A NEW EFFICIENT SYNTHESIS OF TRIFLUOROACETYL HALIDES AND MIXED ANHYDRIDES OF PHOSPHORUS AND TRIFLUOROACETIC ACIDS

Abstract

Reaction of trifluoroacetic anhydride with chloroanhydrides of phosphorus acids R₂P(O)CI results in formation of mixed anhydrides R₂P(O) OCOCF₃ and trifluoroacetic acid halides CF₃COX (X=Cl, Br, I) in quantitative yield.     

MIXED HALIDE DIALKYL AND ALKYLENEDITHIOPHOSPHATE DERIVATIVES OF RUTHENIUM (III)

Abstract

Mixed chloride dialkyl and alkylenedithiophosphates of ruthenium (III). RuC1_3-n|(S₂P(OR)₂|n (R = Prⁿ, and Ph) and RuCl_3-n,[S₂ POGO]n G =-CMe₂CMe₂,- CH₂CMe₂CH₂-, -CH₂CEt₂CH₂-. and -CMe₂CH₂CHMe-, n = 1,2 have been synthesized for the first time by the reactions of ruthenium trichloride with ammonium dialkyl and alkylenedithiophosphate or alternatively by disproportionation reactions of ruthenium trichloride with ruthenium tris(dialkyl and alkylenedithiophosphates) in different stoichiometric ratios in benzene.

These new complexes have been characterized by elemental analysis, molecular weight determinations, as well as IR and NMR (¹H and ³¹P) data. Chelated structures with bidentate dialkyl and alkylenedithiophosphates groups have been proposed for all these derivatives.     

SOLVOLYSIS OF CHLORODIALKYLAND DIARYLPHOSPHINES,DIALKYL PHOSPHOROCHLORIDITES AND DIALKYL PHOSPHINYL CHLORIDES

Abstract

The kinetics of solvolysis of chlorodiethylphosphine, chloro(di-n-propyl)phosphine and chlorodiphenylphosphine was studied by conductometry in pure ethanol and in various mixed solvents, and was compared with that of dialkyl phosphorochloridites and of dialkyl and diaryl phosphinyl chlorides. The rate of ethanolysis of chloro(di-n-propyl)phosphine was found to be larger at higher initial concentrations. Addition of sulfuric or perchloric acid enhanced the rate of solvolysis, while sodium perchlorate and lithium chloride had no influence. In ethanof containing water, the rate of solvolysis of chloro(di-n-propylphosphine is approximately proportional to the concentration of water. In formic acid, the solvolysis of chloro(di-n-propyl)phosphine is slower than in ethanol. Addition of acetone to ethanol increases the rate of solvolysis of chloro(di-n-propyl)phosphine—possibly due to a condensation reaction producing a 1-chloroalkyl dialkylphosphine oxide. The rate of ethanolysis of chloro(di-n-propyl)phosphine is considerably enhanced in the presence of isobutylamine, di-n-butylamine and triethylamine. The solvolysis of di-t-butylphosphinyl chloride in absolute ethanol is very much slower than that of dimethyl and diethyl phosphinyl chloride.     

ON THE NATURE OF THE NUCLEOPHILE IN THE MIXTURE OF PHOSPHITES AND AMINES

Abstract

It is now commonly accepted that in the presence of strong bases (like metal alcoholates) an equilibrium between phosphite and phosphonate forms of dialkyl phosphites exists and that the phosphite form is highly reactive in the reaction with carbonyl compounds. There is a controversy on the structure of the active form of the phosphite when the addition is catalyzed by amines. We have found that aliphatic amines and dialkyl phoshites form a complex which is a reactive species. Its stoichiometry depends on the nature of the solvent.     

STUDIES ON ORGANOPHOSPHORUS COMPOUNDS PART IX.1 THE ACTION OF Di-, TRIALKYL PHOSPHITES AND THIOL ACIDS ON SOME ENAMINOLACTONES

Abstract

Di-, and trimethylphosphites react with enaminolactone, 4, only in methanol to give N-benzoyl-3-phenyl-3-phosphonoalanine-trimethylester (7) in good yields. Diphenylphosphinodithioic acid also reacts with 4 to give N-benzoyl-3-phenylcysteine-methyl ester-diphenylphosphinodithioate (9). A mechanism is proposed to account for the formation of 7. Compatible analytical and spectroscopic results were obtained for the new compounds.     

