Photochemical reactivity of α,β-unsaturated δ-lactams: Synthesis of seco-steroids. Photochemical reactions. XIII [1]

The UV. irradiation of 17 β-hydroxy-2-aza-4-androsten-3-one (1) , N-methyl-17 β-hydroxy-2-aza-4-androsten-3-one (3) , 17 β-hydroxy-4-aza-5 β-androst-1-en-3-one (2) and N-methyl-17 β-hydroxy-4-aza-5 β-androst-1-en-3-one (4) , gives rise to 1,10-seco (from 1 and 3 ) and 5, 10-seco (from 2 and 4 ) steroids.     

Synthese eines steroidischen 17 β-Pyrrolinons. Partialsynthetische Versuche in der Reihe der Herzgifte. 10.Mitteilung

Synthesis of a steroidal 17 β-pyrrolinone We describe the synthesis of 4′-(3 β-hydroxy-androst-5-ene-17 β-yl)-3′-pyrrolin-2′-one (6) starting from 3β-acetoxy-21-hydroxy-pregn-5-ene-20-one (1).     

Synthese und IR.-spektroskopische Identifizierung epimerer 3-Äthinyl-5 α-cholestan-3-ole

Synthesis and IR. Spectroscopic Identification of Epimeric 3-Ethinyl-5α-cholestan-3-ols The syntheses of the 3β-ethinyl-5α-cholestan-3α-ols 2a, 2b, 2c and of the corresponding epimeric 3α-ethinyl-5 α-cholestan-3 β-ols 3a, 3b, 3c are described. Bands at 1000 cm^?1 for the α-alcohols and at 1030 cm^?1 for the β-alcohols are found to be useful for the IR. spectroscopic identification of epimeric 3-ethinyl-5α-cholestan-3-ols.     

Theoretical calculations of β-lactam antibiotics. III. AM1, MNDO,and MINDO/3 calculations of hydrolysis of β-lactam compound (azetidin-2-one ring)

Semiempirical AM1, MINDO/3, and MNDO methods have been used in the study of the alkaline hydrolysis of β-lactam antibiotics through a base-catalyzed, acyl-cleavage, bimolecular mechanism. In this work, the hydroxyl ion has been chosen as nucleophilic agent and the azetidin-2-one ring like a model of β-lactam antibiotic. The MINDO/3 method does not predict correctly the energies of small rings. This, together with the fact that, like MNDO, it cannot detect the occurrence of hydrogen bonds, gives rise to uncertain estimates of energy barriers. The AM1 method can be considered the most suitable for studying the hydrolysis of β-lactam compounds.     

Die Kristallstrukturen von Me3SiI · β-Picolin und Me3SiI · γ-Picolin Vergleich der Lewis-Basen Pyridin, β-Picolin und γ-Picolin

The Crystal Structure of Me₃SiI · β-Picoline and Me₃SiI · γ-Picoline A Comparison between the Lewis-Bases Pyridine, β-Picoline, and γ-Picoline The reaction of Iodinetrimethylsilane with β- und γ-Picoline (Pic) leads to solid 1 : 1 compounds Me₃SiI · β-Picoline 1 , Me₃SiI · γ-Picoline 2. The reaction was performed at room temperature. Yellow single crystals were obtained by sublimation. Single crystal X-ray investigations confirm that both compounds are ionic [Me₃SiPic]⁺I^?. The comparison of β-Picoline with γ-Picoline and Pyridine (Py) demonstrates that the presence of a methyl group and also its position has no significant influence on the Si? N bond length in compound 1, 2 and on the adduct Me₃SiI · Py.     

Heterocyclen aus α-nitroolefinen. XII . 3-Acetyl-4,5-dihydro-5-(methylenamino)furane und 3-acylpyrrole aus α-nitroolefinen und β-diketonen

From α-nitroolefines 1 and β-diketones 2 3-acetyl4,5-dihydro-5-(methy1eneamino)furans 5 are prepared. Furans 5 react in acid medium to yield 1-unsubstituted 3-acylpyrroles 6 , catalytic hydrogenation yields 1-substituted 3-acylpyrroles 9 . The ¹H-nmr and ¹³C-nmr investigations prove the constitutions.     

