N-1,3,4-噻二唑-2-基取代Schiff碱的合成及光学性质研究

本文以对甲苯磺酸为催化剂,通过2-氨基-5-烃基-1,3,4-噻二唑与水杨醛的反应合成了一系列N-1,3,4-噻二唑-2-基取代Schiff碱类化合物2,利用IR,1H NMR,13C NMR和元素分析表征了化合物的结构。采用紫外光谱和荧光光谱研究了化合物的光谱性能,结果表明,所合成的化合物2具有较强的荧光发射光谱,λem为554～573 nm。     

一锅法合成4-(5-芳基-1,3,4-噻二唑-2-氨甲基)苯酚衍生物

以2-氨基-5-芳基噻二唑衍生物和对羟基苯甲醛为原料,经亲核加成/脱水、还原两步一锅法合成了一系列新的4-(5-芳基-1,3,4-噻二唑-2-氨甲基)苯酚衍生物,反应具有时间短、后处理简单等优点.采用元素分析,NMR,IR以及质谱等多种谱学技术对产物进行了详细表征.     

Synthesis of N-pyrimidin[1,3,4]oxadiazoles and N-pyrimidin[1,3,4]-thiadiazoles from 1,3,4-oxadiazol-2-amines and 1,3,4-thiadiazol-2-amines via Pd-catalyzed heteroarylamination

An efficient and practical procedure was developed to prepare various N-pyrimidin[1,3,4]oxadiazole and thiadiazole scaffolds using a Buchwald-type coupling. The products of this reaction are otherwise difficult to access and could be used as building blocks in drug design.     

Electrochemical oxidation of substituted catechols in the presence of pyrazol-5-ones: characterization of products and reaction mechanism

The electrochemical oxidation of substituted catechol derivatives has been investigated in the presence of pyrazol-5-ones as C-H acid nucleophiles by using constant current technique in acetate buffer solution. The results indicate that different reaction mechanisms are involved and not only 1,4-Michael adducts but also 1,6-Michael adducts are formed, depending on the nature of the starting catechols and the nucleophiles, as well as the reaction conditions.     

芳醛-[5-(3,4,5-三甲氧基苯基)-1,3,4-噻二唑-2-巯基]-乙酰腙衍生物的合成及生物活性研究

采用活性基团拼接法, 以2-巯基-5-(3,4,5-三甲氧基苯基)-1,3,4-噻二唑为原料, 经硫醚化、肼解、腙化反应合成了8个芳醛-[5-(3,4,5-三甲氧基苯基)-1,3,4-噻二唑-2-巯基]-乙酰腙衍生物, 并经过元素分析, IR, ¹H NMR, ¹³C NMR对其结构进行了确认. 初步生物活性测试表明, 部分化合物具有一定的抑菌生物活性.     

N-(5-三氟甲基-1,3,4-噻二唑-2-基)-N'-芳酰基脲的合成、晶体结构及生物活性

通过2-氨基-5-三氟甲基-1,3,4-噻二唑与芳酰基异氰酸酯反应, 合成了10种新的芳酰基脲．它们的结构经元素分析、红外光谱、核磁共振氢谱进行了表征．并用X射线单晶衍射法测定了化合物2j的晶体结构, 结果表明, 该化合物晶体属三斜晶系, 空间群为P-1, a＝0.54191(15) nm, b＝0.7766(2) nm, c＝1.7161(5) nm, α＝98.668(5)°, β＝95.103(5)°, γ＝101.070(5)°, V＝0.6955(3) nm³, Z＝2, D_c＝1.653 g/cm³, F(000)＝352, μ＝0.289 mm^–1．初步的生测试验结果表明一些目标化合物具有良好的植物生长调节活性．     

[5-(芳氧乙酰氨基)-1,3,4-噻二唑-2-基]硫乙酸乙酯的合成及生物活性研究

以2-氨基-5-巯基-1,3,4-噻二唑和氯乙酸乙酯为原料,水相快速合成中间体(5-氨基-1,3,4-噻二唑-2-基)硫乙酸乙酯,该中间体再与芳氧乙酰氯反应,高产率得到6种目标化合物[5-(芳氧乙酰氨基)-1,3,4-噻二唑-2-基]硫乙酸乙酯(5a-5f)。所有这些化合物都经过了红外、元素分析以及核磁共振氢谱的表征。采用离体平皿法对目标化合物进行了除草活性试验,部分化合物显示出良好的除草活性,而小麦对其耐受。     

A simple and efficient approach for the synthesis of a novel class aliphatic 1,3,4-thiadiazol-2(3H)-one derivatives via intramolecular nucleophilic substitution reaction

