CpRu-catalyzed O-H insertion and condensation reactions of α-diazocarbonyl compounds

[CpRu(CH(3)CN)(3)][PF(6)] and diimine ligands catalyze together the decomposition of α-diazocarbonyl compounds leading to O-H insertion and condensation reactions. In comparison with Rh(II) and Cu(I) complexes, the CpRu catalysts produce rapid and often more selective reactions. Promising enantioselectivities are obtained in dioxole syntheses.     

Syntheses and transformations of α-azido ketones and related derivatives

Organic azides are known and utilized in the synthetic organic chemistry as amine precursors, potential sources of nitrenes, dipoles useful in 1,3-dipolar cycloadditions and starting materials of phosphoranes for a long time, and their literature has been overviewed by several authors. On the other hand, there are some special subclasses within the azides which possess peculiar and interesting properties differing from those of the majority and offering extra synthetic possibilities. In this critical review we wish to give an exhaustive overview on the synthesis and synthetic potential of α-azido ketones and related systems, an underestimated group of compounds. The enhanced acidity of the α-hydrogen offers various new synthetic applications including the creation of a new C-C bond, while the joint presence of the carbonyl and vinyl functions of α-azido-α,β-unsaturated ketones results in a special reactivity, too. Chemo- and stereoselectivity issues also represent important points which are discussed in detail. Finally, the usefulness of the titled derivatives in the synthesis of various heterocycles is reviewed (273 references).     

Copper-catalyzed chemoselective cross-coupling reaction of thioamides and α-diazocarbonyl compounds: Synthesis of enaminones

The development of operationally simple and cost-effective methods for CC bond formation reactions are highly important in pharmaceutical, agrochemical and material research. In this article we describe the first copper-catalyzed cross-coupling reaction of thioamides with acceptor/acceptor-substituted and acceptor-only substituted α-diazocarbonyl compounds to yield enaminones. The reaction shows broad substrate scope in terms of thioamides and diazocarbonyl compounds. Primary, secondary and tertiary thioamides all give enanminones when reacted with α-diazodiesters, α-diazoketoesters, α-diazodiketones, α-diazoketoamides, α-diazoesteramides, α-diazoketosulfones and α-diazomonoketones.     

Recent progress in insertion and cyclopropanation reactions of metal carbenoids from α-diazocarbonyl compounds

Research on Chemical Intermediates - Metal–carbenoids from α-diazocarbonyl compounds are well-known reactive intermediates with a long history of useful applications in synthetic organic...     

Conformational study of α-phenylthiocarbonyl compounds

Electrical and electrooptical characteristics of-phenylthioacetone,-phenylthiocyclohexanone, and-phenylthio-4-caranone have been determined and used in establishing the structure of the compounds in solution. It has been shown that the preferred conformer with respect to the bond , is the ac-conformer [(O=C-C-S)>90°], in which the gauche conformer with respect to the C-S bond is realized, with a 1,3-parallel position of the C=O and S-Ph bonds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2483–2488, November, 1991.     

Reactions of CF3-substituted boranes with α-diazocarbonyl compounds

Boranes substituted with a CF₃-group can be generated from methyl boronic esters RB(OMe)₂ and Me₃SiCF₃/KF followed by treatment with Me₃SiCl. These boranes are stable only in coordinating solvents, and due to the increased Lewis acidity of boron, react rapidly with α-diazocarbonyl compounds to give the products of transfer of the organic group from boron. Alkyl, aryl, vinyl, and alkynyl boronic esters can be used in this reaction.     

Derivatives of heterocyclic α-iminocarboxylic acids 3. Synthesis of N-alkoxycarbonyl and N-alkoxycarbonylalkenyl derivatives of α-iminocarboxylic acids

By the interaction of L-proline, L-thioproline, pipecolic acid, tetrahydro-1,4-thiazine-3-carboxylic acid, and diastereomeric esters of tetrahydro-1,4-thiazine-3,5-dicarboxylic acid with methyl chloroformate, methyl propiolate, and acetylenecarboxylic acid, we have obtained N-alkoxycarbonyl and N-alkoxycarbonylalkenyl derivatives of -iminocarboxylic acids. By the reaction of N-methoxycarbonyltetrahydro-1,4-thiazine-3-carboxylic acid with hydrazine hydrate, we have obtained 8-amino-7,9-dioxo-4-thia-1,8-diazabicyclo[4.3.0]nonane.For communication 2, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1561–1566, November, 1993.     

