- Low-Temperature Reactions of Metal Atoms with Methyl Bromide
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The atoms of a series of metals were codeposited with CH3Br under matrix conditions (argon diluent at 12 K and pure CH3Br at 77 K).Oxidative addition of CH3Br to Fe, Co, Ni, and Pd did not occur upon simple codeposition or upon matrix photolysis, which is rationalized by the formation of a favored CH3Br-M complex.Cu, Ag, and Au behaved similary.Main-group metals Mg, Al, Ga, and In did react to form CH3MBr whereas Zn, Tl, Ge, Sn, and Pb did not.For the group 1B - 4B (Cu, Zn, B, C) families the most important reactivity parameter is a low ionization potential.However, a high heat of vaporization of the element also has a positive effect on reactivity.In the case of Mg, clusters may be necessary for high reactivity.
- Tanaka, Yasutaka,Davis, Stephen C.,Klabunde, Kenneth J.
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Read Online
- Method for preparing 1, 1 and 1 -trifluoro -2 -methyl -2 - propanol
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The invention discloses a method for preparing 1, 1 and 1 -trifluoro -2 -methyl -2 - propanol. To the method, methyl magnesium halide Grignard reagent is prepared from halogenated methane as a raw material in ether solvents, 1, 1 and 1 - trifluoroacetone are reacted in the presence of a catalyst to obtain 1, 1, 1 -trifluoro -2 -methyl -2 -propanol. The method has the advantages of easily available raw materials, convenience in post-treatment and purification, simplicity in operation, relatively low cost, high yield and the like.
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Paragraph 0042
(2021/12/07)
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- Cross-coupling of aryl/alkenyl silyl ethers with grignard reagents through nickel-catalyzed CO bond activation
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CO activation and its application have drawn much attention since oxygen-based electrophiles are easily available, less toxic, and more environmentally benign. This letter presents systematically results on the Ni-catalyzed KumadaTamaoCorriu coupling based on siloxy arenes/alkenes, which provides a new strategy of silyl protection/CC bond formation sequence in organic synthesis.
- Zhao, Fei,Yu, Da-Gang,Zhu, Ru-Yi,Xi, Zhenfeng,Shi, Zhang-Jie
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supporting information; experimental part
p. 1001 - 1003
(2011/12/05)
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- Enantioselective copper-catalysed allylic alkylation of cinnamyl chlorides by Grignard reagents using chiral phosphine-phosphite ligands
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The copper(I)-catalysed SN2'-type allylic substitution of E-3-aryl-allyl chlorides (cinnamyl chlorides) using Grignard reagents represents a powerful method for the synthesis of compounds carrying a benzylic stereocentre. By screening a small library of modular chiral phosphine-phosphite ligands a new copper(I)-based catalyst system was identified which allows the performance of such reactions with exceptional high degrees of regio- and enantioselectivity. Best results were obtained using TADDOLderived ligands (3 mol%), copper(I) bromide?dimethyl sulfide (CuBr?SMe2) (2.5 mol%) and methyl tert-butyl ether (MTBE) as a solvent. Various (1- alkyl-allyl)benzene derivatives were prepared with up to 99% ee (GC) in isolated yields of up to 99%. In most cases the product contained less than 3% of the linear regioisomer (except for ortho-substituted substrates). Both electron-rich and electron-deficient cinnamyl chlorides were successfully employed. The absolute configuration of the products was assigned by comparison of experimental and calculated CD spectra. The substrates were prepared from the corresponding alcohols by reaction with thionyl chloride. Initially formed mixtures of regioisomeric allylic chlorides were homogenised by treatment with CuBr?SMe2 (2.5 mol%) in the presence of triphenyl phosphine (PPh3) (3 mol%) in MTBE at low temperature to give the pure linear isomers. In reactions with methylmagnesium bromide (MeMgBr) an ortho-diphenylphosphanyl-arylphosphite ligand with an additional phenyl substituent in ortho'-position at the aryl backbone proved to be superior. In contrast, best results were obtained in the case of higher alkyl Grignard reagents (such as ethyl-, n-butyl-, isopropyl-, and 3-butenylmagnesium bromides) with a related ligand carrying an isopropyl substituent in ortho'-position. The method was tested on a multimmol scale and is suited for application in natural product synthesis.
