- A NEW METHOD FOR EVALUATING THE STERIC HINDRANCE BY SUBSTITUENT
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New steric parameter, Οs, evaluating the steric hindrance around the reaction center was defined on the basis of molecular mechanics.
- Komatsuzaki, Tamiki,Sakakibara, Kazuhisa,Hirota, Minoru
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Read Online
- Alkaline Hydrolysis of N-Methyl-2,4-dinitroacetanilide and N-Alkyl-N-(5-nitro-2-pyridyl)acetamides
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The kinetics of the alkaline hydrolysis of N-methyl-2,4-dinitroacetanilide (2), N-ethyl- (3), and N-methyl-N-(5-nitro-2-pyridyl)acetamide (4) was carried out.The reaction path consists of two stages: the first one is the rate-limiting formation of the first tetrahedral intermediate (monoanionic) and the second one the fast decomposition of the intermediate.The latter fast decomposition of the intermediate (monoanionic) involves two processes: one is the direct decomposition of the intermediate to the products and the other is a proton abstraction of the hydroxyl group of the intermediate by -OH giving the second tetrahedral intermediate (dianionic), followed by its deconposition to the products.For the alkaline hydrolysis of 2-4, the decomposition of the first intermediate occurred predominantly via the latter process.
- Kijima, Atsushi,Sekiguchi, Shizen
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Read Online
- Flavin mimetics: Synthesis and photophysical properties
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We report the synthesis of new isoalloxazines using a microwave-assisted approach to make N-substituted-2-nitroanilines followed by one-pot reduction and condensation via Hemmerich's method. The influence of substituents on positions 7, 8, and 10 of flavin core on the optical properties is investigated. The aliphatic functionalities on N10 give rise to quantum yields of 0.7, while aromatic side-chains quench fluorescence. Relaxed geometries (DFT) of chiral and achiral derivatives have been used for TD-DFT calculations, which yielded good agreement with the experimental UV and CD data.
- R?s?dean, Dora-M.,Machida, Takashi,Sada, Kazuki,Pudney, Christopher R.,Panto?, G. Dan
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- Chemoselective Deprotection of Sulfonamides under Acidic Conditions: Scope, Sulfonyl Group Migration, and Synthetic Applications
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Chemoselective acidic hydrolysis of sulfonamides with trifluoromethanesulfonic acid has been evaluated as a deprotection method and further extended to more complex synthetic applications. In contrast to conventional troublesome sulfonamide hydrolysis, a near-stoichiometric amount of acid was found to be sufficient to bring about efficient deprotection of various neutral or electron-deficient N-arylsulfonamides, whereas electron-rich substrates provided sulfonyl group migration products. The deprotection method developed is fully selective for N-arylsulfonamides, and the possibility to discriminate among various different sulfonamides is demonstrated.
- Javorskis, Tomas,Orentas, Edvinas
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p. 13423 - 13439
(2017/12/26)
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- Pd(OAc)2-catalyzed dinitration reaction of aromatic amines
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Taking advantage of Pd(OAc)2-catalyzed dinitration reactions with Bi(NO3)3·5H2O in trifluoroethanol (TFE) and trifluoroacetic acid (TFA), we have developed an efficient and practical method for the synthesis of secondary dinitro-aromatic amines. The products could be applied to the preparation of 5-amine-N-methyl-benzimidazolone, the azo-dyes, economic advantages. The method has also been expanded to the dinitration reaction of some tertiary aromatic amines.