Isolation of polyphenol compounds from olive waste and inhibition of their derivatives for α-glucosidase and α-amylase

Abstract

Olive waste was used as a sustainable resource because it contained a variety of valuable compounds. The polyphenols active fraction from enrichment by microporous resin and extraction with ethyl acetate were analysed by different chromatographic methods. A total of 14 polyphenolic compounds were isolated and identified by structure elucidation. Based on the above obtained compounds, tyrosol was selected as a characteristic polyphenol and participated in transesterification reaction to synthesise β-ketoester using Yb(OTf)₃. Then the Biginelli reaction with benzaldehyde, urea and ketoester (1:1.2:1.2) was performed at 90?°C for 3.0?h under the acidic condition. In addition, the β-ketoester prepared using tyrosol with benzyl had a greater inhibitory effect on α-glucosidase and α-amylase, and the inhibition of enzyme activity for 3, 4-dihydropyrimidinone derivatives prepared using abovementioned β-ketoester was improved significantly. Meanwhile, fluorine-containing dihydropyrimidinone derivatives were considerable inhibitors for both enzymes.     

Developments in the synthesis of α,α-dibromoacetophenones and related compounds

Increasing demand of α,α-dibromoketones, as highly reactive and easy-to-handle precursors to carry out selective organic transformations, to synthesize heterocyclic compounds of therapeutic interest and lack of any compilation on this subject prompted us to assemble the methods available for their synthesis.     

Quantum chemical interpretation of reactivities of aliphatic amines and α-amino acids in acylation

Quantum chemical calculations of geometrical, electronic, and energy characteristics for aliphatic amines, ammonia, some α-amino acids, and 4-nitrophenyl benzoate (4-NPB) have been performed. By the QSPR method, it was found that the rate constants for the reactions of amino compounds specified with 4-NPB in water—propan-2-ol solvent mixture are linearly dependent on the contribution of the 2p_z-AO of nitrogen into the HOMO, as well as on the population of the 2p_z-AO of nitrogen. Different character of the dependencies for 6h-amino acids and aliphatic amines can be explained by their involvement into formation of solvato-complexes with different reactivity.     

Quantum chemical study on the thermal rearrangements of HNCRCR''''CO

MINDO/3 molecular orbital theory has been used to study the thermal rearrangements of HNCRCR'CO.The results obtained show that the activation energy of this rearrangement depends on the migrating group R and the group R'.     

α-Dimethylaminomethylene-γ-thiobutyrolactone and synthesis of heterocyclic derivatives

By the interaction of -thiobutyrolactone with bis(dimethylamino)-tert-butoxymethane, -dimethylamino-methylene--thiobutyrolactone has been obtained. Its reactions with arylhydrazines have been investigated. With phenylhydrazine, 4-(2-mercaptoethyl)-1 phenylpyrazolone-5 is formed; but with -substituted phenylhydrazines, as a result of the Fischer reaction and expansion of the thiolactone ring, 9-substituted 4, 9dihydrothiopyrano[3,4-bjindol-1(3H)-ones are formed. Analogous reactions with 1-amino derivatives of tetrahydroquinoline and tetrahydroquinaldine lead to the formation of 5, 6,10,11-tetrahydro-4H, 8H-thiopyruno(4,3:4,5jpyrrolo[3,2,1-ijlquinolin-8-ones, representatives of a new heterocyclic system.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 180–185, February, 1996.     

Quantum chemical studies on antimalarial of artemisinin (qinghaosu) derivatives

In this paper theoretical studies were performed on artemisinin (qinghaosu) derivatives with semiempirical quantum chemical methods AMI and PM3. The antimalarial activity -logC has an obvious correlation with the net charge of C(16) and bond orders of bonds O(1)-C(10), O(2)-C(6), O(1)-O(2) and O(5)-C(16). According to the calculation results, we derived structure-activity relationship, presented the probable pharmacophore of qinghaosu derivatives and the interaction fashion between the drugs and the plasmodium receptor.     

