1,3-Diphosphetane-2,4-diyles--Cryptocarbenes?

1,3-Diphosphetane-2,4-diyles ( A ) possess a diradical molecular structure. Experimental studies reveal interconversions of different valence isomers of the diradicals. As a consequence of the facile thermal ring opening of 1,3-diphosphetane-2.4-diyles A , we obtained crypto-phosphinocarbenes ( B ), confirmed by the results of intramolecular rearrangements as well as reactions with multiple bonded systems. A new range of five- and six-membered phosphorus heterocycles are isolated, including transition-metal complexes. The mechanism for the ring-expansion are predicted by quantum chemical calculations.     

Poly[3,3-bis(azidomethyl)oxetane]–2,4-dinitro-2,4-diazapentane

Constructing phase diagrams for the mixtures of semicrystalline polymers and low molecular mass substances by DSC can meet with difficulties in the case of slow polymer crystallization. A problem of this kind is encountered for high-energy compositions poly[3,3-bis(azidomethyl)oxetane] (PBAMO)–2,4-dinitro-2,4-diazapentane (DNAP). In this study, the experimental phase diagram PBAMO–DNAP is constructed by an optical method, which makes it possible to visualize structural transformations. The kinetic studies by DSC and XRD reveal that 30–50 days of storing a homogenized PBAMO–DNAP mixture at room temperature are needed to attain stationary values of the crystallinity degree and heat of fusion. Even after that, the DSC method cannot deliver a solubility curve of DNAP in PBAMO, which is naturally generated by the optical method. This curve separates a domain of physical gels, effectively crosslinked by polymer crystallites and swollen with the plasticizer molecules, from a two-phase domain, in which the above gel reaches osmotic equilibrium with the pure plasticizer. It is also shown that the melting temperature of DNAP drops with growing the PBAMO content in the mixture, which is consistent with a decrease in the mean size of plasticizer crystals formed in polymer pores during the previous cooling.     

一步法合成2,4-二硝基苯甲醚

以1-氯-2,4-二硝基苯（CDNB）为原料,不使用相转移催化剂,用KOH溶液为反应介质,一步合成了2,4-二硝基苯甲醚,其结构经¹H NMR, FT-IR和元素分析确证。最佳反应条件为：CDNB 0.20 mol, 30%KOH溶液为反应介质,甲醇100 mL,于55 ℃反应60 min,收率96.5%,纯度99.8%。     

Über 2,4-Difluorzimtsäure

Zusammenfassung Aus 2,4-Difluortoluol wurden nach üblichen Methoden 2,4-Difluorbenzaldehyd und 2,4-Difluorzimtsäure hergestellt.     

2,4-Dinitrophenylhydrazone unges?ttigter Ketone

Ohne Zusammenfassung     

Synthesis of (E) α,2,4-Trinitrostilbenes from (E) 2,4-Dinitrostilbenes

Abstract

A convenient synthesis of (E) α,2,4-trinitrostilbenes 2a–d from (E) 2,4-dinitrostilbenes la–e by direct nitration is reported. Isomerization of the trans geometry of the reactant stilbenes to cis in the products was found. The structures of stilbenes 2a, 2c and 2d were confirmed by XRD.     

2,4-二氯苯肼盐酸盐的合成

从2,4-二氯苯胺出发,经重氮化、还原、酸析等反应合成了2,4-二氯苯肼盐酸盐,总收率74%。     

Michael Reaction of 2,4-Dioxohexahydro-1,3,5-triazine

With the extensive investigation of the Michael reaction, not the methylene compounds activated by electron withdrawing group[1,2] but other activated unsaturated compounds containing such as activate N-H or O-H have been used as Michael acceptor.[3,4] However, the research on the Michael reaction of 2,4-dioxohexahydro-1,3,5-triazine (DHT) has not been reported. After the systematic researches on the substitution reactions of DHT, we first report the Michael reaction of DHT with acrylic esters in this paper.     

