- Metal complex catalysts and method for catalytically reducing carboxylic acids
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The invention relates to a metal complex catalyst, which contains at least one of metal complexes with a chemical formula comprising a structural unit represented by a formula I. According to the invention, the center metal of the metal complex catalyst is iridium, and the metal complex catalyst is composed of pentamethylcyclopentadienyl, a bitetrahydropyrimidine ligand and proper coordination anions; the metal complex catalyst has activity on a carboxylic acid reduction reaction, and a carboxylic acid compound is reduced into an alcohol compound in the presence of hydrogen; and the method ismild in reaction condition, can be carried out at room temperature, and is good in catalytic performance and high in reduction product yield.
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Paragraph 0156; 0161; 0162; 0178; 0179
(2020/06/20)
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- Cobalt Pincer Complexes for Catalytic Reduction of Carboxylic Acid Esters
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A selection of cobalt(I) and cobalt(II) pincer type complexes with different substitution patterns was tested in the catalytic reduction of carboxylic acid esters to alcohols. The cobalt pincer type complex 4 is suitable for the hydrogenation of aromatic as well as aliphatic and cyclic esters. Mechanistic investigation indicated a metal ligand cooperated reaction pathway.
- Junge, Kathrin,Wendt, Bianca,Cingolani, Andrea,Spannenberg, Anke,Wei, Zhihong,Jiao, Haijun,Beller, Matthias
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supporting information
p. 1046 - 1052
(2018/01/01)
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- Selective Hydrogenation of Carboxylic Acids to Alcohols or Alkanes Employing a Heterogeneous Catalyst
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The chemoselective hydrogenation of carboxylic acids to either alcohols or alkanes is reported, employing a heterogeneous bimetallic catalyst consisting of rhenium and palladium supported on graphite. α-Chiral carboxylic acids were hydrogenated without loss of optical purity. The catalyst displays a reverse order of reactivity upon hydrogenation of different carboxylic functions with esters being less reactive than amides and carboxylic acids. This allows for chemoselective hydrogenation of an acid in the presence of an ester or an amide function.
- Ullrich, Johannes,Breit, Bernhard
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p. 785 - 789
(2018/02/14)
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- Synthesis method of analgesic intermediate bromomethyl cyclobutane
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The invention relates to a synthesis method of analgesic intermediate bromomethyl cyclobutane. The synthesis method comprises the following steps: by taking ethylene and acrylic acid as starting materials, carrying out Diels-Alder reaction to obtain cyclobutanecarboxylic acid, then reducing to obtain cyclobutanemethanol, and then brominating to obtain high-purity bromomethyl cyclobutane, wherein the total yield reaches more than 65%. The synthesis method provided by the invention has the advantages of available raw materials, mild reaction conditions, simple postprocessing operation, small environmental pollution, short reaction time, high reaction operational safety, high reaction yield, good product quality and low cost, and industrial production is facilitated.
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Paragraph 0009; 0010; 0011; 0012; 0013; 0014
(2017/07/21)
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- Hydrogenation of esters to alcohols with a well-defined iron complex
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We present the first base-free Fe-catalyzed ester reduction applying molecular hydrogen. Without any additives, a variety of carboxylic acid esters and lactones were hydrogenated with high efficiency. Computations reveal an outer-sphere mechanism involving simultaneous hydrogen transfer from the iron center and the ligand. This assumption is supported by NMR experiments.
- Werkmeister, Svenja,Junge, Kathrin,Wendt, Bianca,Alberico, Elisabetta,Jiao, Haijun,Baumann, Wolfgang,Junge, Henrik,Gallou, Fabrice,Beller, Matthias
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supporting information
p. 8722 - 8726
(2014/08/18)
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- Hydroesterification of alkenes with sodium formate and alcohols promoted by cooperative catalysis of Ru3(CO)12 and 2-pyridinemethanol
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(Figure Presented) A chelation-assisted hydroesterification reaction of alkenes with sodium formate and alcohols that involves cooperative catalysis by Ru3(CO)12 and 2-pyridinemethanol is described. In this three-component coupling reaction, sodium formate serves as the carbon monoxide source.