In this study, we synthesized a new series of substituted aliphatic 1,3,4-thiadiazol-2(3H)-one derivatives (6-24) in yields ranging from 42 to 70% with an interesting mechanism that involves internal nucleophilic substitution followed by an S_N2-type nucleophilic substitution. First, 1-(4-chlorophenyl)-2-((5-methyl-1,3,4-thiadiazol-2-yl)thio)ethanone (3) was synthesized from the reaction of 5-methyl-1,3,4-thiadiazole-2-thiol (1) with 2-bromo-1-(4-chlorophenyl)ethanone (2) in the presence of potassium hydroxide. Then, 1-(4-chlorophenyl)-2-((5-methyl-1,3,4-thiadiazol-2-yl)thio)ethanol (4) was synthesized by a reduction reaction of this compound using NaBH₄. Finally, 5-methyl-3-alkyl-1,3,4-thiadiazol-2(3H)-one derivatives (6-24), which are the target compounds, were synthesized from the reaction of this compound (4), which is a secondary alcohol with various alkyl halides (5a-n) in the presence of sodium hydride (NaH). This study presents an interesting reaction mechanism related to the synthesis of aliphatic 1,3,4-thiadiazol-2(3H)-one derivatives that is not recorded in the literature.     

2-芳基-5-(4-硝基苯甲酰氨基)-1,3,4-噻二唑的合成

以芳甲酰肼和对硝基苯甲酰氯为主要原料, 合成出了10个酰氨基硫脲化合物5a～5j, 其中有6个(5d, 5f～5j)为新化合物. 在无需任何酸性催化剂条件下, 将制得的酰氨基硫脲在DMF中加热回流直接脱水关环合成出了9个2-芳基-5-(4-硝基苯甲酰氨基)-1,3,4-噻二唑化合物6a～6i, 其中7个(6b～6d, 6f～6i)为新化合物. 利用IR和1H NMR证明了化合物5存在两种异构体. 目标产物的结构通过IR, 1H NMR和元素分析进行了表征.     

N-[5-(4-三氟甲基苯基)-1,3,4-噻二唑-2-基]-N′-芳酰基脲的合成、结构及其生物活性

通过2-氨基-5-(4-三氟甲基苯基)-1,3,4-噻二唑与芳酰基异氰酸酯反应, 合成了14种新的芳酰基脲, 它们的结构用红外光谱、核磁共振氢谱和元素分析进行了表征, 并且采用X-射线单晶衍射分析方法测定了化合物2l的结构．初步的生物活性试验表明, 部分标题化合物具有优良的植物生长调节活性.     

Synthesis, Crystal Structure and Biological Activity of N-(2,6-Difiuorobenzoyl)-N'-[5-(4-trifiuoromethylphenyl)-1,3,4-thiadiazol-2-yl] ure

The title compound N-(2,6-difluorobenzoyl)-N'-[5-(4-trifluoromethylphenyl)-1,3,4-thiadiazol-2-yl]urea(C17H9F5N4O2S, Mr = 428.34) has been synthesized by the reaction of 2-amino-5-(4-trifluoromethylphenyl)-l,3,4-thiadiazole with 2,6-difluorobenzoyl isocyanate, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 10.7316(13), b = 10.5617(13), c = 16.037(2) (A), β =106.408(2)°, V= 1743.6(4) (A)3, Z = 4, Dc = 1.632 g/cm3, μ = 0.260 mm-1, F(000) = 864, the final R = 0.0599 and wR = 0.1420 for 3467 observed reflections with I ＞ 2o(Ⅰ). The urea group, which adopts a planar configuration mediated by the intramolecular N-H…O hydrogen bond, is nearly coplanar with the thiadiazole and 4-trifluoromethylbenzene rings. The title compound was found to exhibit good fungicidal activity against Rhizoctonia solani and Botrytis cinerea.     

3-(5′-乙氧基-1,3,4-噻二唑-2′-亚甲氨基)-2-氰基-3-取代-丙烯酸酯类化合物的合成、晶体结构及生物活性

采用氰基丙烯酸酯与5-乙氧基-1,3,4-噻二唑-2-甲氨在乙醇中加热回流的方法合成了一系列3-(5′-乙氧基-1,3,4-噻二唑-2′-亚甲氨基)-2-氰基-3-取代-丙烯酸酯类化合物.目标化合物结构均经1HNMR和元素分析确证.生物活性测试结果表明,部分化合物对双子叶杂草油菜和苋菜显示出较好的除草活性及良好的选择性,用化合物6j在600g/ha剂量下对油菜和苋菜茎叶进行处理,抑制率仍达100%和95.2%,与对照样B相当;氰基丙烯酸酯3位取代基体积对除草活性影响较大,3位为异丙基时活性最高.     

Microwave-Assisted Synthesis of Propesticides 1,3,4-Thiadiazole Aminophosphonates

A novel and easy synthetic route to diethyl (5-substituted phenyl-1,3,4-thiadiazol-2-ylamino) (substituted phenyl) methylphosphonates has been achieved by the reaction of substituted benzylidene-5-(substituted phenyl)-1,3,4-thiadiazol-2-amines and diethyl phosphite under microwave irradiation. These 1,3,4-thiadiazole aminophosphonates were identified by infrared, ¹H NMR, and elemental analyses. The target compounds were obtained in better yields (71–89%) and shorter time (10 min) than with conventional heating.