- Loelsberg, Wibke,Ye, Shute,Schmalz, Hans-Guenther
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supporting information; experimental part
p. 2023 - 2031
(2010/10/21)
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- Interior surface modifications of molecular sieves with organometallic reagents and the use thereof for the conversion of oxygenates to olefins
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A method for making an organometallic treated molecular sieve is described in which a molecular sieve having at least one hydroxyl group and at least [AlO2] and [PO2] tetrahedral units and having an average pore dimension less than or equal to about 5? is contacted with a solution comprising an organometallic compound and a non-proton donating solvent. The resulting organometallic treated molecular sieve has enhanced ethylene and/or propylene selectivity when used in the conversion of organic oxygenates to olefins. The ethylene and/or propylene selectivity, as well as catalyst life, are further enhanced when the resulting organometallic treated molecular sieve is combined with an oxide of at least one metal selected from Groups 2, 3 and Group 4 of the Periodic Table.
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- Process for the preparation of alicyclic ketones and an alkyl-substituted alicyclic esters
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A high-purity alicyclic ketone which is a raw material for an alkyl-substituted alicyclic ester such as an alkyl adamantyl ester compound which is useful as a resist raw material can be obtained by a simple operation such as extraction without a special purification step such as distillation or recrystallization. In this process, when an alicyclic hydrocarbon is oxidized with concentrated sulfuric acid or fuming sulfuric acid, the reaction solution after oxidation is poured into water and a solid is extracted with an organic solvent, the concentration of sulfuric acid in the water layer at the time of extraction is adjusted to 60 to 90 wt % to carry out extraction so as to obtain an alicyclic ketone.
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- 2,3-oxidosqualene-lanosterol cyclase inhibitors
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The present invention relates to aminocyclohexanol derivatives useful for the treatment and/or prophylaxis of diseases which are associated with 2,3-oxidosqualene-lanosterol cyclase such as hypercholesterolemia, hyperlipemia, arteriosclerosis, vascular diseases, mycoses, gallstones, tumors and/or hyperproliferative disorders, and treatment and/or prophylaxis of impaired glucose tolerance and diabetes.
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- Adamantanemethanol derivatives and production processes thereof
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An adamantanemethanol derivative of the invention is represented by the following formula (1), wherein Rais a hydrogen atom or a hydrocarbon group; Rbis a hydrocarbon group having a carbon atom, to which carbon atom at least one hydrogen atom is bonded, at a bonding site with the adjacent carbon atom; Rc, Rdand Reare each a hydrogen atom, a hydroxyl group which may be protected by a protective group or the like; provided that a hydroxyl group protected by a protective group or the like is bonded to at least one carbon atom constituting the adamantane skeleton when Rais a hydrogen atom or a methyl group and Rbis a methyl group; and at least one substituent, in addition to the HO—C(Ra)(Rb)— group indicated in the formula (1), is bonded to the adamantane ring when one of Raand Rbis a methyl group and the other is an ethyl group.
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- An ESR and HPLC-EC assay for the detection of alkyl radicals
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The correlation of lipid peroxidation with release of alkanes (RH) is considered a noninvasive method for the in vivo evaluation of oxidative stress. The formation of RH is believed to reflect a lipid hydroperoxide (LOOH)-dependent generation of alkoxyl radicals (LO·) that undergo β-scission with release of alkyl radicals (R·). Alternatively, R· could be spin-trapped with a nitrone before the formation of RH and analyzed by ESR. Extracts from the liver and lung of CCl4- and asbestos-treated rats that were previously loaded with nitrones exhibited ESR spectra suggesting the formation of iso-propyl, n-butyl, ethyl, and pentyl radical-derived nitroxides. In biological systems, various nitroxides with indistinguishable ESR spectra could be formed. Hence, experiments with N-tert-butyl-α-phenylnitrone (PBN) for spin trapping of R· were carried out in which the nitroxides formed were separated and analyzed by HPLC with electrochemical detection (EC). The C1-5 homologous series of PBN nitroxides and hydroxylamines were synthesized, characterized by ESR, GC-MS, and HPLC-EC, and used as HPLC standards. For in vivo generation and spin trapping of R·, rats were loaded with CCl4 and PBN. The HPLC-EC chromatograms of liver extracts from CCl4-treated rats demonstrated the formation of both the nitroxide and hydroxylamine forms of PBN/·CCl3, as well as the formation of a series of unidentified PBN nitroxides and hydroxylamines. However, formation of PBN adducts with retention times similar to these of the PBN/C2-5 derivatives was not observed. In conclusion, we could not correlate the production of PBN-detectable alkyl radicals with the reported CCl4-dependent production of C1-5 alkanes. We speculate that the major reason for this is the low steady-state concentrations of R· produced because only a small fraction of LO· undergo β-scission to release R·.
