N-(Diethoxyphosphoryl)-O-benzylhydroxylamine—a convenient substrate for the synthesis of N-substituted O-benzylhydroxylamines

Easily available N-(diethoxyphosphoryl)-O-benzylhydroxylamine was shown to be convenient, orthogonally protected substrate for regioselective N-alkylation by means of diverse halides under basic conditions (sodium hydride/tetrabutylammonium bromide). An efficient procedure for dephosphorylation of N-substituted N-(diethoxyphosphoryl)-O-benzylhydroxylamine to provide N-substituted O-benzylhydroxylamines was also established.     

Preparation ofN-nitrohydroxylamines by direct nitration

The possibilities for stabilization of compounds with the A-B-NO₂ fragment, where A is an atom containing a lone electron pair, were examined. It was shown thatN-methyl-O-2,4-dinitro- and 2,4,6-trinitrophenylhydroxylamines undergo nitration with nitronium tetrafluoroborate or with a mixture of nitric acid and acetic anhydride to give the correspondingN-nitrohydroxylamines in high yields.N-Nitro-2,4-dinitrohydroxylamine that contains no methyl group at the nitrogen atom is unstable and forms a product ofO-alkylation upon reaction with diazomethane.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2276–2278, November, 1995.The work was supported by the International Science Foundation (Grant NGN 000).     

Alkylation of salts ofN-nitrohydroxylamines with chloromethylnitramines

The reactions of Ag-salts ofN-nitmhydroxyumines withN-methyl-N-chloromethylnitramine afford mainly products ofO-alkylation, whereas the reactions of the corresponding Li-, Na-, K-, Mg-, and NH₄-sals in the presence of tetrabutylammonium (TBAB) give mainly products ofN-alkylation. The reactions of the corresponding. NH₄-salts with bis-(chloromethyl)nitramine in the presence of TBAB lead solely to products ofO-alkylation. Increasing in the amount of TBAB results in the appearance of theN-isomer.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1740–1744, July, 1996.     

Synthesis, Conformational Studies and Inclusion Properties of Tetrakis[(2-pyridylmethyl)oxy]thiacalix[4]arenes

An attempted O-alkylation of the flexible macrocycle 1with 2-(chloromethyl)pyridine in the presence of Cs₂CO₃ under THF reflux afforded a mixture of twoconformers of tetra-O-alkylated product 4a in a ratio of 91:9 (cone-4a:1,2-alternate-4a)in 70% yield, while other possible isomers were not observed. In the case of Na₂CO₃, there was no reaction product,only the starting compound 1, whereasonly monoalkylated compound 3 was obtained when usingK₂CO₃ as the base. The distribution of cone conformer decreased in the case of O-alkylation of tetraol 1with 4-(chloromethyl)pyridine or benzyl bromide in the presence of Cs₂CO₃ in comparison with that ofO-alkylation with 2-(chloromethyl)pyridine, while the 1,2-alternate conformer increased in the same sequence. The larger Cs⁺might increase the contribution of the metal template effect, which can hold the 2-pyridylmethyl group(s) and theoxide group(s) on the same side of the tetrathiacalix[4]arene 1 through the cation-O^- and -N-interaction in the caseof O-alkylation of tetraol 1 with 2-(chloromethyl)pyridine.Only when the template metal can hold the 2-pyridyl group(s) andthe oxide group(s) on the same side of the tetrathiacalix[4]arene is the conformation immobilized to thecone. The template effect of the cesium cation plays an important role in this alkylation reaction. The structuralcharacterization of these products is also discussed.The two-phase solvent extraction data indicated thattetrakis[(2-pyridylmethyl)oxy]thiacalix[4]arenes 4a show strong Ag⁺ affinity and a high Ag⁺ selectivity wasobserved for cone-4a. A good Job plot proves 1:1 coordination of cone-4a with Ag⁺ cation.¹H-NMR titration of cone-4a with AgSO₃CF₃ also clearly demonstrates that a 1:1complex is formed with retention of the original symmetry. In contrast, the 1,2-alternate-4a can form a 2:1 metal/thiacalix[4]arene complex and the two metal-binding sites display positive allostericity. The conformational changes ofpyridine moiety from the original outward orientation of the ring nitrogen to the inside orientation toward thethiacalixarene cavity were observed in the processof Ag⁺ complexation.     