Die 2,4-Dinitrophenylhydrazone von ges?ttigten Aldehyden, ges?ttigten Methylketonen, 2-Enolen und 2,4-Dienolen

Ohne Zusammenfassung     

2,4-二硝基苯丙氨酸钠盐·2,4-二硝基苯丙氨酸的合成、分子结构和二次谐波效应

合成了一种新的有非线性光学性能的标题化合物晶体NaAP·HAP,晶体属正交晶系,空间群为P2_12_12_1,a=25.773(6),b=12.377(3),c=7.2037(6)(?),z=4,D_c=1.54g·cm~(-3)。晶体结构由HAP分子(2,4-二硝基苯丙氨酸)、AP~-离子和Na~+离子组成。Na~+离子由周围的六个氧原子形成扭曲的八面体配位。这些NaO_6八面体通过共点形成无限链状结构。可用晶体结构的空间因素来解释实验测定的MAP和NaAP·HAP的二次谐波相对强度的顺序。     

2,4-二甲氧基苯甲酰氯的合成

2,4-二羟基苯甲酸与硫酸二甲酯经甲基化反应得到2,4-二甲氧基苯甲酸(3);3与SOCl2发生氯化反应合成了2,4-二甲氧基苯甲酰氯(4)。较佳的氯化反应条件为:325mmol,苯70mL,AlCl3250mg,回流反应1.5h,重结晶溶剂为石油醚(90℃～120℃),总产率达74.1%。2～4的结构经1HNMR和FT-IR表征。     

Zur Analyse von technischer 2,4-Diehlorphenoxyessigs?ure

Ohne Zusammenfassung     

紫外分光光度法测定2,4-二氯苯酚

2,4-二氯苯酚被世界野生动物基金会列为潜在的内分泌修正化学物质,即环境荷尔蒙物质.这类物质在环境中虽然含量低,但却显示出超常的内分泌效应,因而对其的监测分析显得尤为重要.目前,分析2,4-二氯苯酚的方法有比色法[1]和色谱法[2].色谱法虽然快速、准确,但对仪器要求高,操作复杂,而比色法灵敏度低.用紫外分光光度法测定河水中的2,4-二氯苯酚.     

2,4-二氯苯氧乙酰氯的气相色谱分析

建立了柱前衍生化气相色谱法测定2，4—二氯苯氧乙酰氯含量的方法；采用OV—17填充柱和火焰离子化检测器(FID)，内标法定量，样品加标平均回收率96．6％，标准偏差1．48，相对标准偏差1．71％；该方法简单、快速，结果准确。     

2,4-二硝基苯酚与肌红蛋白的相互作用

利用荧光光谱技术研究了2,4-二硝基苯酚与肌红蛋白分子的相互作用.2,4-二硝基苯酚与肌红蛋白结合生成基态复合物,导致肌红蛋白内源荧光的猝灭.测定了二者结合反应的物理化学参数,上述作用过程是一个熵增加、自由能降低的自发分子间作用过程,二者之间以疏水作用力为主;并用同步荧光、三维荧光光谱法探讨了2,4-二硝基苯酚对肌红蛋...     

Synthesis and Crystal Structure of Salicylaldehyde-2,4-dinitrophenylhydrazone

Some phenylhydrazone derivatives have been shown to be potentially DNA-damaging and mutagenic agents.[1] In order to investigate the relationship of the biological activity and the molecular structure, a series of new phenylhydrazone derivatives have been synthesized and their structures have been determined in our laboratory.     

2,4-二硝基苯丙氨酸钠盐·2,4-二硝基苯丙氨酸的合成、分子结构和二次谐波效应

合成了一种新的有非线性光学性能的标题化合物晶体NaAP·HAP,晶体属正交晶系,空间群为P2₁2₁2₁,a=25.773(6),b=12.377(3),c=7.2037(6)Å,z=4,D_c=1.54g·cm^-3。晶体结构由HAP分子(2,4-二硝基苯丙氨酸)、AP^-离子和Na⁺离子组成。Na⁺离子由周围的六个氧原子形成扭曲的八面体配位。这些NaO₆八面体通过共点形成无限链状结构。可用晶体结构的空间因素来解释实验测定的MAP和NaAP·HAP的二次谐波相对强度的顺序。     

Visible light-sensitized semiconductor photocatalytic degradation of 2,4-dichlorophenol

Sensitized-photocatalytic decomposition of 2,4-dichlorophenol (2,4-DCP) using xan-thene dyes as photosensitizer on TiO2 particles under visible light irradiation was studied. 2,4-DCP can be decomposed efficiently by this method and the decomposition efficiency of 2,4-DCP decreases in the following order: eosin Y ≈ rose bengal > erythrosine B > rhodamine B.