Reactivity of n-aryl-α, α-dichlorinated arylketimines

N-Aryl-α,α-dichloroalkylarylketimines are formed from N-aryl-alkylarylketimines with N-chloro succinimide in carbon tetrachloride. Reaction of N-1-(2,2-dichlor-1-arylpropylidene)anilines with sodium methoxide the latter compounds formally involves migration of the notrogen atom from the 1- to the 3-position. The reaction of higher substituted N-aryl-α,α-dichloroalkylarylketimines with sodium methoxide leads mainly to α-chloro-α,β-unsaturated ketones. In the case of long-chain α,α-dichloroketimines, a formal γ-functionalization was observed. The reaction mechanisms are discussed in detail.     

Reactivity of 2-amino-1,3,4-thiadiazoles. Methylation reactions of some 2-amino-5-benzoyl-1,3,4-thiadiazoles

Methylation reactions of 2-amino-5-benzoyl-1,3,4-thiadiazoles 1a-d are reported as a function of alkylating agents (methyl iodide, dimethyl sulfate-potassium carbonate, diazomethane, dimethyl-sulfate-sodium methoxide). Methylation occurs at both the ring nitrogen in position 3 and the exocyclic nitrogen atom.     

Synthesis of propylene carbonate and some dialkyl carbonates in the presence of bifunctional catalyst compositions

Poly(ethylene glycol)–potassium iodide complexes were found to have high catalytic activities in the esterification of propylene oxide and carbon dioxide under smooth experimental conditions. Furthermore, the complexes were combined with sodium methoxide to form bifunctional catalyst compositions sequentially for the above esterification, as well as the transesterification of the propylene carbonate formed in situ with some aliphatic alcohols, such as methanol, ethanol, propanol and butanol. It was found that the compositions were very effective, giving corresponding dialkyl carbonate, propylene carbonate and propylene glycol. It was noticed that the resulting dialkyl carbonate from n-butanol was diisobutyl carbonate, instead of di-n-butyl carbonate.     

Studies in the benzazole and naphthazole series. VIII. Reaction of 2-hydrazinonaphth[1, 2-d]imidazole and its 1- and 3-methyl derivatives with carbon disulfide

When heated with carbon disulfide in pyridine 2-hydrazinonaphth[1, 2-d]imidazole yields S-triazolo[4, 3-b]-naphth[1, 2-d]imidazole-3-thione. Kinetic and not steric factors determine the formation of this compound. Its trans-angular structure is demonstrated by the agreement between its UV spectrum and that of 11-methyl-S-triazolo[4, 3-b]naphth[1, 2-d]imidazole-3-thione, prepared from 1-methyl-2-hydrazinonaphth[1, 2-d]imidazole and carbon disulfide, as well as by the identity of their methylation products. Methyl iodide methylation, in the presence of sodium methoxide, of S-triazolo[4, 3-b]naphth[1, 2-d]imidazole-3-thione, like that of S-triazolo[4, 3-a]benzimidazole-3-thione, takes place stepwise. First the methyl group adds to the nitrogen atom of the imidazole ring, and only then to the thiol group of the triazole ring.For Part VII see [3].     

Heterogeneous reactions : VIII. The heterogeneous gas/solid reaction of 3-chloropropyltrimethoxysilane with lithium,sodium and potassium methoxides

The heterogeneous gas/solid reaction of 3-chloropropyltrimethoxysilane with the solid alkoxide bases lithium, sodium and potassium methoxide has been studied at 150 and 190°C. The lithium compound yields solely 3-methoxypropyltrimethoxysilane in a convenient, high yield reaction. Reaction with sodium methoxide gave products resulting from substitution at silicon and carbon as well as elimination products. Potassium methoxide is the least reactive of the three bases studied and gave products similar to those of the sodium methoxide system. Under the conditions of heterogeneous reaction, some cleavage of the chloropropyl groups is observed. It is suggested that this cleavage follows base-induced elimination to give allyltrimethoxysilane.     

Reaction of difluoromethyl pentafluorophenyl sulfoxide with nucleophiles

Reactions of 1-(difluoromethanesulfinyl)pentafluorobenzene with sodium methoxide, sodium phenoxide, potassium hydrosulfide, and methylamine resulted in substitution of fluorine atom in the 4-position (in the reaction with methylamine, also in the 2-position). Treatment of the title compound with sodium hydroxide afforded pentafluorobenzene due to cleavage of the C_arom?S bond.     

Perfluoroallyl fluorosulphonate

Perfluoroallyl fluorosulphonate, procured $\text{via}$ treatment of perfluoropropene with stabilized sulphur trioxide (‘Sulfan’), reacts with potassium iodide, potassium bromide, sodium methoxide, and phenylmagnesium bromide to yield the corresponding perfluoroallyl derivatives CF₂CFCF₂X, where X = I, Br, OMe, and Ph respectively.     

