Synthesis of 6, 9, 11-Trihydroxy-6a, 12a-dehydrorotenoid

6, 9, 11-Trihydroxy-6a, 12a-dehydrorotenoid 1 (coccineone B) was synthesized from 2-hydroxybenzaldehyde 2 and phloroglucinol.     

SYNTHESIS OF 6-AMINO, 6-METHOXY AND 6-ETHOXY PURINENUCLEOSIDE DERIVATIVES

A convenient route for the conversion of inosine to the corresponding 6-amino, 6-methoxy and 6-ethoxy derivatives is reported. This conversion can be achieved by ammoniation or etherification of the 6-pyridinium intermediate(3) which can be readily produced under mild reaction conditions. The chemistry and characterization of these compounds are presented, A plausible mechanism of the reaction is proposed.     

Pyrolysis Kinetics of Nylon 6–6, Phenolic Resin,and Their Composites

Abstract

A multistep kinetic process is postulated to describe the pyrolysis of nylon 6–6, phenolic CTL-91LD (a phenolic novalac resin), and their composites. Kinetic coefficients are derived from thermogravimetric analysis data (TGA) at heating rates varying from 3–60°C/min for each component. Three correlation techniques are used to obtain consistent coefficients. A two-step kinetic equation is derived to describe the phenolic pyrolysis and a single-step kinetic equation is found to adequately represent nylon 6–6 pyrolysis. These equations are then combined to obtain an overall pyrolysis rate equation for the composite.     

Isomerization of B6, B6 − and B6 + clusters

The interconversions between isomers with the same spin multiplicity of neutral B₆ and charged B₆ ^? and B₆ ⁺ clusters have been investigated at the B3LYP/6-311+G* level of theory, including determination of the minimum energy pathways with transition states connecting the corresponding reactants and products. In dynamic calculations, 26 isomers were optimized, including 11 novel isomers. In order to further refine the energies, single-point B3LYP/6-311+G(3df) calculations were carried out on the corresponding B3LYP/6-311+G* geometries of all isomers of B₆, B₆ ^? and B₆ ⁺ and the corresponding isomerization transition states. The stability of each isomer of B₆ (singlet and triplet states), B₆ ^? (doublet state) and B₆ ⁺ (doublet state) was analyzed from both thermodynamic and dynamic viewpoints.     

Synthesis of 6-chloronicotinates of steroidal 3β,5α,6β-triols and 3β,5-dihydroxy-6-ketones

New esters of 3β,5α,6β-trihydroxysteroids and 3β,5-dihydroxy-6-ketosteroids containing 6-chloropyridine groups characteristic of the alkaloid epibatidine were synthesized by acylation with 6-chloronicotinoylchloride. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 175-179, March-April, 2009.     

Three-Component Reaction of Triphenylphosphine,Acetylenic Esters,and 6-Aminouracil or 6-Amino-N,N′-dimethyluracil

Protonation of the reactive 1:1 intermediate produced in the reaction of acetylenic esters and triphenylphosphine by 6-aminouracil or 6-amino-N,N′-dimethyluracil leads to vinylphosphonium salts, which undergo Michael addition with the conjugate base of the NH acid to produce highly fanctionalized, salt-free phosphorus ylides in excellent yields.     

Ab Initio Study of Prednisolone, 6α-Fluoroprednisolone, 9α-Fluoroprednisolone,and 6α,9α-Difluoroprednisolone

A theoretical study of prednisolone, 6-fluoroprednisolone, 9-fluoroprednisolone, and 6,9-difluoroprednisolone has been performed at the ab initio HF/6-31G, MP2/6-31G, and B3LYP/6-31G levels. Structural information and the electronic features of prednisolone and its derivatives and the synergistic effect of 6,9-difluoroprednisolone was examined. Contrary to the AM1 and MNDO results, we found 9-fluoroprednisolone is more stable than the 6-fluoroprednisolone. The increased corticosteroid activity of the 6,9-difluoroprednisolone is most likely due to electronic effects, mainly related to the receptor binding.     

Acta Polymerica Sinica,2000,No.6

Abstracts No.6,December,2000 RADIATION PREPARATION OF KAPPA-CARRAGEENAN/PVP BLEND HYDROGEL Mao-lin Zhai and Hong-fei Ha Department of Technical Physics,Peking University,Beijing 100871 Fumto Yoshii and Keizo Makuuchi Takasaki Radiation Chemistry Research Establishment,JAERI A series of hydrogels in the form of rods were prepared from Kappa-carrageenan(KC)，N-vinyl pyrrolidone(N-VP)and polyethylene glycol dimethacrylate(14G)by gamma radiation with 60Co γ source at room temperature.The properties of the     

STUDIES ON STEREOSELECTIVE SYNTHESIS OF 4R,6R,4-ACETOXY-6-PENTYLVALEROLACTONE

The title compound has been synthesized from the chiralbuilding block 2 through five steps.     

C60NH5/6, 6/6异构体的理论研究

用半经验的AM1, PM3及ab initio方法对C60NH两种异构体的结构及光谱进行了理论计算。结果表明, 具有开环结构的C60NH的5/6异构体稳定性要高于具有闭环结构的6/6异构体。计算了两种异构体开环与闭环过程的反应坐标, 发现6/6开环异构体是势能面上的一局部最小点, 而5/6闭环异构体不存在6/6异构体的H可以在两种镜面异构体之间快速翻转, 使其核磁共振谱呈现C2v对称性。通过振动分析确认了所优化的构型确实为势能面的能量最低点, 并得到了C60NH各异构体的红外光谱。     

Über das 2, 4, 6-Trichlor-3-Bromphenol und das 2-Chlor-4, 6-Dibromphenol

Ohne Zusammenfassung     

2, 2, 6, 6-四甲基哌啶氧化物催化的高选择性羟基氧化反应

次氯酸钠在2,2,6,6-四甲基哌啶氧化物(TEMPO)的催化下, 可在温和的条件下选择性氧化胆酸类化合物的C3位羟基. 该方法提供了与常规的氧化剂相反的区域选择性, 为胆酸类化合物的结构改造提供了简洁的路线.     

