Synthesis of 4＂-benzyloxyimino-4＂-deoxyavermectin B 1 a derivatives

Six new 4＂-benzyloxyimino-4＂-deoxyavermectin B la derivatives were synthesized from avermectin Bla by the selective protection of C-5-hydroxy group, oxidation of C-4＂-hydroxy group, and deprotection followed by reaction with O-substituted hydroxylamine hydrochlorides. Their structures were confirmed by IR, 1H NMR, 13C NMR and MS. Insecticidal activities of the derivatives against Phopalosiphum pseudobrassicae, Spodoptera exigua and Pluteua xylosteua were evaluated.     

Synthesis and antibacterial activity of brominated 2′(4′)-nitro-3-hydroxy diphenyl ethers

Eight new brominated 2′(4′)-nitro-3-hydroxy diphenyl ethers have been designed and synthesized.The structures of new compounds were confirmed by ~1H NMR,IR and HRMS.The bioactivity tests showed that these compounds possessed antibacterial activities against the tested bacteria.These new compounds cannot be transformed into dioxins when they were manufactured and used.     

Synthesis and in vitro antitumor activity of 1,3,4-thiadiazole derivatives based on benzisoselenazolone

A series of novel 1,3,4-thiadiazole derivatives based on benzisoselenazolone were synthesized and evaluated for their cytotoxicity in vitro against human liver cancer cell SSMC-7721,human breast cancer cell MCF-7 and human lung cancer cell A549 by CCK-8 assay.The results showed mat compounds 7e,7f,7h,7k,71 and 7m displayed good cytotoxicity against MCF-7 cell lines.Compound 71 exhibited the most potent antitumor activities among the tested compounds.     

Synthesis and bioactivity of N-tert-butyl-N′-acyl-5-methy 1-1,2,3-thiadiazole-4-carbohydrazides

A series of novel N-tert-butyl-N′-acyl-5-memyl-l,2,3-thiadiazole-4-carbohydrazides were designed and synthesized.Their structures were characterized by melting points,~1H NMR,IR,ESI-MS,and elemental analysis.The bioassay tests indicated that compound 7o exhibited excellent direct anti-TMV activity and induction activity in vivo at 50μg/mL,which was better than that of Ninamycin and tiadinial.Our studies indicated that 1,2,3-thiadiazole was an active substructure for novel pesticide development.     

Synthesis,Characterization and X-ray Structure of N-(4-bromobutanoyl-N’-(2-3- and 4-methylphenyl)thiourea

N-4-(bromobutanoyl)-N'-(o-, m- and p-tolyl)thioureas 3a, 3b and 3c respectively, were synthesized by the reaction of 4-bromobutanoylisothiocyanate with p-, m- and o-toludine. The products were characterized by IR, and NMR spectroscopic techniques. The two carbonoylthiourea isomers N-(4-bromobutanoyl)-N'-(3-methylphenyl)thiourea(3b) and N-(4-bromobutanoyl)-N'-(4-methylphenyl)thiourea(3c) were obtained in crystalline form by recrystallization from DMSO. Xray crystallographic studies showed that both compounds 3b and 3c crystallize in triclinic system with space group of P1. The molecules adopt trans-cis configuration with respect to the positions of 4-bromobutanoyl and tolyl groups respectively, against the thiono C=S bond across their C–N bonds. The configuration is attributed by the intrahydrogen bond between the carbonyl oxygen and amide hydrogen atoms. Both crystal structures are stabilized by N–H···S intermolecular hydrogen bonds to form dimers and arranged along the b axis.     

微波辐射合成4,4′,4″-三硝基三苯胺

以对硝基苯胺(1)和4-氯硝基苯(2)为原料,二甲基亚砜为溶剂,叔丁醇钾为缚酸剂,氟化钾和四甲基氯化铵为催化剂,在微波辐射下合成了4,4′,4″-三硝基三苯胺(3),其结构经IR表征.正交实验确定最佳反应条件为:13 mmol,n(1)∶n(2)∶n(叔丁醇钾)=1∶3∶2,在125 W下,于130℃反应30 min,3的收率达98.2%.     

Synthesis and Characterization of Novel 4-Methyl-3-isoxazolidinone Derivatives

IntroductionSulfonylureas, as inhibitors of acetohydroxyacidsynthase(AHAS), are a class of herbicides that areused for crop protection. They are used for lowconcen-tration ranges(10—100 g of active ingredient/ha) andare advanced herbicides used in agricu…     

Synthesis and biological activity of new avermectin 5-O- and 4″-O-acyl derivatives

Acylation of avermectin B₁ with vicinal 1,2-dicarboxylic acid anhydrides leads only to 5-O-acyl derivatives in high yields. Avermectin 4″-O-acyl derivatives were obtained under similar conditions from avermectin B₁ 5-O-TBS-derivatives in good yields. The compounds obtained are of interest as antiparasitic agents.     