Copper-mediated sequential cyanation of aryl C-B and arene C-H bonds using ammonium iodide and DMF

The cyanation of aromatic boronic acids, boronate esters, and borate salts was developed under copper-mediated oxidative conditions using ammonium iodide and DMF as the source of nitrogen and carbon atom of the cyano unit, respectively. The procedure was successfully extended to the cyanation of electron-rich benzenes, and regioselective introduction of a cyano group at the arene C-H bonds was also achieved. The observation that the reaction proceeds via a two-step process, initial iodination and then cyanation, led us to propose that ammonium iodide plays a dual role to provide iodide and nitrogen atom of the cyano moiety.     

C→N migration of methoxycarbonyl and acetyl groups in reactions of functionally substituted carbanions with aryl isocyanates. Kinetics and mechanism of the reactions

The kinetics and mechanism of C→N migrations of methoxycarbonyl and acetyl groups in the reactions of the sodium derivative of methyl (2-cyano-2-phenyl)acetate and 1,1-diacetyl-2-phenyl-2-tributylphosphonioethanide with aryl isocyanates were studied by spectrophotometry. The reactions afford a prereaction complex via a concerted mechanism, according to which the nucleophilic attack of the carbanionic center to the carbon atom of the isocyanate group and the subsequent nucleophilic attack of the nitrogen atom to the carbonyl carbon atom, resulting in the C-C bond cleavage, occur almost simultaneously in the framework of the same transition state. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 850–853, May, 2006.     

Chlorination of geminal bis(alkoxy-NNO-azoxy) compounds with sodium hypochlorite

Chlorination of geminal bis(alkoxy-NNO-azoxy) compounds with sodium hypochlorite involves the central carbon atom and gives 1,1-bis(alkoxy-NNO-azoxy)-1-chloroalkanes with high yield. Dichlorobis-(methoxy-NNO-azoxy)methane oxidizes sodium iodide to elemental iodine. The signal from the central carbon atom in the ¹³C NMR spectra of bis(alkoxy-NNO-azoxy)dichloromethanes is broadened and displaced downfield relative to those of the initial compounds.     

Study of the heavy atom-induced room temperature phosphorescence properties of melatonin and its analytical application

Liquid phase room temperature phosphorescence (RTP) properties of melatonin were studied using heavy atom induced-room temperature phosphorescence (HAI-RTP) technique. 1.2 M potassium iodide was used as a heavy atom reagent together with 0.002 M sodium sulphite as deoxygenating agent to produce the RTP signal. The maximum phosphorescence emission and excitation wavelengths of melatonin were 290 and 457 nm, respectively. The effect of potassium iodide concentration on the RTP lifetime of melatonin was also investigated and based on the results, the rate constants for phosphorescence decay (k(p)) and radiationless deactivation through reaction with heavy atom (k(h)) were determined. Based on the obtained results, a simple and sensitive room temperature phosphorimetric method was developed for the determination of melatonin. The method allowed the determination of 10.0-200 ng ml(-1) melatonin in aqueous solution with the limits of detection and quantification of 3.6 and 12 ng ml(-1), respectively. The proposed method was satisfactorily applied to the determination of melatonin in commercial pharmaceutical formulations.     

An efficient Bi/NH4I-mediated addition reaction for the highly diastereoselective synthesis of homoallylic alcohols in aqueous media

An efficient water-based bismuth-mediated addition reaction of carbonyl compound with cyclic allylic halide was developed.The reactions proceeded smoothly in aqueous DMF in the presence of ammonium iodide to afford the corresponding syn-homoallylic alcohols in moderate to good yields with excellent diastereoselectivities(>99:1 syn:anti).Reversal of product diastereoselectivity was observed when heteroaryl aldehyde possessing an adjacent chelating nitrogen atom was employed as substrate.     

5-取代氧化呋咱并[3,4-b]吡啶衍生物的合成与表征

以廉价易得的2,6-二氯吡啶为原料,经过硝化、叠氮化、热解环化步骤得到中间体[1,2,5]噁二唑并[3,4-e]四唑并[1,5-a]吡啶-3-氧化物(4b),再与浓硫酸/硝酸钾、甲醇钠和甲胺水溶液反应分别得到5-取代的氧化呋咱并[3,4-b]吡啶衍生物5~7。 研究了化合物4b结构的稳定性,发现其中的氧化呋咱环在强酸性、强碱性和弱碱性条件下较稳定,而吡啶环与叠氮基形成的四唑环结构则不太稳定。     

Interaction of the Azole N‐Sodium Derivatives with Freon‐113: Synthesis of N‐(2,2‐dichlorotrifluoroethyl)azoles

The synthesis of 2,2‐dichlorotrifluoromethyl derivatives of azoles and diphenylamine by the interaction of N‐sodium salts with Freon‐113 has been carried out. The sodium salts of heterocycles, having a one‐ring nitrogen atom, react with Freon‐113 without catalysis. The sodium salts of heterocycles, having two‐ or three‐ring nitrogen atoms, react with Freon‐113 in the presence of tetrabutylammonium iodide as a catalyst.     

