An Efficient,Microwave-Assisted,One-Pot Synthesis of Dioxolano Quinoline/benzo[h]quinolines as Potent Antibacterial Agents

Quinolines/benzo[h]quinolines are associated with a broad spectrum of biological activities. In view of this, 3-(1,3-dioxolan-2-yl)quinoline/benzo[h]quinoline-2-thiol/selenols were prepared under microwave irradiation through one-pot reactions, and these quinolines/ benzo[h]quinolines were evaluated for potential antibacterial activity.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

On the tautomerism of 2,4-disubstituted 3,4,5,6-tetrahydrobenzo[h]quinazolines

Summary The tautomerism of the title compounds was investigated by¹H-,¹³C-NMR and UV spectroscopy. Compound5 was compared with respect to its spectra with those of appropriate model compounds1,3,4, and6. This gave evidence that5 predominates in the tautomeric from5A.

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Zur Tautomerie von 2,4-disubstituierten 3,4,5,6-Tetrahydrobenzo[h]chinazolinen

Zusammenfassung Die Tautomerie von 2,4-disubstituierten 3,4,5,6-Tetrahydrobenzo[h]chinazolinen wurde durch¹H-,¹³C-NMR- und UV-Spektroskopie untersucht. Der Vergleich der Spektren von5 und der Modellverbindungen1,3,4 und6 legt nahe, daß für5 das Tautomere5A dominiert.

     

Zur Synthese von 9,9-Dimethyl-2-oxa-bicyclo[3.3.1]nonan

Summary The diketone1 undergoes base induced ring opening to the -ketoacid2 a. Subsequent stereoselective reduction of the carbonyl-group affords the corresponding hydroxyacid4 a and condensation leads to the bicyclic lactone5 which can be reduced to the title compound6. Similar O-cage-compounds are known for antiviral activity. The olfactory properties of the compounds5 and6 are described.

     

2-氨基-3-氰基-4-(4-氟苯基)-4H-苯并[h]苯并吡喃的合成和晶体结构

标题化合物与N,N-二甲基甲酰胺(DMF)形成的1:1混合结晶物C20H23FN2OC3H7NO由对氟苯甲醛、丙二腈、-萘酚在六氢吡啶存在下合成并经DMF与水的混合溶剂重结晶而得, 其结构通过元素分析、IR 和1H NMR对化合物进行了表征,用X-射线单晶衍射法测定了该化合物的晶体结构。结果表明,晶体属于单斜晶系,P21/n空间群,a = 6.365(1), b = 10.620(2), c = 29.122(6) ? b = 92.00(1), V = 1967.3(6) ?, Mr = 389.42, Z = 4, Dc = 1.315 g/cm3, m (MoKa) = 0.092 mm-1, F(000) = 816。晶体结构用直接法解出,经全矩阵最小二乘法修正,最终偏离因子R = 0.047, wR = 0.1053。化合物分子中,原子C(1), C(2), C(3), C(4), C(5) 和O(1)形成1个六员环,该六员环中C(1)C(2)键长为1.346(3) 牛砻魑肆被肺焦瓜蟆?     

Acetylenchemie, 33. Mitt.: Synthese von 2-substituierten Dihydrofuro[2,3-b]chinolinen

Summary The reaction of 3-iodo-4-methoxy-2(1H)-quinolinone (1) and 3-iodo-4,6,8-trimethoxy-2(1H)-quinolinone (2) with 2-methyl-3-butyn-2-ol under modified Heck-conditions gave the 2-substituted derivatives 2-(1-hydroxy-1-methylethyl)-4-methoxyfuro[2,3-b]-quinoline (3) and 2-(1-hydroxy-1-methylethyl-4,6,8-trimethoxyfuro[2,3-b]-quinoline (4). By a subsequent hydrogenation-reaction with a homogeneous catalyst (PtO₂/Rh₂O₃), the furoquinoline-derivatives yielded the dihydrofuro-[2,3-b]quinolines, identified as 2-(1-hydroxy-1-methylethyl-4-methoxy-2,3-dihydrofuro[2,3-b]quinoline (5) (racemic platydesmine) and 2-(1-hydroxy-1-methylethyl)-4,6,8-trimethoxy-2,3-dihydrofuro-[2,3-b]quinoline (6) (racemic precursor of O⁴-methylptelefolonium salt).

