Reactions of 1,2-Epoxy-2-Methyl-3-butene with Lithio Derivatives of Allylic Sulfoxides. Syntheses of 2,6-Dimethylocta-3,7-dien-2,6-diol and of 5,8-Dehydro-4-0xo-nerolidol

Our preceding studies have shown that lithio carbanions of protected cyanohydrins can undergo Michael additions to an isoprenic sulfoxide to yield lithio derivatives of allylic sulfoxides¹. These results have led us to investigate the utilization of these lithio sulfoxides for new simple syntheses of aliphatic terpenes by head-to-tail linking of functionalized isoprenoid units. For this purpose, 1,2-epoxy-2-methyl-3-butene 2 was one especially appropriate electro-phile, but at the outset of our work, there had been very few investigations of the reactivity of lithio carbanions of allylic sulfoxides with epoxides²     

Formation of diaryl sulfides and sulfoxides: Synthesis,characterization and structure activity correlation studies

Abstract

The synthesis of a series of stable diarylsulfides and sulfoxides is reported. All the newly synthesized compounds were characterized by ¹H, ¹³C NMR and mass spectroscopic techniques. A detailed mechanistic study indicates that the formation of sulfoxides follows the oxidation. In addition to synthesis, characterization and mechanistic studies, the glutathione peroxidase(GPx) mimetic activity of the newly synthesized compounds is described. It is observed that the diaryl sulfides having a heterocyclic ring attached to the nitrogen atom facilitates the oxidation of the sulfur center to form the corresponding sulfoxides. The substituents attached to the nitrogen atom play an important role in the catalytic activity of the substituted diaryl sulfides. The obtained data supports for the higher antioxidant activity of diaryl sulfides than that of the corresponding sulfoxides.     

ON THE REARRANGEMENT OF N-ARYL SULFIMIDES

Abstract

N-Aryl-S,S-dialkylsulfimides, 1, with R¹ = alkyl other than CH₃, have been rearranged by heating in ethanol yielding o-alkylthiomethyl-anilines, 2, as main products. Isomeric o-methylthioalkyl-anilines, 14, are formed in minor amounts only. Reactions of sulfimides, 1, with R¹ = CH₃, with certain alkylating or acylating agents yielded o-methylthiomethylated, N-alkylated or -acylated products 9. Mechanistic considerations are discussed. The rearrangement of sulfimides 1 has been assumed to occur via [2,3]-sigmatropic reactions of intermediate azasulfonium ylids 3. Attempts to resolve (+)-camphor-10-sulfonates of N-aryl sulfimides failed, but optically active N-aryl sulfimides could be obtained by reaction of anilines with optically active sulfoxides and P₄O₁₀. Optically active 2,6-disubstituted sulfimides, 1, could be rearranged in ethanolic KOH to yield optically active cyclohexadienimines 12, indicating a transfer of asymmetry from sulfur to carbon and supporting the assumption of a sigmatropic rearrangement.     

Soluble Ni alkoxides based on dimethylaminoisopropoxide ligands: molecular structure of [Li(PrOH)Ni (η-OR)2Cl]2 and of cis-NiCl2(ROH)2 (R = CHMeCH2NMe2)

Various routes to Ni^II aminoalkoxides have been investigated. A nickel isopropoxide derivative 1 was prepared by anodic dissolution of the metal in the presence of LiCl as electrolyte. Alcoholysis reactions of 1 with 1-dimethylamino-2-propanol afforded the homoleptic nickel(II) aminoalkoxide 2 together with a NiLi species 3. 2 was also obtained by metathesis reactions between sodium alkoxide and the nickel hexammine complex whereas the reaction between the latter and the aminoalcohol led to an halide solvate, cis-NiCl₂(η²-ROH)₂, 4. The various compounds were characterized by elemental analysis, FT-IR and UV-vis spectroscopies as well as by X-ray diffraction for 3 and 4. 3 corresponds to [Li(PrⁱOH)Ni(η²-OCHMeCH₂NMe₂)Cl]₂ and the overall structure can be seen as two [Ni(η²-OCHMeCH₂NMe₂)₂Cl]⁻ moieties assembled by Li(PrⁱOH)⁺. The lithium atom is 4-coordinate due to its interaction with the oxygen atoms of the aminoalkoxide ligands. Nickel is 5-coordinate with a distorted tetragonal pyramidal stereochemistry, one nitrogen being in the apical position. The metal displays a distorted octahedral surrounding for the NiCl₂ adduct 4. The bond distances vary in the order NiOR < NiN ≈ NiO(H)R < NiCl for 3 and 4. The various compounds (except 1) are soluble in organic media.     