碱金属醇盐甲醇羰基化催化剂活性研究

利用红外、气相色谱、色谱－质谱联用方法对甲醇羰基化反应过程中甲醇钾和甲醇钠催化剂的失活情况进行了研究。结果表明：在本研究条件下,甲醇钠（甲醇钾）催化剂活性在保持一段时间的稳定后,随反应时间的继续延长逐渐降低。导致催化剂活性降低的主要原因是甲醇钠（甲醇钾）可以直接与产物甲酸甲酯反应形成甲酸钠（甲酸钾）和二甲醚。甲酸钠对甲醇羰基化反应也具有一定的催化作用,但其活性远远低于甲醇钠。降低瓜在温度可以减缓催     

Synthesis of carbo- and heterocycles via a palladium-catalysed allene insertion-nucleophile incorporation-Michael addition cascade

A novel palladium catalysed three-component cascade process is described involving allenylation of an aryl iodide to generate a (π-allyl)palladium species which is intercepted by a carbon or nitrogen nucleophile followed by intramolecular Michael addition to afford carbo- and heterocycles in good yield.     

3- Substituted 3- Azabicyclo[3.3.1]nonan- 9- ols and Their Transformations Involving the Hydroxy Group

The reduction of 3-benzyl- and 3-tert-butoxycarbonyl-3-azabicyclo[3.3.1]nonan-9-ones with sodium tetrahydridoborate gave the corresponding alcohols as mixtures of á- and ä-epimers at a ratio of 2: 3. The resulting alcohols reacted with acetyl chloride and methanesulfonyl chloride at the hydroxy group to form O-acetyl and O-methylsulfonyl derivatives. Reactions of the latter with potassium iodide and sodium azide afforded 3-substituted 9-iodo(azido)-3-azabicyclo[3.3.1]nonanes. 9-Iodo derivatives were treated with triphenylphosphine to obtain triphenylphosphonium salts which were converted into the corresponding phosphonium ylides by the action of sodium methoxide in methanol, and the ylides readily reacted with benzaldehyde according to Wittig.     

Determination of ammonia with chloramine T

Chloramine T in the presence of an excess of potassium bromide and pH 5.9 ± 0.05 is used for oxidation of ammonia. The excess of chloramine T is determined iodometrically with potassium iodide and sodium thiosulfate. The method can be used for 30–300 μg of inorganic as well as organic nitrogen.     

The determination of microgram quantities of organic nitrogen

A method is descriibed for the determination of microgram quantities of nitrogen in a wide variety of materials. This method involves the Kjeldahl procedure for the conversion of nitrogen to ammonium or amine sulphate. Digestion of the sample with concentrated sulphuric acid and catalyst, and, if necessary, pretreatment with hydriodic acid and red phosphorus, are followed by steam-distillation into a dilute acid solution. The final determination depends on the reaction of ammonia, in a suitably buffered solution, with sodium hypobromite reagent, and measurement of the excess reagent by titration of the iodine liberated by it from acidified potassium iodide, with a standard $\text{N}\text{500}$ sodium thiosulphate solution, using sodium starch glycollate indicator.Since sample size is relatively unrestricted and the final titration can measure 5 micrograms of nitrogen, the sensitivity of the method is very high.Reference is made to existing sub-micro methodes which, although sensitive, are time-consuming and specific in application.     

Novel synthesis of 2-aminopentanedinitriles from 2-(bromomethyl)aziridines and their transformation into 2-imino-5-methoxypyrrolidines and 5-methoxypyrrolidin-2-ones

1-Arylmethyl-2-(bromomethyl)aziridines were transformed into 2-[N-(arylmethyl)amino]pentanedinitriles upon treatment with an excess of potassium cyanide in DMSO through an unprecedented and peculiar reaction mechanism, involving base-induced ring opening of intermediate 2-(cyanomethyl)aziridines into allylamines, followed by migration of the double bond out of the conjugation towards aldimines via enamine intermediates. The resulting aminopentanedinitriles served as substrates for the synthesis of novel 2-imino-5-methoxypyrrolidines upon treatment with sodium methoxide in methanol, which were either acetylated at the free imino group to afford the more stable N-acetylimino derivatives or hydrolyzed towards the corresponding synthetically relevant 5-methoxypyrrolidin-2-ones.