- Feng, Yi-Si,Mao, Long,Bu, Xiao-Song,Dai, Jian-Jun,Xu, Hua-Jian
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p. 3827 - 3832
(2015/06/02)
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- Compounds for use in inhibiting HIV capsid assembly
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The present invention relates to a compound or a pharmaceutically acceptable salt or solvate thereof for use in inhibiting HIV capsid assembly, the compound comprising the core structure wherein E is CR7or S, and wherein f is 0 or 1, and wherein in case E is S, f is 0, and wherein the core structure is at least substituted in 2 and 4 position, and wherein the residue R6 and R7, are, independently of each other, selected from the group consisting of -H, -D, -alkyl, alkoxy, alkenyl, alkynyl, halides, -NO2, - OH, - NH2, -NHR4#, -CN, -S(O)R4#, -SO2R4#, -P(O)R4#R5#, -P(O)(OR4#)R5#, - P(O)(OR4#)(OR5#), -C(O)NR4#R5#, -C(O)SR4#, -C(O)R4#, -C(O)O-R4#, alkoxy and glycol chains; and wherein R6 may optionally form a cyclic residue, with a further substituent present 5 or 6 position, and wherein R4# and R5# are, independently of each other, selected from the group consisting of -H, -alkyl, -alkenyl, - heterocycloalkyl, aryl and heteroaryl.
- -
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Paragraph 0160-0161
(2014/09/03)
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- COMPOUNDS FOR USE IN INHIBITING HIV CAPSID ASSEMBLY
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The present invention relates to a compound or a pharmaceutically acceptable salt or solvate thereof for use in inhibiting HIV capsid assembly, the compound comprising the core structure wherein E is CR7or S, and wherein f is 0 or 1, and wherein in case E is S, f is 0, and wherein the core structure is at least substituted in 2 and 4 position, and wherein the residue R6 and R7, are, independently of each other, selected from the group consisting of -H, -D, -alkyl, alkoxy, alkenyl, alkynyl, halides, -NO2, - OH, -NH2, -NHR4#, -CN, - S(O)R4#, -SO2R4#, -P(O)R4#R5#, -P(O)(OR4#)R5#, -P(O)(OR4#)(OR5#), -C(O)NR4#R5#, - C(O)SR4#, -C(O)R4#, -C(O)O-R4#, alkoxy and glycol chains; and wherein R6 may optionally form a cyclic residue, with a further substituent present 5 or 6 position, and wherein R4# and R5# are, independently of each other, selected from the group consisting of -H, -alkyl, -alkenyl, -heterocyclo alkyl, aryl and heteroaryl.
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Page/Page column 51
(2014/09/03)
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- Efficient synthesis of N-methylamides and amines via 4-(alkylamino)benzyl- N-methylamine as a new protecting group
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4-(Alkylamino)benzyl-N-methylamine is a good protecting group for the synthesis of N-methylamides and amines. The N-debenzylation of N-methylamides and amines can be carried out selectively and efficiently under condition using trifluoroacetic acid (TFA).
- Lee, Sang-Hak,Mu, Yu,Kim, Gun-Woo,Kim, Jin-Seok,Park, Seok-Hwi,Jin, Tian,Lee, Kee-Young,Ham, Won-Hun
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p. 1749 - 1764
(2013/09/12)
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- PROCESS FOR PREPARING BENDAMUS TINE HYDROCHLORIDE MONOHYDRATE
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The present invention provide processes for the preparation of Bendamustine hydrochloride monohydrate of formula (I) The present application also provides a process of purification of Bendamustine hydrochloride or monohydrate to get substantially pure Bendamustine hydrochloride monohydrate crystalline Form-SM. The said Bendamustine hydrochloride monohydrate crystalline Form-SM is characterized by X-ray powder diffraction pattern comprising at least 5 characteristic peaks selected from the XRPD 2 theta degrees peaks at 7.42, 10.60, 11.17, 16.43, 17.94, 22.89, 26.33, 28.77, 30.28, 31.92, 40.89±0.1 2θ°. The present application also provides a process for the preparation of Bendamustine hydrochloride monohydrate crystalline Form-SM useful in making pharmaceutical composition for the treatment of cancer or similar proliferative disorders.
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Paragraph 0158-0159
(2013/08/28)
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- 2, 4 -DIAMINOPYRIMIDINE DERIVATIVES AS PROTEIN KINASE INHIBITORS
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The present invention relates to novel pyrimide derivatives of formula (I): that are useful as kinase inhibitors. More particularly, the present invention relates to novel pyrimidine compounds, methods for their preparation, pharmaceutical compositions containing these compounds and uses of these compounds in the treatment of proliferative disorders.