Ruthenium(Ⅲ) chloride as an efficient catalyst for the synthesis of perimidine derivatives under mild conditions

Various biologically important perimidine derivatives have been synthesized efficiently from various ketones and naphthalene1,8-diamine by using a catalytic amount of RuC13 (1 mol%). This method is a very simple and high yielding reaction for the synthesis of perimidine derivatives.     

Synthesis of 4-Aminosalicylglycine

To search for a better prodrug of 4-aminosalicylic acid that is expected to deliver stably parent drug to colon against the inflammatory bowel disease, a novel 4-aminosalicylic acid derivative was designed and synthesized from 4-aminosalicylic acid. 4-Aminosalicylglycine was prepared from 4-aminosalicylic acid by protecting amino and hydroxyl groups with benzyloxycarbonyl and acetyl, respectively, then the carboxylic acid was converted to acyl chloride which was treated with glycine. After removing the protection groups, 4-aminosalicylglycine wasobtained. All the compounds were characterized by FT-IR, ^1H-NMR, ^13C-NMR spectra. In vivo experiment on rats suggested that the curative effect of 4-aminosalicylglycine was more effective than that of 4-aminosalicylic acid.     

Synthesis of azo derivatives of 4-aminosalicylic acid

For searching a better 4-aminosalicylic acid derivative with higher activity and less side effects against the inflammatory bowel disease, 4-aminosalicylic acid (4-ASA) was protected by benzyloxycarbonyl and acetyl, respectively. The resultant was hydrogenized to remove protective group of amino group, then the product was reacted with NaNO2 to give diazonium salt, which was conjugated with salicylic acid, hydroxybenzene, TV-salicyloyl glycine acid to get azo derivatives of 4-ASA. The azo derivatives were hydrolyzed under the alkaline condition to get the target products. All compounds were characterized by FT-IR, 1H NMR, 13C NMR spectra in details. New derivatives of 4-ASA were characterized. The synthetic route was reasonable and feasible.     

Synthesis of Hydroxylated Sterols(Ⅱ)--Synthesis of 24-Methylenecholest-4-en-3β,6α-diol

In our study on the soft coral,Alcyonium patagonicum,a new hydroxylated sterol,24-methylenecholest-4-en-3β,6α-diol(1) exhibiting a potent activity to murine leukemia cells(IC50=1 μg/mL) has been isolated[1] and synthesized[2,3].As a part of our studies on the relationship between the chemical structure and the biological activity of the hydroxylated sterols,the synthesis of 24-methylenecholest-4-en-3β,6α-diol(2) is reported here.     

Synthesis and biological activities of(E)-β-farnesene analogues containing 1,2,3-thiadiazole

In order to discover novel compounds with high-activity to control aphid,a series of novel(E)-β-farnesene analogues containing 1,2,3-thiadiazole were designed and synthesized,and their structures were confirmed by IR,~1H NMR,~(13)C NMR,and HRMS(ESI).The stability of representative compounds was studied by HPLC and ~1H NMR techniques.Repellent activity results indicated that compounds 8h and 8j displayed 60.3%and 62.0%repellent rates,respectively.The aphicidal bioassay results showed that most analogues exhibited considerable aphicidal activity against Myzus persicae.Especially,analogues 81,8s and 8t exhibited high activity with LC_(50) values of 33.4 μg/mL,50.2 μg/mL and 61.8 μg/mL,respectively,which were higher than the lead compound(E)-β-farnesene,but lower than commercial insecticide pymetrozine with a LC_(50) of 7.1 μg/mL     

6′，6″-二吡啶基-2，2′：4′，4″：2″，2′′′-四联吡啶稀土配合物的合成、表征及荧光性质研究(英)

Two series of solid complexes of rare earth nitrates and picrates with the “back-to-back” terpyridine, 6′,6″-bis(2-pyridyl)-2,2′:4′,4″:2″,2′′′-quaterpyridine (L) have been synthesized. These complexes have been characterized by elemental analysis, conductivity measurements, thermal analysis and IR spectroscopy. At the same time, the luminescent properties of the Eu(Ⅲ) and Tb(Ⅲ) complexes were also studied.     

