(S)-(-)-5-对苄氧基苄基-2,4-噁唑烷二酮的合成

L-酪氨酸经O-苄基化和重氮化反应得到关键中间体--手性3-(对苄氧基苯基)-α-羟基丙酸(4); 4经酯化、氨化和环化反应合成了(S)-(-)-5-对苄氧基苄基-2,4-噁唑烷二酮,总收率10%, 95.4%e.e.,其结构经1H NMR和HR-MS表征.     

3-(吗啉吡啶基)-5-取代异噁唑类化合物的合成及抗菌活性研究

以6-氯-3-吡啶甲醛为原料, 通过多步反应合成了一系列3-(吗啉吡啶基)-5-取代异噁唑类化合物, 并用IR, 1H NMR, 13C NMR和MS进行了结构确证. 这些化合物均以异噁唑为母核, 具有近似的平面结构, 在异噁唑环的3-位引入吗啉吡啶基, 而在5-位引入酯基、取代氨基、三唑环和噁唑烷酮环. 研究了这些化合物对金黄色葡萄球菌、耐甲氧西林金黄色葡萄球菌、表皮葡萄球菌、粪肠球菌和大肠杆菌的抑制活性, 发现与噁唑烷酮类上市药物利奈唑胺相比, 目标化合物均显示出更低的抗菌活性, 最低抑制浓度(MIC)大于32 mg/L, 这些试验结果表明异噁唑母核的5-位缺乏sp3杂化结构, 可能会导致抗菌活性的显著降低.     

2-芳基-5-(6-哒嗪酮-3-基)-1,3,4-噁二唑的合成

1,4,5,6-四氢-6-哒嗪酮-3-甲酰肼(1)和1,6-二氢-6-哒嗪酮-3-甲酰肼(2)与芳香醛反应得到相应的芳香醛腙3a～3g和5a～5g, 再将3a～3g, 5a～5g在溴的作用下, 合环得到一系列1,3,4-噁二唑的衍生物4a～4g和6a～6g. 化合物的结构经1H NMR, IR, MS和元素分析得以证实.     

手性2-噁唑烷酮的无溶剂合成法

手性2-噁唑烷酮的无溶剂合成法;手性氨基醇;脲;手性噁唑烷酮     

5-(3′-芳基-5′-噁唑烷酮基甲氧基)-3(2H)哒嗪酮类化合物的合成及生物活性

5-(3′-芳基-5′-噁唑烷酮基甲氧基)-3(2H)哒嗪酮类化合物的合成及生物活性;芳基噁唑烷酮基甲氧基哒嗪酮;合成;生物活性     

手性5-异丙基-2-噁唑烷酮的酶催化立体选择性互补合成

以2-异丙基环氧乙烷为底物,氰酸钠为亲核试剂,筛选获得两种卤醇脱卤酶HheA10和HheG,可以分别催化合成(S)-5-异丙基-2-噁唑烷酮和(R)-5-异丙基-2-噁唑烷酮。通过对其反应条件进一步考察,建立了立体选择性互补合成手性5-异丙基-2-噁唑烷酮的生物催化技术路线。      

3-取代胺甲基-5-连三唑基-1,3,4-噁二唑-2-硫酮的合成

2-苯基-1,2,3-三唑-4-甲酰肼(1)在CS_2/KOH作用下环化得到5-(2-本基-1,2,3-连三唑-4-基)-1,3,4-噁二唑-2-硫酮(2),2经Mannich反应合成得到标题化合物3-取代胺甲基-5-(2-本基-1,2,3-连三唑-4-基)-1,3,4-噁二唑-2-硫酮(3)。     

新型2-(2,2,3,3-四甲基环丙基)噁唑啉的合成

2,2,3,3-四甲基环丙烷甲酸和手性氨基醇经酰化反应制得6个N-β-羟基烷基酰胺(3a～3f)。以DDQ/PPh3为羟基活化剂,3a～3f经分子内脱水环合合成了6个2-(2,2,3,3-四甲基环丙基)噁唑啉,其结构经1 H NMR,13 C NMR,IR和HR-MS表征(其中5个为新化合物)。     

