-Like Reaction

An efficient method has been successfully developed for the synthesis of oxygen-bridged pyrimidine tricyclic derivatives from salicylaldehyde, ethyl acetoacete, and urea catalyzed by PdO in very good yield. A series of different oxygen-bridged pyrimidine tricyclic derivatives has been synthesized, in which two compounds’ x-ray crystal structure were obtained.     

新型1,2,4-三取代-1,2,3-三氮唑盐的合成

以邻溴苄醇(1)和水杨醛(2)为原料,经5步反应合成了一种分子内同时具有羟基和1,2,3-三氮唑环的新型类卡宾前体盐中间化合物(7),在三氟甲磺酸酐的催化下,分子内六元环化反应得到一种新型的1,2,4-三取代-1,2,3-三氮唑并三环体系类卡宾前体盐(8),其结构经1H NMR,13C NMR和MS(ESI)表征。     

Asymmetric synthesis of ABC tricyclic systems in Daphniphyllum alkaloid

Efficient synthetic routs for the direct and rapid construction of[5-6-6]ABC tricyclic systems of daphmanidin A-type and calyciphylline A-type alkaloids have been successfully developed.For the daphmanidin A-type,the synthesis of[5-6-6]tricyclic framework utilize a HCl-mediated intramolecular Aldol reaction to construct the bicyclo[2.2.2]octane core and a thermal condensation to afford the ABC ring system.In addition,for the calyciphylline A-type,an improved synthesis of ABC[5-6-6]tricyclic system was developed,featuring an introduction of methyl ester group at C2 before the Pd-catalyzed intramolecular oxidative alkylation to construct the desired bowl-shape tricyclic core with stereochemical control.     

Synthesis of 3,7-disubstituted imipramines by palladium-catalysed amination/cyclisation and evaluation of their inhibition of monoamine transporters

We describe a novel approach for the synthesis of a series of 3,7-difunctionalised symmetric and unsymmetrical analogues of the tricyclic antidepressant (TCA) imipramine, which uses a key palladium-catalysed amination/cyclisation of an ester-functionalised dibromide. Of the ester, methyl, hydroxymethyl and methoxymethyl disubstituted compounds prepared, 3,7-dimethyl-imipramine was found to be the most potent against the human serotonin transporter (hSERT). The inhibitory potency of 3,7-dimethyl imipramine was found to be at least as high as the parent imipramine. This novel TCA also exhibits an increased selectivity (relative to imipramine) in binding to hSERT versus the human norepinephrine transporter (hNET). Even higher selectivity could be obtained with 3,7-dihydroxymethyl imipramine, which was found to be 167-fold more selective for hSERT over hNET, representative of a 120-fold gain in selectivity relative to the parent imipramine. These results further validate our previous model for the binding of imipramine and high-affinity analogues of imipramine to the central binding site of hSERT.     

New compounds with 4-azatricyclo[4.3.1.13,8]undecane framework

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