Syntheses based on anabasine. Preparation and transformations of N-oxides

The oxidation of N-acetyl-and N-benzoylanabasine with the tert-butyl hydroperoxide (TBHP)— MoCl₅ system or MCPBA proceeds selectively at the nitrogen atom of the pyridine ring. The oxidation of N-methylanabasine under similar conditions gives a mixture of stereo-isomeric N-oxides at the piperidine nitrogen atom, their ratio depending on the reagent used. The oxidation of anabasine by TBHP— MoCl₅ or MCPBA is accompanied by dehydrogenation and results in anabaseine N-oxide. The reactions of anabasine and anabaseine pyridine N-oxides with acetic anhydride were investigated. The substituted 1H-3-pyridin-2-ones were prepared. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 322—328, February, 2006.     

A simple and efficient synthesis of 3-substituted derivatives of pentane-2,4-dione

A novel and efficient method of synthesis of 3-substituted derivatives of pentane-2,4-dione is proposed, wherein cheaper and easily accessible chloro derivatives are conversed into more reactive iodo derivatives. The method is based on the Finkelstein reaction for which the literature suggests highly polar organic solvents as ideal reaction media. In the presented work, the use of industrially used ketones, especially methyl isobutyl ketone, is proposed. The use of MIBK as a solvent additionally allows an azeotropic removal of water from the reaction mixture, enabling the application of moisture sensitive alkylating agents i.e. (3-chloropropyl)trimethoxysilane. The obtained products are isolated through distillation, which does however not allow the separation of C-alkylation products from O-alkylation ones. The products not containing water-sensitive substituents were isolated as copper complexes. The pure product of C-alkylation was obtained by decomposition of the copper complex with a hydrochloric acid solution and extraction of the formed ligand to an organic phase i.e. hexane. The obtained ligand can be further purified by distillation. Presented at the 35th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 26–30 May 2008.     

New organically templated photoluminescence iodocuprates(I)

Two types of organic cyclic aliphatic diamine molecules piperazine (pip) and 1,3-bis(4-piperidyl)propane (bpp) were used, respectively, to react with an inorganic mixture of CuI and KI in the acidic CH₃OH solutions under the solvothermal conditions, generating finally three new organically templated iodocuprates as 2-D layered [(Hpip)Cu₃I₄] 1, 1-D chained [tmpip][Cu₂I₄] 2 (tmpip=N,N,N′,N′-tetramethylpiperazinium) and dinuclear [H₂bpp]₂[Cu₂I₅] I·2H₂O 3. Note that the templating agent tmpip²⁺ in compound 2 originated from the in situ N-alkylation reaction between the pip molecule and the methanol solvent. The photoluminescence analysis indicates that the title compounds emit the different lights: yellow for 1, blue for 2 and yellow-green for 3, respectively.     

N-alkylation of 2,3-dihydroimidazo[2,1-b]quinazolin-1(10)H-5-one. On the cryptoanionic mechanism of N-substitution

Quantum chemical methods involving studies of transition states of the reaction showed that the main products of N-alkylation of prototropic 2,3-dihydroimidazo[2,1-b]quinazolin-1(10)H-5-one (1) in the gas phase and under neutral conditions in solution occurring via the S_N2 mechanism should be N(10)-alkyl-substituted derivatives formed from the 1H-tautomer. Minor N(1)-substituted derivatives in solution can be produced from both tautomers. For the alkylation of the free N-anion of compound 1, position 1 is attacked first. Validity of conclusions concerning the overall regioselectivity of the reaction was confirmed experimentally. In the absence of solvent, the alkylation proceeds abnormally with a sharp increase in the content of the 1-substituted isomers up to inversion of the regioselectivity of the reaction, which is explained by the participation in the process of the H-bonded dimer of the substrate (1a)₂, which undergoes alkylation via the cryptoanionic mechanism. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 876–887, May, 2006.     