Keyword Index Vol. 6, 1995

Ｋｅｙｗｏｒｄ　Ｉｎｄｅｘ　Ｖｏｌ．６，１９９５ＡＭＩＣＯｍｅｔｈｏｄ（７９７）ＭＰ（８０１）Ａｈｉｎｌｔｌｏｃａｌｃｕｌａｔｉｏｎ（４１１）（４９１）ＡｈＩｎｌｔｌｏｓｔｕｄｙ（９６１）Ａｂｓｏｌｕｔｅｃｏｎｆｉｇｕｒａｔｉｏｎ（７５９）Ａｃｅｔａ...     

Author Index Vol. 6, 1995

Ａｕｔｈｏｒ　Ｉｎｄｅｘ　Ｖｏｌ．６，１９９５ＡｂｌｌｚＺ．（３９５）ＡｎＬ．Ｄ．（３４５）（４４７）ＡｏｋｉＪ．（３９５）ＢａｂａＫ．（３８５）ＢａｌＤ．Ｌ．（１９３）ＢａｌＦ．Ｌ．（２０１）ＢａｌＪ．（９０３）ＢａｔＪ．Ｆ．（８２３）ＢａｌＴ．（...     

SYNTHESIS AND EVALUATION OF A NEW PHOTOSTABILIZER—2, 2, 6, 6-TETRAMETHYL-4-PIPERIDINYL SALICYLATE FOR POLYMERS

A new photostabilizer--2,2,6,6-tetramethyl-4-piperidinylsalicylate (TMPS) has been syn-thesized by ester-exchange reaction between 2,2, 6, 6-tetramethyl-4-piperidinol and methylsalicylate.The photostabilizing effect of TMPS and Tinuvin 770, PDS on the photodegradation of cis-1,4-polybutadiene has been investigated for comparison. The results observed show that the mosteffective stabilizer of the three is TMPS. The reason of the good photostabilizing effect of TMPSwas discussed by fluorescence spectra.     

Molecular and Crystal Structure of 2, 3, 5, 6-dipropylene-r-pyrone

11NTRODUCT1ONWeattemptedtosynthesizeanextractant(1)bythereactionofadipylchloridewithcyclopentanonepiperidineenamineaccordingtoHunig'sprocedure"',however,wemainlyobtainedthetitlecompound,whichmaybepossiblyapotentialmedicinet2'3i.Itsmolecularstructurewasfinallyconfirmedbythesingle-crystalstructuredeterminationafterconventionalUV,IR,lHNMR,MSandelementana-lyticalworks.2EXPER1MENTALSECT1ON2.1SynthesisToastirredsolutioncontaining8Omlofchloroform,2.8mloftri-ethylamineand1.51g(O-Olmol)…     

2, 3, 4, 5, 6-五苯基苯甲醛的新合成途径

从四苯基环戊二烯酮与乙二醇缩肉桂醛通过干法在260-270℃直接加成并脱CO,接着经氧化、水解制备了2,3,4,5,6-五苯基苯甲醛,对目标产物的结构进行了^1HNMR,IR,UV-Vis和元素分析表征。在对反应中间产物进行分离、鉴定的基础上提出了该反应的可能途径。     

Asymmetric Synthesis of （S）-Dimethyl -4, 4＇-dimethoxy-5, 6, 5＇, 6＇-dimethenedioxybiphenyl-2, 2＇-dicarboxylate

(S)-Dimethyl-4, 4‘-dimethoxy-5, 6, 5‘, 6‘-dimethenedioxy-biphenyl-2, 2‘-dicarbonylate was synthesized in reasonable yield through a series of reactions, including chiral oxazolinemediated asymmetric Ullmann coupling, from methyl 2-bromo-5-methoxy-3, 4-methenedioxybenzoate.     

Metal complexes of phytohormones. Part IV. Interactions of tetrakis-μ-acetato dirhodium(II) with 6-furfurilaminopurine, 6-benzylaminopurine, 6-furfurilaminopurine riboside and 6-benzylaminopurine riboside

Summary Interactions of tetrakis--acetato-dirhodium(II) with purine-derived ligands of biological interest such as the cytokinins 6-furfurilaminopurine (K), 6-benzylaminopurine (BAP), 6-furfurilaminopurine riboside (KR) and 6-benzylaminopurine riboside (BAPR) have been studied by means of magnetic susceptibility measurements at room temperature, i.r. and electronic spectroscopy and thermogravimetric analysis 11 metal:ligand adducts were obtained with all ligands; in addition 12 adducts were obtained with KR and BAPR. The most plausible structure for the 11 adducts is a polymeric bridging one, involving both axial positions of the Rh^II dimer and two N-sites of the purine moiety; for the 12 adducts only one N-site is involved.     

3, 6-二芳基-5, 6-二氢均三唑[3, 4-b][1, 3, 4]噻二唑的合成 及生物活性

研究了在L-(+)-酒石酸存在下3-芳基-4-氨基-5-巯基-1,2,4-均三唑与醛的Mannich反应及分子内的加成反应,合成了15个新的手性稠杂环化合物3,6-二芳基-5,6-二氢均三唑[3,4-b][1,3,4]噻二唑,利用IR、^1HNMR和MS确证了其结构,并测试了部分化合物的生物活性。