Design and synthesis of two triazonine-carbaldehyde derivatives using several chemical tools

Several triazonine-carbaldehyde derivatives have been prepared using different protocols; however, some require special reagents and conditions. The aim of study involved the synthesis of two triazonine-carbaldehyde derivative using testosterone or OTBS-testosterone as chemical tool. Triazonine-carbaldehyde derivatives were prepared by a series of reactions that involve the following: (1) synthesis of two nitrobenzamide derivatives by reaction of testosterone or OTBS-testosterone with p-nitrobenzoyl azide using Copper(II) as catalyst; (2) reaction of the nitrobenzamides with ethylenediamine to form two triazonine derivatives using boric acid as catalyst; (3) preparation of hexynyl-triazonine derivatives by the reaction of two triazonines 6-chlorohex-1-yne in basic medium; (4) reaction of hexynyl-triazonine derivatives with benzaldehyde to form two triazoninol analogs; (5) preparation of triazoninynal derivatives through oxidation of triazoninol analogs with dimethyl sulfoxide; and (6) synthesis of triazonine-carbaldehyde derivatives by the reaction of triazoninynal derivatives with hexyne-1 using Copper(II) as catalyst. The chemical structure of compounds was determined by spectroscopic and spectrometric methods. In conclusion, in this work were prepared two triazoninone derivatives using several chemical techniques, which are simple procedures and easy to handle.     

Cross-coupling of highly pyramidalized alkenes: A straightforward access to functionalized tetrasecododecahedradienes

The synthesis and chemical trapping of a highly pyramidalized pentacyclo[6.4.0.0(2,10).0(3,7).0(4,9)]dodec-8-ene containing ketal functions is reported. Its cross-coupling reaction with 3, 7-dimethyltricyclo[3.3.0.0(3,7)]oct-1(5)-ene followed by a [2 + 2] retrocycloaddition reaction gives a straightforward access to functionalized tetrasecododecahedradienes.     

Synthesis and characterization of an amidinate-stabilized cis-1,2-disilylenylethene [cis-LSi{C(Ph)=C(H)}SiL] and a singlet delocalized biradicaloid [LSi(μ(2)-C(2)Ph(2))(2)SiL

The synthesis and characterization of novel cis-1,2-disilylenylethene [cis-LSi{C(Ph)=C(H)}SiL] (2; L=PhC(NtBu)(2)) and a singlet delocalized biradicaloid [LSi(μ(2)-C(2)Ph(2))(2)SiL] (3) are described. Compound 2 was prepared by the reaction of [{PhC(NtBu)(2)}Si:](2) (1) with one equivalent of PhC[triple chemical bond]CH in toluene. Compound 3 was synthesized by the reaction of 1 with two equivalents of PhC[triple chemical bond]CPh in toluene. The results suggest that the reaction proceeds through an [LSi{C(Ph)==C(Ph)}SiL] intermediate, which then reacts with another molecule of PhC[triple chemical bond]CPh to form 3. Compounds 2 and 3 have been characterized by X-ray crystallography and NMR spectroscopy. X-ray crystallography and DFT calculations of 3 show that the singlet biradicals are stabilized by the amidinate ligand and the delocalization within the "Si(μ(2)-C(2)Ph(2))(2)Si" six-membered ring.     

3(2H)isoquinolones. 2. Studies on the structure and formation of aminonaphthols obtained in the preparation of 3(2H)isoquinolones

The reaction of a 2-acylphenylacetic acid derivative (I) with primary amines in glacial acetic acid produces novel, colorless aminonaphthols (III) which are isomeric with the brilliant yellow 3(2H)isoquinolones (II) obtained in the same reaction. A combination of chemical and spectral techniques allowed identification of the isomers as derivatives of 4-amino-2-naphthol. A plausible mechanism of formation of aminonaphthols versus 3(2H)isoquinolones is discussed and supported by chemical synthesis of N-substituted 2-aeylphenylacetamides (VIII) and a 1,4-dihydro-1-hydroxy-3(2H)isoquinolone derivative (IX).     