- Kim, Dong-Su,Park, Woo-Jin,Lee, Chang-Hee,Jun, Chul-Ho
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p. 12191 - 12196
(2015/01/09)
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- Iron-catalyzed reduction of carboxylic esters to alcohols
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A novel catalytic system formed from Fe(stearate)2/NH 2CH2CH2NH2 and polymethylhydrosiloxane was directly developed for the hydrosilylation of carboxylic acid esters to alcohols. The catalytic method exhibits broad substrate scope, including 20 aliphatic, aromatic, and heterocyclic esters. The corresponding alcohols are obtained in moderate to very good yields. The first iron-catalyzed hydrosilylation of carboxylic acid esters to alcohols is described. A catalytic system formed by Fe(stearate)2/NH 2CH2CH2NH2 and polymethylhydrosiloxane (PMHS) is used for this transformation, which has a broad substrate scope, including 20 aliphatic, aromatic, and heterocyclic esters. The corresponding alcohols are obtained in moderate to very good yields. Copyright
- Junge, Kathrin,Wendt, Bianca,Zhou, Shaolin,Beller, Matthias
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p. 2061 - 2065
(2013/05/09)
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- Preparation, characterization and use of 1,3-disulfonic acid imidazolium hydrogen sulfate as an efficient, halogen-free and reusable ionic liquid catalyst for the trimethylsilyl protection of hydroxyl groups and deprotection of the obtained trimethylsilanes
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Novel 1,3-disulfonic acid imidazolium hydrogen sulfate, a halogen-free ionic liquid, is a recyclable and eco-benign catalyst for the trimethylsilyl protection of hydroxyl groups at room temperature under solvent free conditions to afford trimethylsilanes in excellent yields (92-100%) and in very short reaction times (1-5 min). Deprotection of the resulting trimethylsilanes can also be achieved using the same catalyst in methanol. The catalyst was characterized by IR, 1H NMR, 13C NMR and MS studies. All the products were extensively characterized by IR, 1H NMR, MS, and elemental and melting point analyses. This new method consistently has the advantages of excellent yields and short reaction times. Further, the catalyst can be recovered and reused for several times without loss of activity. The work-up of the reaction consists of a simple separation, followed by concentration of the crude product and purification.
- Shirini, Farhad,Khaligh, Nader Ghaffari,Akbari-Dadamahaleh, Somayeh
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- Zinc-catalyzed chemoselective reduction of esters to alcohols
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Economical alcohols! A general and chemoselective catalytic reduction of esters to alcohols using inexpensive zinc acetate and silanes has been developed. The operational simplicity and the high functional group tolerance, without the need for protecting and deprotecting steps, make this procedure particularly attractive for organic synthesis. Copyright
- Das, Shoubhik,Moeller, Konstanze,Junge, Kathrin,Beller, Matthias
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experimental part
p. 7414 - 7417
(2011/08/05)
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- 4-aminopyrimidine derivatives
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This invention is 4-aminopyrimidine derivatives of the formula wherein R1, R2, R3 and R4 are as defined in the specification or a pharmaceutically acceptable salt thereof. The invention also is the preparation of compounds of formula I, pharmaceutical compositions containing therapeutically effective amounts of compounds of formula I or pharmaceutically acceptable salts thereof and to a method of treatment comprising administering therapeutically effective amounts of the compound of formula I for the prevention or treatment of mGluR5 receptor mediated disorders.
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- Resistance-modifying agents. 8. Inhibition of O6-alkylguanine-DNA alkyltransferase by O6-alkenyl-, O6-cycloalkenyl-, and O6-(2-oxoalkyl)guanines and potentiation of temozolomide cytotoxicity in vitro by O6-(1-cyclopentenylmethyl) guanine
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A series of O6-allyl- and O6-(2-oxoalkyl)guanines were synthesized and evaluated, in comparison with the corresponding O6-alkylguanines; as potential inhibitors of the DNA-repair protein O6-alkylguanine-DNA alkyltransferase (AGT). Simple O6-alkyl- and O6-cycloalkylguanines were weak AGT inactivators compared with O6-allylguanine (IC50 = 8.5 ± 0.6 μM)with IC50 values ranging from 100 to 1000 μM. The introduction of substituents at C-2 of the allyl group of O6-allylguanine reduced activity compared with the parent compound, while analogous compounds in the O6-(2-oxoalkyl)guanine series exhibited very poor activity (150-1000 μM). O6-Cycloalkenylguanines proved to be excellent AGT inactivators, with 1-cyclobutenylmethylguanine (IC50 = 0.55 ± 0.02 μM) and 1-cyclopentenylmethylguanine(IC50 = 0.39 ± 0.04 μM) exhibiting potency approaching that of the benchmark AGT inhibitor O6-benzylguanine (IC50 = 0.18 ± 0.02 μM). 1-Cyclopentenylmethylguanine also inactivated AGT in intact HT29 human colorectal carcinoma cells (IC50 = 0.20 ± 0.07 μM) and potentiated the cytotoxicity of the monomethylating antitumor agent Temozolomide by approximately 3- and 10-fold, respectively, in the HT29 and Colo205 tumor cell lines. The observation that four mutant AGT enzymes resistant to O6-benzylguanine also proved strongly cross-resistant to 1-cyclopentenylmethylguanine indicates that the O6-substituent of each compound makes similar binding interactions within the active site of AGT.
