Chemistry of diazocarbonyl compounds: XXVIII. Reaction of acyclic N-arylsulfonylacetamides with Rh(II)-carbenoids as a new synthetic route to alkyl acetimidoates

A new procedure was proposed for the synthesis of alkyl acetimidoates via alkylation of the carbonyl group in N-arylsulfonylacetamides with Rh(II)-carbenoids. The procedure ensures preparation in good yield of acetimidoates having a polyfunctionalized O-alkyl group. The obtained alkyl acetimidoates in crystal exist as E isomers with respect to the C=N bond and as s-cis conformers relative to the C-OCHRR’ bond. Alkyl N-arylsulfonylacetimidoates react with ammonia and hydrazine hydrate to give in good yield the corresponding carboximidamides(hydrazides) via replacement of the O-alkyl group. Unlike structurally related compounds having simple alkyl or aryl groups on the nitrogen atom, N-arylsulfonylacetimidoates readily undergo hydrolysis in the presence of moisture and traces of acids.     

An efficient strategy for N-alkylation of benzimidazoles/imidazoles in SDS-aqueous basic medium and N-alkylation induced ring opening of benzimidazoles

A sustainable route for the N-1 alkylation of imidazole and benzimidazole derivatives has been developed under volatile organic solvent free condition in alkaline water-SDS system. Incorporation of SDS in the reaction medium enhances the reaction rate by suppressing the solubility issue that arises for different substrates. This method provides high yield of the alkylated product in a shorter reaction time. For reactive alkyl halides reaction proceeds at ambient temperature whereas in the cases of less reactive alkyl halides require 55–60?°C to complete alkylation process. N-alkylation induced ring opening of the heterocyclic ring in benzimidazole derivatives to multifunctional aromatic compounds were noticed at 60?°C when more than two equivalents of alkyl halide was used.     

2-Hydroxy-N,N,N-tributylethanaminium thiocyanate as solvent and reagent for the preparation of alkyl thiocyanates

2-Hydroxy-N,N,N-tributylethanaminium thiocyanate was utilized as both solvent and reagent for the conversion of alkyl halides to the corresponding alkyl thiocyanates in good yields under mild conditions.     

A convenient method for the preparation of primary amines using tritylamine

A simple method for the preparation of primary amines by treating N-tritylamines with trifluoroacetic acid has been established. The N-tritylamines were prepared by the reaction of alkyl halides or alkyl p-toluenesulfonates with tritylamine, or by the reaction of alkyl bromides with lithium tritylamide.     

Conformational Analysis of N-Alkyl-N-[2-(diphenylphosphoryl)ethyl]amides of Diphenylphosphorylacetic Acid: Dipole Moments,IR Spectroscopy,DFT Study

Experimental and theoretical conformational analysis of N-methyl-N-[2-(diphenylphosphoryl)ethyl]diphenylphosphorylacetamide, N-butyl-N-[2-(diphenylphosphoryl)ethyl]diphenylphosphorylacetamide, and N-octyl-N-[2-(diphenylphosphoryl)ethyl]diphenylphosphorylacetamide was carried out by the methods of dipole moments, IR spectroscopy, and Density Functional Theory (DFT) B3PW91/6-311++G(df,p) calculations. In solution, these N,N-dialkyl substituted bisphosphorylated acetamides exist as a conformational equilibrium of several forms divided into two groups—with Z- or E-configuration of the carbonyl group and alkyl substituent, and syn or anti arrangement of the phosphoryl-containing fragments relative to the amide plane. The substituents at the phosphorus atoms have eclipsed cis- or staggered gauche-orientation relative to the P=O groups, and cis orientation of the substituents is due to the presence of intramolecular H-contacts P=O...H−C_phenyl or p,π conjugation between the phosphoryl group and the phenyl ring. Preferred conformers of acetamides molecules are additionally stabilized by various intramolecular hydrogen contacts with the participation of oxygen atoms of the P=O or C=O groups and hydrogen atoms of the methylene and ethylene bridges, alkyl substituents, and phenyl rings. However, steric factors, such as a flat amide fragment, the bulky phenyl groups, and the configuration of alkyl bridges, make a significant contribution to the realization of preferred conformers.     

