Studies on the Reaction of α‐Chloroformylarylhydrazine Hydrochloride with Imidazole and 1,2,4‐Triazole

α‐Imidazolformylarylhydrazine 2 and α‐[1,2,4]triazolformylarylhydrazine 3 have been synthesized through the nucleophilic substitution reaction of 1 with imidazole and 1,2,4‐triazole, respectively. 2,2′‐Diaryl‐2H,2′H‐[4,4′]bi[[1,2,4]‐triazolyl]‐3,3′‐dione 4 was obtained from the cycloaddition of α‐chloroformylarylhydrazine hydrochloride 1 with 1,2,4‐triazole at 60 °C and in absence of n‐Bu₃N. The inducing factor for cycloaddition of 1 with 1,2,4‐triazole was ascertained as hydrogen ion by the formation of 4 from the reaction of 3 with hydrochloric acid. 4 was also acquired from the reaction of 3 with 1 and this could confirm the reaction route for cycloaddition of 1 with 1,2,4‐triazole. Some acylation reagents were applied to induce the cyclization reaction of 2 and 3.1 possessing chloroformyl group could induce the cyclization of 2 to give 2‐aryl‐4‐(2‐aryl‐4‐vinyl‐semicarbazide‐4‐yl)‐2,4‐dihydro‐[1,2,4]‐triazol‐3‐one 6. 7 was obtained from the cyclization of 2 induced by some acyl chlorides. Acetic acid anhydride like acetyl chloride also could react with 2 to produce 7D . 5‐Substituted‐3‐aryl‐3H‐[1,3,4]oxadiazol‐2‐one 8 was produced from the cyclization reaction of 3 induced by some acyl chlorides or acetic acid anhydride. The 1,2,4‐triazole group of 3 played a role as a leaving group in the course of cyclization reaction. This was confirmed by the same product 8 which was acquired from the reaction of 1 , possessing a better leaving group: Cl, with some acyl chlorides or acetic acid anhydride.     

固相β-环糊精包结物诱导7-羟基-2-甲氧基-2-甲基色满的不对称合成

研究了室温下间苯二酚和甲基乙烯基酮分别与β-环糊精（ β-CD）形成包结物后的几种不同固相反应,结果表明包结物A（间苯二酚/β-CD）与包结物B（甲基乙烯基酮/β-CD）反应能够很好地得到目的产物,产率及ee值分别为82.8%和78.4%;间苯二酚与包结物B反应仅得到低光学活性产物（ee值为19.5%）;包结物A与甲基乙烯基酮反应却没有得到手性目的产物。以熔点、X-粉末衍射、固相核磁碳谱及ROESY多种方法对所形成的包结物进行了表征,包结物中主客体的比例（1：1）通过¹H NMR (400 MHz)得以确定,文章对固相环加成反应的机制也进行了初步探讨。     

Chemoselective Synthesis of β‐Amino Ester or β‐Lactam via Sonochemical Reformatsky Reaction

A series of β‐amino esters were synthesized by the reaction of N‐tosyl aldimine or N‐hydroxy aldimine with bromoacetate by sonochemical Reformatsky reaction. The β‐N‐hydroxyamino ester was obtained and the formed sensitive hydroxylamino functionality was resistant under the reaction condition. The β‐lactam also was synthesized by the reaction of N‐p‐methoxy aldimine as reacting substrate under this sonochemical Reformatsky reaction condition.     

Highly Enantioselective Direct Asymmetric Aldol Reaction Catalyzed by 4,5‐Methano‐L‐proline

The 4,5‐methano‐L‐proline was used as chiral organocatalysts in direct asymmetric aldol reactions. Under the optimal conditions, excellent enantioselectivities (up to 99% ee) were obtained with high chemical yields (up to 95%) for a series of aldehydes using only 5 mol% catalyst loading. To show the practicality of the method, the reaction was tested at a large scale. The reaction was complete in 16 h, and the aldol product was obtained in 86% yield and 93% ee.     

