Synthesis and structural study of quinuclidine spiro derivatives

The synthesis of quinuclidine-3-spiro-5′-oxazolidine-2′,4′-dione, quinuclidine-3-spiro-5′-hydantoin, and some 3′-derivatives is described. Based on the data from ¹H and ¹³C-nmr spectra the structure of the above mentioned compounds is established. A relationship between second order effects in ¹³C-nmr spectra and H-C-C-H dihedral angles is deduced.     

A novel ferroelectric based on quinuclidine derivatives

The compound [(CH_3)_2 CH-C_3 H_(17) N][CoBr_4](1) based on quinuclidine derivatives was achieved by the solution synthetic method and characterized by elemental analysis,infrared spectroscopy,single-crystal X-ray structural analysis and dielectric measurement,respectively.Variable-temperature single-crystal X-ray diffraction suggested that the compound unde rwent the phase transition from the space group C2/c to Cc.The polarization curve was measured using the Sawyer-Tower circuit.The structural phase transitions of 1 was ascribed to the distortion of a [(CH_3)_2 CH-C_3 H_(17)N]~(2+) cation from this inorganicorganic hybrid material [(CH_3)_2 CH-C_3 H_(17)N][CoBr_4].The strong change in dielectric anomalies makes compound 1 a suitable candidate for promising switchable dielectric materials.This work represents a feasible strategy thought for the targeted harvesting of low temperature ferroelectrics.     

Study of the tautomerism of 2-ethoxycareonyl-3-oxo derivatives of quinuclidine and benzo[b]quinuclidine

The tautomerism of 2-ethoxycarbonyl-3-oxoquinuclidine and 2-ethoxycarbonyl-3-oxobenzo-[b]quinuclidine was investigated by means of IR and UV spectra and potentiometric titration. It was found that tautomeric equilibrium between the ketone, enol, and internally ionized forms is realized for 2-ethoxycarbonyl-3-oxoquinuclidine, and the position of the equilibrium is determined by the aggregate state of the substance and the nature of the solvent. The internally ionized form predominates in the crystals and in polar solvents (alcohol and water), while the ketone and enol forms are the primary ones in solvents of low polarity (chloroform and dioxane), and the percentage of the ketone form is always larger than that of the enol form. In contrast to this, 2-ethoxycarbonyl-3-oxobenzo[b]quinuclidine exists practically completely as the keto form in crystals and solutions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 229–233, February, 1972.     

Novel heterocyclic organoboranes

Novel heterocyclic organoboranes are obtained from the interaction of an organic isocyanate and heterocyclic aminoboranes     

Novel heterocyclic Tröger's base derivatives containing N-methylpyrrole units

Novel analogues of Tröger's base were prepared regioselectively from 4-amino-N-methylpyrrole carboxylates in good yield. Catalytic hydrogenation of dibenzyl-4,9-methano-1,6-dimethyl-4,5,9,10-tetrahydro-1H,6H-dipyrrolo-[3,2-b:3′,2′-f][1,5]diazocin-2,7-dicarboxylate 2b led to 4,9-methano-1,6-dimethyl-4,5,9,10-tetrahydro-1H,6H-dipyrrolo-[3,2-b:3′,2′-f][1,5]diazocin-2,7-dicarboxylic acid 3 which was used for the preparation of Tröger's base derivatives of natural antibiotics via an amide protocol. The novel heterocyclic Tröger's bases were characterized by a variety of spectroscopic techniques and compound 2b by X-ray crystallography. Incorporation of guanidine as the terminal group in the N-methylpyrrole Tröger's base skeleton opens the possibility for preparation of water soluble derivatives.     

Some heterocyclic sulfonyl derivatives

2,3-Diphenylpyrazine, 3,4-diphenylfurazan and 2-methyl-4,5-diphenyl oxazole react with chlorosulfonic acid to give the sulfonyl chlorides Ia, IIa, IIIa. The chlorides were condensed with nucleophiles to give thirteen derivatives. 4′,4″-bis-Dimethylsulfamoyl-2-methyl-4,5-diphenyloxazole (Illb) was oxidized with bromine to give 4,4′-bis-dimethylsulfamoylbenzil (IV), which by heating with ethylenediamine afforded the 4′,4″-bis-dimethylsulfamoylpyrazine (V). The spectral data of the various compounds are briefly discussed.     