Investigatins of the extraction of adenosine phosphates with N,N′-dioctadecyl-1,4-diazabicyclo[2.2.2.]octane and N,N,N′,N′-tetramethyl-N,N′-dioctadecyldiammonium alkanes

The extraction of adenosine phosphates with hydrophobic cyclic diammonium or alkyl diammonium salts is described. The selectivity of these compounds is governed by two factors, the length of the spacer arm between the two ammonium nitrogens and the pH of the system. The cyclic compound exhibits less selectivity than the similar noncyclic alkyl compounds. It is shown that several of the compounds are fairly selective for adenosine 5′-triphosphate (ATP). The best of these, N,N,N′-tetramethyl-N,N′-dioctadecyldiammoniumethane, is tested for assay of ATP in spiked urines.     

Preparation of C5-substituted O,5′-cyclouridine

The synthesis of hitherto unknown C5-substituted O⁶,5′-cyclouridines is described. The 2′,3′-isopropylidene-uridine was treated with N-halogenosuccinimides forming appropriate bridged 5-halogeno derivatives. Using lithiation method, bromine substituent at C5 position was exchanged into various alkyl and alkenyl derivatives.     

Trihaloacetaldehyde N,O-acetals: useful building blocks for dihalomethylene compounds

The reaction of trifluoroacetaldehyde N,O-acetals with more than 2 equiv of alkyllithiums at −78 °C resulted in regiospecific defluorinative alkylation with unusual regioselectivity to give α,α-difluoroketone N,O-acetals in excellent yield. In contrast, under similar conditions, trichloroacetaldehyde N,O-acetals gave simple mono-dechlorinated product without the alkyl transfer reaction from alkyllithiums to the generated intermediates.     

Hydrazines in the synthesis of N-substituted 1,5,3-dithiazocan-3-amines catalyzed by Ti and Cu compounds

Efficient preparation method was developed for N-aryl(benzyl, alkyl)-1,5,3-dithiazocan-3-amines consisting in the transamination of 3-tert-butyl-1,5,3-dithiazocane with aryl(benzyl)hydrazines, and also in the reaction of N ¹,N ¹,N ⁷,N ⁷-tetramethyl-2,6-dithiaheptane-1,7-diamine with aryl(benzyl, alkyl)hydrazines in the presence of catalytic amounts of Ti and Cu compounds.     

Cu2O/1-(2-methylhydrazine-1-carbonyl)-isoquinoline 2-oxide catalyzed C-N cross-coupling reaction in aqueous media

An experimentally simple, efficient, and inexpensive catalyst system was developed for the N-arylation of imidazole, indole, pyrrole, alkyl alcohol amines, and alkyl amines with aryl iodides and bromides. The reaction proceeds in water-ethanol media at 120 °C for 12 h with Cu₂O as the catalyst, 1-(2-methylhydrazine-1-carbonyl)-isoquinoline 2-oxide (L2) as the ligand, NaOH as the base to generate a wide range of N-arylated products in moderate to excellent yields. Aqueous medium, ease of operation, and broad substrate scope give the process a benign environmental profile.     

Three-Component Reaction of 4-Methylpyridine with Alkyl Propiolates and Secondary Phosphine Chalcogenides

The reaction between 4-methylpyridine, alkyl propiolates, and secondary phosphine oxides proceeded as N-vinylation-C-phosphorylation with stereo- and regioselective formation of (E)-N-ethenyl-C²- phosphoryl-1,2-dihydropyridines [when using bis(2-phenylethyl)phosphine oxide] or (E)-N-ethenyl-C⁴- phosphoryl-1,4-dihydropyridines (when using diphenylphosphine oxide). The process occurred at 60–62°C within 3 h to give functional dihydropyridines in 40–82% yield. Under similar conditions, bis(2-phenylethyl) phosphine sulfide and selenide reacted with alkyl propiolates preferably by nucleophilic PH-monoaddition at the triple bond.     