三苯甲醇-4,4′,4″-三羧酸及其氯化物的合成

以4溴甲苯为原料,合成了几种三芳基甲烷衍生物:三甲苯甲醇(TTMO)、三苯甲醇-4,4＇,4″-三羧酸(TOTA)、三苯基氯甲烷-4,4＇,4″-三羧酸(TCITA);利用红外光谱仪、核磁共振谱仪及元素分析仪表征了合成产物的结构和组成.结果表明,将4-溴甲苯与镁条在四氧呋喃中反应,可得到对甲苯基溴化镁;对甲苯基溴化镁随后与碳酸二乙酯反应,可得到TTMO;TTMO经硝酸氧化得到TOTA;TOTA与乙酰氯反应得到TCITA.     

三苯甲醇-4,4′,4″-三羧酸及其氯化物的合成

以4-溴甲苯为原料,合成了几种三芳基甲烷衍生物:三甲苯甲醇(TTMO)、三苯甲醇-4,4′,4″-三羧酸(TOTA)、三苯基氯甲烷-4,4′,4″-三羧酸(TClTA);利用红外光谱仪、核磁共振谱仪及元素分析仪表征了合成产物的结构和组成.结果表明,将4-溴甲苯与镁条在四氢呋喃中反应,可得到对甲苯基溴化镁;对甲苯基溴化镁随后与碳酸二乙酯反应,可得到TTMO;TTMO经硝酸氧化得到TOTA;TOTA与乙酰氯反应得到TClTA.     

Synthesis of 4″O,5O-bis(2-amino-2-thioxoacetyl)ivermectin derivatives

Reaction of 4″O,5O-bis(chloroacetyl)ivermectin with amines in the presence of sulfur provided the corresponding bis(2-amino-2-thioxoacetyl) derivatives that are potential antiparasitics.

     

Synthesis of two mono-deoxy β-cyclodextrin derivatives as useful tools for confirming DIBAL-H promoted bis-de-O-methylation mechanism

Diisobutylaluminium hydride(DIBAL-H) promotes secondary rim regioselective bis-de-O-methylation of permethylatedβ-cyclodextrin (β-CD) to give diol 2.To gain an insight into the mechanism of this remarkable regioselective behavior,two corresponding permethylatedβ-CDs with an alcohol function at either 2- or 3-position were synthesized in our previous study.As a step further to this work,the two compounds were subjected to deoxygenation reaction with tributyltin hydride in the present of 2,2’- azobisisobutyronitrile affording the corresponding 2- and 3-deoxy permethylatedβ-CD derivatives(19 and 16).The structures of these two compounds were characterized by ID and 2D NMR and HRMS.Compounds 16 and 19 were unable to react with DIBALH which suggests that O-2~A and O-3~B are necessary for DIBAL-H promoted bis-de-O-methylation reaction of permethylatedβ-CD.     

Synthesis of naphthalene derivatives through inexpensive BF3·Et2O-catalyzed annulation reaction of arylacetaldehydes with arylalkynes

An inexpensive BF3·Et2O-catalyzed annulation reaction of arylacetaldehydes with arylalkynes has been developed. Various substituted phenylacetaldehydes and phenylacetylenes can undergo this reaction, producing corresponding α-aryl substituted naphthalene derivatives. Use of inexpensive and readily available BF3 ·Et2O catalyst constitutes the most attractive advantage of this transformation.     

Synthesis and Quantum Chemistry Study of Novel Bifurazano [3,4-b : 3′, 4′-f] furoxano [3″, 4″-d] oxacyclohetpatriene

以3,4-双(4′-硝基呋咱-3′-基)氧化呋咱为原料,设计并合成了新型双呋咱并[3,4-b∶3′,4′-f]氧化呋咱并[3″,4″-d]氧杂环庚三烯(1),收率50.1％,其结构经13C NMR,15N NMR,IR,MS和元素分析表征.最佳的反应条件为:以无水碳酸钠为催化剂,乙腈(含水量0.04％)为溶剂,于80℃反应3.5h.用B3LYP方法在6-31G**基组水平上对1的结构进行了计算,得到了稳定的几何构型和键级.在振动分析的基础上求得体系在不同温度下的热力学性质,得到了温度对热力学性能影响的关系式.1的性能研究表明,1的m.p.92℃～94℃,爆速8 256m·s-1(1.85 g·cm-3),摩擦感度0％(90°摆角),撞击感度12％(10 kg,25 cm),特性落高H50 =57.5 cm(5 kg).