Ethyl (1R∗,3aS∗,7aS∗)-Octahydro-7a-methyl-7-oxo-1H-indene-1-acetate Using Tandem Reactions

The title compound was prepared in 29.5% overall yield using a five-step sequence involving two tandem reactions. The current work supports the earlier finding that a strong thermodynamic preference exists for an all-cis relationship across the three contiguous stereocenters at C(1), C(3a), and C(7a).     

Eine photometrische Bestimmung von 5-Ketoglucons?ure mit 1-Methyl-1-phenylhydrazin

Ohne Zusammenfassung     

Eine photometrische Bestimmung von 5-Ketogluconsäure mit 1-Methyl-1-phenylhydrazin

Analytical and Bioanalytical Chemistry -     

Synthesis of 1,2,3,4-Tetrahydro-1-Indolizinones and 3-Methyl-1,2-dihydro-1-Pyrrolizinones

lthasbeenrePortedthat1,2dihydro-1-pyrmIizinone(1)andsomeofitsderivativesshowedsignificantanaIgesicandantiinnammatory.Cti.iti..ll1.Theketonewassynthesizedfrom3(1-pyrmIyI)propanenitriIe(2)byanimprovedHoesCh'sprocedure.lnoedertostudythestruCture-aCtivityreIationshipdeepIy,theanaIogueoftheketone,1,2,3,4-tetrahydro-1-indolizinone(3)andsomeofitsderivativesweredesignedandsynthesized.ComPOund3wnsfirstsynthesizedbyG.R.CIemoet.aI.withHoeSChreaCtionfrom4-(1-pyrrolyI)bUtanenitriIe(4)m.ThenitriI…     

Synthese des 1-Methyl-2-äthyl- und des 1-Äthyl-2-methylnaphthalins

Ohne Zusammenfassung     

3,4-Benzoxanthene, 4. Mitt.: Synthese und Oxydation von 1-Methyl-, 2-Methyl-, 1,3′-Dimethyl- und 7-Brom-3,4-benzo-xanthen

Zusammenfassung 1-Methyl-, 2-Methyl- und 1,3-Di-methyl-3,4-benzoxanthen wurden durch Erhitzen von 3-Methyl- bzw. 4-Methyl- bzw. 3,7-Di-methyl-2-(2-methoxybenzyliden)-1-tetralon mit geschmolzenem Kaliumbisulfat und Natriumsulfat gewonnen. Auch 7-Brom-3,4-benzoxanthen wurde auf diesem Wege hergestellt. Die genannten 3,4-Benzoxanthene wurden zu den entsprechenden 3,4-Benzoxanthonen oxydiert.3. Mitt.: J. Chem. Soc. [London]1953, 893.     

Photo-induced Coupling Reaction of 1, 1-Diphenyl-2, 2-dicyanoethylene with 10-Methyl-9, 10-dihydroacridine

In a previous communication1, we reported a novel photo-induced coupling of 9-fluorenylidenemalononitrile 1 with the coenzyme NADH model 10-methyl-9, 10-dihydroacridine (AcrH2) to give 9-dicyanomethyl-9-(10-methyl-9-acridinyl)fluorene and proposed a mechanism involving photo-induced electron transfer-proton transfer and radical coupling. This is a scarce mechanism for the reaction of NADH models2, which usually takes place by a formal hydride transfer pathway3. In view of the novelty of t…     

Vibrational spectra of β-lactams—II. 1-Methyl-2-azetidinone and its deuterated compounds

The i.r. and Raman spectra of 1-methyl-2-azetidinone and its 3,3-d₂ and methyl-d₃ compounds have been recorded, and the observed bands have been assigned on the basis of the isotope effects and the normal coordinate analysis. Comparison of the CO and CN force constants between 2-azetidinone and 1-methyl-2-azetidinone indicates that, depending on amide resonance, these constants are related to each other. The solvent effects on the CO frequencies of four to seven-membered lactams have also been examined.     

Methyl 2,6-Dideoxy-4-α-Methyl-α-D-Arabino-Hexopyranoside

Abstract

Synthesis of methyl 2,6-dideoxy-4-O-methyl-α-D-arabino-hexopyranoside (2) has been accomplished starting from readily available methyl 2-deoxy-α-D-arabino-hexopyranoside (3). The derived 4,6-dimesylate derivative 7 was simultaneously deoxygenated and hydrolysed at C-6 and C-4 with lithium aiuminatm hydride in refluxing tetrahydrofuran. subsequent methyíaíion and debenzy[icaron]ation of 8 gave the title product.     