5-(4-氟苯基)-1,3,4-噁二唑-2-巯基乙酰腙类化合物的合成、表征及生物活性

以4-氟苯甲酸为原料,经过酯化、肼解、关环生成5-(4-氟苯基)-1,3,4-噁二唑-2-硫酮,再与溴乙酸乙酯、水合肼反应得到中间体2-[(4-氟苯基)-1,3,4-噁二唑-2-硫基]-乙酰肼,最后中间体酰肼与取代苯甲醛在冰乙酸中回流得到一系列含有1,3,4-噁二唑环的乙酰腙类化合物。目标化合物结构经元素分析、IR、1H NMR、ESI-MS得到确证,并通过K-B纸片法初步测定了它们的生物活性。结果表明,部分化合物具有一定的抑菌活性。     

2-[2-(4, 6-二甲基)-嘧啶基]-4-苯基-1, 2, 4-恶二唑烷-3, 5-二酮的合成

异氰酸苯酯和N-[2-(4, 6-二甲基)-嘧啶基]-羟胺(5)反应生成1-[2-(4, 6-二甲基)-嘧啶基]-1-羟基-3-苯基脲(6)。化合物(6)在三乙胺存在下和氯甲酸乙酯反应生成2-[2-(4, 6-二甲基)-嘧啶基]-4-苯基-1, 2, 4-恶二唑烷-3, 5-二酮(1)。     

Facile Synthesis of Enantiomerically Pure 1-（5-Bromo-2-chlorophenyl）-1-（4-ethoxyphenyl）ethane

A facile 7-step procedure for the synthesis of enantiomerically pure 1-（5-bromo-2-chlorophenyl）-1-（4-ethoxyphenyl）ethanes[（R）-2 and（S）-2] that started from （5-bromo-2-chlorophenyl）（4-ethoxyphenyl）methanone 3 was developed.The key step was the resolution of 2-（5-bromo-2-chlorophenyl）-2-（4-ethoxyphenyl）acetic acid 6 by crystallizations of its L-and D-menthyl esters 7 and 8 from petroleum ether to give optically pure enantiomers 9 and 10,respectively.The absolute configurations of the products were unambiguously determined by single-crystal X-ray diffractions of four key intermediates,9,10,13 and 14.This procedure is characterized by inexpensiveness,scalability and ability to produce two individual enantiomers of a diarylethane with unambiguously determined absolute configurations and high enantiomeric purities.     

Synthesis and Crystal Structure of （4S）-5-（2-Methoxy-2-oxoethylamino）-5-oxo-4-（3,4,5-trimethoxybenzamido） Pentanoic Acid

1 INTRODUCTION Aminopeptidase N (APN), a member of mem- brane-bound zinc-dependent exopeptidase, is known to be high expression on the brush border membran- es of the small intestine and renal proximal tubules[1]. The over-expression of APN has been involved in several pathological conditions including cancer[2], leukemia, diabetic nephropathy[3], rheumatoid arth- ritis[4], angiogenesis[5] and central nervous system di- seases, such as Alzheimer’s disease[6]. This has led to the sear…     

Design, synthesis, and 1,3-dipolar cycloaddition of (5R)- [and (5S)]-5,6-dihydro-5-phenyl-2H-1,4-oxazin-2-one N-oxides as chiral (E)-geometry-fixed alpha-alkoxycarbonylnitrones