Synthesis of new quinuclidine derivatives via Pd-mediated cross-coupling and cross-benzannulation reactions

New functionalized quinuclidines were prepared via palladium-catalyzed addition reactions of terminal alkynes (donors) to internal alkynes (acceptors). The enantiopure terminal alkynes were derivatives of quincoridine and quincorine, two semi-natural Cinchona alkaloids. The processes exhibited high chemoselectivity and excellent diastereoselectivity, the E-enynes being obtained as single products in almost all cases. The synthesis of new tetra and pentasubstituted benzene derivatives in good yields by [2+2+2] benzannulation of the diynes, obtained by the palladium-catalyzed homodimerization of 10,11-didehydro quincoridine and 10,11-didehydro quincorine, with terminal alkynes and in fair yield by [4+2] benzannulation of an enyne derivative of 10,11-didehydro quincoridine with 2,4-hexane-diyne are reported.     

New heterocyclic derivatives of trifluoroalanine

A new method of the synthesis of heterocyclic derivatives of trifluoroalanine based on the cyclocondensation of methyl trifluoropyruvate tert-butoxycarbonylimine with C,N- and N,N-binucleophiles, like Nsubstituted ureas, 1-benzyl-6-aminouracil, benzamidine, and 3-aminocrotononitrile, followed by hydrolysis of the resulting Boc-derivatives to 5-amino-5-trifluoromethylimidazolidine-2,4-diones, 5-amino-5-trifluoromethyl-1-benzyl-5,7-dihydropyrrolo[2,3-d]-pyrimidine-2,4,6-3H-trione, 4-amino-2-methyl-5-oxo-4-(trifluoromethyl)-4,5-dihydro-1H-pyrrole-3-carbonitrile, or 5-amino-5-trifluoromethyl-2-phenyl-3,5-dihydroimidazol-4-one, respectively, was developed.     

Iodonium derivatives of heterocyclic compounds

5-Phenyliodonio-2,4-dihydroxypyrimidine tosylate (I) was obtained from the reaction of uracil with phenyl iodosoacetate in the presence of p-toluenesulfonic acid. Treatment of I with alkali gave 5-phenyliodonio-2,4-dihydroxypyrimidine (II). 5-Phenyliodonio-2,4-dihydroxypyrimidine chloride, bromide, iodide, and fluoborate were obtained. The IR and UV spectra were recorded, and the ionization constants were calculated. The phenyliodonium residue increases the acidity of uracil at N₍₁₎ by 3.5 orders of magnitude and at N₍₃₎ by two orders of magnitude.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 553–555, April, 1973.     

Iodonium derivatives of heterocyclic compounds

Reaction of indole with phenyl iodosoacetate in alkaline media leads to the unstable Β-phenyliodonioindole betaine, the more stable tosylate and fluoborate of which were used for the introduction of a pyridine, quinoline, and isoquinoline molecule into the Β-position of indole to give the corresponding tosylates and fluoborates of Β-(N-pyridinio)-, Β-(N-quinolinio)-, and Β-(N-isoquinolinio)indole. Intramolecular charge transfer from the donor indole system to the acceptor onium systems is detected from the UV spectral data. The acidity constants of a number of Β-onium derivatives of indole were determined by spectrophotometry.     

Iodonium derivatives of heterocyclic compounds

A method for the preparation of phenyliodonium derivatives of pyrazoles was developed. The reaction of pyrazole and 3,5-dimethyl- and 3,5-diphenylpyrazoles with phenyl iodosoacetate in the presence of p-toluenesulfonic acid gives pyrazole-4-phenyliodonium tosylates, which are converted to pyrazole-4-phenyliodonium betaines on treatment with alkali. The tosylates are converted to pyrazole-4-phenyliodonium chlorides, bromides, and iodides by exchange reactions, and pyrazole-4-phenyliodonium fluorides and borofluorides are obtained by reaction of the betaines with hydrofluoric and fluoboric acids. The ionization constants for a number of phenyliodonium derivatives of pyrazoles were calculated on the basis of the electronic absorption spectra. The 4-phenyliodonium grouping increases the acidity of pyrazoles by 4.5–5 orders of magnitude.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 245–248, February, 1973.     

