Ultrasound assisted multicomponent reactions:A green method for the synthesis of N-substituted 1,8-dioxo-decahydroacridines usingβ-cyclodextrin as a supramolecular reusable catalyst in water

We demonstrate a superficial method for the synthesis of N-substituted 1,8-dioxo-decahydroacridines using β-cyclodextrin as a supramolecular,biodegradable,and reusable catalyst in aqueous medium.The reaction product is in excellent yield with moderate to excellent selectivity.The mechanistic transformation presumably proceeds via a one-pot,multicomponent cyclization of dimedone in the presence of aromatic aldehydes and aromatic amines/INH,undergoing a tandem Michael addition reaction.The proposed approach in this study provides a highly efficient and environmentally benign route to N-substituted 1,8-dioxo-decahydroacridines.

Facile and Stereoselective Synthesis of N-Substituted Benzotriazole with Baylis-Hillman Adducts

A convenient method has been developed toward the stereoselective synthesis of N-substituted benzotriazole derivatives under mild conditions. The good stereolectivity, high yields and the simple procedure make the present protocol attractive.

A new method for the synthesis of N-substituted pyrroles

An unexpected reaction of 10-bromomethyl-12-oxocalanolide A（2） with primary amine was demonstrated and studied. Consequentially,a new method for the preparation of N-substituted pyrroles starting fromγ-halo-α,β-unsaturated ketone was presented.

Synthesis of N-Substituted （Z）-3-（ （2-Benzyl）-4-Ox opent-2-yl） Pyrrole-2,5-Diones （Maleimides）

A series of N-substituted （Z）-3-（（2-benzyl）-4-oxopent-2-yl）pyrrole-2,5-diones were synthesized and characterized. The compounds were synthesized from dimethyl-2-（（Z）-2-（benzylamino）-4-oxopent-2-en-3-yl） fumarate （9） and dimethyl acetylenedi-carboxylate followed by reaction with some amines in refluxing ethanol. The identification of the compounds were based on spectroscopic analysis such as 1R （infrared）, UV （ultraviolet）, ^1H-NMR （nuclear magnetic resonance） and the microanalysis of the elements （CHN （microanalysis）） data.

N-Substituted benzoxazolyl ureas and thioureas in Biginelli reaction promoted by trifluoromethane sulfonic acid:An efficient and convenient synthesis of substituted benzoxazolyl 3,4-dihydropyrimidine(1H)-(thio)-ones

An efficient synthesis of 3,4-dihydropyrimidine 2 （1H）-ones and thiones （3,4-DHPMs） core was prepared by one-pot threecomponent Biginelli condensation and which was catalyzed by trifluoromethane sulfonic acid. The classical BigneUi reaction has been extended by the use of N-substituted benzoxazolyl semicarbazides and thiosemicarbazides and this method has the advantage of excellent yields and short reaction times. ？2009 M. Saranga Pard. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

非光气合成N-取代氨基甲酸酯的研究进展

简述了近年来国内外非光气合成N-取代氨基甲酸酯的主要方法,重点阐述了以CO、碳酸二甲酯、CO2、氨基甲酸烷基酯等为羰基化试剂的合成途径,并对各合成方法的优缺点进行了系统的评述。指出氨基甲酸烷基酯以其毒性低、活性高以及制备简单等优点使其成为合成N-取代氨基甲酸酯最具工业化应用前景的羰基化试剂;而以CO2为羰基化试剂合成N-取代氨基甲酸酯的路线符合当前绿色化学的主题,为CO2的资源化利用提供了新途径,是今后的研究热点。

Synthesis and Tumor Cytotoxicity of Novel N-Substituted Glucosamine-bearing Oleanolic Acid Derivatives

Eleven novel triterpenoid saponins,N-substituted-β-D-glucosaminide derivatives of oleanolic acid,were designed and synthesized via a stepwise glycosylation strategy.These compounds were evaluated for in vitro cytotoxic activity against six different tumor cell lines.Most of the compounds inhibited the growth of,at least,one tumor cell line effectively at micromolar concentrations.Preliminary structure-activity relationships（SARs） indicate that acylation of the nitrogen of the glucosamine-bearing triterpenoid saponins affords the compounds that are highly cytotoxic towards specific tumor cell lines.

Synthesis and Biological Activity of Novel Anthranilic Diamides Containing N-Substituted Arylmethylene Moieties

A series of novel anthranilic diamides containing N-substituted arylmethyl moieties was designed and synthesized, in which the bond distance and conjugation pattern between pyrazole and pyridine rings contained in Chlorantraniliprole were changed. Their structures were confirmed by JH NMR, IR, elemental analysis or high resolution mass spectromentry{HRMS）, and the conformation of compound 4d was confirmed by X-ray diffraction. The preliminary bioassay results indicate that all the target compounds exhibited moderate insecticidal activity against oriental armyworm at 200 mg/L and some of them presented favorable antitumor activities against human lung cancer cells（A549）, liver cancer cells（BelT402） and colon cancer celIs（HCT-8） in vitro by microculture tetrazolium（MTT） method, among which compound 6j afforded the best anti-proliferative activity at 5μg/mL.