Haloacetylated enol ethers. 11. Synthesis of 1-methyl- and 1-phenyl pyrazole-3(5)-ethyl esters. A one-pot procedure

A one-pot synthesis of 1-methyl- and 1-phenylpyrazole-3(5)-ethyl esters 2,3a-e by the cyclocondensation of β-alkoxyvinyl trichloromethyl ketones 1a-e with methyl and phenyl hydrazine hydrochloride under mild conditions, is reported. A study using compounds 1a-e with different substituents proved that these are versatile building blocks for the synthesis of pyrazole derivatives, having a 3(5)-ethoxycarbonyl substituent in good yields (60–89%). The hydrazine and β-alkoxyvinyl trichloromethyl ketone substituent effects on the reaction regiochemistry on the formation of the 1,3- and 1,5-isomer were observed.     

Haloacetylated enol ethers: 3. Synthesis of 3,3a,4,5,6,7-hexahydro-3-halomethylbenzoisoxazoles

The investigation of the halomethyl group effect on the regiochemistry of the reaction of 2-acetylcyclo-hexanones 1a-d and β-methoxyvinyl trifluoro methyl ketone derivative 2a with hydroxylamine to afford 3,3a,4,5,6,7-hexahydro-3-halomethyl-3-hydroxy[2,1]benzoisoxazoles 3a-c , and the respective dehydrated compounds 4a-c , is reported. Compounds 1a-c, 2a proved to be versatile building blocks for the regiospecific synthesis of isoxazole derivatives having a 3-halomethyl substituent, in good yields.     

Synthesis and structure of 5-oxo-1-phenylpyrazoline-3- and 4-alkanoic acids. Antiinflammatory agents

Condensation of appropriate β-keto esters with phenylhydrazine gave 5-oxo-1-phenyl-2-pyrazoline-3-and 4-alkanoic esters 1 and 3 which were saponified to the corresponding alkanoic acids 2 and 4 . Analogous condensation of the same β-keto esters with hydrazobenzene gave 5-oxo-1,2-diphenyl-3-pyrazoline-3-and 4-alkanoic esters 5 and 7 which were similarly converted to acids 6 and 8 . The structures of the oxopyrazolines as revealed by their infrared absorption are discussed, and results of their antiinflammatory screening are reported.     

Zur Kinetik der Spinellbildung von β-Ga2O3 mit zweiwertigen Oxiden. V. Die Festkörperreaktion 2. Art im System NiO – β-Ga2O3

The Formation of Spinels from β-Ga₂O₃ and Metal Oxides with the Metal in the Oxidation State +2. V. The Solid State Reaction of the Second Kind in the NiO—β-Ga₂O₃ System The reaction of the second kind between Ni_1–zGa_2z/3O, that is NiO presaturated with β-Ga₂O₃, and pure β-Ga₂O₃, which has a negligible solubility for NiO, was investigated between 1 249 and 1 527°C. In accordance with the phase diagram of the NiO—β-Ga₂O₃ system a spinel with the general formula Ni_1–yGa_2+2y/3O₄ is formed in a sandwich type diffusion couple. The reaction follows a parabolic rate law with an activation energy of 84 880 cal/mole; the mechanism is the Wagner mechanism of counterdiffusion of cations. The reaction rate constants of the second kind, determined from interdiffusion profiles in NiO/β-Ga₂O₃ diffusion couples are in good agreement with experimental values.     

Neue β-Lactam-Antibiotika. Zur Funktionalisierung von 3-Hydroxy-3-cephem-4-carbonsäureestern durch die Wittig-Reaktion. Modifikationen von Antibiotika. 16. Mitteilung [1]

New β-lactam antibiotics. Functionalisation of 3-hydroxy-3-cephem-4-carboxylic esters through the Wittig reaction The 3-hydroxy-ceph-3-em-esters 1a, b reacted smoothly with stabilized phosphor-ylids to give a series of derivatives which were converted into the microbiologically active acids 14a, c, 15c and 20 by known procedures. The synthesis of the amides 23, 24, 26 and of the ester 28 from the 3-carboxymethyl-derivative 19 is also reported.     