- Novakov,Feierman,Cederbaum,Stoyanovsky
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p. 1239 - 1246
(2007/10/03)
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- Alkyl tetralin aldehyde compounds
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The present invention relates, inter alia, to novel alkyl tetralin aldehyde compounds having fragrant musk-like aroma.
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- Cat-1 inhibitors, pharmaceutical compositions and methods of use
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The invention relates to compounds of the formula STR1 wherein R1, R2, R2 ' X, Y, Z, A, B, Q and n are as described herein. Their pharmaceutically acceptable salts, and when appropriate, enantiomers, racemates, diastereomers or mixtures thereof or geometric isomer or mixtures thereof, and pharmaceutically acceptable salts thereof. The compounds of formula I inhibit enzyme carnitine acyltransferase 1 (CAT-1) and are therefore useful in the prevention of injury to ischemic tissue, and can limit infarct size, improve cardiac function and prevent arrhythmias during and following a myocardial infarction.
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- Formate ester indane compounds
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The present invention relates to novel formate ester indane compounds having fragrant musk-like aroma.
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- Tetralin formate ester aroma chemicals
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The present invention relates to novel formate ester tetralin compounds having fragrant musk-like aroma.
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- Proton Addition to Silylstyrenes: Overcoming the Predilection for Protiodesilylation
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Normally, organosilyl nucleophiles such as vinylsilanes and allylsilanes undergo protiodesilylation reactions with protons.To favour addition reactions under these conditions, the ligands on silicon have been modified such that the leaving group ability and, simultaneously, the β-effect of the silyl group is reduced.In the case of allylsilanes, the use of dichlorosilyl groups does not significantly favour addition over substitution processes at the olefin.However, with vinylsilanes bearing a second ?-nucleophile, a dichlorosilyl group can be used to regioselectively direct the formation of two bonds (C-H and C-C) sequentially in a process in which the silicon is not lost from the molecule, but may ultimately be cleaved leading to the formation of diols.Thus, benzyldichlorostyrylsilane 7, after cyclization to 9 in the presence of triflic acid, is converted into diol 12.The synthetic utility of this process is restricted by the relatively low reactivity of the styryl ?-system and the necessarily reactive electrophiles needed to initiate the process.The effect of changing from electron-donating groups to electronegative groups on silicon on reaction mechanism is discussed.
- Henry, Courtney,Brook, Michael A.
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p. 11379 - 11390
(2007/10/02)
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- Chemical synthesis
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A process for the production of disubstituted bile acid analogs, including the disubstituted analogs of such bile acids as, lithocholic, hyodeoxycholic, cholic, chenodeoxycholic and ursodeoxycholic acids. This invention was made in the course of work performed under a grant from the U.S. National Heart Lung and Blood Institute.
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- Arylcyclobutylmethylamines
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Compounds of formula I STR1 and pharmaceutically acceptable salts thereof; in which R1 and R2, which are the same or different, are H or an optionally substituted hydrocarbon group or R1 and R2 together with the nitrogen atom to which they are attached form an optionally substituted heterocyclic ring; R3 is an optionally substituted aromatic hydrocarbon group; and R4 is a hydrocarbon group containing at least one substituent selected from the group consisting of hydroxy and acylated derivatives thereof, optionally substituted alkoxy groups, optionally substituted cycloalkyloxy groups, optionally substituted alkylenedioxy groups, oxo and groups of formula S(O)p R5 in which p is 0, 1 or 2 and R5 is an alkyl group, said hydrocarbon group being optionally substituted by additional substituents, are useful in the treatment of depression.