Influence of alkali and alkaline earth ions on the O -alkylation of the lower rim phenolic-OH groups of p-tert -butyl-calix[4]arene to result in amide-pendants: Template action of K+ and the structure of K+ bound tetra-amide derivative crystallized with a p-tert -butyl-calix[4]arene anion

Role of alkali and alkaline earth ions on the formation of calix[4]arene-amide derivatives through O-alkylation of the lower rim phenolic-OH groups in general and template action of K⁺ in particular have been explored. Na⁺ and K⁺ ions among alkali, and Ca²⁺ and Sr²⁺ ions among alkaline earth have shown tetra-amide derivatives bound to metal ion species. Among all these, potassium salts act as template and yields a K⁺ bound tetra-amide derivative where the charge is counter balanced by a calix[4] arene-monoanion and the product is crystallographically characterized. Change in the amide precursor used in these O-alkylation reactions has no effect on the type of the amide derivative formed. Also demonstrated is a direct one-step reaction for the preparation of 1,3-di-amide derivative in high yield and low reaction period using CsHCO₃.     

Si-Containing Amides of Phosphoric Acid

Summary. The first representative of the N-silylmethylamides of phosphoric acid O=P[NMe(CH₂SiMe _n (OEt)_3-n ]₃ have been synthesized by interaction of MeNHCH₂SiMe _n (OEt)_3-n (n = 2, 3) with POCl₃. The interaction of the N,N′,N″-trimethyl-N,N′,N″-tris[(ethoxydimethyl- silyl)methyl]triamide phosphoric acid with BF₃·Et₂O or BCl₃ results in the formation of the N,N′,N″-trimethyl-N,N′,N″-tris[(fluorodimethyl-silyl)methyl]triamide phosphoric acid or N,N′,N″-trimethyl-N,N′,N″-tris[(chlorodimethylsilyl)methyl]triamide phosphoric acid. NMR data show on the tetracoordinate state of silicon in these products. Professor Vadim Aleksandrovich Pestunovich, our chief, teacher and friend died on July 4^th, 2004     

An Efficient Method for the Synthesis of N-Acylsulfonamides: One-pot Sulfonylation and Acylation of Primary Arylamines under Solvent-Free Conditions

Summary. The preparation of N-acylsulfonamides is described using primary amines, arylsulfonyl chlorides and acyl chlorides. Reaction of primary aryl amines with arylsulfonyl chlorides in the presence of NaHCO₃ produced N-arylsulfonamides, which reacted in situ with benzoyl chloride furnishing the corresponding N-benzoyl-N-arylsulfonamides in 72–96% yields. Accordingly, 4-nitrobenzoyl chloride and 3,5-dinitrobenzoyl chloride were used as acylating agents. All the reactions were carried out under solvent-free conditions at room temperature and the products were isolated after simple work-up in high yields and purity.     

Clean and efficient microwave-solvent-free synthesis of 1-(2′,4′-dichlorophenacyl) azoles

Microwave induced N-alkylation of several azoles with 2,2′,4′-trichloroacetophenone (TCA) under solvent-free conditions allowed to obtain the corresponding 1-(2′,4′-dichlorophenacyl) azoles with satisfactory to good selectivities and yields. TGA and DSC measurements were achieved for the synthesized compounds and showed a close relationship between the thermal behavior and the reaction temperature under microwave heating. Non-purely thermal microwave effects were evidenced during the alkylation of pyrazole and 1H-indazole under the selected conditions.     

<Emphasis Type="Italic">O</Emphasis>- and <Emphasis Type="Italic">N</Emphasis>-Alkylation of <Emphasis Type="Italic">N</Emphasis>-halosuccinimides in ionic reactions with 1-phenyltricyclo [4.1.0.0<Superscript>2,7</Superscript>]heptane

N-Bromo and N-chlorosuccinimides add to 1-phenyltricyclo[4.1.0.0^2,7]heptane in CH₂Cl₂ with cleavage of the C(1)-C(7) bond to give isomeric 1 : 1 Markownikoff-type endo, anti-adducts of the norpinane structure in a ∼3 :7 ratio corresponding to N and O alkylation of succinimide.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No.2, pp. 457–460, February, 2005     

离子液体中酮肟O-烷基化反应的研究

以[Bmim]PF6,[Bmim]BF4,[Bmim]OH为介质,以NaOH为缚酸剂,由酮肟与卤烷、硫酸酯等烷基化剂在20～40℃反应1～2h,以52%～94%的收率制备了酮肟醚衍生物,产物结构经1HNMR,GC-MS表征.结果表明,该方法简便易操作,所用离子液体对环境友好,并可循环使用.     