Theoretical Study on Ionic Liquid Based on 1-Ethyl-3-Methyl- Imidazolium Cation and Hexafluorophosphate or Tetrafluoroborate

The Hartree-Fock and DFT/B3LYP methods have been employed to investigate the electronic structures of 1-ethy1-3-methyl-imidazolium cation(EMIM~ ),BF_4~-,PF_6~-,EMIM~ -BF_4~-,and EMIM~ -PF_6~- using the Gaussian-94 soft-package at 6-31 G(d,p)basis set level for hydrogen,carbon,nitrogen,boron, phosphorus,and fluorine atoms.Comparison of the electronic structures of the lowest energy of EMIM~ - BF_4~- and EMIM~ -PF_6~- pairs,and single EMIM~ ,BF_4~- and PF_6~- showed that the optimized EMIM~ -BF_4~- and EMIM~ -PF_6~- pair conformers were BF_4~- and PF_6~- outside the 5-ring plane between the ethyl group and the methyl group.The cohesion of C—H…F hydrogen bond between cation and anion is reinforced by charge assistance.The interaction energy between EMIM~ and PF_6~- is 328.8 kJ/mol at the B3LYP level and 326.6 kJ/mol at the Hartree-Fock level,whereas that between EMIM~ and BF_4~- is 353.5 kJ/mol at the B3LYP level and 350.5 kJ/mol at the Hartree-Fock level.The low energy interactions caused by bulky asymmetric EMIM~ ,and charge dispersion of cation and anion give rise to the low melting point of ionic liquid EMIM~ -BF_4~- and EMIM~ -PF_6~-.The two hydrogen bonding models of single hydrogen bond formation,and the hydrogen transfer between C_2 in EMIM~ and F in BF_4~- or PF_6~- were principally depicted.     

Experimental Study of Vapor–Liquid Equilibrium Data for Acetone + Methanol + 1-Methyl-3-octylimidazolium Thiocyanate

An experimental study on the isobaric vapor–liquid equilibria for the ternary system of acetone?+?methanol?+?1-methyl-3-octylimidazolium thiocyanate ([Omim][SCN]) as well as the two acetone?+?ionic liquid (IL) and methanol?+?IL binary systems was performed at 100 kPa using a recirculating still (VLE 602 Fischer apparatus). A low IL mole fraction of 0.027 was found to be sufficient break the azeotrope due to the high and specific interactions with acetone and methanol. The nonrandom two-liquid model was used to represent the experimental data. The results are compared with those in the literature for the same mixed solvent system using other ILs.     

Synthesis of (22R,23R,24S)-24-Methyl-5α-cholestane-3β,6α,22,23-tetraol, a Biosynthetic Precursor of Brassinolide

A biosynthetic precursor of brassinolide, (22R,23R,24S)-24-methyl-3-cholestane-3,6,22,23-tetraol was synthesized from ^{2 3}-22-keto steroid which was obtained from the corresponding 20-carbonitrile oxide. The side chain was built up by a series of successive transformations: hydride reduction of the initial enone, epoxidation of the allyl-like alcohol, and copper(I) cyanide-catalyzed opening of the 23,24-epoxy ring. The cyclic fragment was completed by opening of the cyclopropane ring with subsequent hydroboration and oxidation of the ⁵-bond.     

Synthesis and Characterization of Novel 4-Methyl-3-isoxazolidinone Derivatives

IntroductionSulfonylureas, as inhibitors of acetohydroxyacidsynthase(AHAS), are a class of herbicides that areused for crop protection. They are used for lowconcen-tration ranges(10—100 g of active ingredient/ha) andare advanced herbicides used in agricu…     

Eine weitere Synthese des 4-Methyl-2,3,6-triacetyl-β-d-methylglucosids

Zusammenfassung Bei der Herstellung von Derivaten der 4-Methylglucose wurde in den meisten Fällen von Glucosederivaten ausgegangen, die mehrere Hydroxylgruppen vor der Methylierung frei haben. Im allgemeinen werden daher Gemische methylierter Produkte erhalten, auch wenn eine selektive Methylierung weitgehend gelingt. Gewisse Unstimmigkeiten bei Angaben über Abkömmlinge der 4-Methylglucose ließen es wünschenswert erscheinen, eine weitere Synthese auszuarbeiten, bei der Methylierung mit Sicherheit nur in Stellung 4 eintreten kann.Herrn Prof. Dr.F. Wessely zum 60. Geburtstag in herzlicher Freundschaft gewidmet (A. W.).     