Synthesis of heterocyclic derivatives of abietane

The methods of synthesis of some new derivatives of abietane including pyridines and indoles fused with diterpene skeleton were described.     

Synthesis of heterocyclic substituted norcantharidin derivatives

Twenty novel norcantharidin derivatives, which were substituted by thiazole ring, were synthesized in a single step by the [3+2] 1,3‐dipolar cycloaddition reaction with oxime or hydrazone in the presence of chloramine‐T when compared with the conventional method. J. Heterocyclic Chem., (2011).     

Nitroalkyl derivatives of some heterocyclic compounds

The 2-(-methyl--nitrobutyl) derivatives of 2-imidazoline, benzimidazole, and benzoxazole and 2,4,6-tris-(-methyl--nitrobutyl)1,3,5-triazine have been synthesized. The nitroalkyl derivatives of 2-imidazoline and benzimidazole have been reduced to the corresponding 2-aminoalkyl derivatives.     

Some heterocyclic sulfonyl chlorides and derivatives

The syntheses of 4- and 5-chlorosulfonylfuran-2-carboxylic acid (Ia,IIa), 4-chlorosulfonylfuran-2-carboxamide (Ib), 3,5-dimethylpyrazole and isoxazole-4-sulfonyl chlorides (IIIa,IVa) and 2,4-dimethylthiazole-5-sulfonyl chloride (Va) are described. The sulfonyl chlorides were converted into a range of amides, hydrazides and azides. Condensation of the sulfonohydrazides with β-dicarbonyl compounds, gave the corresponding β-ketohydrazones (VII), which, with the exception of the derivatives (VIIe,f,g,i), were converted to the sulfonylpyrazoles (VIII). The structures and spectral data of these compounds are briefly discussed. The reaction of the sodio derivative of acetylacetone with thiophene-2-sulfonyl chloride (VIc) gave 3-(thiophene-2-sulfonyl)pentane-2,4-dione (XII), which with hydrazine gave 4-(thiophene-2-sulfonyl)-3,5-dimethylpyrazole (XIII). However, the analogous reaction with thiophene-2-sulfonohydrazide (VIa) failed to give the expected 1,4-bisthiophenesulfonylpyrazole.     

Liquid crystalline oxygen containing heterocyclic derivatives

This paper presents a review of the work on the molecular design of oxygen containing heterocyclic liquid crystals for nematic liquid crystal display applications and examines in some detail the correlations between the molecular structure of liquid crystalline oxygen containing heterocyclic derivatives and their physico-chemical and electro-optical properties.     

Synthesis of some heterocyclic derivatives of adamantane

The reaction of bromomethyt(1-adarnantyl)ketone with urea, thiourea, ammonium formate, and thiosemicarbazide gave a series of new imidazolin-2-ones, imidazolin-2-thiones and 2-aminothiazoles in the adamantane series.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 249–252, February, 1994. Original article submitted October 5, 1993.     

Synthesis of new heterocyclic derivatives of retinoids

Reaction of α- and β-ionones 1 and 2 with dialkylformamide/phosphorus oxychloride affords enamines 6 and 7 along with the expected chloro derivatives 4 and 5 . Reaction of 6a with hydrazines, hydroxylamine and guanidine furnished pyrazoles, isoxazole, pyrimidine 8–10 showing the potential of these enaminones as key intermediates in the synthesis of synthetic retinoids.     

Novel heterocyclic systems. Synthesis of 2,7-dimethyl-10-oxa-1,8-diaza-anthracen-9-one and derivatives

Synthesis of novel heterocycles, which contain the unique 10-oxa-1,8-diazaanthracen-9-one tricyclic core, is reported. The core structure was assembled via a dehydrative-cyclization strategy.     

Synthesis of heterocyclic derivatives of dihydroquinopimaric acid

Heterocyclic derivatives of dihydroquinopimaric acid were synthesized, in which indole, pyrazole, or pyrimidine ring is fused to the E ring of the acid.