Polymerization of optically active β-substituted β-propiolactones. IV. β-1,1-dichloroalkyl β-propiolactones polymerized with aluminum triisopropoxide

The polymerization of three optically active β-1,1-dichloroalkyl β-propiolactones has been investigated in toluene, at 55°C, using aluminum triisopropoxide (Al(OiPr)₃) as initiator in a range of monomer/initiator molar ratios smaller than 150. β-1,1-dichloroethyl β-propiolactone polymerizes according to a living mechanism. However, the ability to polymerize decreases with an increase in the length of the alkyl substituent. For instance, β-1,1-dichloro-n-propyl β-propiolactone is obtained only in low yields, whereas β-1,1-dichloro-n-butyl β-propiolactone does not polymerize at all. Actually, each of the lactones investigated reacts with Al(OiPr)₃ in an initiation step that obeys a coordination-insertion mechanism. However, the size of the chloroalkyl substituent has a critical effect on the propagation: when the alkyl group contains more than two methylene units, the insertion of a second monomer becomes exceedingly slow.     

Reactivity of p-phenyl substituted β-Enamino compounds using K-10/ultrasound. II. Synthesis of isoxazoles and 5-Isoxazolones

The condensation of 4-phenyl substituted β-enamino ketones 1a-d and β-enamino esters 5a-d with hydroxylamine hydrochloride using K-10 as the solid support under sonication was studied to evaluate the formation of isoxazole and 5-isoxazolone rings from β-enamino compounds with a substituted aromatic ring. Isoxazoles 2a-c, 3c-d and 5-isoxazolones 6a-c and 7a-d were obtained. The use of K-10/ultrasound in this reaction furnished novel results in some cases.     

Intramolecular charge transfer effects on 3-aminobenzoic acid

Effect of solvents, buffer solutions of different pH and β-cyclodextrin on the absorption and fluorescence spectra of 3-aminobenzoic acid (3ABA) have been investigated. The solid inclusion complex of 3ABA with β-CD is discussed by UV–Vis, fluorimetry, semiempirical quantum calculations (AM1), FT-IR, ¹H NMR and Scanning Electron Microscope (SEM). The thermodynamic parameters (ΔH, ΔG and ΔS) of the inclusion process are also determined. The experimental results indicated that the inclusion processes is an exothermic and spontaneous. The large Stokes shift emission in solvents with 3ABA are correlated with different solvent polarity scales suggest that, 3ABA molecule is more polar in the S₁ state. Solvent, β-CD studies and excited state dipole moment values confirms that the presence of intramolecular charge transfer (ICT) in 3ABA. Acidity constants for different prototropic equilibria of 3ABA in the S₀ and S₁ states are calculated. β-Cyclodextrin studies shows that 3ABA forms a 1:1 inclusion complex with β-CD. β-CD studies suggest COOH group present in non-polar part and amino group present in hydrophilic part of the β-CD cavity. A mechanism is proposed to explain the inclusion process.     

Reactivity of p-phenyl substituted β-enamino compounds using K-10/ultrasound. I. Synthesis of pyrazoles and pyrazolinones

The reactivity of the β-enamino ketones, 3-amino-1-(p-phenyl-substituted)-2-buten-1-ones 1a-d and β-enamino esters, ethyl 3-amino-3-(p-phenyl-substituted)-2-propenoates 5a-d was systematically studied when allowed to react with hydrazine and methylhydrazine under solid support K -10/ultrasound conditions and in homogeneous media (reflux in ethanol or dichloromethane). The products were pyrazoles 2a-d , N-methylpyrazoles 3a-d, 4a-d and N-methylpyrazolinones 6a-c and 7a-c . The regiochemistry of the cyclization reactions showed dependence upon the reaction conditions employed as well as upon the sub-stituent in the aromatic ring.     