The Effect of 2-Mercapto-5-Methyl-1,3,4-Thiadiazole on Enzymatic Synthesis of Cefazolin

The effect of unreacted residual 2-mercapto-5-methyl-l,3,4-thiadiazole (MMTD), the reagent for 3-[5-methyl-l,3,4-thiadiazole-2-yl]-7-aminocephalosporanic acid (M-7-ACA) synthesis, on the enzymatic acylation of M-7-ACA by the methyl ester of 1,2,3,4-tetrazol-1-acetic acid (MeTzAA) to produce cefazolin (CEZ) was studied. In the two-step process of synthesizing CEZ from 7-aminocephalosporanic acid (7-ACA), one of the key parameters controlling the overall CEZ yield was the ratio of MMTD to 7-ACA in M-7-ACA synthesis. The increase of the ratio showed opposing effects by increasing the M-7-ACA yield in the first step, while decreasing CEZ yield in the subsequent enzymatic reaction by the inhibitory effect of the increased content of MMTD as an impurity in the M-7-ACA preparation. It was revealed that the decrease of CEZ yield in the enzymatic reaction was caused by the selective retardation of the rate of CEZ synthesis reaction by a typical competitive inhibition, while not affecting the rate of MeTzAA hydrolysis reaction. The optimum MMTD-to-7-ACA ratio rendering the highest overall CEZ yield over 7-ACA was 1.2:1.     

AMT异构体互变机理的理论研究

用密度泛函理论(DFT)的B3LYP/6-311G(d, p)和Müller-Plesset微扰理论的MP2/6-31G(d)方法，优化了AMT(2-氨基-5-巯基-1,3,4-噻二唑)各种异构体和过渡态结构的几何构型，并对它们的电子结构、振动光谱和化学键性质进行了研究.还研究了AMT异构体的互变机理，提出了AMT异构体abcda的循环式互变途径.进一步完成了对AMT异构体成键方式的自然键轨道(NBO)分析.     

含嘧啶取代1,3,4-噁二唑(噻二唑)硫醚化合物的合成及抗菌活性研究

以2-甲基-4-氨基-5-氰基嘧啶为原料,通过水解、酯化、肼解、环化和醚化等步骤,合成了12个含1,3,4-噁二唑(噻二唑)取代嘧啶化合物。通过₁H NMR,₁₃C NMR,MS 和元素分析进行确证其结构。初步抑菌活性测试标明,化合物浓度在50 μg/mL时,化合物6f和6f′对油菜菌核病菌(S. sclerotiorum)、马铃薯晚疫病菌(P. infestans)、水稻纹枯病(T. cucumeris)、小麦赤霉病菌(G. zeae)具有中等抑制率,其活性与对照药剂醚菌酯相当。     

2-取代硫醚-5-脱氢松香基-1,3,4-恶二唑/噻二唑类化合物的合成及生物活性

以脱氢松香酸为原料,经酯化、肼解、关环和亲核取代反应得到了2-取代硫醚-5-脱氢松香基-1,3,4-恶二唑和2-取代硫醚-5-脱氢松香基-1,3,4-噻二唑类化合物。通过IR、MS、1H NMR和元素分析对产物进行了表征。初步生物活性检测结果表明,所有目标化合物都表现出一定的除草活性。     

Chemoselective one-pot synthesis of 2-phenylamino-5-alkylthio-1,3,4-thiadiazole derivatives from phenylthiosemicarbazide and CS2

A novel and fairly efficient chemoselective one-pot method has been developed for the synthesis of both 2-phenylamino-5-alkylthio-1,3,4-thiadiazole and bis-(2-phenylamino-5-alkylthio-)1,3,4-thiadiazole derivatives from phenylthiosemicarbazide and CS₂.     

Synthesis of 4,5-Dihydro-1,3,4-thiadiazole-2-carboxamide and 2-Carbamoyl-4,5-dihydro-1,3,4-thiadiazole 1-Oxide Derivatives Based on Hydrazones of Oxamic Acid Thiohydrazides

We have developed a method for obtaining derivatives of 4,5-dihydro-1,3,4-thiadiazole-2-carboxamide by acylation of hydrazones of oxamic acid thiohydrazides. Oxidation of the dihydrothiadiazole ring of the indicated products by hydrogen peroxide leads to formation of 2-carbamoyl-4,5-dihydro-1,3,4-thiadiazole 1-oxides.     

5-氟代苯基糠酰胺的1,3,4-噻二唑衍生物的合成与除草活性测定

设计并合成了20种N-(5-芳基-1,3,4-噻二唑-2-基)-5-氟代苯基糠酰胺类化合物, 均为未见文献报道的新化合物. 目标产物的结构经IR, 1H NMR和元素分析测定确证. 初步生物活性测试表明标题化合物具有一定的除草活性.