Synthesis of spiro(benzo[h]quinazoline-5,1′-cyclohexane) derivatives

3-p-Methoxyphenyl-4-oxo-2-mercapto-3, 4, 5, 6-tetrahydrospiro(benzo[h]quinazoline-4,1 -cyclohexane) wassynthesized by the reaction of 4-amino-3-ethoxycarbonvl-1, 2-dihydrospiro(naphthalene-2,1 '-cyclohexane) (1) with p-methoxyphenvl isothiocyanate without separation of the thioureido derivative. Amino ester 1 is transformed byacetamide and formamideinto 2-methyl-4-oxo-3, 4, 5, 6-tetrahydrospiro(benzo[h]quinazoline-5,1 -cyclohexane) and 4-oxo-3, 4, 5, 6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexane (11), respectively. Alkylation of quinazoline 11 with methyl iodide results in formation of 3-methyl-4-oxo-3, 4, 5, 6-tetrahydro-spiro (benzo[h]quinazoline-5,1 -cyclohexane). Amino ester 1 reacts with caprolactam with formation of 2, 3 pentamethylene-4-oxo-3, 4, 5, 6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexane). 4-Ethoxymethyleneamino-3-ethoxy-carbonyl-1,2-dihydrospiro(naphthalene-2,1-cyclohexane) was synthesized by the reaction of amino ester 1 with o-formic ester, and was converted into 3-amino-4-oxo-3, 4,5, 6-tetrahydro-spiro(benzo[h]quinazoline-5,1-cyclohexane) (VIII) by hydrazine hydrate. Aminoquinazoline VIII is acylated by acid chlorides with formation of 3-acylamino-4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclohexanes) and forms 3-benzyl-ideneamino-4-oxo-3,4,5,6-teirahydrospiro(benzo[h]quinazoline-5,1-cyclohexane) with benzaldehyde.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 530–533, April, 1996     

Synthesis and spectral studies of β-diketone and β-ketoester derivatives of aluminium zirconium isopropoxide

The reactions of aluminium zirconium heptaisopropoxide [AlZr(OPrⁱ)₇] with some β-diketones and β-ketoesters, resulting in the formation of derivatives of type ZrAl(OPrⁱ)_(7−x)L_x (where L = acetylacetone, benzoylacetone, methylacetoacetate or ethylacetoacetate; x = 1 or 2) have been carried out. These newly synthesized compounds have been characterized by elemental analyses, and IR and NMR (²⁷Al, ¹H and ¹³C) spectral studies.     

Synthesis of Spiro[benzo[h]chromene-4,3′-indoles] and Spiro[benzo[f]chromene-1,3′-indoles]

Russian Journal of Organic Chemistry - New spiro heterocycles, spiro[benzo[h]chromene-4,3′-indoles] and spiro[benzo[f]chromene-1,3′-indoles], have been synthesized in 50–60% yield...     

Synthesis and characterization of novel β-amino acid derivatives

In the work discussed in this paper, novel β-amino acid derivatives were prepared by Michael addition between 3-substituted-2-propenic acid and hydrazine hydrate. The optimum reaction conditions were determined by analyzing the effects of the ratio of the starting materials, temperature, and reaction time. The conclusions were: reaction temperature 80 °C, reaction time 8 h, n (3-substituted-2-propenic acid)/n (hydrazine hydrate) = 1:15. Products were characterized by measurement of melting point, elemental analysis, and IR and ¹H NMR spectroscopy.     

Synthesis of novel benzo[b]pyrimido[4',5':5,4]thieno[2,3-e][1,6]naphthyridine-8-ones via Pictet–Spengler cyclization

An efficient method for the synthesis of novel benzo[b]pyrimido[4',5':5,4]thieno[2,3e]-[1,6]naphthyridine-8-one derivatives via Pictet–Spengler cyclization is reported. The reaction of 4-(3-aminopyrimido[4,5-d]thieno-2-yl)quinoline-2-ones, which could be obtained from Thorpe–Ziegler isomerization of 4-bromomethylquinoline-2-ones and 5-cyano-1,6-dihydro-4-methyl-2-phenyl-6-thioxopyrimidine,with aromatic aldehydes in the presence of BF_3·OEt_2 gives pyrimidothieno[1,6]naphthyridines in good yields.     

Synthesis and structure characterization of novel calix[4]（aza）crown derivatives

Three novel calix[4](aza)crown deravatives have been synthesized,including a new [2]pseudorotaxane in which calix[4]- azacrown behaves as a stopper,a novel‘tren’type calix[4]azacrown and a novel‘spiro’type calix[4]azacrown containing morpholine unit.The structures of these compounds have been confirmed by NMR and MS.     