Starch Derivatives of High Degree of Functionalization 11: Studies on Alternative Acylation of Starch with Long-chain Fatty Acids Homogeneously in <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dimethyl acetamide/LiCl

Starch materials of different amylose content were allowed to react with saturated and unsaturated fatty acids of varying chain length from C₁₄ to C₁₈ under homogeneous conditions applying the solvent N,N-dimethyl acetamide in combination with LiCl. As reagent the corresponding acid chlorides and, alternatively, carboxylic acids in situ activated with toluene-4-sulfonyl chloride and N,N′-carbonyldiimidazole (CDI) were studied. Using fatty acid chlorides (FACl) and toluene-4-sulfonyl chloride-activated acids an almost complete substitution of the starch occurs. By in situ activation of the fatty acids with CDI, products with a degree of substitution up to 2 were obtained, which, in particular, represents a simple and very mild procedure.     

Unusual pathway of alkylation of 2-(4-bromobenzylidene)-<Emphasis Type="Italic">p</Emphasis>-menthan-3-one with ethyl bromoacetate

Reaction of enolate carbanion, generated from 2-(4-bromobenzylidene)-p-menthan-3-one, with ethyl bromoacetate proceeds selectively as the O-alkylation. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2420–2423, December, 2007.     

Reactions of 2-bromopropanamides with conjugated bases of representative β-dicarbonyl compounds. Synthesis of 2,5-dioxopyrrolidines and oxazolidine-4-ones

Reactions of 2-bromopropanamides with potassium enolates of representative β-dicarbonyl compounds provide, in high yields, open and heterocyclic compounds through a CC or CO alkylation reaction. Whereas C-alkylation products form in all conditions tested under relevant diastereoselectivity, O-alkylation takes place only in the presence of silver promoters, and shows partial diastereoselectivity.     

N-Alkylation of amines with alcohols catalyzed by a Cp*Ir complex

A new effective catalytic system consisting of [Cp*IrCl₂]₂/K₂CO₃ (Cp*=pentamethylcyclopentadienyl) for the N-alkylation of primary amines with alcohols has been developed. As an example, the reaction of aniline with benzyl alcohol in the presence of [Cp*IrCl₂]₂ (5.0 mol%Ir) and K₂CO₃ (5.0 mol%) in toluene at 110°C for 17 h gave benzylaniline in an isolated yield of 88%.     

INTRODUCTION DE SYSTÈMES CAGE DANS LES MOLÉCULES D'INTÉRĚT BIOLOGIQUE. 2. ALKYLATION DES ESTERS SULFAMIQUES AU MOYEN D'UN DÉRIVÉ DE L'ADAMANTANE

Abstract

Sulfamic esters of the general type R[sbnd]O[sbnd]SO₂[sbnd]NH₂ were alkylated under solid-liquid, liquid-liquid phase transfer catalysis conditions and by noncatalytic procedure, in homogeneous medium, in the presence of an equimolar amount of triethylamine, by means of a 1-adamantyl bromomethyl ketone. According to the procedure and the nature of R, these reactions yield the N-monoalkyl, N-dialkyl derivatives or a cleavage of the O[sbnd]SO₂ bond with formation of the O-alkylation products.

Nous decrivons l'alkylation des esters sulfamiques de formule générale R[sbnd]O[sbnd]SO₂[sbnd]NH₂ au moyen de l'adamantyl-1 bromométhyl-cétone, en catalyse par transfert de phase solide-liquide, liquide-liquide et dans les conditions non-catalytiques, en phase homogène et en présence d'une quantité équimoléculaire de triéthylamine. Selon la méthode utilisée et la nature du radical R. on aboutit à des dérivés N-monoalkylés, N-dialkylés ou à la scission de la liaison O[sbnd]SO₂ avec formation de produits de O-alkylation.     

Selective functionalization at the small rim of calix[6]arene. Synthesis of novel non-symmetrical N3, N4 and N3ArO biomimetic ligands

Eight novel calix[6]arene-based biomimetic ligands for transition metal ions have been synthesized. They display a non-symmetrical N₃, N₄ or N₃ArO binding core that mimics enzyme active sites presenting histidine and tyrosine residues. The key step for their synthesis is the mono-alkylation at the small rim of the C_3v symmetrical trimethyl ether derivative of tBu-calix[6]arene with N-Boc-2-chloroethylamine to yield a novel calix[6]arene synthon. Its combined O-alkylation with a chloromethyl aromatic amine and N-deprotection or alkylation or reductive alkylation with a salicylaldehyde derivative yielded the calix[6]arene-based ligands with mixed N/O donors.