Optically pure (5R)- [and (5S)]-5,6-dihydro-5-phenyl-2H-1, 4-oxazin-2-one N-oxides [(5R)- and (5S)-2] were designed as chiral (E)-geometry-fixed alpha-alkoxycarbonylnitrones 1. The nitrones (5R)- and (5S)-2 were synthesized by three-step oxidation of (R)- and (S)-phenylglycinols [(R)- and (S)-3], condensation of the resulting (R)- and (S)-2-hydroxylamino-2-phenylethanols [(R)- and (S)-5] with glyoxylic acid, and cyclization of the intermediary nitrones (R)- and (S)-6b. The nitrone (5R)-2reacted with olefins 7-14 under mild conditions to afford the corresponding cycloadducts 15-22 as the main products via the least sterically demanding exo modes. Cycloadduct 30 obtained from (5S)-2 and cyclopentadiene was effectively elaborated to (1S,4S, 5R)-4-benzyloxycarbonylamino-2-oxabicyclo[3.3.0]oct-7-en-3-one (28), the key synthetic intermediate of carbocyclic polyoxin C.     

Synthesis of (R)-5-(2′-pentyl)barbituric acid derivatives of high optical purity

Natural (R)-(+)-pulegone ( 1 ) was converted to 3-methylhexanoic acid ( 4 ) by a sequence which precluded racemization. Conversion of this to malonic esters 8 , 5 , and 11 permitted the synthesis of pentobarbital ( 6 ) secobarbital ( 12 ), thiopental ( 9 ), thiamylal(10 ), and 5-(2′-pentyl)barbituric acid ( 7 ), all having the ( R )-configuration in the side chain.     

(5R,6R)-6-苯基-5-(苯磺酰基乙酰基)二环[2.2.1]-2-庚烯的合成及结构表征

报道了一种制备4-苯基-1-苯磺酰基-3-丁烯-2-酮的新合成方法. 4-苯基-3-丁烯-2-酮与溴化试剂Ph₃P^＋CH₂CH₂- COOHBr 作用, 得到1-溴-4-苯基-3-丁烯-2-酮, 不经分离直接与苯亚磺酸钠发生亲核取代反应, 得到4-苯基-1-苯磺酰基-3-丁烯-2-酮. 将此反应产物作为亲双烯体与环戊二烯在手性钛金属催化剂催化下进行不对称Diels-Alder反应, 得到了＞99% ee 的环加成产物(5R,6R)-6-苯基-5-(苯磺酰基乙酰基)二环[2.2.1]-2-庚烯. 用X衍射法对产物的晶体结构进行了测定, 讨论了反应机理, 通过元素分析, NMR, MS对产物的结构进行了表征.     

Synthesis of α-(aminomethylene)-9-(methoxymethyl)-9H-purine-6-acetic acid derivatives

α-(Aminomethylene)-9-(methoxymethyl)-9H-purine-6-acetamide and the ethyl acetate, 3 and 8 , have been synthesized by catalytic hydrogenation of 6-cyanomethylene-9-methoxymethylpurine derivatives 2 and 7 which were obtained by the substitution of 6-chloro-9-(methoxymethyl)purine ( 1 ) with α-cyanoacetamide and ethyl cyanoacetate, respectively. Substitution of 3 and 8 with amines gave the corresponding N-substituted α-(aminomethylene)-9-(methoxymethyl)-9H-purine-6-acetamide and the ethyl acetate 4 and 10 . Reaction of 3 with piperidine gave 9-(methoxymethyl)-9H-purine-6-acetamide ( 5 ).     

The reaction of (4R,5R)- and (4S,5S)-4,5-epoxy-2(E)-hexenoates and secondary amines.

A reaction of methyl (4R,5R)-4,5-epoxy-2(E)-hexenoate 1 with N-benzylmethylamine gave a diastereomerically pure methyl (4R,5R)-4,5-epoxy-(3S)-N-benzylmethylamino hexanoate 6 and methyl (4S,5R)-4-N-benzyl-methylamino-5-hydroxy-2(E)-hexenoate 7. The former was chemoenzymatically converted to (-)-osmundalactone 11, which is an aglycone of osmundalin. On the other hand, the directly conjugated addition of dimethylamine to methyl (4S,5S)-4,5-epoxy-2(E)-hexenoate 1 followed by treatment with MeOH at 40 degrees C exclusively provided methyl (4R,5S)-4-dimethylamino-5-hydroxy-2(E)-hexenoate 16, which was converted into L-(-)-forosamine 18.     