A new strategy for the synthesis of 1,4-benzodiazepine derivatives based on the tandem N-alkylation-ring opening-cyclization reactions of methyl 1-arylaziridine-2-carboxylates with N-[2-bromomethyl(phenyl)]trifluoroacetamides

A new method for the synthesis of novel 1,4-benzodiazepine derivatives has been established from a one-pot reaction of methyl 1-arylaziridine-2-carboxylates with N-[2-bromomethyl(aryl)]trifluoroacetamides. The reaction proceeds through the N-benzylation and highly regioselective ring-opening reaction of aziridine by bromide anion followed by Et3N-mediated intramolecular nucleophilic displacement of the bromide by the amide nitrogen. The easy availability of starting materials, simple and convenient synthetic procedure, and formation of functionalized 1,4-benzodiazepine scaffold ready for further chemical manipulations render this strategy useful in synthetic and medicinal chemistry.     

Synthesis of （2R,3aR,8aR）-6-Chloro-3a-hydroxy-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole-2-carboxylic Acid Methyl Ester by Reductive Cyclization

A synthesis of (2R，3aR，8aR)-6-chloro-3a-hydroxy-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole-2-carboxylic acid methyl ester (1) was achieved. An aldol reaction with Garner aldehyde, a hydroxyl introduction by Davis reagent, and a reductive intramolecular ring-closure reaction were served as the key steps. This piece of work provides a new way to synthesize the analogues of hexahydropyrrolo[2,3-b]indole, starting from readily available chemical substrates and inexpensive reagents.     

苯热GaP纳米微晶介质中水氧对反应过程的影响

分别以磷和GaCl~3的乙醚溶液、GaCl~3的苯溶液为原料,用苯热合成法制备了GaP纳米微晶。初步探讨了反应过程中介质中的水和氧对生成物的影响,并利用化学键的解离能数据对生成物的稳定性进行了分析。结果表明：介质中的水和氧可以在很大程度上影响反应过程,甚至改变反应进行的方向。     

Synthesis of a NO-releasing prodrug of rofecoxib

[reaction: see text] A newly developed synthesis of a NO-releasing prodrug of rofecoxib is described. The highly productive process consists of five chemical steps and produces prodrug 1 in an overall 64% yield from commercially available 3-phenyl-2-propyn-1-ol (4). The synthesis is highlighted by the carbometalation reaction of propargyl alcohol 4 to generate the tetrasubstituted olefin core, sulfone acid 2. Additionally, two alternate end-game strategies to prepare NO-COXIB 1 from this intermediate were explored and developed: (1) a convergent synthesis where a bromonitrate side chain is introduced in one step and (2) a two-step sequence that first installs the requisite six-carbon ester side chain followed by chemoselective nitration.     

Modular Synthesis of Nona-Decasaccharide Motif from Psidium guajava Polysaccharides: Orthogonal One-Pot Glycosylation Strategy

The synthesis of long, branched, and complex carbohydrate sequences remains a challenging task in chemical synthesis. Reported here is an efficient and modular one-pot synthesis of a nona-decasaccharide and shorter sequences from Psidium guajava polysaccharides, which have the potent α-glucosidase inhibitory activity. The synthetic strategy features: 1) several one-pot glycosylation reactions on the basis of N-phenyltrifluoroacetimidate (PTFAI) and Yu glycosylation to streamline the chemical synthesis of oligosaccharides, 2) the successful and efficient assembly sequences (first O3′, second O5′, final O2′) toward the challenging 2,3,5-branched Araf motif, 3) the stereoselective 1,2-cis-glucosylation by reagent control, and 4) the convergent [6+6+7] one-pot coupling reaction for the final assembly of the target nona-decasaccharide. This orthogonal one-pot glycosylation strategy can streamline the chemical synthesis of long, branched, and complicated carbohydrate chains.     

