- Method for preparing halogen propanol and epoxypropane
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The invention provides a method for preparing halogen propanol. The method comprises the following steps (1) halogen alcoholization: adding halogen hydride, H2O2, propylene and an HTS molecular sieve into a reaction device, and carrying out halogen alcoholization reaction to obtain the halogen propanol. The invention also provides a method for preparing epoxypropane with a halogenohydrin method. The method comprises the following steps: (1) halogen alcoholization: adding halogen hydride, H2O2, propylene and an HTS molecular sieve into the reaction device, and carrying out the halogen alcoholization reaction to obtain halogen propanol; (2) saponification: carrying out saponification reaction on halogen propanol and a hydroxide of alkali metal in step (1), and separating to obtain the epoxypropane and alkali halide metal salt; optionally (3) electroosmosis: carrying out bipolar membrane electroosmosis on the alkali halide metal salt obtained in step (2) to obtain the hydroxide of alkali metal and the halogen hydride. According to the methods, the halogen propanol or the epoxypropane can be prepared at extremely high selectivity and yield, and the discharging of waste water and waste residues can be drastically lowered.
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Paragraph 0098; 0099; 0110; 0111; 0129; 0130
(2017/05/19)
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- Asymmetric alkyl-alkyl cross-couplings of unactivated secondary alkyl electrophiles: Stereoconvergent suzuki reactions of racemic acylated halohydrins
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A method for asymmetric alkyl-alkyl Suzuki reactions of unactivated secondary alkyl electrophiles, specifically, cross-couplings of racemic acylated halohydrins with alkylborane reagents, has been developed. A range of protected bromohydrins, as well as a protected chlorohydrin and a homologated bromohydrin, are coupled in good ee by a catalyst derived from commercially available components.
- Owston, Nathan A.,Fu, Gregory C.
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supporting information; experimental part
p. 11908 - 11909
(2010/11/04)
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- O-phenylenediamine as a new catalyst in the highly regioselective conversion of epoxides to halohydrins with elemental halogens - A reinvestigation
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In contrast to a previous report, o-phenylenediamine is not a catalyst in the ring opening reaction of epoxides by means of bromine or iodine. The o-phenylenediamine is just a reactant which reacts with iodine to give phenazine-2,3-diamine and hydrogen iodide, or with bromine to give a mixture of brominated and polymerized products as well as hydrogen bromide. The hydrogen halogenides are in fact the real epoxide ring opening reactants. Springer-Verlag 2006.
- Soroka, Miroslaw,Goldeman, Waldemar
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p. 169 - 174
(2007/10/03)
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- Reinvestigation of the conversion of epoxides into halohydrins with elemental halogen catalysed by thiourea
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In contrast to a previous literature report, thiourea is not a catalyst in the ring opening reaction of epoxides by means of bromine or iodine. Instead, thiourea reacts with the halogen to give a complex mixture of products, among them hydrogen halogenides, which are in fact the real epoxide ring opening reactants. The presence of water is crucial in this reaction.
- Soroka, Miros?aw,Goldeman, Waldemar
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p. 4233 - 4235
(2007/10/03)
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- Comments on a Conversion of Epoxides to Halohydrins with Elemental Halogen Catalyzed by Phenylhydrazine: Tandem Electrophilic Halogenation of Aromatic Compounds and Epoxide Ring Opening to Halohydrins
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The halogenation of aromatic compounds by bromine or chlorine in the presence of an epoxide gives the corresponding halogenated aromatics and 2-halohydrins, both with good yields.
- Soroka, Miroslaw,Goldeman, Waldemar,Malysa, Piotr,Stochaj, Monika
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p. 2341 - 2344
(2007/10/03)
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- Highly regio- and stereoselective synthesis of β-halohydrins from epoxides catalyzed with ceric ammonium nitrate
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Ce(IV) as ceric ammonium nitrate can effectively catalyze ring opening of epoxides with halides under very mild conditions and easy procedure to give the corresponding β-chloro- and β-bromohydrins in excellent yields. The reactions occur with both substituted and unsubstituted quaternary ammonium halides and with high regio- and stereoselectivity. The reaction of optically active styrene oxide with chloride ion was found to be highly stereospecific and afforded the corresponding β-halohydrin in 96% ee.
- Iranpoor,Kazemi,Salehi
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p. 1247 - 1258
(2007/10/03)
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- Free Radical Macrocyclizations from Steroid-Derived Precursors
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Stereoselective free radical addition reactions were studied using steroid-derived templates in an attempt to control product dispersity.Templates were prepared from bifunctional steroids appropriately substituted with initiating and terminating functionality.Free radical initiation in the presence of a polymerizable olefin resulted in the formation of macrocycles that had incorporated monomer.The yield of macrocycle formed was as 51percent for templates derived from lithocholic acid whereas templates derived from androstanolone failed to give significant amounts of macrocycles.The effects of variation of initiating and terminating functionality, steroid, and olefin on macrocycle size and yield were examined.
- Scott, Daniel M.,McPhail, Andrew T.,Porter, Ned A.
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p. 1178 - 1186
(2007/10/02)
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- Highly Regioselective and Stereospecific Functionalization of 1,2-Proanediol with Trimethyl(X)silanes Employing the 1,3,2λ5-Dioxaphospholane Methodology
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The regioselective ring opening of (S)-4-methyl-2,2,2-triphenyl-1,3,2λ5-dioxaphospholanes (2) was initiated with several trimethylsilyl reagents (Me3SiX: X = PhS, I, Br; Cl, CN, and N3) to afford the regioisomeric (silyloxy)phosphonium salts.A stereospecific extrusion of triphenylphosphine oxide from these oxyphosphonium salts gave predominatly the thermodynamically less stable C-2-X-substituted derivatives with nearly complete inversion of stereochemistry at the C-2 stereogenic center (i.e., X = PhS).
