相转移催化下4-氯苯磺酰基乙酸异丙酯的烷基化反应

在有机合成中可用芳磺酰基作暂时性活化基团。芳磺酰基乙酸酯是具有活性亚甲基的弱酸性化合物。通常要在氢化钠、醇钠存在下才能起烷基化反应。Ono等曾报道4-甲苯磺酰基乙酸甲酯在DBu存在下进行烷基化反应,但反应时间长。近年来,相转移催化在有机反应中的应用受到重视,然而用固液相转移催化法使芳磺酰基乙酸酯起烷基化反应还未见报道。我们在K₂CO₃/DMF体系中,用TEBA作催化剂,研究了4-氯苯磺酰基乙酸异丙酯与不同类型卤代烃所起的烷基化反应。合成了尚未见报道的一或二烷基化产物。     

2-Acyl(aroyl)-1,1,3,3-tetracyanopropenides: VI. Reaction with hydrogen halides

Reactions of 2-aroyl-1,1,3,3-tetracyanopropenides with hydrogen halides in solvents of low dielectric permittivity result in the formation of 6-amino-2-aroyl-2-halopyridine-3,5-dicarbonitriles. 2-Acyl-1,1,3,3-tetracyanopropenides under similar conditions afford 2-(2-alkylidene-5-amino-4-cyano-2,3-dihydrofuran-3-ylidene)propanedinitriles. In solvents of high dielectric permittivity the result of the reaction depends on the nature of the hydrogen halide and the acyl(aroyl) substituent: With HCl and HBr 2-aroyl-1,1,3,3-tetracyanopropenides form 2-(5-amino-2-aryl-2-halo-4-cyano-2,3-dihydrofuran-3-ylidene)-propanedinitriles, and 2-acyl-1,1,3,3-tetracyanopropenides give 2-(2-alkylidene-5-amino-4-cyano-2,3-dihydrofuran-3-ylidene)propanedinitriles; with HI depending on the reaction conditions and the structure of the acyl substituent 2-(5-amino-2-aryl-4-cyano-2,3-dihydrofuran-3-ylidene)propanedinitriles, 2-(5-amino-4-cyano-2,3-dihydrofuran-3-ylidene) propane-dinitrile, 2-amino-4-(dimethoxybenzyl)-6-iodo-5-cyanonicotinamide, 4-amino-6-iodo-3-oxo-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-7-carbonitrile, or 4-amino-6-iodo-3-oxo-1-ethylidene-1,3-dihydrofuro[3,4-c]pyridine-7-carbonitrile are obtained.     

第5/6副族高价过渡金属氯化物的有机反应

从制备化学的角度, 对包括作者本人的研究工作在内的由第5/6副族高价过渡金属氯化物参加的有机反应进行了综述. 内容包括以下几个方面: (1)烷烃、烯烃和炔烃与第5/6副族高价过渡金属氯化物的卤化反应; (2)作为Lewis 酸催化的反应; (3)烯烃歧化反应及炔烃的聚合反应; (4) MoCl₅参与的芳烃氧化偶合反应; (5)硫醚化及扩环反应.     

The Suzuki cross‐coupling reaction in pure water catalyzed by ligandless palladium using polyethylene glycol derivatives as surfactant

The results of a ligandless Pd(OAc)₂‐catalyzed Suzuki–Miyaura coupling experiment are presented. It was found that the use of polyethylene glycol phosphonium salts (PEG‐quat) as surfactant resulted in very rapid reactions of aryl halides with phenylboronic acids in pure water. Moreover, aryl chlorides such as 4‐nitrochlorobenezene reacted quantitatively with phenylboronic acid under optimized conditions. Copyright © 2013 John Wiley & Sons, Ltd.     