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Page/Page column 162-163
(2012/05/20)
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- PROCESS FOR PREPARING BENDAMUS TINE HYDROCHLORIDE MONOHYDRATE
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A process for preparing Bendamustine hydrochloride monohydrate is provided. A process for purifying said monohydrate to get substantially purne Bendamustine hydrochloride monohydrate crystalline form is also provided.
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Page/Page column 26
(2012/05/20)
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- HYDROXAMIC ACID DERIVATIVES
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The disclosure includes hydroxamic compounds of Formula I: (I) wherein P, Z, and m are defined herein. Also disclosed is a method for treating a neoplastic disease or an immune disease with these compounds.
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Page/Page column 41
(2010/08/08)
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- Synthesis of benzo[1,2-d;3,4-d′]diimidazole and 1H-pyrazolo[4,3-b] pyridine as putative A2A receptor antagonists
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The synthesis and the binding affinity for the putative adenosine receptor antagonist 6-methyl-7-[1,2,3]triazol-2-yl-1,6-dihydrobenzo[1,2-d;3,4-d′] diimidazole (10) and 5-oxazol-2-yl-1H-pyrazolo[4,3-b]pyridin-3-ylamine (16) are reported. The title compounds were prepared from commercially available 1-chloro-2,4-dinitrobenzene (1) and 2-chloro-6-methoxy-3nitropyridine (11), respectively, but proved devoid of affinity for the adenosine A1 and A2A receptors. The Royal Society of Chemistry.
- Piersanti, Giovanni,Giorgi, Luca,Bartoccini, Francesca,Tarzia, Giorgio,Minetti, Patrizia,Gallo, Grazia,Giorgi, Fabrizio,Castorina, Massimo,Ghirardi, Orlando,Carminati, Paolo
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p. 2567 - 2571
(2008/03/14)
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- Low background FRET-substrates for lipases and esterases suitable for high-throughput screening under basic (pH 11) conditions
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FRET-based fluorogenic substrates for lipases and esterases were prepared in four steps from commercially available building blocks. The substrates are pyrenebutyric acid monoesters of aliphatic 1,2-diols bearing a dinitrophenylamino group as a quencher. The most enzyme-reactive substrate is ester 2a. The substrates do not show any measurable background reaction in the absence of enzyme even at pH 11, but react fast and specifically with lipases and esterases. These substrates offer an unprecedented and practical solution to the long-standing problem of a simple yet efficient high-throughput screening tool for lipase activities under basic conditions. The Royal Society of Chemistry 2006.
- Yang, Yongzheng,Babiak, Peter,Reymond, Jean-Louis
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p. 1746 - 1754
(2008/03/11)
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- Synthesis, properties, and molecular structure of nitro-substituted N-methyl-N-nitroanilines
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Ten mono-, di-, and trinitro derivatives of N-methyl-N-nitroaniline were synthesized and studied by spectral, electrooptical, and quantum-chemical methods. Three of these derivatives, N-methyl-N,2,3-trinitroaniline, N-methyl-N,2,5-trinitroaniline, N-methyl-N,3,5-trinitroaniline, were also examined by the X-ray diffraction method. The N-nitroamino group in their molecules is almost planar, the N7-N8 bond is shortened, and the N8 atom is characterized by a strong deficit of electron density. The dihedral angle between the planes of the N-nitroamino group and the benzene ring is 56°-92°, which makes conjugation between these fragments impossible. The N-nitroamino group in the examined compounds acts as a weak electron donor with respect to the nitro groups in the aromatic ring; the mechanism of this effect is inductive. Pleiades Publishing, Inc. 2006.