Heck reactions of aryl halides with alk‐1‐en‐3‐ol derivatives catalysed by a tetraphosphine–palladium complex

cis,cis,cis‐1,2,3,4‐Tetrakis(diphenylphosphinomethyl)cyclopentane–[PdCl(C₃H₅)]₂ efficiently catalyses the Heck reaction of alk‐1‐en‐3‐ol with a variety of aryl halides. In the presence of hex‐1‐en‐3‐ol or oct‐1‐en‐3‐ol, the β‐arylated carbonyl compounds were selectively obtained. Turnover numbers up to 84 000 can be obtained for this reaction. Linalool and 2‐methylbut‐3‐en‐2‐ol led regio‐ and stereoselectively to the corresponding (E)‐1‐arylalk‐1‐en‐3‐ol derivatives. A minor electronic effect of the substituents of the aryl bromide was observed. Quite similar reaction rates were generally observed in the presence of activated aryl bromides such as bromoacetophenone and deactivated aryl bromides such as bromoanisole, indicating that, with these alkenols and this catalyst, the oxidative addition of aryl bromides to palladium is not the rate‐limiting step. It should be noted that this reaction also proceeds with sterically very congested aryl bromides such as 9‐bromoanthracene or 2,4,6‐triisopropylbromobenzene or with a vinyl bromide. On the other hand, low yields were obtained with aryl chlorides. Copyright © 2006 John Wiley & Sons, Ltd.     

One‐Pot Four‐Component Synthesis of Tetrasubstituted Pyrroles

A convenient one‐pot four‐component synthesis of tetrasubstituted pyrroles was carried out through the reaction of butane‐2,3‐dione with α‐aminophosphorous ylides, obtained in situ from the 1 : 1 : 1 addition reaction between triphenylphosphine, dialkyl acetylenedicarboxylate, and ammonium acetate.     

Microwave‐promoted Synthesis of Novel Fused Osthole Analogues

Osthole is a natural coumarin derivative and has a broad scope of biological activities. Two series of novel fused osthole analogues were designed, and synthesized through a highly efficient microwave‐promoted synthetic protocol via the reaction of 4‐hydroxycoumarins and β‐ketoesters. The reaction conditions including solvent, catalyst, microwave power and irradiation time were also optimized. The pyrano[3,2‐c]chromene‐2,5‐diones and furo[3,2‐c]coumarins were obtained through two distinct intramolecular cyclization processes, and the proposed mechanism was also discussed.     

Rhodium(III)‐Catalyzed ortho Alkenylation of N‐Phenoxyacetamides with N‐Tosylhydrazones or Diazoesters through C?H Activation

A coupling reaction of N‐phenoxyacetamides with N‐tosylhydrazones or diazoesters through Rh^III‐catalyzed C H activation is reported. In this reaction, ortho‐alkenyl phenols were obtained in good yields and with excellent regio‐ and stereoselectivity. Rh–carbene migratory insertion is proposed as the key step in the reaction mechanism.     

One‐Pot Four‐Component Synthesis of Thieno[2,3‐d]pyrimidin‐4‐amines via Sequential Gewald/Cyclocondensation Reactions

A one‐pot four‐component synthesis of thieno[2,3‐d]pyrimidin‐4‐amines via sequential Gewald/cyclocondensation reactions is described. 2‐Aminothiophene‐3‐carbonitriles obtained from the Gewald reaction between cyclic ketones, malononitrile, and sulfur underwent a condensation? cyclization reaction with benzonitriles under solvent‐free conditions to afford the title compounds in excellent yields.     