Synthesis and Crystal Structure of N-[1-（2-Methyl-1-methylcarbamoyl- propylcarbamoyl）-2,3-diphenyl- cyclopropyl]-benzamide

N-[1-（2-Methyl-1-methylcarbamoyl-propylcarbamoyl）-2,3-diphenyl-cyclopropyl]-ben- zamide, C29H31N3O3, has been synthesized and characterized by IR, ^1H NMR, ^13C NMR and singlecrystal X-ray diffraction. The crystal is of orthorhombic, space group P212121 with a = 11.0855（11）, b = 18.7756（19）, c = 24.434（2）A, V = 5085.5（9）A^3, Z = 8, Mr = 469.57, Dc = 1.227 g/cm^3, λ = 0.71070 A,μ（MoKα） = 0.080 mm^-1, F（000） = 2000, the final R = 0.0579 and wR = 0.1111 for 4569 observed reflections with I 〉 2σ（I）. The N-H and oxygen atom are involved in intermolecular hydrogen bonds which link the molecules into a one-dimensional chain.     

Studies on Semisynthesis and Anibacterial Activity of 7 β-(5-Methyl-1-Aryl-1H-1,2,3-Triazoly-4-Carboxamido) Cephalosporins

CpeoSPOrinderivativeshavebeenextensivelyinvestigatedduetotheirbroad-SPeCtrUInbiologicalactivities,enormousctricalandcommercialtwOrtance.mshasattraCtedtheattenonofchendstsandPliannacologistSdsareinterestedinchdricaimodificationofcePhalosPorinbackbeeforborovingitSactivityagainsbothGram-positiveandGramwtvel'-'].Durckh.ho.l'lpointedouttlia76-heterocyclicgrouPsubstitutedcePhaloSPorinsexhiitedmorestrijdnyanti-Inicrobialachvitythanthaof7o.-alkyUarylated-alkylsubshforedcePhaloSPoms.Actually,…     

ΔENT Values for 1-Methyl-2-pyrrolidinone--SolventBinary Mixtures at 20, 30, and 50 °C

E ^N _T values were determined for 8 1-methyl-2-pyrrolidinone--solvent mixturesover the whole mole fraction range at 20, 30, and 50°C. The solvents used wereacetone, dimethyl sulfoxide, 2-propanol, 1,2-dichloroethane, water, 1,4-dioxane,benzyl alcohol, and hexamethylphosphoric triamide. The E ^N _T values werepositive for the NMP + solvent systems, except for the NMP + water system.     

Densities and Volumetric Properties of Butyl Acrylate + 1-Butanol, or +2-Butanol, or +2-Methyl-1-propanol, or +2-Methyl-2-propanol Binary Mixtures at Temperatures from 288.15 to 318.15 K

The densities, ρ, of binary mixtures of butyl acrylate with 1-butanol, 2-butanol, 2-methyl-1-propanol, and 2-methyl-2-propanol, including those of the pure liquids, were measured over the entire composition range at temperatures of (288.15, 293.15, 298.15, 303.15, 308.15, 313.15, and 318.15) K and atmospheric pressure. From the experimental data, the excess molar volume $ V_{\text{m}}^{\text{E}} $ V m E , partial molar volumes $ \overline{V}_{\text{m,1}} $ V ¯ m,1 and $ \overline{V}_{\text{m,2}} $ V ¯ m,2 , and excess partial molar volumes $ \overline{V}_{\text{m,1}}^{\text{E}} $ V ¯ m,1 E and $ \overline{V}_{\text{m,2}}^{\text{E}} $ V ¯ m,2 E , were calculated over the whole composition range as were the partial molar volumes $ \overline{V}_{\text{m,1}}^{^\circ } $ V ¯ m,1 ° and $ \overline{V}_{\text{m,2}}^{^\circ } $ V ¯ m,2 ° , and excess partial molar volumes $ \overline{V}_{\text{m,1}}^{{^\circ {\text{E}}}} $ V ¯ m,1 ° E and $ \overline{V}_{\text{m,2}}^{{^\circ {\text{E}}}} $ V ¯ m,2 ° E , at infinite dilution,. The $ V_{\text{m}}^{\text{E}} $ V m E values were found to be positive over the whole composition range for all the mixtures and at each temperature studied, indicating the presence of weak (non-specific) interactions between butyl acrylate and alkanol molecules. The deviations in $ V_{\text{m}}^{\text{E}} $ V m E values follow the order: 1-butanol < 2-butanol < 2-methyl-1-propanol < 2-methyl-2-propanol. It is observed that the $ V_{\text{m}}^{\text{E}} $ V m E values depend upon the position of alkyl groups in alkanol molecules and the interactions between butyl acrylate and isomeric butanols decrease with increase in the number of alkyl groups at α-carbon atom in the alkanol molecules.