Synthesis and herbicidal activity evaluation of novel β-carboline derivatives

Based on the original structure of harmine, several novel 1,2,3,4-tetrahydro-β-carboline, β-carboline and 1-substituted-β-carboline derivatives bearing a substituted carbohydrazide group at C-3 were designed and synthesized to investigate the structure-activity relationship of their analogues. All of the compounds were characterized by infrared (IR), proton and carbon nuclear magnetic resonance (1H-NMR, 13C-NMR), and mass spectroscopy (MS). The bioassay tests showed that N'-benzylidene-1-phenyl-β-carboline-3-carbohydrazide (C(25)H(18)N(4)O, m.w. 390.4) (c2) and N'-(4-trifluoromethyl-benzylidene)-1-phenyl-β-carboline-3-carbohydrazide (C(26)H(17)N(4)OF(3), m.w. 458) (d2) exhibited good inhibitory activity against dicotyledonous and monocotyledonous weeds, with EC(50) values of 4.83 μM and 14.25 μM, respectively.     

Synthesis and tumor cytotoxicity of novel amide derivatives of β-hederin

Thirteen novel triterpenoid saponins, designed as amide derivatives of the natural cytotoxic saponin β-hederin, were synthesized by a stepwise glycosylation strategy. The in vitro cytotoxic activity of these compounds was evaluated against five different tumor cell lines. Most of the evaluated compounds showed effective inhibitory activity against at least one tumor cell line at micromolar concentrations. The preliminary structure-activity relationships (SAR) indicate that mide derivatization at C-28 resulted in highly cytotoxic derivatives on specific tumor cell lines, and also resulted in an increase in the antitumor selectivity of β-hederin.     

Synthesis and characterization of a novel series of pyrimidinylthiaalkoxycalix[4]arenes

A novel series of pyrimidinylthiaalkoxycalix[4]arenes with the reaction between 4,6-dimethylpyrimidine-2-thiol and thedifferent dibromides calix[4]aryl groups have been synthesized and structurally characterized by IR,1H NMR and MS.From theiranalysis data,it was found that compounds 8,9,11 adopted a cone conformation,while compound 10 existed as a mixture ofconformations.     

Synthesis,luminescence, and cyclic voltammetric studies of novel binuclear ruthenium(II) complexes prepared from β-diketonate derivatives

Two bis-(β-diketonate) ligands [H₂L¹ = 3,6-bis-(4,4,4-trifluorobutane-1,3-dione)-9-butyl-carbazole and H₂L² = 3,6-bis-(4,4,4-trifluorobutane-1,3-dione)-9-hexyl-carbazole] were synthesized, and their corresponding dinuclear ruthenium(II) complexes [Ru₂(bpy)₄(L¹)](PF₆)₂ (1) and [Ru₂(bpy)₄(L²)](PF₆)₂ (2) (bpy = 2,2′-bipyridine)] were prepared by the reaction of Ru(bpy)₂Cl₂ · 2H₂O with H₂L¹ and H₂L² in ethanol, respectively. The structure of the ligand H₂L² was determined by single-crystal X-ray diffraction. The spectral properties of the ligands and their complexes have been studied. The absorption spectra of the complexes exhibit intense ligand-centered bands in the UV region and metal-to-ligand charge-transfer bands in the visible region. The two-photon absorption (TPA) coefficient β and TPA cross-section σ were determined by the Z-scan technique, which revealed that the two complexes exhibit strong TPA due to electronic extensive delocalization. The complexes undergo a reversible or quasi-reversible one-electron metal-centered redox process at E _1/2 = +0.93 V and E _1/2 = +0.92 V, respectively.     

Synthesis of 2,3,4,7-tetrahydro[1,4]thiazepines from thiazolidines and β-enaminonitriles

A wide library of 2,3,4,7-tetrahydro[1,4]thiazepines have been prepared by simple heating of thiazolidine and β-enaminonitrile derivatives in acetonitrile. The procedure, whose yields depend on the nature and position of the substituents, gave good results if the substituents were not very bulky but it is less effective when starting from 2-substituted thiazolidines.     

Synthesis and structure characterization of a novel series of N-alkylphthalimidylaminocarbonylmethoxylcalix [4] arenes

A novel series of N-alkylphthalimidylaminocarbonylmethoxylcalix[4]arenes with the reaction between 4-(N-bromoacetyla- mino)-phthalimide derivatives and calix[4]arene has been synthesized and structurally characterized by IR,~1HNMR and MS.From their analysis data,it was found that compounds 7a-7d adopted a cone conformation.     

Synthesis and cationic selectivity studies of novel calix[4]arene derivatives containing heteroatom at the lower rim

A series of calixarene derivatives 2―5 containing heteroatom at the lower rim have been synthesized. 1H NMR studies and crystallographic structures demonstrated that the calix[4]arene derivatives adopted cone conformations. Their cationic binding abilities and selectivities towards heavy and tran- sition metal ions have been evaluated by solvent extraction of aqueous metal picrates. The obtained results indicated that the introduction of nitrogen, sulfur, and/or phosphor atoms to the calix[4]arene framework could effectively enhance their binding ability and selectivity for heavy and transition metal ions, such as Pb2 or Ag .     