PEGylation of an artificial O2 and CO receptor: synthesis, characterisation and pharmacokinetic study

A synthetic oxygen (O(2)) and carbon monoxide (CO) receptor (hemoCD) composed of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphinatoiron(ii) and a per-O-methylated β-cyclodextrin dimer with a pyridine linker (Py3CD) was functionalised with poly(ethylene glycol) (PEG) to elongate the circulation time of the receptor in the bloodstream. α-PEG monocarboxylic acid (HOOC(CH(2))(3)(CO)O-PEG(mw)-OCH(3); mw = 750 or 5k) or α,ω-PEG dicarboxylic acid (HOOC(CH(2))(3)(CO)O-PEG(mw)-O(CO)(CH(2))(3)COOH; mw = 10k or 20k) was reacted with the amino group of 5-(4-aminophenyl)-10,15,20-tris(4-sulfonatophenyl)porphyrin to afford a porphyrin monomer having a PEG chain or a porphyrin dimer having a PEG linker, respectively. The ferrous complexes of these PEGylated porphyrins (PEG750-, PEG5k-, PEG10k- and PEG20k-hemoCDs) bound O(2) in aqueous solution, P(1/2) values being 6.5-8.1 Torr at pH 7.0 and 25 °C. Each PEG(mw)-hemoCD was infused into the femoral vein of a Wistar male rat. After 6 h of the infusions, 67, 82, 86 and 42% of PEG750-, PEG5k-, PEG10k- and PEG20k-hemoCD were excreted in the urine. PEG750-hemoCD with a hydrodynamic diameter (D(h)) of 3.4 nm seemed to partly leak from the blood vessels (pore size: 2-6 nm) before renal filtration (pore size: 4-14 nm). PEG5k- (D(h) = 6.2 nm) and PEG10k-hemoCDs (9.0 nm) hardly passed through the blood vessels but were fully filtered by the kidney, resulting in high excretion rates. A considerable amount of PEG20k-hemoCD (D(h) = 12.0 nm) was retained in the blood even at 6 h after administration. The present study demonstrates that the behaviour of hemoCD in blood after administration can be controlled by modification of hemoCD with PEG having an appropriate molecular weight.     

Palladium-catalyzed three-component assembling of allenes, organic halides, and arylboronic acids.

An efficient method for the construction of two carbon-carbon bonds in a regio- and stereoselective fashion via palladium-catalyzed assembling of allenes, organic halides, and arylboronic acids is described. Organic halides (RI = C(6)H(5)I, o-, m-, and p-CH(3)OC(6)H(4)I, p-C(2)H(5)OCOC(6)H(4)I, p-CH(3)COC(6)H(4)I, p-CH(3)C(6)H(4)I, p-CH(3)C(6)H(4)Br, p-CH(3)C(6)H(4)Cl, p-NO(2)C(6)H(4)I, p-NO(2)C(6)H(4)Br, p-NO(2)C(6)H(4)Cl, p-IC(6)H(4)Cl, 1-iodonaphthalene, 2-iodothiophene, 3-iodo-2-cyclopenten-1-one, 3-iodo-5,5-dimethyl-2-cyclohexen-1-one, C(6)Eta(5)(Br)C=CH(2) and ICH(2)CO(2)C(2)H(5)), and arylboronic acids (ArB(OH)(2), Ar = C(6)H(5), p-CH(3)OC(6)H(4), m-NO(2)C(6)H(4), p-FC(6)H(4), 1-C(10)H(7), and o-, m-, and p-CHOC(6)H(4)) undergo Suzuki-type three-component assembling with 1,1-dimethylallene to give the corresponding allylic derivatives, (CH(3))(2)=CRCH(2)Ar, in DMF at 70 degrees C in the presence of CsF using Pd(dba)(2) as the catalyst. Higher yields of products were obtained for aryl iodides than for the corresponding aryl bromides and chlorides. This three-component assembling is highly regioselective, with the organic group on halides adding to the middle carbon and the aryl group on arylboronic acids to the unsubstituted terminal carbon of allenes. Monosubstituted allenes 1b-e (cyclopentylallene, cyclohexylallene, tert-butylallene, and n-butylallene) also undergo similar assembling reaction with organic halides and arylboronic acids to afford the corresponding products 7a-i with high regio- and stereoselectivity. Based on the known palladium chemistry, a mechanism is proposed to account for the catalytic reaction and the stereochemistry.     

