A simple one-pot procedure for the direct conversion of alcohols into alkyl nitriles using TsIm

A convenient and efficient one-pot preparation of nitriles from alcohols using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, treatment of alcohols with a mixture of NaCN, TsIm and triethylamine in the presence of catalytic amounts of tetra-n-butylammonium iodide (TBAI) in refluxing DMF furnishes the corresponding alkyl nitriles in good yields. This methodology is highly efficient for various structurally diverse alcohols with selectivity for ROH: 1° > 2° > 3°.     

A simple one-pot procedure for the direct conversion of alcohols into azides using TsIm

A facile and efficient method for one-pot conversion of alcohols into azides using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, alcohols are refluxed with a mixture of NaN₃, TsIm and triethylamine in the presence of catalytic amounts of tetra-n-butylammonium iodide (TBAI) in DMF affording the corresponding alkyl azides in good yields. This methodology is highly efficient for various structurally diverse alcohols with selectivity for ROH: 1° > 2° > 3°.     

A simple procedure for the esterification of alcohols with sodium carboxylate salts using 1-tosylimidazole (TsIm)

An efficient and selective method for esterification of alcohols using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, alcohols are refluxed with a mixture of RCO₂Na (R: alkyl and aryl), TsIm, and triethylamine in the presence of catalytic amounts of tetra-n-butylammonium iodide (TBAI) in DMF to afford the corresponding esters in good yields. This methodology is highly efficient for various structurally diverse alcohols with selectivity for ROH: 1° > 2° > 3°.     

PTSA catalyzed straightforward protocol for the synthesis of 2-(N-acyl)aminobenzimidazoles and 2-(N-acyl)aminobenzothiazoles in PEG

An efficient PTSA catalyzed synthesis of 2-(N-acyl)aminobenzimidazoles and 2-(N-acyl)aminobenzothiazoles has been described using S-ethylated-N-acylthioureas as substrates and polyethylene glycol as solvent.     

Copper(I) complexes of N-(aryl)pyridine-2-aldimines: Spectral, electrochemical and catalytic properties

The reactions of N-(aryl)pyridine-2-aldimines (L-R; R = OCH₃, CH₃, H, Cl and NO₂), derived from pyridine-2-aldehyde and para-substituted anilines, with CuI in methanol under ambient conditions afford a series of brown complexes of the type [{Cu(L-R)I}₂]. The structure of the [{Cu(L-OCH₃)I}₂] complex has been determined by X-ray crystallography. In these dimeric complexes the two copper centers are linked through an iodo-bridge, and the L-R ligands are coordinated to the metal center through the pyridine-nitrogen and imine-nitrogen. All the complexes show characteristic ¹H NMR signals and intense MLCT transitions in the visible region. These complexes also show an emission near 465 nm, whilst they are excited at 340 nm, with relatively poor quantum yields (φ ∼0.002 at 298 K). Cyclic voltammetry on all the complexes shows two successive Cu(I)-Cu(II) oxidations on the positive side of SCE, and a reduction of the coordinated imine ligand on the negative side. These copper(I) complexes are found to efficiently catalyze Suzuki type C-C coupling reactions.     

Catalytic amination reactions mediated by Co(II) Schiff base complexes

Co(acacen), 1, (acacen = 2,11-dihydroxy-4,9-dimethyl-5,8-diaza-2,4,8,10-dodecatetraene dianion) was found to be a highly efficient catalyst for the allylic amination of non activated alkenes, using N-(p-toluensulfonyl)iminophenyliodinane (PhINTs) as nitrene precursor. This reactivity has been extended to the less reactive C-H bond of toluene. The effect of reaction times and of added cosolvent on yields and selectivities was investigated. Under the best conditions, allylic amines were obtained in a 40-70% isolated yield. A complex derived from the stoichiometric reaction of Co(acacen), 1, with PhINTs has been isolated and spectroscopically characterized. Such a complex, although not able to transfer its NTs moiety to alkenes, is still active in catalyzing allylic amination of cyclohexene.     

Syntheses and structures of iron carbonyl complexes derived from N-(5-methyl-2-thienylmethylidene)-2-thiolethylamine and N-(6-methyl-2-pyridylmethylidene)-2-thiolethylamine