KF-蒙脱土催化下丙二腈与α,β-不饱和酮的迈克尔加成反应

本论文研究了KF-蒙脱土催化下丙二腈与α,β-不饱和酮的迈克尔加成反应,研究发现在不同的反应温度下可以得到加成和环化两种不同的产物。该方法和现有的方法相比具有产率高、反应条件温和、操作简单、试剂易得等优点。     

Synthesis of head‐to‐tail polyurethanes from nonsymmetric diisocyanate and ethylene glycol with organotin catalysts

An ordered head‐to‐tail (HT) polyurethane was successfully prepared by the polyaddition reaction of p‐isocyanatobenzyl isocyanate with ethylene glycol with dibutyltin dilaurate as a catalyst. Furthermore, the HT regularity of polyurethane was improved to 83% with 1,1,3,3‐tetraphenyl‐1,3‐dichlorodistannoxane. The polymerization was conducted in N,N‐dimethylformamide at 30 °C with both monomers mixed at once. The microstructure of the polymer was investigated by ¹H and ¹³C NMR spectroscopy, and the polymer obtained by the polyaddition reaction had the expected HT linkages. The constitutional regularity of the polymers influenced the thermal properties and crystallinity. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 416–429, 2001     

Synthesis and characterization of new optically active poly(amide‐imide)s containing epiclon and L‐methionine moieties in the main chain

Epiclon [3a,4,5,7a‐tetrahydro‐7‐methyl‐5‐(tetrahydro‐2,5‐dioxo‐3‐furanyl)‐1,3‐isobenzofurandione] (1) was reacted with L ‐methionine (2) in acetic acid and the resulting imide‐acid 3 was obtained in high yield. The diacid chloride 4 was prepared from diacid derivative 3 by reaction with thionyl chloride. Thermostable poly(amide‐imide)s containing epiclon structure were synthesized by reacting of diacid chloride 4 with various aromatic diamines. Polymerization reaction was performed by two conventional methods: low temperature solution polycondensation and short period reflux conditions. In order to compare conventional solution polycondensation reaction methods with microwave‐assisted polycondensation, the reactions were also carried out under microwave conditions with a small amount of o‐cresol that acts as a primary microwave absorber. The reaction mixture was irradiated for 6 min with 100% radiation power. Several new optically active poly(amide‐imide)s with inherent viscosity ranging from 0.15 to 0.36 dl/g were obtained with high yield. All of the above polymers were fully characterized by ¹H‐NMR, FT‐IR, elemental analyses and specific rotation techniques. Some structural characterizations and physical properties of these new optically active poly(amide‐imide)s are reported. Copyright © 2005 John Wiley & Sons, Ltd.     

Efficient asymmetric addition of diethylzinc to aldehydes using C2‐novel chiral pyridine β‐amino alcohols as chiral ligands

A series of novel C₂‐symmetric chiral pyridine β‐amino alcohol ligands have been synthesized from 2,6‐pyridine dicarboxaldehyde, m‐phthalaldehyde and chiral β‐amino alcohols through a two‐step reaction. All their structures were characterized by ¹H NMR, ¹³C NMR and IR. Their enantioselective induction behaviors were examined under different conditions such as the structure of the ligands, reaction temperature, solvent, reaction time and catalytic amount. The results show that the corresponding chiral secondary alcohols can be obtained with high yields and moderate to good enantiomeric excess. The best result, up to 89% ee, was obtained when the ligand 3c (2S,2′R)‐2,2′‐((pyridine‐2,6‐diylbis(methylene))bisazanediyl))bis(4‐methyl‐1,1‐diphenylpentan‐1‐ol) was used in toluene at room temperature. The ligand 3g (2S,2′R)‐2,2′‐((1,3‐phenylenebis(methylene))bis(azanediyl))bis(4‐methyl‐1,1‐diphenylpentan‐1‐ol) was prepared in which the pyridine ring was replaced by the benzene ring compared to 3c in order to illustrate the unique role of the N atom in the pyridine ring in the inductive reaction. The results indicate that the coordination of the N atom of the pyridine ring is essential in the asymmetric induction reaction. Copyright © 2014 John Wiley & Sons, Ltd.     

