Cyclopropylidenebis(diphenylphosphine): Note on its Synthesis,Properties and Spectral Data

The title compound has been synthesized through cyclopropanation of vinylidenebis(diphenylphosphine) using dimethylsulfoxonium methylide. It is easily converted into its dioxide and disulfide. NMR data of these first geminal diphosphinocyclopropanes are presented.     

Synthesis of methyl derivatives of uronic acids. I. Synthesis of methyl (methylα-D-galactopyranosid)uronate and its 2-, 3-, and 4-O-methyl ethers

Alternative unidirectional methods for synthesizing methyl (methyl α-D-galactopyranosid)uronate and its mono-O-methyl ethers by the oxidation (with CrO₃-H₂SO₄-acetone) of the corresponding methyl O-benzyl-O-methyl-α-D-galactopyranosides having unsubstituted 6-OH groups to the corresponding methyl O-benzyl-O-methyl-α-D-galactouronic acids followed by esterification with CH₂N₂ and the catalytic hydrogenolysis of the benzyl groups are proposed.     

6，6＇－二（二苯基氧化膦甲基）－1，1＇－氮氧化－2，2＇－联吡啶与硝酸铒配合物的合成与结构

合成了硝酸铒与四功能团含磷萃取剂６，６＇－二（二苯基氧化膦甲基）－１，１＇－氮氧化－２，２＇－联吡啶的配合物。用四圆衍射仪测定了配合物的晶体结构。晶体属单斜晶系，空间群Ｃ２／ｃ，晶体学参数，ａ＝１．９８３０（４）ｎｍ，ｂ＝２．３１３５（４）ｎｍ，ｃ＝１．８６００（３）ｎｍ；β＝９６．１８（２）°，ｚ＝４。配合物中有机配体以四齿形式与中心离子铒配位，金属离子的配位数为８。配位几何构形为稍变形的四方反棱柱。金属离子周围的配位水分子已全部被取代。     

2-吡嗪羧酸银的合成、晶体结构及热化学性质

以二次蒸馏水为溶剂,合成了2-吡嗪羧酸银(Ag(pyza)(s)),并利用X-射线单晶衍射法表征了其晶体结构.根据晶体结构数据计算得到2-吡嗪羧酸银的晶格能为554.10 kJ/mol.利用TG/DSC热分析技术研究了该化合物的热分解过程;用精密自动绝热热量计测量了其在78~378 K温区的低温热容;通过最小二乘法拟合得到了摩尔热容随折合温度变化的多项式方程,利用此方程计算出该化合物的舒平热容和各种热力学函数.通过设计合理的热化学循环,利用等温环境溶解-反应热量计分别测定了所设计热化学反应的反应物和产物在选定溶剂中的溶解焓,通过计算得到反应的反应焓为:?(31.919±0.526)kJ/mol.利用Hess定律计算出2-吡嗪羧酸银的标准摩尔生成焓为:?(243.659±1.298)kJ/mol.利用紫外-可见光谱仪对反应物和产物溶解所得溶液分别进行测量,从而证实了所设计热化学循环的可靠性.     

Synthesis of functionalized 3-pyridyl methyl ketones

A synthesis of 3-pyridyl methyl ketones is described that employs a palladium-catalyzed olefination of 3-bromopyridines with butyl vinyl ether followed by acid hydrolysis of the intermediate pyridyl vinyl ether in situ. This method has been applied to bromoquinoline substrates as well. The reaction is compatible with a variety of functional groups.     

Synthesis of a stable,foamable, gold-containing organic carboxylate polymer

The functionalized polyethylene acrylic acid copolymers Primacor 1430 (P1430, containing 9.5% acrylic acid) and Primacor 5980 (P5980, containing 20% acrylic acid) have been used to synthesize gold/polymer dispersions and gold/polymer ionomers, respectively. When [Ph₃PAu]⁺ is bonded directly to the carboxylate, work-up of the polymer leads to decarboxyation and metallic gold formation. However, ionic bonding of [(Ph₃P)₂Au]⁺, and related bis phosphine cations produce workable, foamable polymers. Analysis shows samples from these reactions to contain between 4–15 wt % of Au depending on the type of gold complex used and the reaction conditions. The gold/polymer (ionomer) sample with about 12% Au has been worked to mold sheets of foam. © 1993 John Wiley & Sons, Inc.     

Synthesis and transformation of [difluoro(phenylseleno)methyl]- trimethylsilane

[reaction: see text] A novel and efficient strategy was developed to synthesize [difluoro(phenylseleno)methyl]trimethylsilane (PhSeCF(2)TMS, 2), which was further utilized as a nucleophilic difluoromethylating reagent to incorporate the difluoro(phenylseleno)methyl (PhSeCF(2)) group into carbonyl compounds in good yields. The resulting PhSeCF(2)-containing alcohols 3 could be conveniently converted into corresponding difluoromethyl alcohols 4 by a radical deselenylation.     