AlAr3(THF): highly efficient reagents for cross-couplings with aryl bromides and chlorides catalyzed by the economic palladium complex of PCy3

Novel and highly efficient cross couplings of aryl bromides and chlorides with AlAr3(THF) (Ar = Ph, 2,4,6-Me3C6H2, 2-naphthyl or 4-Me3SiC6H4) catalyzed by the economic palladium catalyst of PCy3 are reported without the use of a base and under mild reaction conditions at room temperature or temperatures < or = 60 degrees C even for couplings of bulky aryl halides and the Al(2,4,6-Me3C6H2)3(THF) reagent.     

Carbonylative cross-coupling reaction of ethynylstibane with aryl iodides

Palladium-catalyzed carbonylative cross-coupling reaction of ethynylstibane (PhSbPh(2)) and aryl iodides (Ar-I) is described. The reaction of the stibanes and the halides under 1 atm of carbon monoxide in N,N-dimethylacetamide using a combination of 5 mol% Pd(OAc)(2) and 4 equivalents (20 mol%) of PPh(3) brought about carbonylative cross-coupling reaction to afford arylethynylketones [ArC(O)Ph] in good yields along with a small amount of directly coupled products, aryl acetylens (ArPh). Formation of the side product was completely suppressed by conducting the reaction under high CO pressure (20 atm) conditions. The present method provides a variety of carbonylated products in good yield even with electron-deficient aryl iodides which usually give inferior results due to their tendency to undergo decarbonylation in the cross-coupling reaction of ethynylstibanes and acyl halides.     

Pressure-induced formation of molecular B2X4(μ-X)2 (X = Cl, Br, I) species

Boron(III) halides (BX(3), where X = F, Cl, Br, I) at ambient pressure conditions exist as strictly monomeric, trigonal-planar molecules. Using correlated ab initio calculations, the three heavier halides (X = Cl, Br, I) are shown to possess B(2)X(4)(μ-X)(2) local minima, isostructural with the diborane molecule. The calculated dissociation barrier of the B(2)I(4)(μ-I)(2) species [≈14 kJ/mol with CCSD(T)/cc-pVTZ] may be high enough to allow cryogenic isolation. The remaining dimer structures are more labile, with dissociation barriers of less than 6 kJ/mol. All three dimer species may be stabilized by application of external pressure. Periodic density functional theory calculations predict a new dimer-based P1 solid, which becomes more stable than the P6(3)/m monomer-derived solids at 5 (X = I) to 15 (X = Cl) GPa. Metadynamics simulations suggest that B(2)X(4)(μ-X)(2)-based solids are the kinetically preferred product of pressurization of the P6(3)/m solid.     

Etherification of Phenols Catalysed by Solid-Liquid Phase Transfer Catalyst PEG400 without Solvent

Aromatic ethers were synthesised in excellent yields(above 86 %) and purity by the etherification of phenols with dimethyl sulfate or alkyl halides, catalysed by phase transfer catalyst PEG400 under solvent-free conditions, and the effects of some key reaction conditions were also studied.     

PEG 400 promoted nucleophilic substitution reaction of halides into organic azides under mild conditions

Abstract

Polyethylene glycol 400 (PEG 400) has been demonstrated as an efficient and eco-friendly reaction medium for the preparation of organic azides from structurally diverse halides by nucleophilic substitution reaction with NaN₃ under mild conditions. The advantages of this protocol are: operational simplicity, environmental safety, broad substrate scope, excellent functional group tolerance, and short reaction time. The PEG 400 can be recovered and reused.     

Novel Regioselective Synthesis and Biological Activity of 6‐Phenylazo and 3,6‐Bis(arylazo)‐7‐hydroxy‐1H‐[1,2,4]triazolo[4,3‐a]pyrimidin‐5(4H)‐one

Treatment of 6‐hydroxy‐5‐phenylazo‐2‐thioxo‐4(1H)‐pyrimidinone 1 with a series of hydrazonoyl halides 2 and N,2‐diaryl‐diazinecarbohydrazonoyl halides 9 in dioxane in the presence of triethylamine under reflux furnishes 6‐phenylazo and 3,6‐bis(arylazo)‐7‐hydroxy‐1H‐[1,2,4]triazolo[4,3‐a]pyrimidin‐5(4H)‐one derivatives 7 and 10 , respectively. The biological activities of the products were evaluated.     