Asymmetric Henry reactions of aldehydes with various nitroalkanes catalyzed by copper(II) complexes of novel chiral N‐monoalkyl cyclohexane‐1,2‐diamines

A number of novel chiral diamines 3 , (1R,2R)‐N‐monoalkylcyclohexane‐1,2‐diamines, were designed and synthesized from trans‐cyclohexane‐1,2‐diamine and applied to the catalytic asymmetric Henry reaction of benzaldehyde and nitromethane to provide β‐nitroalcohol in high yield (up to 99%) and good enantiomeric excess (up to 89%). By using ligand (1R,2R)‐N¹‐(4‐methylpentan‐2‐yl)cyclohexane‐1,2‐diamine ( 3g ), the reaction was optimized in terms of the metal ion, temperature, solvent and base. Further experiments indicated that the complex, 3g –Cu(OAc)₂, was an efficient catalyst in the asymmetric Henry reaction between different aldehydes and nitromethane, and the desired products have been obtained with high chemical yields (up to 99%) and high enantiomeric excess (up to 93%). The optimized catalyst promoted the diastereoselective Henry reaction of various aldehyde substrates and nitroalkane, which gave the corresponding anti‐selective adduct with up to 99% yield and 83:17 anti/syn selectivity. Upon scaling up to gram quantities, the β‐nitroalcohol was obtained in good yield (96%) with excellent selectivities (93% ee). The chiral induction mechanism was tentatively explained on the basis of a previously proposed transition‐state model. Copyright © 2014 John Wiley & Sons, Ltd.     

Reaction control in radical polymerization of di‐n‐butyl itaconate utilizing a hydrogen‐bonding interaction

We have reported that intramolecular chain‐transfer reaction takes place in radical polymerization of itaconates at high temperatures and/or at low monomer concentrations. In this article, radical polymerizations of di‐n‐butyl itaconate (DBI) were carried out in toluene at 60 °C in the presence of amide compounds. The ¹³C‐NMR spectra of the obtained poly(DBI)s indicated that the intramolecular chain‐transfer reaction was suppressed as compared with in the absence of amide compounds. The NMR analysis of DBI and N‐ethylacetamide demonstrated both 1:1 complex and 1:2 complex were formed at 60 °C through a hydrogen‐bonding interaction. The ESR analysis of radical polymerization of diisopropyl itaconate (DiPI) was conducted in addition to the NMR analysis of the obtained poly(DiPI). It was suggested that the suppression of the intramolecular chain‐transfer reaction with the hydrogen‐bonding interaction was achieved by controlling the conformation of the side chain at the penultimate monomeric unit of the propagating radical with an isotactic stereosequence. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4895–4905, 2004     

Novel Synthesis of 2‐Alkylquinolizinium‐1‐olates and Their 1,3‐Dipolar Cycloaddition Reactions with Acetylenes

Several 2‐alkylquinolizinium‐1‐olates 9 , i.e., heterobetaines, were prepared from ketone 11 , the latter being readily available either from pyridine‐2‐carbaldehyde via a Grignard reaction, followed by oxidation with MnO₂, or from 2‐picolinic acid (=pyridine‐2‐carboxylic acid) via the corresponding Weinreb amide and subsequent Grignard reaction. Mesoionic heterobetaines such as quinolizinium derivatives have the potential to undergo cycloaddition reactions with double and triple bonds, e.g., 1,3‐dipolar cycloadditions or Diels? Alder reactions. We here report on the scope and limitations of cycloaddition reactions of 2‐alkylquinolizinium‐1‐olates 9 with electron‐poor acetylene derivatives. As main products of the reaction, 5‐oxopyrrolo[2,1,5‐de]quinolizines (=‘[2.3.3]cyclazin‐5‐ones’) 19 were formed via a regioselective [2+3] cycloaddition, and cyclohexadienone derivatives, formed via a Diels? Alder reaction, were obtained as side products. The structures of 2‐benzylquinolizinium‐1‐olate ( 9a ) and two ‘[2.3.3]cyclazin‐5‐ones’ 19i and 19l were established by X‐ray crystallography.     