Synthesis of methyl 3-bromomethylbut-3-enoate and its reactions with aldehydes and tributylchlorostannane in the presence of zinc

Methyl 3-bromomethylbut-3-enoate smoothly reacted with prenal, β-ionylideneacetaldehyde, benzyloxyacetaldehyde, and tributylchlorostannane in the presence of zinc and aqueous ammonium chloride in tetrahydrofuran to give the corresponding δ-hydroxy-β-methylidenecarboxylic acid esters. In the absence of ammonium chloride, satisfactory yields of the products were obtained only in the reactions with prenal and benzyloxyacetaldehyde; these reactions involved lactonization of intermediate δ-hydroxy-β-methylidenecarboxylic acid esters, and the double carbon-carbon bond migrated to the conjugated position with the lactone carbonyl group. The condensation of β-ionylideneacetaldehyde with methyl 3-bromomethylbut-3-enoate was successfully used to obtain isotretinoin. Initial methyl 3-bromomethylbut-3-enoate was synthesized in a good yield from readily accessible ethyl 3,3-diethoxypropionate via cyclopropanation with ethylmagnesium bromide in the presence of titanium tetra(isopropoxide), oxidation of the acetal moiety to ester, and cleavage of the cyclopropane ring in intermediate methyl (1-methylsulfonyloxycyclopropyl)acetate.     

Synthesis of methyl 3-deoxy-3-methylaminoarabinopyranoside,a component of some aminoglycoside antibiotics

Amino sugar $\text{1}$ has been synthesized in racemic form as a mixture of anomers from sorbic aldehyde. An intramolecular N-sulfinyl dienophile Diels-Alder strategy was used to stereospecifically generate the chiral centers of pentose $\text{1}$.     

Synthesis of acrylates based on tetracyclododecene and its methyl derivative

The reaction of catalytic and thermal addition of acrylic acid to tetracyclo[4.4.1^2,5.1^7,10.0^1,6]dodec-3-en and its 8-methyl-substituted derivative was studied. The reaction is intended for the synthesis of corresponding acrylates, which are reactive monomers suitable for producing high-molecular compounds.     

Synthesis of methyl ester of 4-bromo-2, 3-butadienoic acid

Conclusions The synthesis of the methyl ester of 4-bromo-2, 3-butadienoic acid was described.Translated from Izvestiya Akadeemii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1494–1495, August, 1965 Original article submitted December 2, 1964     

Highly Efficient Diastereoselective Synthesis of Tetrahydro-isoquinoline-3- carboxylate Ester Analogs from L-DOPA

Tetrahydroisoquinoline-3-carboxylate esters are an important motif of naturally occurring bioactive alkaloids and pharmacophores. They are generally regarded as neurotoxic compounds and are putatively involved in a variety of pathologic conditions of central nervous system, including alcoholism, phenylketonuria, and neurodegenerative disorders such as Parkinson's disease.     

Et3B-induced radical addition of diphenylphosphine oxide to unsaturated compounds

Et₃B-catalysed addition of diphenylphosphine oxide to unsaturated compounds, alkenes, unsaturated acids, allylic alcohols, and allylic α-O-acetyl nitriles constitutes a practical route to a variety of functionalized diphenylphosphine oxides. The very mild conditions employed, together with the short reaction times, make the procedure highly versatile and tolerant to a range of functionalities.     

Synthesis of benzo[b]selenophene and its methyl homologs

A method for the synthesis of benzo[b]selenophenes was perfected. 3-Oxo-2,3-dihydrobenzo[b]selenophene and 2-methyl-3-oxo-2,3-dihydrobenzo[b]selenophene exist only in the keto form. 3-Methylbenzo[b]selenophene was obtained by the reaction of 3-oxo-2,3-dihydrobenzo[b]selenophene with methylmagnesium iodide. Metallation of benzo[b]selenophene with butyllithium proceeds at the 2 position of the selenophene ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1475–1480, November, 1970.     

Synthesis,free-radical polymerization,and stereochemical configuration of methyl α-p-cyanobenzylacrylate

Methyl α-p-cyanobenzylacrylate was synthesized from dimethyl malonate following well-known organic reactions. The purified monomer was polymerized by a free-radical mechanism in benzene solution, using AIBN as initiator in the interval 50–90°C. The kinetic results seem to indicate an apparent ceiling temperature near 90°C. The analysis by ¹³C-NMR of polymers obtained indicates that the macromolecular chains are predominantly syndiotactic and the tacticity is independent of the polymerization temperature in the experimental interval studied. However, the determination of conditional probabilities for iso- and syndiotactic additions and the persistence ratios indicate that the propagation mechanism for the radical polymerization of methyl α-p-cyanobenzylacrylate does not follow a typical Bernoullian statistics.     

NiCl2(dppp)]-catalyzed cross-coupling of aryl halides with dialkyl phosphite, diphenylphosphine oxide, and diphenylphosphine

We present a general approach to C-P bond formation through the cross-coupling of aryl halides with a dialkyl phosphite, diphenylphosphine oxide, and diphenylphosphane by using [NiCl(2) (dppp)] as catalyst (dppp=1,3-bis(diphenylphosphino)propane). This catalyst system displays a broad applicability that is capable of catalyzing the cross-coupling of aryl bromides, particularly a range of unreactive aryl chlorides, with various types of phosphorus substrates, such as a dialkyl phosphite, diphenylphosphine oxide, and diphenylphosphane. Consequently, the synthesis of valuable phosphonates, phosphine oxides, and phosphanes can be achieved with one catalyst system. Moreover, the reaction proceeds not only at a much lower temperature (100-120?°C) relative to the classic Arbuzov reaction (ca.?160-220?°C), but also without the need of external reductants and supporting ligands. In addition, owing to the relatively mild reaction conditions, a range of labile groups, such as ether, ester, ketone, and cyano groups, are tolerated. Finally, a brief mechanistic study revealed that by using [NiCl(2) (dppp)] as a catalyst, the Ni(II) center could be readily reduced in situ to Ni(0) by the phosphorus substrates due to the influence of the dppp ligand, thereby facilitating the oxidative addition of aryl halides to a Ni(0) center. This step is the key to bringing the reaction into the catalytic cycle.