Diastereo- and enantioselective ruthenium-catalyzed hydrohydroxyalkylation of 2-silyl-butadienes: carbonyl syn-crotylation from the alcohol oxidation level

Exposure of alcohols 2a-2j to 2-silyl-butadienes in the presence of ruthenium complexes modified by (R)-SEGPHOS or (R)-DM-SEGPHOS results in redox-triggered generation of allylruthenium-aldehyde pairs, which combine to form products of carbonyl crotylation 4a-4j in the absence of stoichiometric byproducts and with high levels of syn-diastereo- and enantioselectivity. In the presence of isopropanol under otherwise identical conditions, aldehydes 3a-3j are converted to an equivalent set of adducts 4a-4j. Whereas reactions conducted using conventional heating require 48 h, microwave irradiation enables full conversion in only 4 h. Finally, as illustrated in the conversion of adduct 4a to compounds 6a and 6b, diastereoselective hydroboration-Suzuki cross-coupling with aryl and vinyl halides followed by Fleming-Tamao oxidation enables generation of anti,syn-stereotriads found in numerous polyketide natural products.     

Studies on Pd(0)-catalyzed cyclization of N-3,4-alkadienyl toluenesulfonamides with organic halides: selective synthesis of 2,3-dihydropyrroles, 1,2,3,6-tetrahydropyrridines, and azetidines

The palladium-catalyzed coupling-cyclization of beta-amino allenes with organic halides ranging from aryl halide to 1-alkenyl halide was studied. 2,3-Dihydro-1H-pyrroles were obtained by reaction of 3-substituted-5-unsubstituted-3,4-allenyl amides under conditions A, while the reaction of 5-substituted-3,4-allenyl amides afforded 1,2,5,6-tetrahydropyridines and/or azetidines with high de under conditions B or C. The skeleton and relative configuration of the six-membered products were established by the X-ray diffraction studies of 10 ka. Allenyl amide 4 q reacted with 1,4-diiodobenzene 6 r to afford double cyclization product 15. The structure of its major stereoisomer was also determined by the X-ray diffraction study.     

An electrochemical synthesis of functionalized arylpyrimidines from 4-amino-6-chloropyrimidines and aryl halides

A range of novel 4-amino-6-arylpyrimidines has been prepared under mild conditions by an electrochemical reductive cross-coupling between 4-amino-6-chloro-pyrimidines and functionalized aryl halides. The process, which employs a sacrificial iron anode in conjunction with a nickel(II) catalyst, allows the formation of coupling products in moderate to high yields.     

Mono- and dialkylations of pyrrole at C2 and C5 positions by nucleophilic substitution reaction in ionic liquid

[reaction: see text] A novel ionic liquid methodology for pyrrole C-alkylation is described. The pyrrole alkylation is achieved with various simple alkyl halides and mesylates selectively at C2 and C5 positions in good yields with minimal byproducts under relatively mild conditions in various ionic liquids. 2-(3-Phenylpropyl)pyrrole (2a) was synthesized from pyrrole and 1-bromo-3-phenylpropane in a mixture solvent system, [bmim][SbF6] and CH3CN, in 81% yield at 115 degrees C for 44 h with 5% yield of dialkylated compound 3a.     

Formation of an 6α, 14-epoxy-bridged isomorphinan,an unusual product from a substituted 6α,14-dihydroxymorphinan

During alkylation of 3-O-benzyl-6α-naltrexol ( 1 ) with large aralkyl halides like 2-bromomethylnaphthalene and 9-chloromethylanthracene under phase transfer catalysis conditions (potassium hydroxide, tetrabutylammonium bromide, methylene chloride), formation of a new 6α,14-epoxide-bridged isomorphinan ( 4 ) was noted. Chemical and spectral evidence, including nmr and mass spectral data, are presented to prove its structure. Its formation results from 6α-oxygen displacement of a 14-O-aralkyl ether intermediate under the phase transfer catalysis alkylation conditions.     