一种新型纺锤状α-Fe_2O_3纳米晶的合成、表征及其表面性能(英文)

合成了一种新型的具有单晶结构的α-Fe2O3纳米晶(NFO-1).在我们的合成方法中,样品的形貌和结构在低反应浓度体系中运用无机盐和有机模板进行双重调控,同时用溶剂挥发诱导自组装(EISA)来加速反应和在不改变形貌结构的前提下获得高产率样品.所得α-Fe2O3纳米晶的形貌和结构对其表面修饰功能有明显的影响,NFO-1因其特殊的纺锤状形貌而与表面功能试剂(多巴胺)之间的化学作用有明显的增强.并且,本文所描述的合成方法同样适用于其他过渡金属氧化物纳米单晶的合成.我们预期,这种方法可为新型纳米材料的合成提供新的途径.     

3-羟基丁酸的气相色谱分析

采用ＢＦ３－ＣＨ３ＯＨ酯化衍生法,以正辛酸作内标,建立了３－羟基丁酸、巴豆酸、３羟基丁醛、巴豆醛等混合体系中３－羟基丁酸的气相色谱分析方法,利用标准样对照并结合质谱分析确定了化学合成３－羟基丁酸反应混合物的组成。该法线性范围为０．４０～１６０．６７ｇ／Ｌ,相关系数为ｒ＝０．９９９５。方法快速、简单、重现性好,并用于化学合成３－羟基丁酸反应混合物的分析,结果令人满意。     

Enantioselective synthesis of (2S,3R)-3-hydroxy-3-methylproline, a novel amino acid found in polyoxypeptins

The enantioselective synthesis of (2S,3R)-3-hydroxy-3-methylproline (3) was achieved by the Sharpless AD, regioselective opening of cyclic sulfate by NaN(3) and intramolecular ring-closing reaction. The reported route has the advantage of a high overall yield and good enantiomeric purity, as well as starting from readily available chemical substrates and inexpensive reagents.     

Modular Synthesis of Nona‐Decasaccharide Motif from Psidium guajava Polysaccharides: Orthogonal One‐Pot Glycosylation Strategy

The synthesis of long, branched, and complex carbohydrate sequences remains a challenging task in chemical synthesis. Reported here is an efficient and modular one‐pot synthesis of a nona‐decasaccharide and shorter sequences from Psidium guajava polysaccharides, which have the potent α‐glucosidase inhibitory activity. The synthetic strategy features: 1) several one‐pot glycosylation reactions on the basis of N‐phenyltrifluoroacetimidate (PTFAI) and Yu glycosylation to streamline the chemical synthesis of oligosaccharides, 2) the successful and efficient assembly sequences (first O3′, second O5′, final O2′) toward the challenging 2,3,5‐branched Araf motif, 3) the stereoselective 1,2‐cis‐glucosylation by reagent control, and 4) the convergent [6+6+7] one‐pot coupling reaction for the final assembly of the target nona‐decasaccharide. This orthogonal one‐pot glycosylation strategy can streamline the chemical synthesis of long, branched, and complicated carbohydrate chains.     

Synthesis of 2-Methoxy-3-pentene in a Liquid Phase over a Sulfoionite Catalyst: I. Chemical Equilibrium and Reaction Mechanism

The thermodynamic equilibrium and mechanism of the catalytic synthesis of 2-methoxy-3-pentene from 1,3-pentadiene isomers and methanol are considered. The structures of reaction products were identified by spectroscopic methods, the chemical equilibrium parameters were determined experimentally, and the partial thermodynamic functions were determined by approximation techniques. The mechanism and direction of the main reaction up to the formation of 2-methoxy-3-pentene were substantiated in terms of the most probable intermediates, secondary allyl carbonium ions.     

Study on products and reaction paths for synthesis of 3,4-dihydro-2H-3-phenyl-1,3-benzoxazine from phenol,aniline and formaldehyde

To study the synthesis of 3,4-dihydro-2H-3-phenyl-1,3-benzoxazine (benzoxazine), the reaction paths of phenol, aniline and formaldehyde were investigated by analyzing the synthesis crude products. With the aid of high-performance liquid chromatography (HPLC), chromatographic column and preparative HPLC, seven compounds originated from the crude products were obtained and their chemical structures were elucidated. Possible reaction paths are proposed based on these compounds. Results show that Nhydroxymethyl aniline (HMA) derived from the reaction of formaldehyde and aniline is probably the key intermediate during the reaction. HMA can react with itself or other reactants to form other intermediates, such as 1,3,5-triphenyl-1,3,5-triazinane and 2-((phenylamino)methyl)phenol, and further form benzoxazine and byproducts.     