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- SOME APPLICATIONS OF THE METHYLENE DI-GRIGNARD REAGENT FOR THE SYNTHESIS OF MAIN GROUP IV ORGANOMETALLIC COMPOUNDS
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The di-Grignard reagent methylenedimagnesium dibromide, CH2(MgBr)2 (1), which can be prepared from dibromomethane and magnesium amalgam in diethyl ether/benzene 1/1, has been obtained in a pure form.Treatment of 1 with tetrahydrofuran gave insoluble 5'', a reagent with the approximate composition CH2Mg*CH2(MgBr)2.Both reagents were used for the synthesis of the dimetallomethanes (Me3M)2CH2 (M = Si, Ge, Sn) and (CH2(HgBr)2.Reaction of 1 or 5'' with dichlorodimethylgermane or dichlorodimethylstannene gave the polygermacycloalkenes ((Me2GeCH2)n; n = 2,3,4) or polystannacycloalkenes ((Me2SnCH2)n; n = 3,4), respectively, in useful yields (10 to 35percent).In the germanium series, there is a pronounced tendency to form the smaller ring system; in particular, the reaction of 5'' with Me2GeCl2 gave 30-35percent of 1,1,3,3-tetramethyl-1,3-digermacyclobutane.In contrast, the corresponding distannacyclobutane was not observed, but the eight-membered species (Me2MCH2)4 was formed more readily for M = Sn (9percent yield) than for M = Ge (2percent yield).
- Bruin, J. W.,Schat, G.,Akkerman,O. S.,Bickelhaupt, F.
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- SYNTHESIS OF PREGNANE DERIVATIVES
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Pregnane derivatives have been obtained from the cyanohydrins of androst-4-en-3,17-dione and of 3β-acetoxyandrost-5-en-17-one.It has been shown that when both a nitrile group and an ethylenedioxy group are present in a androstane derivative a Grignard reaction in anisole takes place simultaneously at the two groups.
- Popova, E. V.,Andryushina, V. A.,Grinenko, G. S.
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p. 302 - 304
(2007/10/02)
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- Thermochemical Bond Dissociation Energies of Carbon-Magnesium Bonds
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The heats of formation of 29 alkylmagnesium bromides, isobutyl bromide, and neopentyl bromide have been determined, and bond dissociation energies have been derived for the Grignard reagents.For saturated alkyl derivatives the C-Mg bond strength decreases with an increasing number of β-hydrogens in the series methyl, neopentyl, isobutyl, butyl, ethyl, 1-ethylpropyl, 1-methylpropyl, isopropyl, and t-butyl.Bonding in alkyl bromides and alkylmagnesium bromides is discussed.
- Holm, Torkil
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p. 464 - 467
(2007/10/02)
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- Infrared Matrix Isolation Study of Magnesium Metal Atom Reactions. Spectra of an Unsolvated Grignard Species
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Reactions of magnesium atoms with methyl halides in argon matrices have given rise to four product bands which can be assigned to a new chemical species, at 543, 1305, 2800, and 2892 cm-1.All four are hydrogenic in nature, and are assigned to the four vibrations of a C3v methyl group in the reaction product.Evidence is presented for insertion of the magnesium atom into the carbon-halogen bond of the methyl halide to form a species H3CMgX, for X = Cl, Br, I.Similar reactions were observed with calcium and strontium atoms, while zinc atoms did not react with methylhalides under these conditions.No evidence was detected for a strong polar covalent carbon-magnesium bond, suggesting that the unsolvated Grignard reagent formed here has a structure other than that of the solvated solution species.
- Ault, Bruce S.
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p. 3480 - 3484
(2007/10/02)
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- Microbiological degradation of sterol side chains to a 17-keto group
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The side chains of sterols are degraded by fermentation with microorganisms capable of doing so in an improved manner by employing in such fermentations sterol derivatives of the formula STR1 wherein n is 1 or 2; R1 is H or lower alkyl, R2 is alkyl, whose chain optionally is interrupted by an oxygen atom, or when n is 2, also a hydrogen atom; and R3 is a sterol side chain.
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- Anesthesia methods using benzopyrans and esters thereof as pre-anesthesia medication
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Improved anesthesia methods comprising pretreating a patient to be anesthetized with a benzopyran of formula I STR1 wherein, in the C ring, X is NR1, S, CH2 or STR2 R1 is hydrogen, loweralkyl, loweralkenyl, loweralkynyl, loweralkanoyl, cycloalkyloweralkyl, cycloalkylloweralkanoyl, cycloalkyl, haloloweralkyl, haloloweralkenyl, phenylloweralkyl, phenyloweralkenyl or phenyloweralkylnyl; m is an integer from 0 to 3, n is an integer from 0 to 3 and n + m = 2 or 3; or the C ring is quinuclidine ring STR3 R2 is loweralkyl; R3 is hydrogen or STR4 wherein Y is a straight or branched chain alkylene group having from one to eight carbon atoms, a is an integer from 1 to 4, b is an integer from 1 to 4, Z is CH2, O, S or NR6, R6 being hydrogen or loweralkyl, with the limitation that when Z is O, S or NR5, the sum of a and b is 3 or 4, and R5 is hydrogen or loweralkyl; R4 is C1 -C20 straight or branched chain alkyl, cycloalkyl, or STR5 wherein Y is a straight or branched chain alkylene group having from one to ten carbon atoms, and each R7, R8 and R9 are the same or different members of the group consisting of hydrogen, halo, trifluoromethyl or loweralkyl; and the pharmaceutically acceptable salts thereof, with the limitation that when X is STR6 m = 2 and n = 2, R3 cannot be hydrogen.
