Sodium Hydride In Dimethylformamide Research Articles

Synthesis 1,2-bis ((3-methylbut-2-en-1-yl)oxy) -4-(((3methylbut-2-en-1-yl)oxy)methyl)benzene

Kojic acid and arbutin are materials that are used to inhibit melanogenesis, but in their development, these two compounds have an adverse effect on the skin. 3,4-dihydroxybenzaldehyde is a simple phenol compound whose derivatives are used as flavorers and fragrance. The research carried out aims to obtain 3,4-dihydroxybenzaldehyde derivatives in the form of 1,2-bis((3-methylbut-2-en-1-yl)oxy) 4-(((3-methylbut-2-en-1-yl)oxy)methyl)benzene which is estimated based on its structure is able to inhibit melanogenesis, and has a similar structure to the commercial fragrance of methyl diantilis. The synthesis of the target compound is carried out in three step. The first step involves the alkylation of 3,4-dihydroxybenzaldehyde with 3,3-dimethylalyl bromide and sodium hydride in the dimethylformamide solvent at room temperature to obtain 3,4-bis ((3-methylbut-2-en-1-il) benzaldehyde. Reduction of formyl 3,4-bis((3-methylbut-2-en-1-il) benzaldehyde which is carried out in the second stage with sodium borohydride in ethanol obtained 3,4-bis((3-methylbut-2-en-1-yl)oxy)phenyl)methanol. Etherification 3,4-bis ((3-methylbut-2-en-1-il)oxy)phenyl)methanol with 3,3-dimethylalyl bromide and sodium hydride in the solvent dimethylformamide at room temperature is obtained target compound 1,2-bis((3-methylbut-2-en-1-il)oxy)-4-(((3-methylbut-2-en-1 il)oxy)methyl)benzene whose structure is determined by NMR, mass, and IR spectroscopy.

Green Chemistry: Comparison of Ionic Liquid vs Conventional Solvent for Indole Alkylation

A comparison of the effectiveness of two synthetic methods was done for a green chemistry method using an ionic liquid-based solvent relative to a conventional method using organic solvents for the N-alkylation of indole. The green method used potassium hydroxide in the ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, followed by addition of the alkyl halide. The conventional method used sodium hydride in dimethylformamide. Possible advantages of the green method would be the use of a non-volatile solvent, the possibility of recycling the solvent, and the use of a less reactive base. However, its reaction yield was lower than for the conventional method, the reagent expense was higher, and recycling and reuse of the ionic solvent require considerable amounts of conventional solvent to clean it up sufficiently for reuse. On a laboratory scale, the ionic liquid method yielded neither a “green” nor an efficiency advantage. It is possible that with optimization on an industrial scale involving solvent reclamation that the green method could realize its promise. KEYWORDS: Green Chemistry; Sustainable Chemistry; Ionic Liquids; N-alkylation; Indole; Solvent Recycling; Organic Chemistry; 1-Butyl-3-methylimidazolium Tetrafluoroborate; Synthesis

Synthesis, UV-curing behavior and surface properties of fluorine-containing vinyl ether polymers

Five fluorine-containing vinyl ether monomers were prepared by the reaction between 2-vinyloxy ethanol, a fluorinated alcohol and hexafluorobenzene in the presence of sodium hydride in dimethylformamide. Two representative properties of these monomers, UV-curing behavior initiated by a cationic photo-initiator PAG 201 and surface free energy of coating films, were investigated. Photo-polymerization proceeded both rapidly and completely with a high double-bond conversion (> 90%) and a fast curing rate (maximum curing time < 21 s) for three monomers. The surface energies of the monomers and the resulting polymer films were then investigated. The minimum surface free energy of the UV-cured homopolymer films reaches 7.1 mJ/m2. X-ray photoelectron spectroscopy data show that the low surface tension is influenced by fluorine content in the soft segments and fluorinated chains’ migration to the surface. The five monomers exhibit low viscosity, low surface energy, good thermal stability and good photo-polymerization properties, which make them great candidates for UV coating and photoresist applications.