The reaction of N-(5-methyl-2-thienylmethylidene)-2-thiolethylamine (1) with Fe₂(CO)₉ in refluxing acetonitrile yielded di-(μ₃-thia)nonacarbonyltriiron (2), μ-[N-(5-methyl-2-thienylmethyl)-η¹:η¹(N);η¹:η¹(S)-2-thiolatoethylamido]hexacarbonyldiiron (3), and N-(5-methyl-2-thienylmethylidene)amine (4). If the reaction was carried out at 45 °C, di-μ-[N-(5-methyl-2-thienylmethylidene)-η¹(N);η¹(S)-2-thiolethylamino]-μ-carbonyl-tetracarbonyldiiron (5) and trace amount of 4 were obtained. Stirring 5 in refluxing acetonitrile led to the thermal decomposition of 5, and ligand 1 was recovered quantitatively. However, in the presence of excess amount of Fe₂(CO)₉ in refluxing acetonitrile, complex 5 was converted into 2-4. On the other hand, the reaction of N-(6-methyl-2-pyridylmethylidene)-2-thiolethylamine (6) with Fe₂(CO)₉ in refluxing acetonitrile produced 2, μ-[N-(6-methyl-2-pyridylmethyl)-η¹ (N_py);η¹:η¹(N); η¹:η¹(S)-2-thiolatoethylamido]pentacarbonyldiiron (7), and μ-[N-(6-methyl-2-pyridylmethylidene)-η²(C,N);η¹:η¹(S)-2- thiolethylamino]hexacarbonyldiiron (8). Reactions of both complex 7 and 8 with NOBF₄ gave μ-[(6-methyl-2-pyridylmethyl)-η¹(N_py);η¹:η¹(N);η¹:η¹(S)-2-thiolatoethylamido](acetonitrile)tricarbonylnitrosyldiiron (9). These reaction products were well characterized spectrally. The molecular structures of complexes 3, 7-9 have been determined by means of X-ray diffraction. Intramolecular 1,5-hydrogen shift from the thiol to the methine carbon was observed in complexes 3, 7, and 9.     

Ti(IV)-based catalytic membranes for efficient and selective oxidation of secondary amines

The incorporation of homogenous Ti(IV)/trialkanolamine catalyst in polymeric membranes provided new polymeric catalytic Ti(IV)-based membranes, stable and efficient as heterogeneous catalysts for chemoselective oxidations of secondary amines to nitrones by alkyl hydroperoxides. Polyvinylidene fluoride (PVDF)-based catalytic membranes gave the best results affording products in short reaction times, high yields and selectivity using as little as 1% of catalyst, comparable with the performances of the corresponding homogeneous system. PVDF-Ti membrane could be recycled up to five runs with no loss of activity.     

Asymmetric synthesis of organoelemental analogs of natural compounds. 7. (2R,3S)-2-amino-3-hydroxy-5-phosphonovaleric acid

The reaction of the Ni(II) complex of the Schiff base of glycine with (S)-2-N-(N¹-benzylprolyl)-o-aminobenzophenone with diethyl-3-bromo-2-hydroxypropyl phosphonate yields the corresponding complex from which (2R, 3S)-2-amino-3-hydroxy-5-phosphonovaleric acid is separated with HCl.See [1] for Communication 6.Institute of Bioorganic Chemistry and Petrochemistry, Ukrainian Academy of Sciences, 252660 Kiev; N. A. Nesmeyanov Institute of Organoelemental Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 5, pp. 1172–1175, May, 1992.     

Benzylic-acetoxylation of alkylbenzenes with PhI(OAc)2 in the presence of catalytic amounts of TsNH2 and I2

Treatment of alkylbenzenes with (diacetoxyiodo)benzene in the presence of catalytic amounts of p-toluenesulfonamide or p-nitrobenzenesulfonamide, and molecular iodine in 1,2-dichloroethane at 60 °C gave the corresponding (α-acetoxy)alkylbenzenes in good to moderate yields. The present reaction is a simple method for the introduction of an acetoxy group to the benzylic position of alkylbenzenes.     

The preparation of a stable 2-pyridylboronate and its reactivity in the Suzuki-Miyaura cross-coupling reaction

The preparation and reactivity of a 2-pyridylboronate stabilised by N-phenyldiethanolamine is described. In Suzuki-Miyaura cross-coupling reactions employing this boronate, significant aryl-aryl exchange from the phosphine ligand was observed with some combinations of ligand and substrates. The amount of the exchange by-product can be minimised by appropriate choice of phosphine ligand.     

One-pot synthesis of N-alkyl purine and pyrimidine derivatives from alcohols using TsIm: a rapid entry into carboacyclic nucleoside synthesis

A convenient and efficient one-pot N-alkylation of nucleobases from alcohols using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, treatment of alcohols with a mixture of purine or pyrimidine nucleobase, TsIm, K₂CO₃, and triethylamine in refluxing DMF regioselectively furnishes the corresponding N-alkyl nucleobases in good yields. This methodology is highly efficient for various structurally diverse primary alcohols.     

N-Polyfluoroethyl and N-2-chlorodifluorovinyl derivatives of azoles

Reactions of tetrafluoroethylene, chlorotrifluoroethylene and 1,2-dichlorodifluoroethylene with N-potassium salts of imidazole, 2-methylbenzimidazole, 3,5-dimethylpyrazole, 1,2,4-triazole, and benzotriazole lead to the formation of the corresponding N-(1,1,2,2-tetrafluoroethyl), N-(2-chloro-1,1,2-trifluoroethyl), and N-(2-chloro-1,2-difluorovinyl) azoles. Treatment of N-(2-chloro-1,2-difluorovinyl) and N-(2-chloro-1,1,2-trifluoroethyl) derivatives of azoles with tetramethylammonium fluoride is a useful synthetic method for the preparation of heterocycles with 1,2,2,2-tetrafluoroethyl group attached to nitrogen.     