- Mathieu-Pelta, Isabel,Evans, Slayton A.
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p. 3409 - 3413
(2007/10/02)
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- SULFUR INHIBITORS OF PHOSPHOLIPASE A-Z
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Phospholipase A2 inhibitors having the formula wherein R" is a C2-C20 alkyl group, R1" is a C1-C4 alkyl group, y is an integer from 2 to 10, and J- is a pharmaceutically acceptable anion, are described
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- &β-Lactamase-Stable Penicillins. Synthesis and Structure-Activity Relationships of (Z)-Alkyloxyimino Penicillins; Selection of BRL 44154
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A series of (Z)-2-alkyloxyimino-2-(2-aminothiazol-4-yl)acetamidopenicillins has been prepared.New methodology has been developed to prepare tertiary alkyl oximes.High stability to β-lactamases and potent antibacterial activity have been achieved against Gram-positive and certain Gram-negative organisms.Activity against methicillin-resistant Staphylococcus aureus was an unexpected finding.The cyclopentyl analogue 4f, BRL 44154, has been selected for further study.
- Brown, Pamela,Calvert, Stephen H.,Chapman, Pauline C. A.,Cosham, Suzanne C.,Eglington, A. John,et al.
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p. 881 - 891
(2007/10/02)
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- Antihypertensive phosphate derivatives
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Antihypertensive phosphate derivatives having the following formula are described: STR1 wherein X is selected from one or more of: (a) C1 -C24 branched or straight chain alkyl; (b) C1 -C24 branched or straight chain alkoxy; (c) STR2 wherein n and m are integers from 0 to 25 and the sum of n and m is less than or equal to 25; phenyl; substituted phenyl wherein the substituents are selected from the group consisting of C1 -C20 branched or straight chain alkyl, C1 -C20 branched or straight chain alkoxy, halogen, trifluoromethyl, phenyl, and substituted phenyl, phenoxy; and substituted phenoxy, wherein the substituents are selected from the group consisting of C1 -C20 branched or straight chain alkyl, halogen, trifluoromethyl, phenyl and substituted phenyl; Q is selected from the group consisting of: STR3 wherein R1 is selected from the group consisting of hydrogen, C1 -C4 branched or straight chain alkyl, C1 -C4 branched or straight chain alkoxy and C1 -C4 branched or straight chain alkylamino and wherein R3 is C1 -C4 alkyl, with the proviso that when Q is STR4 then R1 is C1 -C4 branched or straight chain alkyl; T is a bivalent radical selected from the group consisting of --(CHR)p -- and STR5 wherein p is an integer from 1 to 15, the moiety --(CHR)p -- represents an alkylene chain substituted at any position with one or more C1 -C10 alkyl groups or phenyl groups, and the moiety STR6 is bound with the oxygen atom attached directly to the aromatic ring; and Z is STR7 wherein R2 is hydrogen or C1 -C4 branched or straight chain alkyl and q is an interger from 4 to 7; in either the racemic or optically active forms.
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- Catalytic Asymmetric Cyclization of Some Bromohydrins with Chiral Cobalt Complex
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Asymmetric cyclization of a variety of bromohydrins with base was examined in the presence of an optically active cobalt(salen) type complex.Optically active oxiranes of modest optical purities were obtained. erythro-3-Bromo-2-butanol and threo-3-bromo-2-butanol were cyclized similarly, and only trans-2,3-dimethyloxirane and cis-2,3-dimethyloxirane were obtained, respectively, indicating that the cyclization of bromohydrin proceeds by complete SN2 type reaction.
- Takeichi, Tsutomu,Takakura, Teruo,Ishimori, Michihiro,Tsuruta, Teiji
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p. 603 - 605
(2007/10/02)
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- CONVERSION OF EPOXIDES TO BROMOHYDRINS BY B-BROMOBIS(DIMETHYLAMINO)BORANE
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Reaction of the title reagent with 1-alkene oxides regioselectively yields the corresponding 1-bromo-2-alkanols, while the more substituted bromide predominates in the cases of styrene oxide and 1-methylcyclohexene oxide.
- Bell, Thomas W.,Ciaccio, James A.
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p. 827 - 830
(2007/10/02)
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- DILITHIUM TETRABROMONICKELATE (II) AS A SOURCE OF SOFT NUCLEOPHILIC BROMIDE: REACTION WITH EPOXIDES
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Dilithium tetrabromonickelate (II) in THF serves as a source of "soft" nucleophilic bromide and reacts regioselectively with epoxides to give bromohydrins in high yield.
- Dawe, Robert D.,Molinski, Tadeusz F.,Turner, John V.
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p. 2061 - 2064
(2007/10/02)
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- Optical resolution, absolute configuration, and activity of the enantiomers of proxyphylline
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The enantiomers of proxyphylline have been separated via their corresponding camphanates. Synthesis of (+)-proxyphylline from theophylline and (S)-propylene oxide derived from (S)-lactic acid established the absolute configuration of the (+) and (-) isomer as S and R, respectively. The activity of the enantiomers as cyclic nucleotide phosphodiesterase inhibitors was tested in human lung tissue homogenate. No differences were found either between the two enantiomers or between the enantiomers and racemic proxyphylline.
- Selvig,Ruud Christensen,Aasen
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p. 1514 - 1518
(2007/10/02)
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