An Efficient Synthesis of Benzazocines by Gold(I)‐Catalyzed Tandem 1,2‐Acyloxy Shift/[3+2] Cycloaddition of Terminal 1,9‐Enynyl Esters

An effective synthesis of structurally diverse benzazocines was accomplished in good to excellent chemical yields (55–82 %) through a gold(I)‐catalyzed cascade reaction involving tandem 1,2‐acyloxy shift/[3+2] cycloaddition of terminal 1,9‐enynyl esters. The reaction proceeds under extremely mild conditions and represents one of the relatively few transition‐metal‐catalyzed intramolecular cycloaddition reactions for the synthesis of benzazocines.     

A new glycosylation method. Part 2: Study of carbohydrate elongation onto the gold nanoparticles in a colloidal phase

A new reaction for carbohydrate elongation for synthesis of oligosaccharide using gold colloidal nanoparticles (GCNPs) has been developed. The gold core in this colloidal phase synthesis was prepared by a reduction of tetrachloroauric acid with 30,31-dithia-3,6,9,12,15,18,43,46,49,52,55,58-dodecaoxa-1,60-hexacontanediol. The presented alkanethionyl oligomeric ethylene glycol worked as a stabilizer of GCNPs and as a linker in chemical elongations of carbohydrates. This colloidal phase synthesis has several advantages such as (1) remnants of reagents and glycosyl donors in each reaction could be easily removed by ultrafiltration or gel filtration column chromatography, (2) further purifications are not required, and (3) the reactions can be monitored by MALDI-TOF MS directly without any pretreatment. In fact, we have successfully synthesized lactose derivative on GCNPs and will report these results in this paper.     

Synthesis of antisense oligodeoxyribonucleotide analogues by use of deoxyribonucleoside 3′-bis(1, 1, 1, 3,3,3-hexafluoro-2-propyl) phosphites as new key intermediates

The deoxyribonucleoside 3′-bis(1,1,1,3,3,3-hexafluoro-2-propyl) phosphite units ( 3 ) are used in the chemical synthesis of oligodeoxyribonucleotides on solid supports. The new phosphite units ( 3 ) were prepared easily by reaction of nucleosides and tris-(1,1,1,3,3,3-hexafluoro-2-propyl) phosphite ( 2 ). They are readily activated by N-methylimidazole under very mild conditions on a solid support. This operation involves a one step reaction, which is an advantage over both the phosphite and H-phosphonate approaches. The use of deoxyribonucleoside phosphite intermediates in the synthesis of antisense oligodeoxyribonucleotides is also described.     

One-pot synthesis of novel fused pentacyclic chromenopyrimidobenzimidazolones and benzimidazolyl-chromenyl-substituted thiazolidinones

The ultrasound promoted synthesis of a number of novel fused pentacyclic chromenopyrimido[1,2-α]benzimidazolones by the one-pot reaction of 3-formylchromones with 2-aminobenzimidazole is described. Moreover, the isolated pentacyclic chromone derivatives upon microwave irradiation with 2-mercaptocarboxylic acids afforded benzimidazolyl-chromenylthiazolidinones incorporating three pharmacophoric heterocycles; the same thiazolidinones were also formed through a multicomponent reaction under microwave irradiation involving 3-formylchromones, aminobenzimidazole and 2-mercaptocarboxylic acids. The structural elucidation of the products was accomplished by 1D and 2D NMR experiments and for thiazolidinones was also confirmed by X-ray crystallographic analysis. Full assignment of all ¹H and ¹³C NMR chemical shifts has been unambiguously achieved. The proposed reaction mechanism is also discussed.