A practical synthesis of 2-(N-substituted)-aminobenzimidazoles utilizing CuCl-promoted intramolecular cyclization of N-(2-aminoaryl)thioureas

A practical protocol for synthesis of 2-(N-substituted)-aminobenzimidazoles was developed. N-(2-Aminoaryl)thioureas undergo a CuCl-promoted intramolecular cyclization to give the corresponding 2-(N-substituted amino)benzimidazoles in good to excellent isolated yields.     

A new enlargement methodology for the preparation of 2H-1- and 2H-3-benzazepin-2-one derivatives

An investigation of the one-carbon homologation of some 1-tribromomethyl-isoquinoline and 2-tribromomethyl-quinoline derivatives was conducted. Under the influence of an aqueous solution of silver nitrate in the presence of a nucleophilic species (MeOH, H₂O, EtNH₂), these derivatives led to the respective expanded heterocycles, 2H-1- and 2H-3-benzazepin-2-one derivatives. A mechanism for this novel ring enlargement involving initial formation of an aziridinium, and its subsequent opening to form a stabilized benzylic carbocation, is proposed to explain the results.     

A facile synthesis of 2-(N-alkylamino)-pyrimidin-4-one derivatives

Substituted 2-(N-alkylamino)-pyrimidin-4-ones were synthesized from N-alkyl β-amino acid esters starting with guanidinylation using Pbf-activated thiourea. The six-membered pyrimidinones were obtained in good yields via intramolecular cyclization during TFA cleavage of the Pbf protecting group.     

Dimolybdenum complexes containing anions of N,N′-bis(pyrimidine-2-yl)formamidine and N-(2-pyrimidinyl)formamide

The reactions of Mo₂(O₂CCH₃)₄ with different equivalents of N,N′-bis(pyrimidine-2-yl)formamidine (HL1) and N-(2-pyrimidinyl)formamide (HL2) afforded dimolybdenum complexes of the types Mo₂(O₂CCH₃)(L1)₂(L2) (1) trans-Mo₂(L1)₂(L2)₂ (2) cis-Mo₂(L1)₂(L2)₂ (3) and Mo₂(L2)₄ (4). Their UV–Vis and NMR spectra have been recorded and their structures determined by X-ray crystallography. Complexes 2 and 3 establish the first pair of trans and cis forms of dimolybdenum complexes containing formamidinate ligands. The L1 ligands in 1–3 are bridged to the metal centers through two central amine nitrogen atoms, while the L2 ligands in 1–4 are bridged to the metal centers via one pyrimidyl nitrogen atom and the amine nitrogen atom. The Mo–Mo distances of complexes 1 [2.0951(17) Å], 2 [2.103(1) Å] and 3 [2.1017(3) Å], which contain both Mo?N and Mo?O axial interactions, are slightly longer than those of complex 4 [2.0826(12)–2.0866(10) Å] which has only Mo?O interactions.     

New approach to preparation of N-acylphosphoramido(thio)(seleno)ates

N-[2-(X)-1,3,2-Oxathiaphospholane] derivatives (X = S, Se, O) of carboxamides were prepared and their DBU-assisted reaction with alcohols led to the corresponding O-alkyl-N-acylphosphoramido(thio)(seleno)ates. Their structures were confirmed by MS analysis and ¹H and ³¹P NMR spectroscopy. Independently N-acylphosphoramidoselenoates were converted to N-acylphosphoramidates by treatment with tert-butylperoxytrimethylsilane. The oxathiaphospholane approach was also applied to the synthesis of derivatives having N-prolylphosphoramido(thio)(seleno)ate linkages on the 5′-OH group of AMP.     

N′-(取代嘧啶-2-基)-N-菊酰硫脲的合成与生物活性研究

采用活性基团拼接法, 将第一菊酸构型中的最高活性组分(＋)-反式菊酸以及二氯菊酸引入到含取代嘧啶环的酰基硫脲结构中, 合成了5个未见文献报道的N′-(取代嘧啶-2-基)-N-(＋)-反式菊酰硫脲衍生物(3a～3e)和3个均未见文献报道的N′-(取代嘧啶-2-基)-N-二氯菊酰硫脲(3f～3h), 结构经元素分析、IR和¹H NMR得到确证. 初步的生物活性测试结果表明: 大部分化合物具有较好的杀菌活性, 有的化合物兼具除草和杀菌活性, 有的化合物兼具杀虫和杀菌活性.     

Oxidative entry to α-oxy N-acyl aminals and hemiaminals: efficient formation of 2-(N-acylaminal) substituted tetrahydropyrans

An efficient new method to synthesize α-oxy N-acyl aminals and hemiaminals in a single step from readily synthesized N-acyl enamines has been developed using PhI(OAc)₂ as the oxidant. The reaction conditions are very mild and the products are obtained in good yields (65-92%). A possible mechanistic pathway is laid out.