α-B-Keggin型杂多化合物K~5H[Co~4(VW~9O~3~3)~2]·5H~2O的 合成和结构

合成了新化合物K~5H[Co~4(VW~9O~3~3)~2]·5H~2O,并运用IR,UV-Vis,DTA和单晶X射线衍射对其结构进行了表征。测定结果证实标题化合物具有α-B-Keggin型结构,两个(VW~9O~3~3)^7^-结构单元由四个Co(Ⅱ)O~6八面体连接。杂多化合物属单斜晶系P2~1~/~n,a=1.2307(3)nm,b=2.1250(4)nm,c=1.5817(3)nm,β=91.86(3)°,V=4.1343(14)nm^3,R=0.0895,R~W=0.2180。     

The parent of 2-(4,5-dihydro-1H-tetrazol-5-ylidene)-2-cyanoacetate: Synthesis and reactivity X-ray structure of (E)2-[1-(2,2-dimethylpropyl)-4,5-dihydro-1H-tetrazol-5-ylidene]-2-cyanoacetate

Reaction of 3,3-diazido-2-cyanoacrylate 5 with four moles of ammonia gives tetrazolyl-bisammonium salt 7 . The key-intermediate is the amino-vinyl azide 6 which spontaneously undergoes a 1,5′ ring-closure reaction followed by double deprotonation. Treatment of 7 with hydrochloric acid yields the parent of 2-(4,5-dihydro-1H-tetrazol-5-ylidene)-2-cyanoacetate 9 (R = Me, Et) as the only tautomer. Regiospecific monoalkylation of bisammonium salt 7a with dimethyl sulfate and reaction of ammonium salt 12 with hydrochloric acid gives (E)2-(1-methyl-4,5-dihydro-1H-tetrazol-5-ylidene)-2-cyanoacetate ( 13 ) (X-ray structure of derivative 14 ). Compound 13 can also be obtained from vinyl azide 10 and methylamine. This experiment as well as AM1 calculations of 9a, 23 and 24 strongly favour tautomer 9a .     

Synthesis and Crystal Structure of 5-（p-Toly1）-4- [2-（2,4-dichlorophenoxy）acetamido]-l,2,4- triazole-3-thione Ethyl Acetate Solvate

A novel compound 5-（p-tolyl）-4-[2-（2,4-dichlorophenoxy）acetamido]-1,2,4-tria zole- 3-thione 2a has been synthesized by the reaction of 5-（p-tolyl）-4-amino-1,2,4-triazole-3-thione 1 with 2-（2,4-dich/orophenoxy）acetyl ch/oride. Interestingly, the title compound 2 was obtained when 2a crystallizes from a mixed solution of petroleum ether and ethyl acetate, and it has been characterized by elemental analysis, IR, ^1H NMR spectra and single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 9.780（5）, b = 10.876（6）, c = 11.615（6） /A, a = 104.822（7）, β= 94.105（6）, ）, = 94.305（6）°, V= 1185.7（11）/A3, Z = 2,μ = 0.397 mm^-1, Mr= 497.39, Dx= 1.393 g/cm^3, F（000） = 516, S = 1.097, the final R = 0.0730 and wR = 0.2133 for 4111 unique reflections （Rint = 0.0525） with 3212 observed ones. The dihedral angles made by the triazole ring with the methyl- and chloro-substituted benzene rings are 43.5（7） and 50.2（9）°, respectively. Some intra- and intermolecular hydrogen bonds together with C-H…π interactions existing in the lattice stabilize the crystal structure.