Reaction of lithium acetylides with car-3-ene-2,5-dione

The reaction of car-3-ene-2,5-dione (1), an oxidation product of (+)-car-3-ene, with lithium acetylides proceeds stereospecifically, but not regioselectively, to give only mixtures of regioisomeric acetylenic alcohols with thesyn-orientation of the hydroxy group. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 183–185, January, 1998.     

Palladium-catalyzed [3+2+1] cyclocarbonylative coupling of 1,3-cyclohexanediones, alkynes, and carbon monoxide: an atom-economic route to chromene-2,5-dione derivatives

3,4,7,8-Tetrahydro-2H-chromene-2,5(6H)-dione derivatives were efficiently synthesized with excellent selectivity via a [3+2+1] cyclocarbonylative coupling of 1,3-cyclohexanediones, terminal alkynes, and CO catalyzed by Pd(PPh₃)₄.     

Amino-terminated poly(ethylene glycol) as the initiator for the ring-opening polymerization of 3-methylmorpholine-2,5-dione

Block copolymers with poly[3-methylmorpholine-2,5-dione] (PMMD) and poly[ethylene glycol] (PEG) blocks, PMMD-b-PEG-b-PMMD, were synthesized via ring-opening polymerization of 3-methylmorpholine-2,5-dione with amino-terminated PEG as the initiator at 140 °C within 10 h. Three kind of amino terminated PEG with different average molecular weight were used. The block copolymer was amorphous and the glass transition temperature decreased with increase of PEG block in the copolymer.     

(3S,6S)-及(3S,6R)-3-苄氧甲基-6-甲基-吗啉-2,5-二酮的 制备及其晶体结构

以2-溴丙酸和N-叔丁氧羰基-O-苄基-L-丝氨酸为起始试剂首先制得N-(2-溴丙基)-O-苄基-L-丝氨酸(BPBS), 在N,N-二甲基甲酰胺(DMF)/三乙胺(Et3N)溶剂中80 ℃经9 h后BPBS发生分子内环化反应生成(3S,6S)-3-苄氧甲基-6-甲 基-吗啉-2,5-二酮[(3S,6S)-BMMD]及(3S,6R)-BMMD共存体, 产率70%. 将所制得的共存体以乙酸乙酯为重结晶溶剂, 采用微分重结晶法, 经4次“溶解-部分重结晶”操作循环制得两种纯光学构型的(3S,6S)-BMMD和(3S,6R)-BMMD. 将两种光学纯双手性中心的BMMD分别溶于乙酸乙酯, 室温下培养得(3S,6S)-BMMD和(3S,6R)-BMMD的单晶体, 以X射线衍射法测定上述两种BMMD的分子结构.     

Photochromic Dihetarylethenes. 8. A Novel Route to the Synthesis of 3,4-Bis(2,5-dimethyl-3-thienyl)furan-2,5-dione as a Potential Photochrome

There is proposed, and in the case of 2,5-dimethylthiophene carried out, a novel route to the synthesis of 3,4-dithienylfuran-2,5-dione type photochromes. This is done in two stages, the first being a Friedel-Crafts reaction of the starting thiophene with the dichloride of squaric acid and the second is a Baeyer-Villiger oxidation of the 3,4-bis(2,5-dimethyl-3-thienyl)cyclobutenedione to give the target 3,4-bis(2,5-dimethyl-3-thienyl)furan-2,5-dione.     

2-Aminopyrrole-2,5-diones 2. Vinyl nucleophilic substitution of the alkylamino group in 1-alkyl-3-alkylaminopyrrole-2,5-diones by arylamines

In vinyl nucleophilic substitution (S_N vin) with the hydrochlorides or 4-toluenesulfonates of primary arylamines 1-alkyl-3-alkylaminopyrrole-2,5-diones form the corresponding 1-alkyl-3-arylaminopyrrole-2,5-diones, which are also produced in situ from the corresponding arylaminofumarates and primary alkylamines. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 668–675, May, 2008.     

Synthesis and Infrared Spectra Computation of Sterically Congested 2,2-Disubstituted Indane-1,3-dione Derivatives

Sterically congested 2,2-disubstituted indane-1,3-dione derivatives have been syn-thesized and characterized by 1H NMR,13C NMR,FT-IR and elemental analysis.The B3LYP/HF calculations for computation of IR spectra have been carried out for the title compounds at the 6-31G and 6-311++G basis set levels.Predicted vibrational frequencies have been assigned and compared with the experimental FT-IR spectra and they are supported each other.     

