硼中子捕获疗法中使用的1,2-C2B10H12异腈衍生物的结构和电子特性

利用密度泛函方法在B3LYP/6-31G(d)水平上对1,2-C2B10H12的两种异腈类衍生物的结构特性进行了研究. 结果表明, 1,2-C2B10H11NC的活性较强; 1,2-C2B10H11NC和1,2-C2B10H11CH2NC可以通过结构中的C4原子与过渡金属原子成键而形成碳硼烷异腈金属配合物. 1,2-C2B10H11NC和1,2-C2B10H11CH2NC的分子极性均比1,2-C2B10H12的弱, 这不利于它们在硼中子捕获疗法中的应用.     

The Chemistry of Vicinal Diamines

Especially in the field of enantioselective synthesis , vicinal diamines (1,2-diamines) 1 and compounds easily prepared from them—such as 1,2-bisimines, 1,2-diamides, or imidazolidin-2-ones—are widely used by organic chemists. Various strategies have been developed to produce these compounds selectively. Many natural products and medicinal agents also contain a 1,2-diamino unit.     

1,2-Diarylethylenediamines as fluorogenic reagents for catecholamines

Twenty-eight 1,2-diarylethylenediamines were investigated in a search for highly sensitive fluorogenic reagents for catecholamines (norepinephrine, epinephrine and dopamine). They all react with epinephrine used as a model catecholamine under mild conditions (pH 6.5–6.8, 37–50°C) in the presence of potassium hexacyanoferrate (III) to produce fluorescence. Of the compounds tested, 1,2-bis(3,4-dimethoxyphenyl)ethylenediamine, 1,2-bis(4-methoxyphenyl)ethylenediamine and 1,2-bis (4-ethoxyphenyl)ethylenediamine, all in the meso-form, are the most sensitive for all the catecholamines. 1,2-Diphenylethylenediamine, 1,2-bis(4-methoxyphenyl)ethylenediamine and 1,2-bis (4-methylphenyl) ethylenediamine in the dl-form are more sensitive to dopamine than the corresponding compounds in the meso-form. Catecholamines can be determined at concentrations as low as 10–15 pmol ml^?1 by using those compounds as reagents. The reactions of other catechol compounds are reported. Other types of biologically important compounds do not interfere.     

二硅烯化合物顺反异构化过渡态动力学参数的计算

本文介绍了过渡态理论对双键取代物顺反异构化过程的处理方法. 计算了1,2-二叔丁基-1,2-二(2,4,6-三甲苯基)二硅烯、1,2-二[二(三甲硅基)]-氨基-1,2-二(2,4,6-三甲苯基)二硅烯和1,2-二甲基-1,2-二苯基二硅烯等化合物的顺反异构化的活化熵变和相应过程的Arrhenius A因子. 前两个化合物的计算结果与West的实验值符合得很好. 后一个化合物, 尚未见到动力学实验结果的报道. 本文指出了这类化合物构型熵贡献的重要性.     

Functionalization of Heterocycles through 1,2-Metallate Rearrangement of Boronate Complexes

Over the last decade, 1,2-metallate rearrangement of boronate complex has been dominating the literature of organoboron chemistry for the construction of very important C−C and C−boron bonds. Owing to the coordinative unsaturated nature of the boron atom, a nucleophile can attack on boron center for the formation of a boronate complex, which triggers 1,2-migration under electrophilic activation at the α-carbon. Apart from using stochiometric electrophilic activating reagents, several catalytic methods using transition metals in the presence or absence of light have been reported. The 1,2-migration of boronate complexes allows synthesis of many different classes of racemic and chiral compounds including a wide range of substituted heterocycles. Synthesis of chiral and achiral substituted heterocycles by using 1,2-metallate rearrangement of boronate complexes has been extensively reported by several groups owing to its prevalence in medicinal chemistry. This minireview highlights the methods known to date for the synthesis of heteroaryls by using 1,2-migration of boronate complexes, organized in a chronological manner.     

Theoretical determination of chromophores in the chromogenic effects of aromatic neurotoxicants

We report the first computational study of the chromophores responsible for the chromogenic effects of aromatic neurotoxicants containing a 1,2-diacetyl moiety in their oxidation metabolites. A series of ab initio electronic structure calculations was performed on two representative aromatic compounds, 1,2-diacetylbenzene (1,2-DAB) and 1,2-diacetyl tetramethyl tetralin (1,2-DATT), the putative active metabolites of the neurotoxic aromatic hydrocarbon compounds 1,2-diethylbenzene (1,2-DEB) and acetyl ethyl tetramethyl tetralin (AETT), and on the products of their possible reactions with proteins that result in chromogenic effects. The electronic excitation energies determined by three different computational approaches were found to be consistent with each other. The calculated results are consistent with the conclusion/prediction that the chromogenic effects of 1,2-DAB (or 1,2-DEB) and 1,2-DATT (or AETT) could result from ninhydrin-like reactions, rather than the formation of pyrrole-like compounds. Our pK(a) calculations further indicate that the chromophore, i.e., the product of the ninhydrin-like reaction showing the blue color, is deprotonated in neutral aqueous solution. The corresponding protonated structure has a different color as it absorbs in the blue region of the visible spectrum, and its chromogenic contribution would be significant in solution at low pH.     