SYNTHESIS AND REACTVITY OF N-[N-PHOSPHORAMIDO-1H-BENZIMIDAZOL-2-YL] IMIDATES

N-(-1H-Benzimidazol-2-yl) imidates 1a–c react with chlorophosphoramide to give the N-[-1-N,N,N′,N′-tetramethylphosphoramidoyl-1H-benzimidazol-2-yl]-imidates 2a–c or with dichlorophosphoramide to yield the bis[(N-1-benzimidazol-2-yl)-imidate] phosphoramide derivatives 3a–b. The reaction of compounds 2a–c toward primary amines is studied. The obtained amidine derivatives 4a–b were unambiguously characterized by different spectroscopic techniques (IR, ¹H, ¹³C, and ³¹P NMR, and in some cases MS).     

Facile synthesis of some new functionalized 2-selenoxopyrimidines

Abstract

Some new functionalized 2-selenoxodihydropyrimidines 1–6 were synthesized in good yields via a simple one-pot reaction. The simple method depended on the reaction of selenourea with some nitrile active methylene compounds under basic-catalyzed conditions. Also, treatment of selenourea with each of malononitrile and ethyl cyanoacetate in the presence of benzaldehyde under the same basic reaction conditions afforded the 2-selenoxopyrimidine-5-carbonitriles 7 and 8, respectively. Furthermore, selenourea reacted with benzaldehyde and different β-dicarbonyl compounds under Biginelli reaction conditions to afford the 2-selenoxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates 10, 11 and 13. Using acetylacetone as a substrate in Biginelli reaction yielded the unexpected 5-benzylidene-4,6-dimethyl-pyrimidine-2(5H)-selenone (14). The structures of the synthesized compounds were established on the basis of elemental analysis, IR, ¹H- and ¹³C-NMR and mass spectral data.     

Synthesis and antitumor activities of novel 2-substituted pyrimidinone-5-carboxylic acid benzylamides

The title compounds were synthesized via N-benzylmalonamic acid methyl ester (3). As the key intermediate, 3 was prepared from methyl malonyl chloride and benzylamine. Then, compound 3 was reacted with dimethyl-formamide dimethyl acetal yielding vinylogue amides 4 and 5. Isomers 4 and 5 were respectively treated with amidine and guanidine to afford the title compounds 2-substituted pyrimidinone-5-carboxylic acid benzylamides 6 and 7. All of the new compounds were characterized by ¹H-NMR (nuclear magnetic resonance), ¹³C-NMR, MS and High Resolution Mass Spectrometer (HRMS). The antitumor activities of the compounds were tested in vitro against LoVo cells and Hep3B cells. Both compounds 6 and 7 show activity against these two cell lines. Translated from Huaxue Tongbao (Chemistry), 2006, 69(8): 623–626 (in Chinese)     