Synthesis of 3-aminopropyl glycosides of branched β-(1→3)-glucooligosaccharides

Russian Chemical Bulletin - The synthesis of branched β-(1→3)-glucooligosaccharides bearing a β-d-glucose residue at position 6 of one of the monosaccharides of the linear chain at...     

4-Substituted-3-alkyl-3,4-dihydro-2H-1,3-benzoxazin-2-ones. IV (2-4). Keto-Enol tautomerism of β-keto ester derivatives. Reaction of β-dicarbonyl compounds with diamines

A series of α-[3-alkyl-3,4-dihydro-2-oxo-2H-1,3-benzoxazin-4-yl]-β-keto ester derivatives 1 (Table I) were synthesized by the condensation of 3-alkyl-3,4-dihydro-4-hydroxy-2H-1,3-benzoxazine-2-ones 3 (2) with β-keto esters 4 in the presence of traces of mineral acids under azeotropic conditions. Condensation of 1 with hydrazines 5 gave pyrazolone derivatives 2 (Table II). Condensation of β-diketone derivatives 6 with hydrazines 5 and with 1,2-benzenediamine ( 8 ) resulted in the formation of pyrazoles ( 7a-c ) and diazepine derivatives 12 (Table III) and 13 , respectively.     

Spectral Parameters of Nd^3＋ Ion in Nd^3＋：NaGd（MoO4）2 Crystal

1 INTRODUCTION Since the diode-laser pumped solid-state lasers were found in a wide variety of applications in the fields of military, industry, medical treatment and scientific researches due to the advantages of high stability, compactness, high efficiency and long life- time, the research on more efficient new materials with improved spectral properties for diode pumping has become more important. Molybdate crystals with general formula M’Re(MoO4)2 (M’ = Li, Na, K) have been repor…     

Haloacetylated enol ethers. 13. Synthesis of N-[1-aryl(alkyl)-3-oxo-4,4,4-trichloro-1-buten-1-yl]-o-phenylenediamines and 2-trichloromethyl-4-aryl-3H-1,5-benzodiazepines

The synthesis and isolation of the intermediates N-[1-aryl(alkyl)-3-oxo-4,4,4-trichloro-1-buten-1-yl]-o-phenylenediamines 2a-f and the corresponding 2-trichloromethyl-4-aryl-3H-1,5-benzodiazepines 3c-g or benzimidazoles 4a-b derivatives obtained from the intramolecular cyclization of 2a-f or from direct cyclo-condensation reaction of β-alkoxyvinyl trichloromethyl ketones 1a-g with o-phenylenediamine, is reported. Depending of the structure of the β-alkoxyvinyl trichloromethyl ketones or the N-[1-aryl(alkyl)-3-oxo-4,4,4-trichloro-buten-1-yl]-o-phenylenediamines and the reactions conditions, benzimidazoles or 3H-1,5-benzodiazepines were obtained.     

Tetracyclic phenothiazines. VI. Attempted pummerer cyclization of 10-(2-Keto-3-methylsulfinylpropyl)phenothiazine

The title compound ( 3 ), a β-ketosulfoxide prepared by a Claisen-type condensation of ethyl 2-(10-phenothiazino)acetate ( 4 ) with dimsyl carbanion, was subjected to a variety of catalysts in attempts to achieve a Pummerer cyclization to 1,2-dihydro-3-methylthio-2-oxo-3H-pyrido[3,2,1-kl]phenothiazine ( 2 ). Although the Pummerer rearrangement product, 10-(2-oxo-3-hydroxy-3-methylthiopropyl)phenothiazine ( 5 ), could be obtained in excellent yield under mild conditions, neither it nor the β-ketosulfoxide could be successfully cyclized under any of the conditions attempted. Instead, phenothiazine, 2-hyroxy-3-(10-phenothiazinyl)-2-propen-1-al ( 7 ), 3-(10-phenothiazinyl)-1,1-di(methylthio)propan-2-one ( 8 ), 3-(10-phenothiazinyl)-1-methylthiopropan-2-one ( 9 ) and 10-phenothiazinylformamide ( 10 ) were variously obtained.