- Griffin,Arris,Bleasdale,Boyle,Calvert,Curtin,Dalby,Kanugula,Lembicz,Newell,Pegg,Golding
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p. 4071 - 4083
(2007/10/03)
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- General Synthesis of Methyl- and Dimethyl-cyclobutanes from Simple 1,3-Diols by Phase Transfer Catalysis
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A general method is described for the preparation of methyl- and dimethyl-cyclobutanes from simple 1,3-diols.The key steps of the procedure are a phase transfer catalysed ring closure and the transformation of a carboxyl group to a methyl group.Phase transfer catalysis provides good yields in the synthesis of the cyclobutane skeleton.
- Toeroek, Bela,Molnar, Arpad
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p. 801 - 804
(2007/10/02)
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- NEW ORGANOCOPPER REAGENTS PREPARED UTILIZING HIGHLY REACTIVE COPPER
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Highly reactive copper solutions have been prepared by the lithium naphthalide reduction of copper(I) iodide/trialkylphosphine complexes.These activated copper solutions will react with organic halides under very mild conditions to form stable organocopper reagents.Significantly, the organocopper reagents can contain considerable functionalities such as ester, nitrile, chloride, epoxide, and ketone groups.These functionalized organocopper species undergo many reactions typical of other organocopper species.Intermolecular 1,4-additions, epoxide-opening reactions, and ketone formation with acid chlorides have been successfully achieved.In addition, this methodology has been applied to an intramolecular epoxide-cleavage reaction.The influence of the connecting chain length, substitution pattern, reaction solvent, and CuI/phosphine complex upon the regioselectivity of the intramolecular cyclization is described.
- Rieke, Reuben D.,Wehmeyer, Richard M.,Wu, Tse-Chong,Ebert, Greg W.
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p. 443 - 454
(2007/10/02)
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- Synthesis and Liquid Crystal Properties of Dimethylene Linked Compounds Incorporating the Cyclobutane or Spiroheptane Rings
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The preparation of sixteen dimethylene linked compounds is described heptane ring>, and a comparison is made between the transition temperatures of these compounds and those of the corresponding esters.This comparison once again highlights the fact that the cyclobutane ring should be regarded, in terms of its ability to promote nematic thermal stability, as a "chain stiffener rather than as a ring system.A comparison is also made of the nematic thermal stabilities of the trans-cyclobutane and the spiroheptane systems and of the trans-cyclohexane and the spiroundecane systems.
- Chan, L. K. M.,Gemmell, P. A.,Gray, G. W.,Lacey, D.,Toyne, K. J.
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p. 229 - 246
(2007/10/02)
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- DIRECT FORMATION OF EPOXYALKYLCOPPER REAGENTS FROM ACTIVATED COPPER AND EPOXYALKYL BROMIDES AND THEIR INTRAMOLECULAR CYCLIZATIONS
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Epoxyalkylcopper compounds have readily been prepared by the direct oxidative addition of active copper to epoxyalkyl halides.The intramolecular cyclization of the epoxyalkylcopper reagents via an epoxide cleavage process is described.Significantly, many functional groups can be present in the bromoepoxides yielding highly functionalized carbocycles.The regioselectivity of this cyclizations is affected by the connecting chain length, substitution pattern, reaction solvent, and the CuI-phosphine complex used to generate the copper.
- Wu, Tse-Chong,Rieke, Reuben D.
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p. 6753 - 6756
(2007/10/02)
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- REGIOCHEMISTRY OF THE METAL-HALOGEN EXCHANGE INDUCED CYCLIZATION OF ω-IODOEPOXIDES
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The regiochemistry of the cyclization reactions of some ω-lithioepoxides as a function of chain length and substitution pattern has been examined.Striking changes in regiochemistry have been observed in the presence of certain Lewis acids and metal halides.