Quantum chemical studies on the structures, properties and decomposition of the azido derivatives of trinitrobenzenes

The geometries,heats of formation and electronic structures of 15 azido-derivatives of 1,2,3-TNB (Ⅰ),1,2,4-TNB (Ⅱ) and 1,3,5-TNB (Ⅲ) have been studied using quantum chemical AMI method at HF level.The effect of azido substitution on the structures and properties of TNBs has been discussed and the relative stability of the title compounds has been established.The processes of the decomposition of the title compounds by breaking C-NO2,C-N3 and CN-N2 bonds are investigated at UHF-AM1 level.It is shown that the decomposition of the title compounds may be initiated by the cleavage of both C-NO2 and N-N2 bonds.     

Quantum chemical study on the thermal Diels-Alder reaction of cyclohexadiene and methyl crotonate

AM1 molecular orbital method using the unrestricted Hartree-Fock(UHF) calculations has been applied to investigate the thermal reaction of cyclohexadiene and methyl crotonate. The calculated results indicate that the thermal Diels-Alder reaction proceeds to product through the concerted path and two radical pathways.     

Quantum chemical study on the abstraction reaction of alkylidenegermylene with oxirane and thiirane

The mechanisms of theion reaction of alkylidenegermylene with oxirane and thiirane have been characterized detail in using density functional theory, as well as ab initio method, including geometry optimization and vibrational analysis for the involved stationary points on the potential energy surface. Energies were calculated by CCSD(T)/6-311G(d)//B3LYP/6-311G(d,p) method for the involved conformations. The results show that the reaction pathways for both reactions consist of two ways: (1) the reactants can yield bent products (P1; P4) by syn-isomers; (2) the reactants can also yield three-membered products (P2; P5) by anti-isomers, which then further react with oxirane and thiirane to form the ultimate products (P3-1, P3-2; P6). Furthermore, a comparison with alkylidenecarbene, oxirane, and thiirane was done.     

Synthesis and bioactivity of N-cyclopropanecarboxyl-N′-pyridin-2-yl thiourea derivatives and related fused ring compounds

Cyclopropanecarboxylic acid or 2,2-dimethyl cyclopropanecarboxylic acid was used as a leading compound for its biological activity.Six new N-(substituted) cyclopropanecarboxyl-N′-pyridin-2-yl thioureas were prepared.Compound 5 was obtained by oxidizing cyclization of compound 4 in the presence of bromine in chloroform solution.The structures of 4 and 5 were confirmed by ~1H NMR and elemental analysis.The preliminary biological tests indicate that compound 4b and 4e have excellent herbicidal activity,and ...     

Derivatives of heterocyclic α-iminocarboxylic acids. 4. Reduction of N-alkoxycarbonyl derivatives of α-iminocarboxylic acids

When N-methoxycarbonyl and N-benzoxycarbonyl derivatives of methyl esters of aziridine-2-carboxylic acid, L-proline, L-thioproline, and pipecolic acid interact with NaBH₄ in tert-butanol/methanol, the products of reduction of the C-methoxycarbonyl group of the original compounds are accompanied by bicyclic urethanes and oxazolidines. Reduction of N-maleates and N-fumarates of heterocyclic -iminocarboxylic acids leads to the formation of -hydroxymethyl-N-[4-(2-oxo-2,5-dihydrofuryl)] derivatives of pyrrolidine, piperidine, 1,3-thiazolidine, and 1,4-thiazan. In the latter case, 1-aza-2-hydroxymethyl-4-oxo-5-oxa-9-thiabicyclo [5.4.0]undecene-2 is also obtained. The N-maleates and fumarates of aziridine-2-carboxylic acid are reduced anomalously by sodium borohydride, forming 2-hydroxymethyl-2-(-hydroxyethyl)-3-oxa-1-azabicyclo[3.1.0]hexanes.For Communication 3 see [2].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1567–1573, November, 1993.