Synthesis of per-substituted hydrophilic and hydrophobic β-cyclodextrin derivatives

The aim of this work was to synthesize new cyclodextrin derivatives from native β-cyclodextrin by allylation reactions and indium metal in aqueous and organic medium. The resulted products could be used to prepare a new hydrophilic pharmaceutical active ingredient. A hydrophobic derivative can also be prepared by the same method. Indeed, the allylation reactions allow the creation of a stereogenic centers and the introduction of an allyl group lead to development of various functionalization of CD sites. Natural β-cyclodextrin was treated with allyl bromide and sodium hydride in dimethylformamide (DMF) at room temperature, which resulted in the formation of O-perallylated β-cyclodextrin A1 (98%). Through successive reactions of oxidation, reduction and allylation, the latter was converted into per 2, 3, 6-tri-O-(2-hydroxypent-4-enyl) β-cyclodextrins A4 (40%). Others derivates of CD type B3 and C3 were synthesized by series of reaction to give multifunctionalized cyclodextrins with yield of 25 and 30%, respectively.

An Improved gem-Dimethylcyclopropanation Procedure Using Triisopropylsulfoxonium Tetrafluoroborate

A new procedure for the cyclopropanation of α,β-unsaturated carbonyl compounds and related systems is described which employs triisopropylsulfoxonium tetrafluoroborate and sodium hydride in dimethylformamide. Using this reagent, a range of α,β-unsaturated ketones (and an ester and a vinyl nitro example) has been converted into the corresponding gem-dimethylcyclopropyl carbonyl compounds; in addition, a preliminary result is described in which an activated alcohol is converted directly into a gem-dimethylcyclopropyl ketone by a one-pot tandem oxidation-cyclopropanation sequence, albeit in low yield.

Synthesis of substituted 3‐phenyl‐6h‐pyrazolo[4,3‐d]isoxazoles from corresponding 4‐benzoyl‐5‐hydroxypyrazoles

AbstractTreatment of 1,(3)‐(di)substituted 4‐benzoyl‐5‐hydroxypyrazoles with phosphorus oxychloride affords the corresponding 4‐benzoyl‐5‐chloropyrazoles. Reaction of the latter with hydroxylamine leads to oximes, which can be cyclized to novel 3‐phenyl‐6H‐pyrazolo[4,3‐d]isoxazoles by treatment with sodium hydride in dimethyl formamide. Detailed nmr spectroscopic studies (1H, 13C) with all obtained compounds are presented.

Grob-type fragmentation of N-alkyl-2-cyano-5-bromopiperidines to unsaturated imidoyl cyanides

2-Cyano-5-bromopiperidines, derived from the stereoselective addition of cyanide to 5-bromomethyl-1-pyrrolinium salts, underwent a Grob fragmentation by reaction with sodium hydride in dimethylformamide, affording unsaturated imidoyl cyanides.

Photograft polymerization of acrylate monomers and macromonomers on photochemically reduced PTFE films

The objective of this study was to explore and optimize the photograft polymerization of acrylate monomers and macromonomers upon premodified poly(tetrafluoroethylene) (PTFE) substrates, with a view toward applying these grafted materials as biomaterials. PTFE films were photochemically reduced by exposure to short wavelength ultraviolet (UV) light in the presence of the reducing agents, i.e., diphenyl ketyl radical anion, generated from a solution of benzophenone and sodium hydride in dimethylformamide (Noh et al., J. Polym. Sci. A, Polym. Chem., 35, 1499 (1997)). The photochemically reduced PTFE films were subsequently modified by photograft polymerization of acrylic acid, acrylamide, and poly(ethylene glycol) monoacrylate (PEG-Ac) by employing long wavelength UV irradiation with benzil dimethyl ketal as an initiator. The photochemically reduced PTFE films were good substrates for photograft polymerization, leading to surfaces with chemical compositions close to those of the respective homopolymers as determined by electron spectroscopy for chemical analysis. Photograft polymerization of PEG-Ac on the photochemically reduced surface was also explored with different concentrations (1, 2, 4, 6, and 8%; v/v) and molecular weights (200, 400, 1000, and 2000 g/mol) of PEG-Ac, different durations (5, 10, and 20 min) of long wavelength UV irradiation, and different concentrations (0.1, 0.2, 0.4, and 0.8%; v/v) of benzil dimethyl ketal. Higher concentrations and lower molecular weights of PEG-Ac generally led to more extensive photograft polymerization, whereas the concentration of benzil dimethyl ketal and duration of UV irradiation did not substantially influence the extent of photograft polymerization. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3467–3482, 1997