- Cooke, Manning P.,Houpis, Ioannis N.
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p. 3643 - 3646
(2007/10/02)
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- Solvent Effects on Solvolytic Reactivity. A Diagnostic Test for Neighboring-Group Assistance by ? Conjugation in Solvolysis Reactions
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The solvolysis rates of 13 arenesulfonates have been determined in mixtures of ethanol and water (the E-series solvents) and acetic acid and formic acid (the A-series solvents).The substrates studied include the following: neophyl (1), 2-adamantyl (2), neopentyl (3), and cyclooctyl (4) tosylates; cyclopropylcarbinyl pemsylate (5a) and tosylate (5b); exo-2-norbornyl tosylate (6); cyclobutylcarbinyl (7), cyclobutyl (8), and pinacolyl (9) brosylates; cyclopentyl (10), cyclohexyl (11), and 2-propyl (12) tosylates; and cyclopentylcarbinyl brosylate (13).Correlations of the rate data by eq 1 t(Y) = a + b log kt(neophyl-OTs)> showed that the various substrates responded differently to the examined solvent effects on the solvolytic reactivity.For compounds 2-4, linear correlations were obtained.For compounds 5-9, E-line, A-line dispersions were noted which diverged with increasing ionizing power; for compounds 10-12, parallel E-line, A-line dispersions were obtained; and for compound 13, an E-line, A-line dispersion was observed which converged with increasing ionizing power.Stastistical analyses of the rate data correlations confirmed the significance of the E or A classification of data.The results are interpreted in terms of differences in the involvement of solvent in the transition state for those solvolyses assisted by bridging from those assisted by C-C ? bond hyperconjugation.
- Roberts, Donald D.
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p. 2521 - 2526
(2007/10/02)
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- RING CLEAVAGE REARRANGEMENT OF CYCLOBUTYLMETHYLBORANES
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Boranes derived from hydroboration of methylenecyclobutane with borane/THF, 9-borabicyclononane, and borane-methyl sulfide rearranged on heating in situ at 100-160 deg C to open chain structures.Products after oxidation were the unrearranged cyclobutylmethanol, and 4-penten-1-ol, 1,4-pentane-diol and 1,5-pentanediol.The unsaturated alcohol was the major product in reactions with a stoichiometric ratio of alkene to BH bonds, and the diols were formed with excess borane.With borane-methyl sulfide as hydroborating reagent, the rate of rearrangement at 100 deg C in triglyme was not significantly dependent upon the initial alkene/borane ratio (3/1 or 1.15/1) or the presence of excess methyl sulfide.However, an equivalent amount of pyridine prevented rearrangement.Rearrangement in THF using borane/THF also occurred at comparable rates in the presence and absence of excess borane.Little or no isomerization of the boron function into the cyclobutane ring was observed.Results are interpreted on the basis of a concerted four-center mechanism which requires a vacant boron orbital.
- Hill. E. Alexander,Nylen, Patricia A.,Fellinger, John H.
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p. 279 - 292
(2007/10/02)
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- Importance of the Aromatic Ring in Andrenergic Amines. 5. Nonaromatic Analogues of Phenylethanolamine as Inhibitors of Phenylethanolamine N-Methyltransferase: Role of Hydrophobic and Steric Interactions
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The synthesis of five classes of nonaromatic analogues of β-phenylethanolamine and an evaluation of their inhibitory potency (IC50) for phenylethanolamine N-methyltransferase (PNMT) are described.The key intermediates for the synthesis of the ethanolamines were the appropriate aldehydes or ketones.The aldehydes 11a (cyclobutyl) and 13a (cycloheptyl) of type A were prepared from the correspondingacids by reduction of the acid to the alcohol with lithium aluminum hydride and oxidation of the alcohol to the aldehyde with pyridinium chlorochromate (PCC).The aldehydes 15a (cycloundecyl) and 41a (adamantyl) of type A were prepared by oxidation of the corresponding alcohols with PCC.The first reported synthesis of cyclononanecarboxaldehyde (type A, 14a) is described.This aldehyde was prepared via a multistep route beginning with a Favorskii rearrangement of 2-bromocyclodecanone to cyclononanecarboxylic acid.The acid was reduced with lithium aluminum hydride to the corresponding alcohol, which was subsequently oxidized to the aldehyde with PCC.The aldehydes or ketones were converted (with trimethylsilyl cyanide) into their cyanohydrin ethers, which were subsequently reduced to the desired ethanolamine with lithium aluminum hydride.The ethanolamines were tested as inhibitors (LCEC assay) of PNMT.The most potent inhibitors were the type A compounds 8 (cyclooctyl), 13c (cycloheptyl), 14c (cyclononyl), and 15c (cycloundecyl) and the type D compounds 26c (cyclononyl) and 27c (cycloundecyl) with IC50 values from 6 to 17 μM.It isconcluded that the binding site of PNMT accepts hydrophobic groups of an optimal length (ca. 6.4 Angstroem) and width (ca. 2.5 Angstroem) and has a significant height restriction for the hydrophobic group.The ethanolamine side chain prefers to lie away from and in the longitudinal axis of the hydrophobic group.An ethanolamine side chain attached to a cycloalkyl ring of n carbon atoms (types A and D) is almost always considerably more potent at inhibiting PNMT than the open-chain compounds of n total carbon atoms (types B, C, and E).