Distannane mediated reaction of N-acyliminium ion pools with alkyl halides. A chain mechanism involving radical addition followed by electron transfer

Hexabutyldistannane was found to be an effective mediator allowing the reaction of N-acyliminium ion pools with alkyl halides. A chain mechanism involving the addition of an alkyl radical generated from an alkyl halide to an N-acyliminium ion followed by the one-electron reduction of the resulting radical-cation by distannane was proposed.     

Design and effective synthesis of novel furo[2,3-d]pyrimidine derivatives containing ethylene ether spacers

[1+4] Cycloaddition reaction of ethylene ether-based N,N-dimethybenzylidenebarbituric acid with alkyl isocyanide in DMF produced novel high substituted furo[2,3-d]pyrimidine derivatives containing ether spacers under mild reaction conditions. The structures of the products were deduced from their IR, ¹H NMR, and ¹³C NMR spectroscopy. Good antibacterial activity was found in compound 5c.     

Stereoselective synthesis of cis- and trans-2′,5′-disubstituted N-arylpyrrolo[3′,4′:1,9](C60-I h )[5,6]fullerenes by the 1,3-dipolar cycloaddition of azomethine ylides from dialkyl aziridinedicarboxylates to fullerene C60

A stereoselective method for the synthesis of 2′,5′-disubstituted N-arylpyrrolofullerenes from anilines, alkyl glyoxylates, alkyl diazoacetates, and fullerene C₆₀ was proposed. The key step of the synthesis is the 1,3-dipolar cycloaddition reaction of fullerene with azomethine ylides generated by heating of dialkyl aziridinedicarboxylates. The thermal opening of the aziridine ring to azomethine ylide and the cycloaddition of the latter to C₆₀ at 100 °C are nearly completely stereoselective: only trans-adducts are formed from cis-aziridines, whereas trans-aziridines give exclusively cis-adducts.     

Allylation and alkylation of oxindoleketimines via imine umpolung strategy

When treated with an alkoxide base like t-BuOK in aprotic solvent, N-diphenylmethyl imino oxindoles, made conveniently through condensation of corresponding isatins with N-diphenylmethyl amine, are deprotonated to form azaallyl anions. Allylation and alkylation of this type of intermediates proceed smoothly with diverse C-electrophiles. Acidic work up finishes 3-amino-3-allyl/alkyl oxindoles. The overall transformation equals to an umpolung process at the C3 of isatins.     

Thermolyse et catalyse acide d'azido-steroïdes—6. comparaison avec les reactions de photolyse

Elimination of nitrogen concerted with migration of the alkyl group overlapping the p_y orbital of the N_α atom of the chromophore N_αN_βN_γ is involved during photochemistry and thermolysis of steroidal azides. Acid catalysed decomposition was explained by alkyl migration to nitrogen, in a manner anti to N₂ elimination. Electronic and steric considerations support these different mechanisms.     

N-[1-(Benzotriazol-1-yl)alkyl]amides from N-acyl-α-amino acids or N-alkylamides

A variety of N-(1-methoxyalkyl)amides react with benzotriazole in the presence of PPh₃·HBF₄ and organic bases (Hünig's base, DBU or DABCO) or solid-state-supported bases (SiO₂-Pip or IRA-67) in CHCl₃ to give N-[1-(benzotriazol-1-yl)alkyl]amides in good yields. The most convenient and efficient procedure for obtaining N-[1-(benzotriazol-1-yl)alkyl]amides consists, however, of the addition of benzotriazole sodium salt to a solution of crude 1-(N-acylamino)alkyltriphenylphosphonium salt, obtained in situ from N-(1-methoxyalkyl)amides and PPh₃·HBF₄. A combination of these reactions with the recently described electrochemical decarboxylative α-methoxylation of N-acyl-α-amino acids in the presence of SiO₂-Pip enables an effective two-pot transformation of N-acyl-α-amino acids to N-[1-(benzotriazol-1-yl)alkyl]amides.     