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- Method of producing analgesia and compositions useful therein
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A method of relieving pain in a mammalian patient suffering therefrom by administering 1,2-dihydro-5,5-dimethyl-10-hydroxy-8-(3-methyl-2-octyl)-3H,5H-thiopyrano[2,3-c][1]benzopyran.
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- Method of treating hypertension with, and compositions useful therein containing, a 4H-thieno[2,3-c][1]benzopyran or a 3H,5H-thiopyrano[2,3-c][1]
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A method of reducing blood pressure in a hypertensive mammalian patient by administering 1,2-dihydro-4,4-dimethyl-9-hydroxy-7-(3-methyl-2-octyl)-4H-thieno[2,3-c][1]benzopyran or 1,2-dihydro-5,5-dimethyl-10-hydroxy-8-(3-methyl-2-octyl)-3H,5H-thiopyrano-8 2,3-c][1]benzopyran. Pharmaceutical compositions containing 1,2-dihydro-4,4-dimethyl-9-hydroxy-7-(3-methyl-2-octyl)-4H-thieno[2,3-c][1]benzopyran or 1,2-dihydro-5,5-dimethyl-10-hydroxy-8-(3-methyl-2-octyl)-3H,5H-thiopyrano[2,3-c][1]benzopyran dispersed in a pharmaceutical carrier.
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- Esters of thienobenzopyrans and thiopyranobenzopyrans
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Novel thienobenzopyran and thiopyranobenzopyran esters represented by the formula SPC1 Wherein n is 0 to 3 and m is 0 to 3 and m + n = 2 or 3, R1 is lower alkyl, R2 is alkyl or cycloalkyl-lower alkyl, R4 is hydrogen or lower alkyl, R5 is hydrogen or lower alkyl, and R3 is EQU1 wherein Y is a straight or branched chain C1 to C8 alkylene, R6 is hydrogen or a lower alkyl, a is an integer from 1 to 4, b is an integer from 1 to 4, X is CH2, O, S or NR7 wherein R7 is hydrogen or lower alkyl, with the limitation that when X is O, S or NR7, a and b each must be 2; and the acid addition salts thereof.
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- Heterocyclic esters of benzopyrans
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This invention relates to novel esters of benzopyrans represented by the formulae SPC1 Wherein R and R' are hydrogen or C1 -C6 alkyl and when alkyl are on the same or different carbons; R1 is C1 -C6 alkyl; R2 is C1 -C20 alkyl, lowercycloalkyloweralkyl or lowercycloalkyl; n is an integer from 3 to 7, and particularly 3 to 5; Y is a straight or branched chain C1 -C8 alkylene; and R3 is EQU1 WHEREIN A IS AN INTEGER FROM 1 TO 4, B IS AN INTEGER FROM 1 TO 4, X is O,S, CH2 or NR4 and R4 is hydrogen C1 -C6 alkyl, and R5 is hydrogen or C1 -C6 alkyl; and the acid addition salts thereof. The compounds exhibit analgesic and central nervous system activity.
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- Pharmaceutical compositions containing alryl substituted cyclopenta benzopyrans
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1,2,3,4-Tetrahydrocyclopenta[c] [1]benzopyrans of the formulae SPC1 Wherein R is a lower alkyl group having 1 to 5 carbons, R1 is hydrogen or a lower alkyl group having 1 to 5 carbons, R2 is a lower alkyl group and R3 is an alkyl group having 1 to 20 carbon atoms, a phenyl-lower alkyl group or a cycloalkyl-lower alkyl group. The compounds have anti-hypertensive, antidepressant, analgesic, anticonvulsant, anti-anxiety and tranquilizing activity in animals.
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