- Prezhdo,Bykova,Prezhdo,Daszkiewicz,Kyziol,Zaleski
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- The mechanistic origin of regiochemical changes in the nitrosative N-dealkylation of N,N-dialkyl aromatic amines
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The regioselectivity of the nitrous acid mediated dealkylation of 4-substituted-N-ethyl-N-methylanilines is a function of the acidity of the reaction mixture. At high acidity deethylation predominates, whereas demethylation is the predominant reaction in nitrosamine formation at pH 2 and above. In some cases the regioselectivity of nitrosative dealkylation changes as the run proceeds. Through the use of the corresponding 4-nitroaniline as the primary substrate, CIDNP, kinetics, kinetic deuterium isotope effects and other transformations involving nitrosations with NO2 or NOBF4 in aprotic solvents, a new mechanism of tertiary amine nitrosation has been deduced and proposed to explain regioselective deethylation. The mechanism involves the oxidation of the substrate to the amine radical cation by NO +. This is followed by the abstraction of a hydrogen atom from the carbon adjacent to the amine nitrogen by NO2 to produce an iminium ion which reacts further to produce the corresponding aldehyde and the nitrosamine. Depending upon the acidity, this process competes with three other mechanistic pathways, two of which give the nitrosamine through the iminium ion, and one leads to the formation of C-nitro compounds. The competing pathways to nitrosamine formation involve NOH elimination from a nitrosammonium ion and deprotonation of the radical cation to give an α-amino radical which rapidly oxidized to the iminium ion. Predominant, but not highly regioselective demethylation occurs by these pathways. Nitro compound formation principally arises from the reaction of NO2 with the radical cation followed by deprotonation, but also occurs by para C-nitrosation followed by oxidation. The Royal Society of Chemistry 2005.
- Teuten, Emma L.,Loeppky, Richard N.
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p. 1097 - 1108
(2007/10/03)
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- Molecular rearrangement. 36. Selective α-CH oxidation of alkylarenes by nitrogen dioxide on thermolysis with nitramines
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Thermolysis of 2,4,6-trichloro-N-nitroaniline 1 and N-methyl-2,4-dinitro-N- nitroaniline 2 each with primaryl alkylbenzenes led to the formation of acylbenzenes. Similar reactions with secondary alkylbenzenes afforded a mixture of acetophenone and aliphatic aldehydes. Use of tert-butylbenzene in this reaction yielded formaldehyde and 2,3-diphenyl-2,3-dimethylbutane. The mechanisms of the studied reactions are discussed.
- Badr, Mahmoud Z. A.
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p. 6706 - 6710
(2007/10/03)
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- 15N NMR and FTIR studies of 2,4-dinitroanilines and their salts
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Twenty-two 2,4-dinitroanilines were synthesised and their pK(a) values were determined. The 2,4-dinitroanilines and their protonated forms were studied by 15N NMR spectroscopy. The relations between the 15N NMR chemical shifts and the pK(a) values of the 2,4-dinitroanilines and their salts were found to be linear. The deprotonation reaction of N-methyl-2,4- dinitroanilines and N-methyl-2,4,6-trinitroaniline by MTBD was successful only for the latter and yielded protonated MTBD molecule and the anion in which the electrons are strongly delocalised. The kinetic parameters of the 2,4-dinitroanilines in reactions with hydroxide ions in mixed solvent DMSO:water (95:5, v/v) were determinated and discussed. (C) 2000 Elsevier Science B.V.
- Gierczyk,Leska,Nowak-Wydra,Schroeder,Wojciechowski,Bartl,Brzezinski
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p. 217 - 225
(2007/10/03)
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- Vicarious nucleophilic substitution of hydrogen in 2,4-dinitroanilines and cyanonitroanilines
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Orientation of the VNS reaction in nitroaniline derivatives is mostly governed by the conjugation between the nitro groups and the amino group, which could be also deprotonated under the reaction conditions.
- Makosza,Voskresensky,Bialecki,Kwast
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p. 1969 - 1977
(2007/10/03)
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- Photolysis of some N-nitroso- and N-nitro-anilines in solution
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The photolyses of three N-methyl-N-nitrosoanilines and two N-methyl-N-nitroanilines in organic solvents have been studied in the range of 300-340 nm. The influence of solvent character and the presence or absence of oxygen play important roles in the product composition range. The primary photochemical process involves N-N fission, this being homolytic in aprotic solvents and heterolytic in methanol. Three novel mechanistic conclusions are proposed, namely photosolvolysis of a nitrosamine in methanol, photooxidation of nitrosamines in aprotic solvents and the production of biphenyl derivatives on photolysis of nitro-substituted nitrosamines and nitramines in aromatic solvents.