Synthesis of Dihydrobenzo[h]coumarins and Their 4‐Methyl Analogs

Dihydrobenzo[h]coumarins (5a–7a) and their 4‐methyl analogs (5b–7b) were synthesized from 1‐naphthol via two different synthetic routes. One pathway is the direct condensation of 5,8‐dihydro‐1‐naphthol (9) with malic acid or ethyl acetoacetate, affording 7,10‐dihydrobenzo[h]coumarins 7a and 7b, respectively. The other is through the oxidation of 7,8,9,10‐tetrahydrobenzo[h] coumarins (15a–b), followed by the reduction of the carbonyl group and dehydration of hydroxyl group, giving 7,8-dihydrobenzo[h]coumarins (5a, b) and 9,10-dihydrobenzo[h]coumarins (6a, b). The regio selectivities for the oxidation reactions of 15a, b were rationalized on the basis of quantum chemical calculations and further confirmed by the X‐ray crystallographic analysis of the derivatives of oxidation products.     

Synthesis of two new p-tert-butylcalix[4]arene β-ketoimin derivatives for extraction of dichromate anion

In this study the selective derivatization of p-tert-butylcalix[4]arene was carried out and two new p-tert-butylcalix[4]arene β-ketoimin, 5,11,17,23-tetra-tert-butyl-25,27-bis-3-methyl-[(β-ketoimine)-ethoxy]-26,28-dihydroxycalix[4]arene (4), and 5,11,17,23-tetra-tert-butyl-25,27-bis-3-chloro-[(β-ketoimine)-ethoxy]-26,28-dihydroxycalix[4]arene (5) have been synthesized. In the synthesis, the lower rim of p-tert-butylcalix[4]arene was modified in order to acquire binding site for the recognition of dichromate anion. It was observed that these ionophores 4 and 5 showed high affinity towards dichromate anion. The protonated Schiff-base forms of the receptors were effective for transferring the HCr₂O₇ ^? anion from aqueous phase to a dichloromethane phase.     

Synthesis of novel calix[4]crown telomers and selective extraction of cesium ions

p-tert-Butylcalix[4]diazacrown-4 telomer, which contains hard and soft ion binding sites, was synthesized. It exhibited high selectivity toward cesium ions. The binding sites may complex alkali metal ions selectively.     

Synthesis of 2,3-disubstituted 4-oxo-3,4,5,6-tetrahydrospiro-(benzo[h]quinazoline-5,1′-cyclopentanes)

3-Substituted 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1-cyclopentanes) were obtained by the reaction of 4-amino-3-ethoxycarbonyl-1,2-dihydrospiro(naphthalene-2,1-cyclopentane) with methyl, phenyl, and benzyl isothiocyanates and cyclization of the obtained thioureas. Condensation of the products with various halides gave 2,3-substituted 4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1-cyclopentanes). The reaction of 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1-cyclopentane) with 1,2-dibromoethane and 1,3-dibromopropane led to 6-oxo-7,8-dihydrospiro(benzo[h]thiazolidino[2,3-b]quinazoline-7,1-cyclopentane) and 7-oxo-8,9-dihydrospiro(benzo[h]-perhydrothiazino[2,3-b]quinazoline-8,1-cyclopentane) respectively.A. L. Mndzhoyan Institute of Fine Organic Chemistry, National Academy of Sciences of the Republic of Armenia, Erevan. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 663–667, May, 2000.     

Regioselective synthesis of novel imidazo[1,5-b]pyridazine derivatives from diaminoimidazoles and α-acylacrylonitriles

The heterocyclization of 1,2-diamino-4H-phenylimidazole with α-acylacrylonitriles affords cleanly 7-amino-2-R-5- phenylimidazo[1,5-b]pyridazine-3-carbonitriles. The strating α-acylacrylonitriles can be generated in situ from 3-oxo-3-(het)arylpropanenitriles and triethylorthoformate or dimethylformamide dimethyl acetal, and the products can be prepared in one pot.     

Synthesis of triazoles and tetrazoles condensed with spiro(benzo[h]quinazoline-5,1′-cyclohexane)

Condensation of 3-R-4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1-cyclohexanes) with 2-ethanolamine, 3-propanolamine, and hydrazine hydrate gives the corresponding 2-ethanolamino, 2-propanolamino, and 2-hydrazino derivatives. Triazoles and tetrazoles, a- or b-condensed with benzo[h]quinazolines were obtained from 2-hydrazinobenzo[h]quinazolines depending on the presence of a substituent at position 3.A. L. Mndzhoyan Institute of Fine Organic Chemistry, Armenian Republic Academy of Sciences, Yerevan 375014. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 396–400, March, 2000.