Solvent Effect on Rotational Correlation Times of Symmetric Tetraalkylammonium Ions

The overall rotational correlation times of symmetric tetraalkylammonium ions, R ₄N⁺ (R = ethyl, n-propyl, n-butyl, and n-pentyl), in various solvents were determined by the measurements of the ¹³C NMR spin-lattice relaxation times and the nuclear Overhauser enhancement factors of each α-carbon, considering the contribution of the internal rotation around the N—C bond. Except in water, the observed solvent dependencies of the rotational correlation times, τ_r, showed good correlations with those predicted from an electrohydrodynamic (Hubbard–Onsager–Felderhof) model. The correlation times of R ₄N⁺ increased as the size of the alkyl groups became larger. In the case of the n-Bu₄N⁺ and the n-Pen₄N⁺ ion, the τ _r values were similar to or even higher than those predicted by the HOF model under the stick hydrodynamic boundary condition, in spite of the fact that the ions were too small to allow the solvent to be regarded as a hydrodynamic or a dielectric continuum. A comparison of the results with the rotations of other pseudotetrahedral ions, e.g., tetraphenylborate and tetraphenylarsenium ions and with the translation of the R ₄N⁺ ions suggests that a considerable part of the rotational friction for R ₄N⁺ is brought about by pushing aside the solvent in the spaces between the alkyl groups of R ₄N⁺. A significant slowing in the rotation in water was observed for the n-Pr₄N⁺, n-Bu₄N⁺, and n-Pen₄N⁺ions; the extent of this effect increased with increasing size of the alkyl group. The increase in friction was related to the hydrophobic hydration of the R ₄N⁺ ions.     

Controlled Synthesis of Polyphosphazenes with Chain-Capping Agents

N-alkyl phosphoranimines were synthesized via the Staudinger reaction of four different alkyl azides with tris(2,2,2-trifluoroethyl) phosphite. N-adamantyl, N-benzyl, N-t-butyl, and N-trityl phosphoranimines were thoroughly characterized and evaluated as chain-capping compounds in the anionic polymerization of P-tris(2,2,2-trifluoroethoxy)-N-trimethylsilyl phosphoranimine monomer. All four compounds reacted with the active chain ends in a bulk polymerization, and the alkyl end groups were identified by ¹H-NMR spectroscopy. These compounds effectively controlled the molecular weight of the resulting polyphosphazenes. The chain transfer constants for the monomer and N-benzyl phosphoranimine were determined using Mayo equation.     

A new approach to the synthesis of strained cyclic systems: II. Mass spectrometric study of 2-dialkylamino-3-phenylthiophenes and their structural isomers, iminothietanes and iminocyclobutenes

Triads of isomeric N-alkyl-N-methyl-3-phenylthiophen-2-amines, N-methyl-3-alkyl-4-methylidene-3-phenylthietan-2-imines, and N-methyl-4-alkylsulfanyl-2-phenylcyclobut-2-en-1-imines (Alk = Me, Et, Bu) were synthesized from 1,3-dilithio-3-phenylpropyne, methyl isothiocyanate, and alkyl halides, and their fragmentation under electron impact was studied. Primary decomposition of the molecular ions of 2-aminothiophenes is determined by the localization of a radical cation center on the nitrogen atom, and it follows a path typical of alkyl(aryl)amines with elimination of hydrogen atom or methyl or propyl radical from the α-carbon atom in the N-alkyl substituent. Fragmentation of the iminothietanes involves cleavage of the four-membered ring in half to give neutral MeNCS molecule and 1-alkyl-1-phenylallene radical cation. Alkylsulfanyl(imino)-cyclobutenes undergo cleavage at the sulfur-containing side chain according to general relations holding in the fragmentation of alkyl sulfides.