- Gowenlock, Brian G.,Pfab, Josef,Young, Victor M.
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p. 915 - 919
(2007/10/03)
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- 1-Methyl-1-(2,4-dinitrophenyl)hydrazine as a New Reagent for the HPLC Determination of Aldehydes
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The synthesis and first application of an N-alkylated hydrazine reagent for the HPLC determination of aldehydes and ketones is described. 1-Methyl-1-(2,4-dinitrophenyl)hydrazine (MDNPH) reacts with aldehydes to give the corresponding hydrazones in the presence of an acid as catalyst. In contrast to other hydrazine reagents, MDNPH is oxidized by both ozone and nitrogen dioxide quantitatively to N-methyl-2,4-dinitroaniline (MDNA), which can be separated from the hydrazones of the lower aldehydes by means of HPLC. Unexpected elution orders are observed for the 1-methyl-1-(2,4-dinitrophenyl)hydrazones compared to those of 2,4-dinitrophenylhydrazones. Dual-wavelength detection is employed as a means for identification of different groups of the hydrazones and MDNA.
- Bueldt, Andrea,Karst, Uwe
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p. 3617 - 3622
(2007/10/03)
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- Thermal decomposition of arylnitramines
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The thermal decomposition of various substituted N-methyl-N-nitroanilines dissolved in indifferent solvents and piperidine has been investigated. Activation volumes and product analyses support evidence that the rate-determining step is the reversible homolysis of the nitramine bond. The activation volumes range from +18 to +36 ml mol-1. A non-linear Hammett relationship is attributed to an increase in secondary caged reactions, namely rearrangement and oxidation. Arylnitramines with electron-donating substituents yield greater amounts of the thermal rearrangement products than those with electron-deactivating groups at ambient pressures. Decomposition of arylnitramines with electron-donating substituents under high pressures (ca. 1.2 GPa) favours caged reactions over separative diffusion.
- Naud, Darren L.
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p. 1321 - 1324
(2007/10/03)
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- AROMATIC NUCLEOPHILIC SUBSTITUTION REACTIONS OF ACTIVATED N-ARYLPYRAZOLES WITH FORMAMIDES
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Different activated N-arylpyrazoles, as N-(2',4'-dinitrophenyl)-3,5-dimethylpyrazole, N-picryl-3,5-dimethylpyrazole etc., can react with excess formamides, as formamide N-methylformamide and N,N-dimethylformamide, at 165-175 deg C, for 5-6 hours, resulting amines in high yieds.This reaction is influenced by steric hindrance.
- Chiriac, Constantin I.,Lupu, Viorel,Chiriac, Florentina,Ropot, Radu,Tibirna, Mihaela,Truscan, Ion
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p. 549 - 553
(2007/10/03)
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- Amination of dinitrobenzenes with liquid methylamine/potassium permanganate
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1,3-Dinitrobenzene (1a) and some simple monosubstituted derivatives (1b-g) were aminated with a liquid methylamine solution of potassium permanganate (LMA/PP) to give the corresponding mono- and bis(methylamino)-substituted compounds (3a-e and 4a). 1,2-Dinitrobenzene (1i) was aminated with LMA/PP to give 2-(methylamino)-1-nitrobenzene (3f) in high yield.The intermediacy of 4-(methylamino) ?-adducts of 1,3-dinitrobenzene (2a), 2-chloro- (2b) and 2-amino-1,3-dinitrobenzene (2c) was established by 1H NMR spectroscopy.Quantum-chemical calculations for the dinitrobenzenes suggest that, in general, the experimentally observed regioselectivity of the methylamination is satisfactorily described by frontier molecular orbital (FMO) interaction of the reagents.