Crystal and molecular structure of <Emphasis Type="Italic">E</Emphasis>-3-(1,3-dimethylindol-2-yl)methylene-4-isopropylidenetetrahydrofuran-2,5-dione

The crystal and molecular structure of E-3-(1,3-dimethylindol-2-yl)methylene-4-isopropylidenetetrahydrofuran-2,5-dione, C₁₈H₁₇NO₃ (I), was investigated by XRD. The monoclinic structure of I (space group P2₁/c, a = 12.411(2) Å, b = 7.586(1) Å, c = 16.107(3) Å, β = 96.90(2)°, Z = 4) was solved by direct methods and refined by the full-matrix least squares in an anisotropic approximation to R = 0.044 for all 2842 independent reflections collected (CAD-4 automatic diffractometer, λCuK _α). The geometric parameters of sterically strained molecule I were determined with a high accuracy.     

苯甲酰-1,3-环己二酮类化合物互变异构的理论计算

对苯甲酰-1,3-环己二酮的各异构体进行了HF/6-31G＊水平的几何优化,然后对能量低的三酮式和2个顺式烯醇式异构体进行了更广泛的计算,探讨了计算方法、基组大小对异构体相对稳定性的影响。在此基础上,对该类化合物的互变异构化平衡常数、能垒进行了计算,在平衡常数的计算中充分考虑了溶剂的影响并结合实验结果进行了分析。最后,对有代表性的苯环2-位取代衍生物进行了计算,发现互变异构自由能与其HPPD酶抑制活性间存在着较好的相关关系。     

Synthesis and characterization of inexpensive 3-Nɛ-benzyloxycarbonyl-L-lysyl-morpholine-2,5-dione

In this paper, we call 3-N^ɛ-benzyloxycarbonyl-L-lysyl-morpholine-2,5-dione “Compound A”. The starting material used abroad is expensive and the yield is low (16%–28%); furthermore, to our best knowledge, no characterization of Compound A is available in the open literature. We now use low-cost L-lysine as starting material, succeed in raising the yield of Compound A to about 66%, and characterize it. In the synthesis of Compound A, the reactive processes used by us included the protection of amino group of lysine, acetylation, and intramolecular cyclizative condensation reaction. Benzoxycarbonyl chloride was selected as amino group protection agent, and the yield was elevated by replacing sodium bicarbonate with triethyl amide as the acid’s neutralizer. The resulting material or Compound A was cyclizative; its structure and properties were characterized by infrared (IR), Differential Scanning Calorimetry (DSC), Nuclear Magnetic Resonance (NMR) and elemental analysis. The results of characterization show that: (1) Compound A has a chiral carbon next to the carbonyl group, so the formation of the ring structure is not sterospecific; (2) the melting point is about 254.5°C. The homopolymer and copolymers of Compound A with lactide or caprolactone have reaction-active groups and excellent biocompatibility and biodegradability; so they can be used in tissue engineering and as controlled-drug-release carriers. Translated from Journal of Northwestern Polytechnical University, 2006, 24(4): 444–447 (in Chinese)     

Synthesis and reactivity of pyrrolo[3,2-d][1,3]oxazine-2,4-dione. Access to new pyrrolo[3,2-e][1,4]diazepine-2,5-diones

A convenient synthesis of pyrrolo[3,2-d][1,3]oxazine-2,4-dione 4 is described and its reactivity towards various nucleophiles studied. The regioselective ring opening of anhydride 4 or its N-alkylated analog 25 in the presence of alanine or proline afforded, respectively, imidazolidinedione 22 and N-protected pyrrolo[3,2-e][1,4]diazepines 30 and 31 in a one-pot process. In a last part of this study, an alternative route to produce a library of eight non protected pyrrolo[3,2-e][1,4]diazepine-2,5-diones 35a–h is described to overcome the limited reactivity of anhydride 4.     

离子液体中5,5-二甲基-1,3-环己二酮与N-芳亚甲基芳胺反应合成 吖啶衍生物

在离子液体[bmim]Br中, 5,5-二甲基-1,3-环己二酮与N-芳亚甲基芳胺反应合成了一系列四氢吖啶-1,8-二酮衍生物, 该反应具有适应性广、产率高、污染少、环境友好等优点.     

吲哚-2,3-二酮衍生物抗病毒活性研究进展

吲哚-2,3-二酮是一种广泛存在于天然产物中的化合物,基于其结构特点可以发生不同类型的反应,为其衍生物的合成提供了便利的条件,因此目前其合成和活性的研究备受关注.本文对近年来吲哚-2,3-二酮衍生物抗病毒活性研究情况进行了综述,分别介绍了对HIV、痘病毒、SARS病毒、柯萨奇病毒B3和烟草花叶病毒的抑制活性.重点介绍了吲哚-2,3-二酮衍生物对HIV病毒的作用以及对HIV病毒进入人体破坏人体的免疫功能后容易感染的细菌和结核病的作用.     