1,2-Thio group migration in Rh(II) carbene reactions

[reaction: see text] A series of beta-thio group substituted alpha-diazo carbonyl compounds have been prepared by nucleophilic substitution reactions of thiophenol, thionaphthol, or benzyl mercaptan with beta-acetoxy-alpha-diazo carbonyl compounds. The diazo decomposition of these diazo carbonyl compounds with various transition metal catalysts, including Rh(II) carboxylates and Cu(I) and Cu(II) complexes, has been investigated. It was found that the diazo decomposition of these compounds gave 1,2-thio group migration products. No 1,2-hydride or 1,2-aryl migration products were observed in all cases.     

Improvement in the detection of impurities affecting ethylene glycol UV transmittance by gas chromatography-mass spectrometry

A method was developed for the detection of trace impurities affecting ethylene glycol UV transmittance, using gas chromatography-mass spectrometry in the selective ion monitoring mode. Four 1,2-cyclopentanediones were identified in commercial ethylene glycol as well as in several ethylene glycol plant streams, including 3-methyl-1,2-cyclopentanedione, 3,5-dimethyl-1,2-cyclopentanedione, 3,4-dimethyl-1,2-cyclopentanedione and 3-ethyl-1,2-cyclopentanedione. Quantification of the first three compounds was achieved by monitoring the molecular ion. This method requires no sample preparation and can detect the compounds of interest as low as 0.1 microg ml(-1). As a simple and rapid method, it can be used in tracing these 1,2-cyclopentanediones in glycol plants.     

β-Chlorocinnamonitriles in a New Synthesis of 3-Functionally Substituted 6-amino-1,2-Dihydropyridin-2-ones

β-Chlorocinnamonitriles react with methylene-active compounds containing N-substituted carboxamide group in DMSO solution in the presence of potassium hydroxide, forming 3-functionally substituted 1,2-dihydropyridin-2-ones.     

Metal Hydrogen Sulfates M(HSO4)n: As Efficient Catalysts for the Synthesis of Quinoxalines in EtOH at Room Temperature

A convenient method for the synthesis of quinoxalines catalysed by metal hydrogen sulfates by the reaction of 1,2‐diamino compounds and 1,2‐dicarbonyl compounds in ethanol as solvent at room temperature is reported.     

Conformational and vibrational analysis with the aid of normal coordinate calculations

Many organic compounds exist as equilibrium mixtures of two or more molecular conformations, and vibrational spectroscopy can be used to obtain information about the structure of those conformations. Normal coordinate calculations are often an aid to those conformational studies and to making vibrational assignments for the different conformers. However, sometimes those calculations are partially inconclusive, and a few results are briefly discussed in which both conclusive and inconclusive results were obtained from calculations. Calculations are then applied to some 1,2-dichloro- and 1,2-dibromo-alkanes. Previous calculations on 1,2-dichloropropane and 1,2-dichlorobutane are revised, and calculations are reported for 1,2-dibromopropane, 1,2-dibromopropane-d₆, and 1,2-dibromobutane. Spectra are given for the last two of these compounds. A modified valence force field was determined for each family of 1,2-dihaloalkane that should be transferable to other members of the family.     

Chiral ligand exchange micellar electrokinetic chromatography using borate anion as a central ion

Three compounds having 1,2-diol structure (1-phenyl-1,2-ethanediol, 3-phenoxy-1,2-propanediol, and 3-benzyloxy-1,2-propanediol) were enantioseparated by ligand exchange MEKC using (5S)-pinanediol (SPD) as a chiral selector and borate anion as a central ion together with SDS. When (S)-1,2-propanediol, (S)-1,2,4-butanetriol, or (S)-3-tert-butylamino-1,2-propanediol were used as the chiral ligand instead of SPD, these three compounds were not enantioseparated. When borate was replaced with 2-aminoethane-1-sulfonate or N-cyclohexyl-3-aminopropanesulfonate, no chiral separation was achieved. Therefore, the hydrophobic interaction between the chiral selector and the chiral analytes within the transient diastereomeric complex may play an important role in the enantioseparation achieved by the proposed method.     

反-1,2-双[2-(5-取代苯基恶唑基)]环丙烷的合成与光性能的研究

本文合成了8个反-1,2-双[2-(5-取代苯基恶唑基)]环丙烷和2个1,2-双[2-(5-取代苯基恶唑基)]乙烷,其中9个为新化合物。讨论了化合物的结构与其电子光谱及荧光量子产率间的关系。我们发现恶唑环与三元环间存在一定程度的共轭,并解释了上述化合物荧光量子产率较低的现象。     

Etude du comportement d'organometalliques (M = Zn,Mg, Li) vis a vis d'enynes conjuges : I. Cas des carbures: HCCC(R)C(R)(R); influence de la structure sur la reactivite et la regioselectivite

Reactive organometallic compounds such as allyl-zinc, -magnesium, -lithium and saturated lithium compounds are shown to readily undergo addition reactions with conjugated enynes: HCCC(R)C(R)(R), but the reactivity is reduced when the steric hindrance around the double bond is increased. With each organometallic compound used, this reaction is regioselective: 3,4 addition with organozinc compounds, 1,2 addition with organolithium compounds (allyl, butyl) and both 1,2 and 1,4 addition with organomagnesium compounds.     

