STUDY ON THE INTRAMOLECULAR CVCLIZATION THROUGH OPENING OF EPOXIDE II RING CLOSURE OF N-METHYL-N-BENZOYLMETHYLENE-β-PHENYL-α,β-EPOXYPROPIONAMIDE IN PROTIC SOLVENT

When the title compound was treated in protic solvent with alkali catalyses,γ-lacatam was almost the sole product.The ratio of ketone 1 to ketone 2 depended upon the reaction condition.

Ring-closure Reaction to Novel Quinoline Derivatives and Their Structural Characterization

In the condensation of arylaldehydes with arylethylidenemalononitriles, it was found that, besides the normal product dienes a, the ring-closure product quinoline derivatives b can be also obtained in 26%—50% yields. The substituent effects were also examined and a possible reaction mechanism was proposed for the formation of b. The X-ray crystal structure of 1b confirms the structure of the ring-closure product.

Study on the Intramolecular Cyclization through Openmg of Epoxide IV. Cyclization of N-Methyl-N-benzoylmethylene β-Methyl-α, β- epoxypropionamide in Aprotic and Protic Solvents

Intramolecular cyclization of β -methyl substituted epoxide under aprotics （e.g. LDA in benzene） and protic conditions （e.g. LiOH in MeOH/H2O）both gave a mixture of β-,γ-, δ- and ε-lactam but in different ratio.

Expeditious method for the synthesis of novel 2,3,5,6-tetrahydrobenzo[g] [1,3,5]oxadiazocine-4-thiones linked with isoxazole

Synthesis of novel 3-aryl-5-（3,5-dimethylisoxazol-4-yl）-2,3,5,6-tetrahydrobenzo[g][1,3,5],oxadiazocine-4-thiones 5 has been accomplished from 3,5-dimethylisoxazol-4-amine 1 by condensation with salicylaldehydes, followed by reduction, treatment with aryl isothiocyanates and subsequent smooth ring closure via acetal formation in the presence of formaldehyde.

Design, Synthesis and Activities of Aziridine Derivatives of N^5-Methyltetrahydrofolate Against Methionine Synthase

Aziridine derivatives of N^5-methyltetrahydrofolate were designed and synthesized based on the mechanism of methionine synthase, and their biological activities were investigated as well. The aziridine derivatives 1 and 6 exhibited superior inhibitory activities（IC50：5.05 and 4.15 μmol/L, respectively） compared to the corresponding chain analogue 4（IC55=24.42 μmol/L）. The results suggest that the aziridine derivatives can get potential activities against nucleophilic methionine synthase.

Pseudo four-component and regioselective synthesis of 4-amino-3,5-dicyano-6-arylphthalates using triethylamine catalyst

An efficient triethylamine-catalyzed synthesis of 4-amino-3,5-dicyano-6-arylphthalates is described.A one-pot,simple pseudo four-component reaction between arylaldehydes,dialkyl acetylenedicarboxylates, and twice as much malononitrile gave 4-amino-3,5-dicyano-6-arylphthalates in good to excellent yields.

Decomposition of Al_(13) promoted by salicylic acid under acidic condition: Mechanism study by differential mass spectrometry method and DFT calculation

Decomposition of the polycation Al_(13)O_(4)(OH)_(2)4(H_(2)O)_(12)^(7+)(Al_(13)) promoted by ligand is a vital subject to advance our understanding of natural and artificial occurrence and evolution of aluminum ions,especially in the case of acidic condition that dissolved Al^(3+)species can be released from the Al-bearing substances.However,the microscopic pathway of synchronous proton-promoted and ligand-promoted decomposition process for Al_(13)is still in the status of ambiguity.Herein,we applied differential mass spectrometry method and DFT calculation to study the initial detailed process of Al_(13)decomposition under the presence of proton and salicylic acid (H_(2)Sal).Mass results showed that the mononuclear Al^(3+)-H_(2)Sal complexes dominated the resulting Al species,whereas the monodentate complex Al_(13)HSal6+was not observed in the spectra.The difference of decomposition levels between the ligand/Al ratio 0.2 and 0.5 cases revealed that proton and ligand performed synergistic effect in initial Al_(13)decomposition process,and the proton transfer determined the ring closure efficiency.The ring closure reaction is the prerequisite for the collapse of Al_(13)structure and detachment of the mononuclear complex.DFT calculations reveal that hydrogen bond plays an important role in inducing the formation of chelated complex accompanying proton transfer.Attachment of protons at the bridging OH^(-)can elongate and weaken the critical bond between targeted Al^(3+)and μ4-O_(2)-resulting from delocalization of electron pairs in the oxygen atom.These results demonstrate the detailed mechanism of Al_(13)composition promoted by ligand and proton,and provide significant understanding for further application and control of Al_(13).

Triheterocyclic Thiadiazepine Derivatives of Pharmacological Interest： Synthesis of 2-Aryl-4-[ρ-（2,3-dihydro-5-methyl-2-oxo-1,3,4-oxadiazol-3-yl）phenyl]-6-（u n）su bstituent-1 ＂,2＂ ,4＂- triazolo[3＂,4＂-b]-1 ＇,3＇,4＇-thiadiazepine

Synthesis of novel thiadiazepine derivatives based on the reactivity of 4-acetylphenylsydnone （1） was reported. The structures of the newly synthesized compounds have been proved by their physical, analytical, IR, 1^H NMR, 13^C NMR and mass spectral data.

Rhodium(Ⅲ)-catalyzed chemodivergent annulations between phenyloxazoles and diazos via C-H activation

Acid-controlled,chemodivergent and redox-neutral annulations for the synthesis of isocoumarins and isoquinolinones have been realized via Rh(Ⅲ)-cataIyzed C—H activation.Diazo compounds act as a carbene precursor,and coupling occurs in one-pot process,where adipic acid and trimethylacetic acid promote chemodivergent cyclizations.

Qualitative and quantitative detection of aldehydes in DNA with 2-amino benzamidoxime derivative

An aldehyde-reactive probe based on 2-amino benzamidoxime(ABAO)framework was introduced,which can selectively label aldehydes in DNA through intramolecular ring closure under mild aqueous solutions.We screened ABAO derivatives that can undergo a cyclization with the formylated nucleobases to generate a fluorescence nucleoside,and of these derivatives 5–methoxy-ABAO(PMA)emerged as the optimal choice.PMA can sensitively and selectively react with 5f U,5f C and AP to form fluorogenic dihydroquinazoline derivatives,which also can quantify DNA damages induced byγ-irradiation.PMA-initiated labeling strategy provides great convenience for qualitative and quantitative detection of aldehydes in DNA.

An Efficient Synthesis of [1,2,4]Triazolo[3,2-d][1,5]benzoxazepin-2-thiones, a Kind of Novel Tricyclic O,N-Heterocycles

A series of novel tricyclic O,N-heterocycles, [1,2,4]triazolo[3,2-d][1,5]benzoxazepin-2-thiones 7 were achieved via acid-induced ring closure of the geminal arylazo isothiocyanate compounds 5 which were derived from substituted chroman-4-ones, followed by feasible ring expansion with simultaneous insertion of the nitrogen atom into the carbon skeleton. The X-ray crystal structure of 7d was also described.