557-93-7Relevant articles and documents
Method for synthetizing isopropenyl boric acid ester
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Paragraph 0018, (2016/12/16)
The invention discloses a method for synthetizing isopropenyl boric acid ester. Acetone is used as a raw material and subjected to a reaction with hydrazine hydrate to generate hydrazone, then, isopropenyl halogen is generated at the existence of NXS and organic base and then subjected to a one-pot reaction with metallic lithium and bi(disopropylamine) boron halide, diol and a polymerization inhibitor are added for a backflow reaction to obtain isopropenyl boronic acid ester, and the yield is 65-69%,. The method is easy and convenient to implement, purification is convenient, the yield is high, no ultralow temperature reaction is needed, and the method is suitable for industrial enlarged production.
Synthesis of hydroxylated hydrocarbons
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Page/Page column 5, (2008/06/13)
Ethylene glycol, other diols, triols, and polyols are made in an efficient manner by reacting dibromides with water in the presence of a metal oxide. An integrated process of dibromide formation, alcohol synthesis, metal oxide regeneration, and bromine recycling is also provided.
Flash vacuum pyrolysis over magnesium. Part 1 - Pyrolysis of benzylic, other aryl/alkyl and aliphatic halides
Aitken, R. Alan,Hodgson, Philip K.G.,Morrison, John J.,Oyewale, Adebayo O.
, p. 402 - 415 (2007/10/03)
Flash vacuum pyrolysis over a bed of freshly sublimed magnesium on glass wool results in efficient coupling of benzyl halides to give the corresponding bibenzyls. Where an ortho halogen substituent is present further dehalogenation gives some dihydroanthracene and anthracene. Efficient coupling is also observed for halomethylnaphthalenes and halodiphenylmethanes while chlorotriphenylmethane gives 4,4′-bis(diphenylmethyl)biphenyl. By using α,α′-dihalo-o-xylenes, benzocyclobutenes are obtained in good yield, while the isomeric α,α′-dihalo-p-xylenes give a range of high thermal stability polymers by polymerisation of the initially formed p-xylylenes. Other haloalkylbenzenes undergo largely dehydrohalogenation where this is possible, in some cases resulting in cyclisation. Deoxygenation is also observed with haloalkyl phenyl ketones to give phenylalkynes as well as other products. With simple alkyl halides there is efficient elimination of HCl or HBr to give alkenes. For aliphatic dihalides this also occurs to give dienes but there is also cyclisation to give cycloalkanes and dehalogenation with hydrogen atom transfer to give alkenes in some cases. For 5-bromopent-1-ene the products are those expected from a radical pathway but for 6-bromohex-1-ene they are clearly not. For 2,2-dichloropropane and 1,1-dichloropropane elimination of HCl occurs but for 1,1-dichlorobutane, -pentane and -hexane partial hydrolysis followed by elimination of HCl gives E, E-, E,Z- and Z,Z- isomers of the dialk-1-enyl ethers and fully assigned 13C NMR data are presented for these. With 6-chlorohex-1-yne and 7-chlorohept-1-yne there is cyclisation to give methylenecycloalkanes and -cycloalkynes. The behaviour of 1,2-dibromocyclohexane and 1,2-dichlorocyclooctane under these conditions is also examined. Various pieces of evidence are presented that suggest that these processes do not involve generation of free gas-phase radicals but rather surface-adsorbed organometallic species.
The Synthesis and Molecular Structure of Tetra(isopropyl)silane
Anderson, David G.,Rankin, David W. H.,Robertson, Heather E.,Frazao, Carlos M. F.,Schmidbaur, Hubert
, p. 2211 - 2218 (2007/10/02)
Tetra(isopropyl)silane has been prepared using literature methods, with the individual steps improved by changes in some of the experimental conditions.The key reagent 2-lithiopropene, which can now be obtained in good yields from 1-methacrylic acid via 1,2-dibromo-1-methylpropionic acid and 2-bromopropene by treatment of the latter with ultrasound-activated lithium metal, was shown to contain mono- and dilithiopropyne.The reaction with chlorotrimethylsilane led to the corresponding silylated derivatives, while with silicon tetrachloride tetra(isopropenyl)silane was obtained, which after purification is easily converted into the title compound by catalytic hydrogenation. - The gas phase molecular structure of 4Si has been determined by electron diffraction.The parameters could be successfully refined for a model of S4 symmetry.Bond distances Si-C, C-C, and C-H as well as bond angles Si-C-C and C-C-H show the steric compression of the four isopropyl substituents.Steric strain is minimized by twists of the methyl groups and the isopropyl groups away from the fully staggered conformations, but also by an increase of two of the C-Si-C angles as compared to the remaining four, which are decreased relative to the tetrahedral standard.The structure differs strongly (mainly in the twist angles) from that of the isoelectronic tetra(isopropyl)phosphonium cation in 4P(1+)(1-), but is very similar to those of tetra(cyclohexyl)silane and of tri(isopropyl)phosphonium isopropylide, where the pyramidal configuration of the ylidic carbon atoms leads to a pseudo homoleptic array of the substituents at phosphorus. - Key Words: Conformational analysis / Electron diffraction / Organosilanes / Silane, tetra(isopropyl)-
GAS-PHASE PROTONATION OF ALLENE AND PROPYNE. REMARKABLY SELECTIVE FORMATION OF 2-PROPENYL IONS.
Fornarini,Speranza,Attina,Cacace,Giacomello
, p. 2498 - 2501 (2007/10/02)
The structure of C//3H//5** plus ions, obtained in the dilute gas state from the protonation of propyne and allene by radiolytically formed H//3** plus and C//nH//5** plus (n equals 1,2) ions, has been investigated in the pressure range from 150 to 760 torr. The C//3H//5** plus ions have been trapped with two gaseous nucleophiles, i. e. , benzene and 1,4-dibromobutane, and their structure has been inferred from the nature of the neutral products isolated. The results, in particular those from the systems containing 1,4-dibromobutane, show that 2-propenyl ions are formed almost exclusively in the kinetically significant step of the protonation from both propyne and allene, a partial isomerization to the allyl structure being observed in the systems containing benzene.
Thermocatalytic Reactions of Bromochloropropanes
Levanova, S. V.,Rodova, R. M.,Tereshkina, T. P.,Zabrodina, T. I.
, p. 1142 - 1146 (2007/10/02)
The thermodynamic characteristics of the disproportionation and dehydrohalogenation reactions of halogenopropanes (1,2- and 2,2-isomers) have been calculated and tested experimentally.The legitimacy of using the incremental method for the calculation of the thermodynamic functions of bromochloropropanes has been demonstrated.An increase of the length of the hydrocarbon group and the geminal positions of the halogen atoms in the molecule greatly reduce the probability of disproportionation reactions.