Bis(5-carbomethoxy-1,3-phenylene)-30-crown-4: a macrocyclic monomer of predominantly hydrocarbon character

A general route to 5,5′-difunctionalized bis( m-phenylene) macrocycles ( 1) is reported. Bis(5-carbomethoxy1,3-phenylene)-30-crown-4 ( 1e) has been synthesized in one step from methyl 3,5-dihydroxybenzoate and 1,10-dibromodecane in the presence of sodium hydride in dimethylformamide. This monomer is suitable for synthesis of backbone polymacrocycles of predominantly hydrocarbon character.

Pyridazines, 71. A Novel Type of 1,2-Diazine Æ 1,2-Diazole Ring Contraction

Reaction of the 3,6-dichloro-4-pyridazinecarboxamide derivative (2) with sodium hydride in dimethylformamide does not afford a pyridazino[3,4-b]-[1,5]benzodiazepine system (3) but results in a ring transformation to give the quinoxalinyl-substituted pyrazole derivative (4). The structure of this unexpected reaction product could be elucidated by means of a crystal structure determination; a mechanistic interpretation of this novel type of a pyridazine → pyrazole ring contraction is proposed

Synthesis of amino acids and related compounds. 42. A novel transformation of imidazolines into 2,4,6-trisubstituted pyrimidine derivatives

2,5-Diaryl-4-(chloromethyl)imidazoline derivatives 5a-g, obtained from N-acyl-α-amino ketone derivatives 1, were rearranged with sodium hydride in dimethylformamide. Spontaneous air oxidation led to 2,4-di- and 2,4,6-triarylpyrimidine derivatives 6a-g in good yields

Regioselective N-Alkylation of Methyl Indole-2-carboxylate

Abstract Only N-alkylated roducts were obtained by reacting functionalized halides with methyl indole-Zcarboxylate using potassium carbonate in acetonitrile or sodium hydride in dimethylformamide. Ethyl acrylate also gave rise to N-alkylation.

Application of Magnesium Alkoxides to Syntheses of Benzoheterocyclic Compounds

The Dieckmann condensation of methyl [(2-methoxycarbonyl)phenyl]-X-acetates Ia-Ih (X = O, S, SO2, NH, NCH3) initiated by action of magnesium methoxide, ethoxide, isopropoxide and other basic reagents have been studied under various conditions. Whereas magnesium methoxide has comparable efficiency as sodium methoxide and potassium tert-butoxide in syntheses of benzoheterocyclic compounds IIa-IIh, magnesium ethoxide gives the ethyl ester IIb in medium yield, and magnesium isopropoxide is quite inefficient in the condensation reaction. The alkylation of the esters IIa, IId, and IIg with methyl chloroacetate in the presence of sodium hydride in dimethylformamide gives the diesters IIi - IIk which on action by potassium tert-butoxide undergo the cyclization reaction to give esters III.

Tautomerism in quinaldyl ketones

AbstractThe quinaldyl ketone, 4‐phenyl‐3‐(quinolin‐2‐yl)‐butan‐2‐one was prepared by two methods: (a) benzylation of 1‐(1H‐quinolin‐2‐ylidene)propan‐2‐one in the presence of sodium hydride in dimethylformamide and (b) by the benzylative demethoxycarbonylation of methyl 2‐(1H‐quinolin‐2‐ylidene)‐3‐oxobutanoate in the presence of lithium bromide in hexamethylphosphoramide at 135°. In the absence of acid, the compound exists exclusively in the tautomeric form, 4‐phenyl‐3‐(1H‐quinolin‐2‐ylidene)butan‐2‐one.