Polymerization of conjugated 5‐[(5‐ethynyl‐1‐naphthyl)ethynyl]‐N,N‐dimethylnaphthalen‐1‐amine with rhodium and palladium complexes

The monomer 5‐[(5‐ethynyl‐1‐naphthyl)ethynyl]‐N,N‐dimethylnaphthalen‐1‐amine was satisfactory obtained through the heterocoupling reaction of 5‐ethynyl‐N,N‐dimethylnaphthalen‐1‐amine and 4‐(5‐iodo‐1‐naphthyl)‐2‐methyl‐3‐butyn‐2‐ol catalyzed by a palladium–copper system, followed by acetone elimination. Poly{5‐[(5‐ethynyl‐1‐naphthyl)ethynyl]‐N,N‐dimethylnaphthalen‐1‐amine} was obtained through the reaction of the acetylene monomer with homogeneous rhodium and palladium catalyst complexes. The structure of the polymers always showed a trans–cisoidal chain configuration on the basis of IR and NMR spectra. Moreover, only for the rhodium catalyst complex in methanol was a dimeric product isolated in a very low yield, having a conjugated terminal ene–yne structure, which permitted the consideration of a metallated chain‐transfer intermediate in the polymer propagation. The mass determination of the polymers, by osmometry and gel permeation chromatography techniques, showed low average molecular weights. The kinetics of the catalyzed polymerization were analyzed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2038–2047, 2007     

Synthesis and polymerization of 5‐(N,N‐dimethylamino)naphthylacetylene with homogeneous rhodium and palladium complexes

The monomer 5‐ethynyl‐N,N‐dimethylnaphthalen‐1‐amine ( 2 ) was satisfactorily obtained by a heterocoupling reaction between 5‐iodo‐(N,N‐dimethyl)naphthalen‐1‐amine and 2‐methyl‐3‐butyn‐2‐ol catalyzed by a palladium–copper system and followed by acetone elimination. Poly(5‐ethynyl‐N,N‐dimethylnaphthalen‐1‐amine) was isolated by the reaction of 2 in the presence of homogeneous rhodium and palladium complexes. On the basis of the spectroscopic data, the polymer always showed a cis–transoidal, stereoregular structure. Moreover, only with the rhodium catalyst in methanol was a dimeric product isolated in a very low yield, having a conjugated terminal ene–yne structure, which permitted the consideration of a metallated chain‐transfer intermediate in the polymer propagation. The kinetics of the catalyzed reaction were analyzed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 437–446, 2007     

Reversible Addition–Fragmentation Chain‐Transfer Polymerization of Octadecyl Acrylate

Abstract

Polymerization of octadecyl acrylate (ODA) was carried out in benzene solution using the 2‐cyanoprop‐2‐yl dithiobenzoate (CPDB) as the reversible addition–fragmentation chain‐transfer (RAFT) agent and AIBN as the initiator. The results show the obtained polymer with controlled molecular weight and low PDI value. The relationships between both of the ln([M ₀]/[M]) vs. reaction time and molecular weight vs. conversion showed a straight line. The block copolymer of ODA and styrene (PODA‐b‐PSt) obtained using poly(octadecyl acrylate) (PODA) as a macro‐RAFT agent. The polymers were characterized by ¹H NMR, DSC, and gel permeation chromatograph (GPC). The effect of molar ratio [CPDB]:[AIBN] and reaction temperature on polymerization was investigated.     

Diastereoselective Synthesis of Functionalized Tetrahydropyrimidin‐2‐thiones via ZnCl2 Promoted One‐pot Reactions

In the presence of zinc chloride, the in situ generated β‐enamino ester from the reaction of morpholine, piperidine and pyrrolidine with methyl propiolate reacted, with aromatic aldehydes and thiourea in ethanol resulting in the functionalized tetrahydropyrimidin‐2‐thiones in satisfactory yields and with good diastereoselectivity. When aromatic aldehydes bearing electron‐withdrawing group were used in the reaction, the 4‐hydroxytetrahydropyrimidin‐2‐thione derivatives were obtained as the main product.