- Wozniak, Marian,Grzegozek, Maria,Roszkiewicz, Witold,Szpakiewicz, Barbara
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- Metal ion promoted hydroxide ion and water catalyzed hydrolysis of amides. Effects of the acyl group and the leaving group
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The hydrolysis of anilide derivatives of N-methyl-4-nitroaniline in H2O is hydroxide ion catalyzed; plots of log kobsd vs pH are linear with slopes of 1.0 at pH > 8. When there is a chelating functional group in the acyl portion of the molecule (1,10-phenanthrolinyl or 6-carboxypicolinoyl) and in the presence of saturating concentrations of Cu2+, Co2+, or Zn2+, hydroxide ion catalyzed reactions are observed at pH > 4 (rate enhancements range from 104- to 105-fold), and pH-independent reactions occur from pH 1 to 4. Rate constants are very nearly the same in the metal ion promoted hydrolysis reactions for the anilides with these acyl groups. Thus, the negatively charged carboxylate ligand of N-(6-carboxypicolinoyl)-N-methyl-4-nitroaniline is equally good in facilitating the metal ion promoted hydrolysis reactions as the neutral ligands of the 1,10-phenanthroline derivative. A trifluoroacetyl acyl group produces the same general effect as a chelated metal ion, i.e., a facile OH--catalyzed reaction and a pH-independent reaction at pH 6 is favorable (kOH' = 1.0 × 104 M-1 s-1 at 50 °C), even though the pKa of the anilide N-H function is 5.5 and the second-order rate constant (kOH') is tnat for attack of OH- on the ionized species. Amide deprotonation does not have a large effect on the rate of hydrolysis; ionization of the amide N-H function of N-(trifluoroacetyl)-2-carboxy-4-nitroaniline produces only a 7-fold decrease in kOH. An N-methyl group accelerates the rate of hydrolysis of the (trifluoroacetyl)-2,4-dinitroanilide. N-(Trifluoroacetyl)-N-methyl-2,4-dinitroaniline hydrolyzes very rapidly at 50 °C, kOH = 5 × 106 M-1 s-1 and k0 = 10-2 s-1. The pH-independent reaction governed by k0 proceeds 2.1-fold more slowly in D2O than in H2O. General base catalysis occurs, and the Bronsted coefficient β is 0.3.
- Fife, Thomas H.,Bembi, Ramesh
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p. 11358 - 11363
(2007/10/02)
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- Studies on the synthesis of Strychnos indole alkaloids
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Tetracycles 3b-d, having the ABCD ring substructure of Strychnos alkaloids and a N(b)-(formylmethyl) substituent protected as an oxime or hydrazone derivative, have been prepared by nucleophilic addition of the enolate of indoleacetic ester 1 to pyridinium salts 2b-d followed by acid cyclization. The same one-pot, two-step sequence allowed the preparation of tetracycle 3f, which incorporates an α-methoxyacrylate chain at the piperidine β-position.
- Bosch,Salas,Amat,Alvarez,Morgo,Adrover
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p. 5269 - 5276
(2007/10/02)
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- Aromatic nucleophilic substitution reactions of 1-dialkylamino-substituted activated benzenes with various amines in dimethyl sulfoxide
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In the reactions of 1-dlalkylamino-2,4,6-trinitro- and 1-dialkylamlno-2, 4-dinitrobenzenes with various amines in dimethyl sulfoxide, 1-dialkylamino group is easily replaced with primary n-alkylamines at room temperature, and in a low yield with pyrrolidine only among secondary amines.
- Sekiguchi, Shizen,Ishikura, Hiromi,Hirosawa, Yukitoshi,Ono, Nobuyuki
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p. 5567 - 5578
(2007/10/02)
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- Micellar effect on methylaminolysis of O-(2,4-dinitrophenyl)cyclohexanone oxime
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The cleavage of C-O bond of O-(2,4-dinitrophenyl)cyclohexanone oxime by methylamine in aqueous methanol has been found to be acid-catalysed.Effect of cationic micelles supports the view that the protonation of oxygen of the leaving group is an important step in determining overall rate of the reaction.