PHOSPHONOMETHYLATION OF AMINOALKANOLS PREPARATION OF 4-(PHOSPHONOMETHYL)-2-HYDROXY-2-OXO-1,4,2-OXAZAPHOSPHORINANES1

Abstract

Treatment of aminoalkanols 1 with phosphorous acid and formaldehyde in presence of conc. hydrochloric acid gave mixtures of [(2-hydroxy alkyl)imino] dimethylene diphosphonic acids 3 and 4-(phosphonomethyl)-2-hydroxy-2-oxo-1,4,2-oxazaphosphorinanes 2 from which 2 were isolated as crystalline solids. Similar treatment of 2-amino-2-methyl-1,3-propanediol 8 gave a complex mixture from which dimethylene diphosphonic acid of 5-amino-5-methyl-1,3-dioxane 9 was isolated. 2-Aminoethanethiol, when subjected to phosphonomethylation. gave an unexpected novel quarternary nitrogen product 11. N-Alkylaminoalkanols 4 on phosphonomethylation gave 3:1 mixtures of [N-alkyl-N-(2-hydroxyalkyl)amino] methane phosphonic acid 6 and N-alkyl-2-hydroxy-2-oxo-1,4,2-oxazaphosphorinane 5. Treatment of the crude mixtures of 5 and 6 with aqueous sodium hydroxide gave disodium salts of [N-alkyl-N-(2-hydroxyalkyl)amino] methanephosphonic acid 7. The ratio of the cyclic to the open chain structures obtained as well as the formation of any unexpected novel products is dependent on the structure of the aminoalkanol that is phosphonomethylated. The ¹H, ¹³C and ³¹P spectra are reported for all new compounds.     

Reactivite Des α -Phosphonylketones Dans la Reaction de Gewald: Synthese de Nouveaux Derives de L′aminophosphonothiophene

The reaction of α -phosphonylketones 1 with active methylenenitriles 2 leads to phosphonoalkylidenes 3 . The reaction of compounds 3 with sulfur under basic conditions leads to the new 2-amino-4-phosphonothiophenes 4 . The structure of all obtained products was confirmed by NMR (¹H, ³¹P, ¹³C) and IR spectroscopy, and in some cases by mass spectrometry.     

Synthesis and Ldasic Properties of O,O,O-Triethyl-N-(2-Pyridyl) Imidophosphates

Abstract

The phosphorus (111) compounds are known to react readily with arylazides resulting in the formation of imi-dophosphorus compounds (Staudinger reaction)¹.

We nave obtained O,O,O-triethyl-Ii-(2-pyridyl)imido-pnosphates by the reaction of triethylphosphites with 2-pyridylazides (existing as tetrazoles) with a good yield.     

Oxidation of Sulfides with Hydrogen Peroxide Catalyzed by Vitamin B2 Derivatives

5-Ethyl-3-methyl-2′,4′:3′,5′-di-O-methylenedioxyriboflavinium perchlorate (1, DMRFlEt⁺ClO₄ ^–), derived readily from commercially available vitamin B₂ (riboflavin), exhibits high catalytic activity for the oxidation of organic sulfides with hydrogen peroxide. The reaction provides an efficient and selective method for the oxidative transformation of organic sulfides to the corresponding sulfoxides under mild conditions.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]     

Isolation and structural elucidation of novel antimicrobial compounds from maggots of Chrysomyis megacephala Fabricius

The excretions/secretions from the maggot of Chrysomyis megacephala Fabricius are traditionally used to treat serious infections in China. In this study, bioassay-guided fractionation led to the isolation of three novel antibacterial compounds (1–3), including important fluorinated compounds (3 and 5), together with other nine known compounds from 70% methanol extract of C. megacephala. The structures of the new compounds were elucidated by NMR spectroscopic analysis and high-resolution mass spectroscopy. The antibacterial activities of the isolated compounds were evaluated using agar disc diffusion method. New compounds 1 and 2 exhibited moderate activity against Bacillus subtilis with a minimum inhibitory concentration (MIC) of 250 μg mL^? 1. The most active compounds 3 and 5 displayed a broad spectrum of antimicrobial activity with an MIC of 125 μg mL^? 1 against G⁺ and G^?  bacteria. The structure of the above-mentioned novel compounds and their antimicrobial activities are herein reported for the first time from the natural product of insects.     