二甲苯异构体及其质子络合物的量子化学计算

利用量子化学的CNDO/2法对一系列二甲苯异构体及其质子络合物进行了计算,结果表明,它们的稳定性具有下列次序:定域σ-络合物>定域π-络合物>二甲苯异构体>CH₃离域π络合物并且进一步阐明了二甲苯异构体的异构化能、电离能、酸碱性、质子亲合势、亲电子反应等物理化学性质以及间二甲苯在酸性催化剂中的异构化机理。     

THE PREPARATION OF DIMETHYL PHOSPHOROCHLORIDITE AND ITS HOMOLOGS FROM TRIALKYL PHOSPHITES AND DICHLOROTRIPHENYLPHOSPHORANE

Abstract

A novel convenient synthesis of dialkyl phosphorochloridites based on the reaction of trialkyl phosphites with dichlorotriphenylphosphorane has been described. In this way the commonly used dialkyl phosphorochloridites (3a–e) were prepared in satisfactory yields. Their identity was confirmed by ³¹P-NMR spectroscopy as well as by their refractive index.     

THE PREPARATION OF TRIALKYL PHOSPHITES DIRECTLY FROM THE ELEMENT

Abstract

The reaction between finely divided white phosphorus and several alkoxide ions in the presence of tetrachloromethane and excess of alcohol has been investigated under a variety of conditions. High yields of trialkylphosphite are obtained when two equivalents of alkoxide are used. With one equivalent of alkoxide, dialkylphosphonate is formed in comparable yield. Maximum yields of triester are obtained within 1–3 h at room temperature. Prolonged treatment results in the conversion of trialkylphosphite to phosphate by reaction with tetrachloromethane. Phenolate ions are unreactive under the same experimental conditions. The mechanism of the reaction is discussed.     

氢气在混合溶剂丙酮-水中的溶解度

本文报导一种能准确测定气体在混合溶剂中溶解度并能同时测定溶剂的饱和蒸气压的实验装置, 在20～40 ℃的温度范围内, 分别测定了氢气在丙酮、水和混合溶剂丙酮-水中的溶解度, 及其相应的蒸气压。     

强酸性阳离子交换树脂催化醛与乙酸酐的反应

强酸性阳离子交换树脂能有效地催化醛与乙酸酐的反应合成1，1二酯，获得较好的收率，产物的熔点、红外光谱及元素分析数据均与标准数据相吻合。     

COMPARISON OF THE PATHWAYS AND QUANTUM YIELDS OF DIRECT PHOTOISOMERIZATION OF UNPROTONATED AND PROTONATED N-BUTYLAMINE SCHIFF BASES OF ISOMERIC RETINYLIDENEACETALDEHYDE WITH THOSE OF SCHIFF BASES OF ISOMERIC RETINAL: RATIONALIZATION OF THE SELECTION OF THE RETINYLIDENE CHROMOPHORE BY RETINOCHROME

Abstract— The pathways and quantum yields of direct photoisomerization of unprotonated and pro-tonated n-butylamine Schiff bases (SB and PSB) of isomeric retinylideneacetaldehyde (C22 aldehyde) were determined in n-hexane, acetonitrile and methanol for the former and in acetonitrile and methanol for the latter. The results are compared with those of the Schiff bases of isomeric retinal (C20 SB and C20 PSB) reported previously (Koyama et al., Photochem. Photobiol. 54 , 433–443, 1991). The isomerization pathways and quantum yields of C22 SB are more or less similar to those of C20 SB, but conspicuous differences in the isomerization pathways are found between C22 PSB and C20 PSB. The homogeneous (exclusive) isomerization of the retinylidene chromophore from all-trum to 11-cis in retinochrome is rationalized not by C22 PSB but by C20 PSB.
Almost complete one-way isomerization from cis to trans of C22 SB (in n-hexane) is ascribed to isomerization via the T₁ state, while mutual isomeritation between cis and tram of C22 PSB is ascribed to isomerization via the S₁ (B_u) state. The T_I potential of C22 SB and the S₁ potential of C22 PSB are discussed based on photostationary state compositions.     

酸碱软硬度的电势原子势标度

软硬酸碱原则在化学的各个领域都得到了广泛的应用。在其定量化标度方面也做了不少工作,例如Yingst等的酸度量|α/β|,Klopman的E_n~≠和E_m~≠值,parr和pearson的绝对硬度以及Yatsimirski的ΔA_(FH)等。但是,他们的工作在理论性和应用上都无法统一起来。本文提出一种具有广泛应用性的酸碱软硬度的键参数标度。Mulliken在研究一类弱lewis加合物的光谱时,首先用量子力学原理阐述了lewis     

INTERPHOTORECEPTOR RETINOID-BINDING PROTEIN AND α-TOCOPHEROL PRESERVE THE ISOMERIC AND OXIDATION STATE OF RETINOL

Retinol decomposes rapidly into a number of products, including its aldehyde form, retinal, when introduced into buffer in phospholipid vesicles or ethanol. Interphotoreceptor retinoid-binding protein at low concentrations is found to protect retinol from isomerization and oxidation. The addition of alpha-tocopherol to either liposomes or an ethanolic-buffer solution also prevents decomposition. Neither of these agents interferes with the successful regeneration of pigment with 9-cis retinal in rod outer segment preparations or the restoration of sensitivity by retinoids in isolated rod photoreceptors.     