ChemInform Abstract: A Convenient Preparation of Hex‐5,6‐enopyranosides.

AbstractVarious hex‐5,6‐enopyranosides such as (II) are prepared by sodium hydride‐induced dehydrohalogenation of 6‐halopyranosides such as (I).

A Convenient Preparation of Hex-5,6-enopyranosides

Abstract Hex 5,6-enopyranosides were conveniently prepared from 6-halo-hexopyranosides by treatment with sodium hydride in dimethylformamide. Simultaneous benzylation of free hydroxyl groups can be achieved.

Potential antidepressants: 4-(Thioaryloxy)piperidines

Nucleophilic substitution reactions of a series of thio-substituted fluoroarenes with 1-methyl-4-piperidinol, 1-benzyl-4-piperidinol, and 1-methyl-4-phenyl-4-piperidinol in the presence of sodium hydride in dimethylformamide gave the title compounds V-XI and XIII. The salts of these bases were pharmacologically tested and salts of compounds V, XI, and XIII showed in behavioural tests properties which are indicative of antidepressant activity.

Some further 2-(4-substituted 1-piperazinyl)acetamides derived from 6,11-dihydrodibenzo[b,e]thiepin. Transformations of 6,11-dihydrodibenzo[b,e]thiepin derivatives into anthraquinones, anthrones and anthracenes

Reactions of the secondary amines I and VIII with chloroacetyl chloride gave the 2-chloroacetamides II and IX affording by substitution reactions with 1-methylpiperazine, 2-(1-piperazinyl)ethanol and 3-(1-piperazinyl)propanol in the title compounds III-V and X-XII. The starting amine VIII was prepared from the ketone XIV via XVII and VII. The product of 1,6-addition and the following dehydrogenation XVIII was obtained as a by-product of the reaction of XIV with 1-methyl-4-piperidylmagnesium chloride. Reaction of 2-fluorodibenzo[b,e]thiepin-11(6H)-one (XV) with sodium hydride in dimethylformamide and the following hydrolysis gave 2-fluoroanthraquinone (XXVII). An attempt at trapping the presumed dianion of the type B by treatment with methyl iodide and the following hydrolysis resulted in a mixture of XXVII and the anthracenes XXXI and XXXII. A similar reaction sequence starting from the ketone XIV gave the anthrones XXX and XXXIV, 9-methoxy-10-(methylthio)anthracene (XXXIII) (main product) and anthraquinone (XXVIII). Oxidation of XXXIII with m-chloroperbenzoic acid or hydrogen peroxide gave either the sulfone XXXV or XXXVI.

ChemInform Abstract: Facile Rearrangement of 2‐Amino‐3‐carbethoxy‐4‐ethylfuro(3,2‐b)pyridinium Cation to 2‐Oxo‐3‐cyano‐4‐ethyl‐4H‐furo(3,2‐b)pyridine.

AbstractThe N‐ethylfuropyridinium iodide (III), obtained by ethylation of the furopyridine (I), undergoes the base‐induced rearrangement mentioned in the title, yielding the oxofuropyridine (IV).

Stereospecific synthesis of 2,3-dimethyl-1,4-thiamorpholines by cyclization of β-n-methoxycarbonylaminoalkyl vinyl sulfoxides and related compounds

Synthesis of cis- and trans-N-methoxycarbonyl-2, 3-dimethyl-l, 4-thiamorpholine and their S-oxides and S, S-dioxides by intramolecular reaction of the corresponding 2-methoxy-carbonylaBinoalkyl-2' -chloroethyl thioethers, sulfoxides and sulfones with sodium hydride in dimethylformamide at room temperature is reported. Cyclization of chlorothioethers and -sulfones is Stereospecific although, in the case of sulfones, the formed 1, 4-thiamorpholines S, S-dioxides epimerize at C(2) after long reaction times. In chlorosulfoxides, elimination of HCl is previous to cyclization which also resulted stereospecific except in the case of the acyclic starting material of R*s,S*1,S*2 configuration, where epimerization at sulfur takes place.