- Vincek, William C.,Aldrich, Constance S.,Borchardt, Ronald T.,Grunewald, Gary L.
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- ALICYCLISCHE VERBINDUNGEN-V. DARSTELLUNG DIVERSER 1,3-BUTADIENYLCYCLOBUTANE
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cis-(3) and trans-1,3-Butadienylcyclobutane (4), all-trans-1-(1,3-butadienyl)-2-vinylcyclobutane (10), and all-trans-1,2-bis(1,3-butadienyl)cyclobutane (15) have been prepared from readily available starting materials, and pyrolyzed to various cyclohexenes.
- Schuell, Volker,Hopf, Henning
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p. 3439 - 3442
(2007/10/02)
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- Cyclobutyl substituted derivatives of prostaglandin analogs
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Novel C15 cyclobutyl analogs or derivatives of prostaglandins of the E-, A- and F-classes are useful modifiers of smooth muscle activity. The compounds have valuable pharmacological properties such as platelet antiaggregating agents, gastric antisecretory agents and brochodilating agents.
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- N-alkyl-14-hydroxymorphinans and derivatives
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There is provided a novel and high yield procedure for transforming acid salts of 14-alkanoyloxymorphinans and derivatives thereof into the corresponding N-alkyl-14-hydroxymorphinans wherein the alkyl moiety on the nitrogen contains the same number of carbon atoms as that previously in the 14-alkanoyl moiety. In the process of the present invention, the acid is neutralized to the free base, the alkanoyl moiety at the 14-oxy then spontaneously shifts to the nitrogen and is subsequently reduced to the corresponding alkyl moiety. O-dealkylation at C-3, where an alkoxy group is originally present, is carried out in the usual manner. There is also provided a readily produced and readily disassociated adduct of the corresponding 14-hydroxy-N-alkanoyl morphinan-6-alkylene ketal with benzene, tetrahydrofuran, and the like.
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- Alumina: Catalyst and support. XL (1) ring expansion during the dehydration of alcohols over alumina catalysts (2)
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An investigation of ring expansion during the alumina-catalyzed dehydration of alcohols was made by the micro-pulse technique. The dehydration at 380 °C over fresh alumina of cyclobutane-, cyclopentane-, cyclohexane-, and cycloheptane-methanol yielded 99, 55, 7, and 6% of ring-expanded product, respectively, whereas over alumina which has been deactivated by passing large quantities of alcohol over it, 100, 74, 19, and 18% of the ring-expanded products were found. The stereochemical aspects of this catalytic reaction were investigated by the dehydration of cis- and trans-4-t-butylcyclohexanemethanol. More ring expansion and a higher conversion to olefins occurred in the dehydration of the cis alcohol than of the trans alcohol. In the dehydration of 1-methyl-1-cyclohexanemethanol at 310 °C, 60% of product formation involved methyl migration whereas 40% involved ring expansion. The percentage of ring expansion increased to 55 when deactivated catalyst was used. More skeletal rearrangement was found in dehydrations over alumina which had been deactivated by passing either an unsaturated or a saturated hydrocarbon over it than when fresh catalyst was used. Although the presence of sodium ions or pyridine on the catalyst lowered the amount of double bond isomerization which occurred, it did not affect the amount of skeletal rearrangement or the deactivation of the catalyst. The dehydration of 2-methylpropanol over alumina catalyst was reinvestigated and it was found that the extent of skeletal isomerization to produce n-butenes increases with the deactivation of the aluminas.
- Pines, Herman,Brown, Stanley M.
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