PHOSPHORYL TO CARBONYL MIGRATION OF AMINO GROUPS IN MIXED ANHYDRIDES. REACTIVITY AND CRYSTAL STRUCTURE OF N-METHYL-2-BENZOYLOXY-2-OXO-1,3,2-OXAZAPHOSPHORINANE

Abstract

Cyclic mixed anhydride, N-methyl-2-benzoyloxy-2-oxo-1,3,2-oxazaphosphorinane (1a) has been synthesised and the rate of its fragmentation involving nitrogen migration from phosphorus to carbonyl carbon has been measured. (1a) was found to be ca. 60 times less reactive than the non-cyclic, O-methyl-N,N-dimethyl analogue. The crystal and molecular structure of (1a) has been determined using x-ray diffraction. Pna2₁, a=22.229(6), b=7.597(2), c=7.210(2) Å; V=1217.6(6) ų. Final R=3.08% for 1037 reflections with I(rel) > 2[sgrave]I(rel) and 157 parameters. The observed conformation of the molecule of (1a) is very different from that required for the fragmentation to occur; in order to achieve the geometry postulated for the transition state significant rotations about the P[sbnd]O and O[sbnd]C bonds would be necessary and steric hindrance by the 4,6-axial hydrogens would be expected.     

聚氟氯代羧酸乙烯酯的制备及其立体规整性

氟氯代羧酸与乙炔反应制得氟氯代羧酸乙烯酯,后者分别以过氧化二苯甲酰和三丁基硼为引发剂在不同温度下进行本体聚合。以X-射线衍射图和红外吸收率D_(916)/D_(850)比值观测聚乙烯酯及其水解物聚乙烯醇的立体规整性。不同侧链长度的聚含氟酸乙烯酯的X-射线衍射图并没有反映出高分子链在立体规整性上的差异,但其水解产物聚乙烯醇D_(916)/D_(850)吸收率比值随侧链体积增大而增加、侧基极性效应和空间效应的影响是肯定的。不论是聚乙酸乙烯酯和聚含氟酸乙烯酯聚合温度对它们的立体规整性都没有明显的影响。     

异构化对二苯醚二酐/二苯醚二胺聚酰亚胺结晶行为的影响

合成了一系列基于4,4-′ODPA,3,4-′ODPA以及3,3-′ODPA 3种异构二苯醚二酐单体的异构聚酰亚胺,以苯酐(PA)作为封端剂来控制分子量.用DSC和WAXD为主要手段研究了这几种异构聚酰亚胺的结晶行为.研究发现聚酰亚胺4,4-′ODPA/ODA(二苯醚二胺)在分子量较低的情况下能够在热处理,退火或剪切作用下结晶.并且升高热处理温度和延长热处理时间有利于结晶的完善,在玻璃化温度以上施加剪切能够加速聚酰亚胺的结晶.而对于其他的两种异构体3,4-′ODPA/ODA以及3,3-′ODPA/ODA无论是经过热处理还是施加外力剪切都未能使其结晶.     

ON THE REACTION OF BENZOTHIAZOL-2-YL SULPHENAMIDES WITH PHOSPHITES

Abstract

A study of the synthesis of phosphoramidates from phosphites and benzothiazol-2-yl-sulphenamides, indicates that a quinquecovalent phosphorane is an intermediate. Since the initial step in this reaction does not involve attack of phosphorus on nitrogen, it is unlikely that these sulphenamides will act as electrophilic aminating agents towards non-phosphorus nucleophiles. An efficient new method for preparing benzothiazol-2-yl-sulphenamides is reported.     

KCl在甲醇-非电解质的混合溶剂中溶解度和溶剂化

本文测定了5、15、25和35 ℃时KCl在甲醇-苯、甲醇-甲苯、甲醇-环己烷和甲醇-四氯化碳中的溶解度S, 并得到经验公式: logS=a+bT, 其中T为绝对温度。同时计算了KCl由甲醇到甲醇混合溶剂的标准迁移自由能ΔG_(tr)~°-, 并得到它和组成x_(Ne)的经验关系式; ΔG_(tr)~°-=CX_(Ne)。同时指出在本实验范围内,温度的变化不影响单纯溶剂化模型和第二介质常数公式的适用性。