Alkali-metal hexamethyldisilazide initiated polymerization on alpha-amino acid N-substituted N-carboxyanhydrides for facile polypeptoid synthesis

Polypeptoids have been explored as mimics of polypeptides,owing to polypeptoids'superior stability upon proteolysis.Polypeptoids can be synthesized from one-pot ring-opening polymerization of amino acid N-substituted N-carboxyanhydrides(NNCAs).However,the speed of polymerization of NNCAs can be very slow,especially for NNCAs bearing a bulky N-substitution group.This hindered the exploration on polypeptoids with more diverse structures and functions.Therefore,it is in great need to develop advanced strategies that can accelerate the polymerization on inactive NNCAs.Hereby,we report that lithium/sodium/potassium hexamethyldisilazide(Li/Na/KHMDS)initiates a substantially faster polymerization on NNCAs than do commonly used amine initiators,especially for NNCAs with bulky N-substitution group.This fast NNCA polymerization will increase the structure diversity and application of polypeptoids as synthetic mimics of polypeptides.

Synthesis of novel fullereneα-amino acid conjugates

Aspartic acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fullero pyrrolidine. The products were deprotected, affording two monofuUerene α-amino acids, monofullerene aspartic acid （mFas） and monofullerene glutamic acid （mFgu）. Then a bifullerene glutamic acid conjugate （bFguC） was synthesized by reaction of mFgu containing protected amino group with N-substituted 3,4-fullero pyrrolidine.

Synthesis, Crystal Structure and Non-covalent Interactions Analysis of Novel N-Substituted Thiosemicarbazone

()*￡-1 -(4-Fluorobenzylidene)^l-(4-ethylphenyl)thiosemicarbazone was synthesized via the reaction of 4-(4-ethylphenyl)thiosemicarbazide and 4-fluorobenzaldehyde. The title compound was characterized by FTIR, and 13C NMR, mass spectrometry and elemental analysis techniques. Structural property of the title compound was displayed by the X-ray single crystal diffraction. The title compound crystallized in triclinic space group Pl witli a=0.6494(4) nm,a=0.7971(5) nm, c=1.5492( 10) nm,a=83.690( 11)°,β=84.185(10)。γ=84.348(11)。molecular formula Ci6H16FN3S,Mr=301.39,V=0.7868(9) nm^3, Z=2, Dc=1.272 g/cm……3,^000)=316,“=0.213 mm-1, 5=1.02, 7?=O.O513, and cw7[Z>2o(Z)]=0.1662. The intennolecular interactions in the crystal structure were explained using the Hirshfeld surface and their associated two-dimensional fingerprint plots. The title compound showed C-H-S(l-x,-y,-z) and NH(1-y,-z) intermolecular interactions, and formed the supramolecular self-assemblies through R2^2(12) and R2^2(8) ring motifs. Shape index and curvediiess were performed to further understand some unique weak interactions, for instance, the weakπ…π stacking contacts in molecular structure witli difierent characteristic regions. Besides, the reduced density gradient(RDG) function provided a real-space function for discussing non-covalent interactions within molecule, such as hydrogen bonds, weak van der Waals interactions and attractive or repulsive effects.

Heteropoly acids of the Keggin type with N-substituted β-amminoethylphosphonic acids as coordinate center

Organophosphorus-heteropolytungstic acids of 1 : 12 of P/W ratio, with N-substituted 2-amminoethylphosphonic acids R2R'N+CH2CH2PO3H- (R = R' = H; R = Me, R' = H; R = R' = Me; R = H, R' = Me2CH; R = H , R' = CH3(CH2)2CH2) as coordinate centers were prepared, and characterized by means of elemental analysis, IR, UV spectroscopy, TG and DSC thermal analysis. The results indicate that these organophosphorous-HPAs possess Keggin type structure, and their stoichiometric formulation is R2R'N+CH2CH2PO3H - ·W12O36 ·nH2O. The organic side chain with the ammino-group R2R'N+CH2CH2- and the phosphono-group-PO3H- participate altogether in the formation of the primary structure of the heteropoly anion. In other words, the entirety of each compound R2R'N+CH2CH2PO3H- is as the core or coordinate center of the heteropoly anions. The number of crystal water in the HPA was affected obviously by the N-substituents of the organo-phosphonic acids.