CuCl／SiO2-Al2O3催化剂的表面结构及甲醇氧化羰基化催化性能

通过掺杂Al对无定形层析硅胶进行表面改性,采用固体离子交换法制备了CuCl/SiO2-Al2O3催化剂,并考察了它在甲醇液相氧化羰基化合成碳酸二甲酯反应中的催化性能.结果表明,掺杂Al制备的SiO2-Al2O3载体仍保持了硅胶的无定形结构,比表面积降为200m2/g,但表面酸性明显增强,具有B酸中心.CuCl不仅分散于SiO2-Al2O3载体表面,而且与载体表面的B酸发生离子交换作用形成了表面Cu 物种,使催化剂比表面积降为148m2/g,且两种Cu 物种共同构成了催化活性中心.当CuCl/SiO2-Al2O3催化剂的Si/Al比为5,在500℃焙烧时,催化剂上甲醇氧化羰基化反应的碳酸二甲酯的选择性和时空收率分别达到74%和1.27g/(g.h).     

1,1,3,3,3-Pentafluoro-2-pentafluorophenyl-1,2-epoxypropane and trimethylphosphite: unusual 1,4-dioxan-2,5-dione ring formation

1,1,3,3,3-Pentafluoro-2-pentafluorophenyl-1,2-epoxypropane 1 reacted with trimethylphosphite giving two diastereomers, (Z)- and (E)-3,6-bis(trifluoromethyl)-3,6-bis(pentafluorophenyl)-1,4-dioxan-2,5-dione 2a, b in a 1:1 ratio, cyclodimerisation product of the intermediately generated α-lactone 4. Compounds 2a, b were hydrolysed to furnish 3,3,3-trifluoro-2-hydroxy-2-(2,3,4,5,6-pentafluorophenyl)propionic acid 5.     

Reaction of 2,3-Dihydro-1,5-benzothiazepines and Phenylacetyl Chloride in the Presence of Triethylamine： A New Aspect on the Formation Mechanism of Dihydro-1,3-oxazin-4-one Derivatives

2a,4-Disubstituted 2,2a,3,4-tetrahydro-2-phenyl-1H-azeto[2,1-d][ 1,5]benzothiazepin-1-ones, as well as 2-substi-tuted 2,3-dihydro-3-phenylacetyl-2-styryl-benzothiazoles and 4a,6-disubstituted 3- .benzyl-4a,5-d/hydro-2-phenyl-1H,6H-[1,3]oxazino[2,3-d][1,5]benzothiazepin-1-ones, were obtained from the reaction of 2,4-disubstituted 2,3-dihydro-1,5-benzothiazepines with phenylacetyl chloride in the presence of triethylamine. The mechanism for the formation of 4a,5-dihydro-1H,6H-[1,3]oxazino[2,3-d][1,5]benzothiazepin-1-ones, 2,3-dihydro-1,3-oxazin-4-one derivatives, was suggested.     

Synthesis and characterization of novel conjugated polymers based on 3-cyclobutene-l,2-dione moiety

Three novel conjugated polymers bearing 3,4-bis(4-hexylthiophen-2-yl)-3-cyclobutene-1,2-dione unit in their main chain have been synthesized successfully in good yields through Suzuki or Stille coupling reaction.Their molecular structures have been confirmed by FT-IR,~1H NMR and ~(13)C NMR.All these copolymers exhibit broad and strong absorption bands in UV-vis region,and their optical band gaps are calculated to be 1.6-2.0 eV.suggesting that they have good coverage with the solar spectrum.These polymers...     

2,2-亚戊基-1,3-二氧六环-4,6-二酮与原甲酸三乙酯和芳香胺的反应

剂,在有机合成中已有一定应用。开展Meldrum's 酸系列化合物的研究,旨在:1.寻找有结构特点的新试剂,2.合成一系列新化合物,3.研究新化合物的应用。本文通过控制反应温度(28～29℃)催化剂用量(比文献用量多近一倍),提高了2,2-亚戊基-1,3-二氧六环-4,6-二酮(PDDO,3)的制备得率(由15%     

A domino protocol for the efficient synthesis of structurally diverse benzothiazolylquinoline-2,5-diones and their spiro analogues

Structurally diverse benzothiazolylquinoline-2,5-diones and their spiro analogues have been synthesized by an environmentally benign efficient and convenient synthetic method involving sulfamic acid catalyzed one-pot four-component reaction of Meldrum acid, 2-aminobenzothiazoles, dimedone, and isatin/carbonyl compound.