- Jain, A. K.,Bhattacharjee, G.,Velu, V. K.,Kumar, Anurag
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p. 992 - 993
(2007/10/02)
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- Oxidative Transformations of Minor Components of Nucleic Acids. An Anomalous Reaction Course of Oxidation of N6,N6-Dialkyladenosines and Related Compounds with m-Chloroperoxybenzoic Acid
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Oxidation of N6-methyladenosine (1a) or the corresponding tribenzoate 1b with m-chloroperoxybenzoic acid gave N1-oxides 2a and 2b whereas N6,N6-dimethyladenosine tribenzoate (3a) afforded 2',3',5'-tri-O-benzoylinosine (4a) and N6-methyl-N6-formyl derivative 5.The N6,N6-diethyladenosine 3b and piperidine derivative 3c yielded only 4a, but N6,N6-dibenzyl compound 3d was not oxidized.N,N-Dimethyl-2,4-dinitroaniline (6a) was oxidized with m-chloroperoxybenzoic acid to give N-methyl-N-formyl derivative 7a, N-methyl-2,4-dinitroaniline (8a), N-oxide 10a, and only traces of 2,4-dinitrophenol (9a).By contrast, 2-(dimethylamino)-5-nitropyridine (6b) afforded 5-nitro-2-pyridone (9b) and N-demethylated N1-oxide 11. 2-(Dimethylamino)pyridine (6c) and 2-(methylamino)-5-nitropyridine (8b) gave the respective N2- and N1-oxides 10c and 11.The reaction of 6-chloropurine nucleosides 15a and 15b with N,N-dimethylhydroxylamine gave inosine 4a or 4b accompanied by a smaller amount of 3a or 3e. 2,4-Dinitrofluorobenzene (16) afforded O-(2,4-dinitrophenyl)-N,N-dimethylhydroxylamine (17).Mass spectra of compounds 10a, 10c, and 17 provided evidence for Meisenheimer rearrangement and subsequent cyclic transformation.The N-oxide 10a and hydroxylamino derivative 17 gave 2,4-dinitrophenol (9a), and N2-oxide 10c afforded fragments belonging to 2-pyridone (9c).Compound 17 is thermally stable whereas N-oxide 10a yielded at 100 deg C a mixture of 8a, 8b, 9a, and 17.
- Endo, Takeshi,Zemlicka, Jiri
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p. 1887 - 1894
(2007/10/02)
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- SN2 Displacement on 2-(Alkylthio)ethyl Derivatives
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We have studied the reaction mechanism of various 2-(alkylthio)ethyl and 2-(arylthio)ethyl derivatives with strong nucleophiles in an attempt to overcome powerful neighboring sulfur participation and shift reaction to a direct displacement SN2 mechanism.The 2,4-dinitrophenolate derivative of specifically deuteriated 2-(methylthio)ethanol reacts by an aromatic substitution mechanism (SNAr) when exposed to amines in aprotoc solvents.Use of sulfonate esters avoids competition from the SNAr mechanism.The rate of reaction of these esters in dimethyl sulfoxide (DMSO) or acetonitrile is independent of concentration of added methylamine, thiourea, urea, or iodide, thus indicating continued SN1 reaction with neighboring sulfur participation.Asd would be expected on this basis, but in contrast to previous mechanistic suggestions, the product for reaction with iodide in acetone shows complete scrambling of methylene groups.In contrast, reaction with thiophenolate ions in DMSO proceeds by direct nucleophilic displacement (an SN2 mechanism), as shown by second-order kinetics and unrearranged product.This is the first demonstration of SN2 displacement on a 2-(alkylthio)ethyl or 2-(arylthio)ethyl derivative.
- Herati-Sedaghat, M. R.,McManus, Samuel P.,Harris, J. Milton
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p. 2539 - 2543
(2007/10/02)
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- KINETIC STUDIES AND MICELLAR EFFECT ON THE AMINOLYSIS OF CERTAIN O-ARYL OXIMES
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Rate constants for the aminolysis of a few O-aryl oximes with several primary alkyl amines, CH3NH2-------C6H12NH2 in 1:1 water-acetonitrile are reported.Reactions of methylamine with substrates possessing poor nucleofugues are very weakly sensitive to base catalysis while reactions of higher amines are not.Slightly higher rate of long chain amine may be considered as a consequence of hydrophobic interaction.Cationic micelles of cetyltrimethyl ammonium bromide enhance the rate.Magnitude of micellar catalysis increases towards higher amines.