Systematische untersuchungen über das verhalten von organozinnverbindungen gegenüber flüssigem schwefeldioxid II. Reaktionen von arylstannanen mit flüssigem SO2

The behaviour of tetraarylstannanes, R₄Sn (R = C₆H₅CH₂, C₆H₅, o-, m-, p-CH₃C₆H₄), towards SO₂ under various conditions has now been studied in detail. Compared to aliphatic tetraorganostannanes, the variability of the reaction products is much less, so that in nearly all cases only disulfinates, R₂Sn(O₂SR)₂, are formed. The aromatic tin(IV) mono-, di- and tri-sulfinates are also obtained by metathetical reaction between the corresponding organotin halides and sodium sulfinates. A unique feature of triaryltin chlorides, R₃SnCl (R = C₆H₅, o-, m-, p-CH₃C₆H₄), is their disproportionation in liquid SO₂ leading to disulfinates, R₂Sn(O₂SR)₂, and dichlorides, R₂SnCl₂. (p-CH₃C₆H₄)₂SnCl₂, under more efficient conditions, also accepts SO₂ forming (p-CH₃C₆H₄SO₂)₂SnCl₂. The structural investigations of the newly prepared compounds are carried out on the basis of their IR and ¹H NMR spectra.     

Well-defined N-heterocyclic carbene silver halides of 1-cyclohexyl-3-arylmethylimidazolylidenes: synthesis, structure and catalysis in A3-reaction of aldehydes, amines and alkynes

Structurally well-defined N-heterocyclic carbene silver chlorides and bromides supported by 1-cyclohexyl-3-benzylimidazolylidene (CyBn-NHC) or 1-cyclohexyl-3-naphthalen-2-ylmethylimidazolylidene (CyNaph-NHC) were synthesized by reaction of the corresponding imidazolium halides with silver(I) oxide while cationic bis(CyBn-NHC) silver nitrate was isolated under similar conditions using imidazolium iodide in the presence of sodium nitrate. Single-crystal X-ray diffraction revealed a dimeric structure through a nonpolar weak-hydrogen-bond supported Ag-Ag bond for 1-cyclohexyl-3-benzylimidazolylidene silver halides [(CyBn-NHC)AgX](2) (X = Cl, 1; Br, 2) but a monomeric structure for N-heterocyclic carbene silver halides with the more sterically demanding 1-cyclohexyl-3-naphthalen-2-ylmethylimidazolylidene ligand (CyNaph-NHC)AgX (X = Cl, 4; Br, 5). Cationic biscarbene silver nitrate [(CyBn-NHC)(2)Ag](+)NO(3)(-)3 assumed a cis orientation with respect to the two carbene ligands. The monomeric complexes (CyNaph-NHC)AgX 4 and 5 showed higher catalytic activity than the dimeric [(CyBn-NHC)AgX](2)1 and 2 as well as the cationic biscarbene silver nitrate 3 in the model three component reaction of 3-phenylpropionaldehyde, phenylacetylene and piperidine with chloride 4 performing best and giving product in almost quantitative yield within 2 h at 100 °C. An explanation for the structure-activity relationship in N-heterocyclic carbene silver halide catalyzed three component reaction is given based on a slightly modified mechanism from the one in literature.     

Synthesis of 2(3H)-benzofuranone derivatives by copper (i)-promoted substitution reactions of active methylene carbanions

Activation of soft carbanions by copper(I) in the sub-stitution reaction toward aryl halides and allyl halides was demonstrated. Derivatives of 2(3H)-benzofuranones (2, 14 -18) were prepared in a one-pot procedure by the reaction of copper(I) diethyl malonate with sodium o-bromophenoxide. 2-Hydroxybenzofuran (4) and its 2-amino derivative (5) were obtained by using copper(I) salts of ethyl acetoacetate and ethyl cyanoacetate. The reaction of sodium p-bromophenoxides with copper(I) diethyl malonate yielded p-1,1,2,2-tetracaeboethoxyethylphenols (7, 8). 3-Carboethoxy-3-β-methallyl-2-benzofuranone (14) was converted into spiro[2-benzofuranone-3,3'-(5',5'-dimethyl)-γ-butyrolactone] (22) under acidic conditions. The latter compound was further decarboxylated to give spiro [2-benzofuranone-3,1'-(2',2'-dimethyl)cyclopropane] (23) by the treatment with sodium ethoxide.