On Condensation Reactions of Aceanthrene Quinone: Novel Heterocycles

Summary.  It was found that aceanthrene quinone can be condensed with ethylenediamine, 1,2-diaminobenzene, 4-nitro-1,2-diaminobenzene, 1,2-diaminoanthrene quinone, and 4,5,6-triaminopyrimidine derivatives to give aceanthryleno[1,2-b]pyrazine and aceanthryleno[1,2-g]pteridine derivatives. Condensation of aceanthrene quinone with 2-aminoguanidine, semicarbazide, and thiosemicarbazide yielded aceanthryleno[1,2-e]triazines, condensation with 6-hydrazinopyrimidine derivatives gave 3,4-aceanthrylenopyrimido[4,5-c]pyridazines. Reaction of aceanthrene quinone with 2-cyanoethanoic acid hydrazide afforded 10,11-dihydro-10-oxo-aceanthryleno[1,2-c]pyridazine-9-carbonitrile. Treatment of aceanthrene quinone with malononitrile and hydrazine hydrate resulted in 10-aminoaceanthryleno[1,2-c]pyridazine-9-carbonitrile. The antibacterial effects of the prepared compounds were tested. Three of the compounds were tested against 60 cancer types. Received May 6, 2001. Accepted June 5, 2001     

Synthesis of novel β-dialkylamino-α,β-unsaturated trifluoromethylketones containing cyclobutene fragment and their reactions with organolithium and Grignard reagents

The highly reactive trifluoromethylenaminoketones, with a strained cyclobutene and norbornadiene moieties were firstly prepared from the corresponding β-halogeno-α,β-unsaturated trifluoromethylketones in almost quantitative yields. The ambident properties of these compounds in the reactions with organolithiums were discovered. The simple methods to control the selectivity of 1,2- or 1,4-addition of lithiated nucleophiles have been investigated.     

Studies on antiulcer drugs. II. Synthesis and antiulcer activities of imidazo[1,2-alpha]pyridinyl-2-alkylaminobenzoxazoles and 5,6,7,8-tetrahydroimidazo[1,2-alpha]pyridinyl derivatives.

A series of imidazo[1,2-alpha]pyridinylbenzoxazoles (4) and 5,6,7,8-tetrahydroimidazo[1,2-alpha]pyridinylbenzoxazoles (5) were synthesized and tested for anti-stress ulcer activity in rats. Several compounds were found to be more active than the reference compounds, sucralfate, cimetidine and ranitidine. Some of them exhibited potent protective activity against ethanol-induced gastric lesion. The synthesis and structure-activity relationships of these compounds are discussed.     

Synthesis of 1,2-Azaphosphacyclanes; Generality of the Mechanism of P=N Alkylation and Arbuzov Reaction

A novel convenient "one-pot" synthesis of 2-oxo-1,2 u 5 -azaphosphacyclanes 1 and 1,2 u 4 -azaphosphacyclanium salts 2 via intramolecular N-alkylation of y -halogenalkyl-substituted iminophosphoryl compounds 3 has been developed. The common nature of the reaction of intramolecular cyclization of iminophosphoryl compounds having an alkoxy group at the phosphorus atom and the Arbuzov reaction has been established.     

1,2-vinyl and 1,2-acetylenyl migration in Rh(II) carbene reaction: remarkable bystander effect

A series of beta-(trichloroacetyl)amino alpha-diazo carbonyl compounds have been synthesized, and their Rh(II)-catalyzed reaction was investigated. 1,2-Migration was the predominant reaction pathway, and the migratory aptitude was found to be dramatically affected by the beta-substituents. The 1,2-vinyl and 1,2-acetylenyl group migration occurs preferentially in the presence of beta-hydrogen in Rh(2)(OAc)(4)-catalyzed reaction of beta-(trichloroacetyl)amino alpha-diazo carbonyl compounds. A possible reaction mechanism is discussed.     

Synthesis of 3-aryl-4-methyl-1,2-benzenedisulfonimides, new chiral Brønsted acids. A combined experimental and theoretical study

We have recently reported the use, in catalytic amounts, of 1,2-benzenedisulfonimide as a safe Brønsted acid in some acid-catalyzed organic reactions. With the design of new and chiral acid organocatalysts with the structure of 1,2-benzenedisulfonimide in mind, we herein propose a synthesis of 1,2-benzenedisulfonimide derivatives bearing an aryl group in the 3-position with good overall yields. The chirality of these compounds is due to the hindered rotation of the aryl group (atropisomerism). We resolved the atropisomers of one of these compounds.