Synthesis and Inhibitory Activity Against Epstein-Barr Virus of Some New 1,2,3,4-Tetrahydropyrimidine-2-thiones

1,2,3,4-Tetrahydropyrimidine-2-thiones 4a–n were synthesized through the reaction of aromatic aldehydes 1a–n , ethyl acetoacetate (2) and thiourea ( 3) . The structures of all newly synthesized heterocyclic compounds elucidated by the use of IR, ¹H NMR, mass spectra, and elemental analyses. The inhibitory activity against the Epstein-Barr Virus early antigen (EBA-VA) of all newly synthesized heterocyclic compounds were evaluated.     

Supramolecular structures of Mn2+, Co2+ and Zn2+ complexes containing 1,3-bis(4-pyridyl)propane and aminosalicylate anion

In this study, the synthesis, spectroscopic properties and crystal structures of three new supramolecular compounds named [Mn₂(bpp)₄(H₂O)₄](AS)₄·H₂O (1), [Co₂(bpp)₄(H₂O)₄](AS)₄·H₂O (2) and [Zn(bpp)(AS)₂] (3), have been described, where bpp is 1,3-bis(4-pyridil)propane and AS^?  is aminosalicylate anion. By analysing the similarities between the X-ray powder diffraction results, it has been observed that compounds 1 and 2 are isomorphous, exhibiting an orthorhombic system with space group Pccn; for compound 3, another orthorhombic system was observed, with space group Aba2, which displays coordination between the Zn²⁺ metal ion and the aminosalicylate anion; this can be considered the first case in the literature involving the direct coordination to the metal ion. The vibrational spectra of compounds 1 and 2 are very similar. In the Raman spectra, the main bands are observed at ca. 1625 and 1020 cm^? 1, referring to the ^? O–C = O and CC/CN stretching modes of AS^?  and bpp ligands, respectively.     

1,4-Diacyl-3-acylamino-5-aryl-4,5-dihydro-1H-1,2,4-triazoles: Ring closure products of aromatic carbaldehyde (diaminomethylene) hydrazones with acylating agents

Summary Treatment of aromatic carbaldehyde (diaminomethylene)hydrazones1 with hot acetic anhydride or benzoyl chloride affords 1,4-diacyl-3-acylamino-5-aryl-4,5-dihydro-1H-1,2,4-triazoles2. In contrast, a new type of 0,N-acetal with an 1,2,4-triazole substructure (3) is obtained from 4-pyridine-carbaldehyde (diaminomethylene)hydrazone (li) by using a similar reaction procedure. The structures of all novel compounds were confirmed by spectroscopic data (¹H and¹³C NMR, MS, IR); some representative compounds were also studied by X-ray analysis.Dedicated to Professor Dr.S. Makleit on the occasion of his 65^th birthday.     

A 1,5-SHIFT OF THE PHENYLSULFINYL GROUP IN PHENYL PENTADIENYL SULFOXIDES

Abstract

1,4-Pentadienylic sulfoxides, obtained by reaction of 3-thiabicyclo[3,1,0]-hexane-3,3-dioxides with phenyl magnesium bromide¹, undergo a facile rearrangement with base to the conjugated 2,4-pentadienylic sulfoxides, e.g. 1Z and 1E.     

2-Phenylazo-1-alkene

Zusammenfassung Durch Umsetzung der Methylketon-phenylhydrazone1 mit J₂ in Pyridin werden die kristallinen 2-Phenylhydrazonoalkyl-pyridiniumjodide (2) synthetisiert und daraus mit Alkali unter 1,4-Eliminierung von Pyridin·HJ die in Substanz unbeständigen (E)-2-Phenylazo-1-alkene (4) hergestellt. Die spektroskopischen Untersuchungen (IR, Raman, EA und¹H-NMR) der orange-farbenen Öle4 beweisen dietrans-Konfiguration um die N=N-Bindung und außerdem, daß in Lösung4 a–d vorwiegend die s-trans (transoide) Konformation einnehmen, während4 e bevorzugt in der s-cis (cisoiden) Form vorliegt.