- Jain, Ajay K.,Velu, V. K.,Sarma, K. N.
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p. 2569 - 2574
(2007/10/02)
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- N-Aminoisocyanides by 1,1-Elimination from Formimidoyl Chloride
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The N-aminoisocyanide (6) has been observed in solution and trapped by rate determining nucleophilic attack to give formamides and formamidines.
- Hegarty, Anthony F.,Cunningham, Ian
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- REACTION OF 2,4-DISUBSTITUTED CHLOROBENZENES WITH 3-ALKYLAMINO- AND 3-DIALKYLAMINOPROPIONITRILES
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The reaction of 2,4-disubstituted chlorobenzenes with 3-dialkylaminopropionitriles at 65-170 deg C leads to the formation of 2,4-disubstituted N,N-dialkylanilines, and the reaction with 3-alkylaminopropionitriles at 20-130 deg C leads to the formation of 2,4-disubstituted N-alkyl-N-β-cyanoethylanilines.In addition, in the latter case at high temperature (130 deg C) the cyanoethyl group is removed from the substituted N-alkyl-N-β-cyanoethylaniline with the formation of the 2,4-disubstituted N-alkylaniline.
- Plakidin, Val. L.,Vostrova, V. N.
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p. 295 - 303
(2007/10/02)
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- Oxidation of Aryldialkylamines with Cerium(IV) Ammonium Nitrate and Thallium(III) Nitrate
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Nine alkylmethylanilines were oxidised with cerium(IV)ammonium nitrate and thallium(III) nitrate in acetic acid, acetonitrile, and methanol.Reaction products were those deriving from demethylation, dealkylation, and aromatic nitration at positions ortho and para to the amino-group.The ratio between demethylation and dealkylation and between them and aromatic nitration is discussed in terms of (i) the oxidising power and electrophilicity of the reagent and (ii) the co-ordinative properties of the solvent.
- Galliani, Guido,Rindone, Bruno
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p. 828 - 832
(2007/10/02)
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- The Stabilities of Meisenheimer Complexes. Part 22. The Ionisation of 2,4-Dinitroaniline, its N-Alkylated Derivatives, and 2,6-Dinitroaniline in Methanol-Dimethyl Sulphoxide containing Sodium Methoxide
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2,4-Dinitroaniline and its N-alkylated derivatives react with sodium methoxide in methanol-dimethyl sulphoxide to give conjugate base.However, in the case of 2,6-dinitroaniline, base addition at the 3-position competes with proton loss.The effects of N-alkylation on the acidity of 2,4-dinitroaniline are considered and are compared with the effects of similar substitution in 2,4,6-trinitroaniline.
- Crampton, Michael R.,Wilson, Penelope M.
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p. 1854 - 1858
(2007/10/02)
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- Process for the manufacture of benzimidazolones-(2)
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Process for the manufacture of benzimidazolones-(2) wherein an o-phenylenediamine is reacted with optionally alkylated urea in the ratio of 1 to 1.3 moles per mole o-phenylenediamine in an organic solvent which has a solubility in water of not more than 5 g/l and has a boiling point above 100° C, at a temperature between 100° and 200° C.
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- Water-soluble trisazo 8-amino-naphthol-1 dyes
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Very effective direct dyeing of cotton and other hydroxyl- or nitrogen-containing fibers is effected with water-soluble triasazo dyes having the formula: where A is a radical of a diazoconstituent and A3 is a radical of a coupling constituent STR1 and A1 or A2 or both can have their azo linkages reversed. These dyes are very fast particularly to washing and to perspiration, and are so effective with cotton that dye baths for such use are rapidly exhausted and the disposal of used bath is less of a problem.
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