Highly Efficient One-Pot Synthesis of 2-Arylmethyl N-Substituted Anilines via Yb（OTf）3 Catalyzed Three-Component Reaction

An efficient method has been developed for one-pot three-component coupling reactions of various aldehydes, 1-cyclohexen-2-one, and primary or secondary amines in the presence of a catalytic amount of Yb（OTf）3 under mild conditions to afford the corresponding 2-arylmethyl N-substituted anilines in good yields. In addition, the catalyst was easily recovered and could be reused for at least four cycles without any loss of activity.

Synthesis, Biological Activity and 3D-QSAR Study of Novel Pyrrolidine-2,4-dione Derivatives Containing N-Substituted Phenylhydrazine Moiety

Twenty-seven novel pyrrolidine-2,4-dione derivatives containing N-substituted phenylhydrazine moiety were synthesized. Their structures were confirmed by IH NMR, 13C NMR and MS. The half effective concentration （ECs0） values of the title compounds against the phytopathogenic fungi Rhizoctonia cerealis were evaluated. Com- pounds 61 and 6q displayed good bioactivity with EC50 values of 1.626 and 2.043 μg/mL, respectively. The 3D quantitative structure activity relationship（3D-QSAR） model of CoMFA was established with reliable cross-validated correlation coefficient q2 value of 0.585 and Noncross-validated correlation coefficient r2 value of 0.971. This model provided a tool for guiding further design and synthesis of novel pyrrolidine-2,4-dione derivatives with high fungicidal activity.

Fe-catalyzed regioselective Friedel–Crafts hydroxyalkylation of N-substituted glyoxylamide with indoles

An efficient regioselective Friedel-Crafts hydroxyalkylation of N-substituted glyoxylamide with various indoles catalyzed by Lewis acids was developed. The reactions proceeded smoothly at room temperature and the 2-hydroxy-2-（1H-indol-3-yl）-N-substituted acetamide resulted from the reactions catalyzed by FeSO4 were synthesized in excellent yields （up to 93%）. While the bisindole compounds were obtained when FeCl3 was used as a catalyst in excellent yields （up to 92%）. A possible mechanism was proposed.

Accelerated heterogenous ring-opening polymerization towards well-defined helical poly(N-allyl alanine)with clickable side chains

Well-defined poly(N-allyl alanine)has been synthesized by heterogenous ring-opening polymerization(HROP)of less reactive N-allyl-alanine N-carboxyanhydride,using acetic acid as the catalyst and benzylamine as the initiator,in non-polar n-hexane.Interestingly,the polymerization exhibited typical features of living polymerization though both monomer(liquid)and polymer(solid)have minimal solubility in n-hexane.The obtained polymer showed a stable helix structure independent of the temperatures screened,as evidenced by circular dichroism analysis.Also,the preliminary study demonstrated that the side chains can be post-functionalized through thiol-ene click chemistry with quantitative conversion.Together,this work provides guidance for the development of accelerated HROP of other liquid monomers bearing low reactivity.Besides,the helical and functionalizable poly(N-allyl alanine)could be a useful“clickable platform”for the design of variable biomaterials via efficient click chemistry.

Important Green Chemistry and Catalysis： Non-phosgene Syntheses of Isocyanates - Thermal Cracking Way

Currently, industrial production of isocyanates, or diisocyanates in particular, has been exclusively based on phosgene processes. Phosgene is extremely toxic and large amounts of corrosive HC1 are produced as a side product. In the view of environment protection and society safety, development of non-phosgene processes for isocyanates production will be highly desired, and this should be one of the most important missions for green chemistry and catalysis. In this review, efforts for development of non-phosgene method for syntheses of isocyanates, i.e., catalytic syntheses of N-substituted carbamates from nitro- or amino-compounds with CO, dimethyl carbonate （DMC）, urea and even CO2 etc. as carbonyl sources, then thermal cracking of N-substituted carbamates to afford corresponding i socyanates, are summarized, and a brief prospect for non-phosgene syntheses of isocyanates is also addressed.

METHODS FOR THE SYNTHESIS OF ORGANIC PHOSPHORUS COMPOUNDS WITH ANTI-RADIATION ACTIVITY

The synthesis of anti-radiation active organic phosphorus compounds is an important field in search of radioprotectors.In order to develop new protectors of low toxicity and high potency, more than thirty phosphorus compounds such as dialkylphosphorocyanidates(1), tetraalkylmonothiopyrophosphates(2), N-substituted dialkylphosphoramidates(3) and aminoalkylthiophosphates (4)have been designed and synthesized.

A One-pot Green Synthesis of Alkylidenesuccinimides

A mild and facile Wittig reaction between N-substituted maleimides and aldehydes has been developed. Various synthetically valuable alkylidenesuccinimides were obtained from this one-pot reaction in high yields （up to 99%）. The product was obtained by simple filtration and no extra purification was necessary. Ethanol, an environment-benign solvent, was found to be a suitable reaction medium.