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2-phenylazo-1-alkenes

The reaction of the methyl ketone phenylhydrazones1 with I₂ in pyridine yields the crystalline 2-phenylhydrazonoalkyl-pyridinium iodides (2). Upon alkali induced 1,4-elimination of pyridine·HI the (E)-2-phenylazo-1-alkenes4 are obtained as orange liquids which are unstable when free of solvent. Spectroscopic investigations (ir, Raman, ea and¹H-nmr) reveal thetrans-configuration at the N=N-bond and moreover assign the s-trans (transoid) conformation to4 a–d whereas4 e is correlated to the s-cis (cisoid) conformer.

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Oxidationsprodukte von Arylhydrazon-Verbindungen,6. Mitt.; 5. Mitt.     

Dinucleoside (5′ → 3′)-O,S-Phosphorodithioates - New Class of Dinucleotide Analogues

Abstract

Nucleoside 3′-0- and 5′-O-phosphorodithioates have been recently described by Caruthers et al.¹ as a new type of nucleotide analogues. These compounds have also been obtained in our Laboratory by one-pot dithiaphospholane approach.² We now report on the transformation of some of these derivatives into new class of dinucleotide analogues. We have found that nucleoside 3′-O-phosphorodithioates (1) react in DMF solution with 5′-bromo-5′-deoxythymidine to give in high yield corresponding dinucleoside (5′→3′)-O,S-phosphorodithioates (2) - first examples of a new class of dinucleotide analogues possessing the internucleotide phosphorothioate linkage with one of the sulfur atoms in a 3′-bridging position.     

N-取代-6-(3-氯-4-氯甲基-2-氧吡咯烷-1-基)-7-氟-3,4-二氢-2H-1,4-苯并噁嗪-3-酮衍生物的合成与生物活性研究

采用生物活性基团拼接的分子设计方法, 将活性基团2-氧吡咯烷引入到2H-[1,4]苯并噁嗪-3(4H)-酮分子结构的苯环上, 设计并合成了16个未见文献报道的N-取代-6-(3-氯-4-氯甲基-2-氧吡咯烷-1-基)-7-氟-3,4-二氢-2H-1,4-苯并噁嗪-3-酮衍生物6a～6p, 其结构经IR, ¹H NMR, LC/MS和元素分析确证. 初步的生物活性测试结果表明, 部分化合物具有较高的除草和杀虫活性, 如6c～6f等化合物在用量为150 g/hm²时对苘麻(Abutilon theophrasti)、刺苋(Amaranthus spinosus)和藜(Chenopodium album L)等阔叶杂草具有90%以上的抑制率, 6l和6o在500 mg/L浓度下对蚕豆蚜(Aphis fabae)具有90%以上的致死率, 个别化合物还兼具除草及杀虫活性.     

Diversity of supramolecular aggregation in copper(II) pentane-2,4-dionato compounds with methyl substituted 2-aminopyridines

Three copper(II) bis(pentane-2,4-dionato-κ ² O,O′) compounds with 2-amino-3-methylpyridine (2,3-ampy) (1), 2-amino-5-methylpyridine (2,5-ampy) (2), and 2-amino-4-methylpyridine (2,4-ampy) (3) were prepared by reaction of bis(pentane-2,4-dionato-κ ² O,O′)copper(II) with selected methyl substituted 2-aminopyridines. The coordination of Cu(II) in all three compounds is square pyramidal and intramolecular N–H?···?O hydrogen-bonding is present. X-ray crystallographic studies reveal different crystal aggregation influenced by a methyl substituent on pyridine. No intermolecular N–H?···?O hydrogen-bonding is present in 1. Intermolecular N–H?···?O hydrogen-bonding in 2 forms infinite chains and dimers are formed in 3. Extended 3-D aggregation was found in 2 via π–π and C–H?···?π (arene) interactions, while only chain formation was found in 1 and 3.