     

微波辐射下2-氨基苯并[h]喹唑啉衍生物的合成

2-芳亚甲基-3，4-二氢-2H-1（2H）-萘酮和碳酸胍在以乙二醇为溶剂、微波辐 射下反应，生成一系列新的2-氨基-4-芳基-5，6-二氢化苯并[h]喹啉衍生物，产物 的结构通过单晶X射线衍射分析确证。     

One-pot multicomponent synthesis of some 5,6-dihydro-benzo[h]quinoline derivatives

5,6-Dihydrobenzo[h]quinoline derivatives 4a–f and 5a–c were prepared via condensation of the corresponding arylidenes 2, with 1-tetralone in the presence of ammonium acetate and sodium methoxide, respectively, following thermal, microwave and ultrasound methodologies. The yields of 4a–f were moderate when the latter two methodologies used, but the products were pure. Ultrasound and microwave irradiation methods were also used in the synthesis of 4-aryl-3-cyano-1,2,5,6-tetrahydro-benzo[h]quinoline-2-ones (6a–e) and its analogues 7a,b. The majority of compounds 4–7 were synthesized via one-pot multicomponent reactions of aldehydes, active cyanomethylene compounds, 1-tetralone and ammonium acetate. Attempts to cyclocondensation of the aminocyano derivative 4a,d with acetic anhydride in presence of conc. H₂SO₄ failed; instead the acetylamino derivative 8 was isolated. On the other hand, refluxing of 4d with formamide in DMF led to the formation of dihydrobenzo-pyrimidoquinoline 9 giving good yield. All prepared condensates were structurally elucidated by various spectroscopic methods. Screening of the potential cytotoxicity for compounds 4a–f on five cell lines, namely: colorectal carcinoma (HCT-116), Hepatocellular carcinoma (HEPG2), Human breast adenocarcinoma (MCF7), Cervix adenocarcinoma (HELA) and Glioblastoma (U251), did not show any cytotoxic activity.     

Synthesis and structure of 2-phenyl-4-aryl-3,4,5,6-tetrahydrobenzo[h]quinazolines

Summary The reaction of 2-arylidene-1-tetralones1 with benzamidine gave 2-phenyl-4-aryl-3,4,5,6-tetrahydrobenzo[h]quinazolines2. Investigations on the tautomeric equilibria of2 by IR,¹H- and¹³C-NMR showed the compounds to exist predominantly in the tautomeric form2A both in the solid state and in solution. Acetylation and oxidation of the heterocyclic ring of2 provided further evidence for the structural assignment of the title compounds.

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Synthese und Struktur von 2-Phenyl-4-aryl-3,4,5,6-tetrahydrobenzo[h]chinazolinen

Zusammenfassung Die Reaktion von 2-Aryliden-1-tetralonen1 mit Benzamidin ergab 2-Phenyl-4-aryl-3,4,5,6-tetrahydrobenzo[h]chinazoline2. Untersuchungen über das tautomere Gleichgewicht von2 mittels IR,¹H-NMR, und¹³C-NMR Spektroskopie zeigten, daß für die Verbindungen das Tautomere2A dominierte (sowohl in fester Phase als auch in Lösung). Acetylierung und Oxidation des heterocyclischen Ringes von2 ergab weitere Beweise für die Struktur der Titelverbindungen.

     

Synthese von 4H-Pyrano[2,3-d]pyrimidinen

Summary Good yields of substituted 5-(5R-2-furyl)-4H-pyrano[2,3-d]pyrimidines4 were obtained in the reaction of 2-ethoxymethyleneamino-3-cyano-4H-pyranes2 with ammonia. Compounds2 were prepared by the condensation of the starting 2-amino-5-acetyl-3-cyano-6-methyl-4H-pyranes1 with ethyl orthoformate. Spectral properties of the bicyclic system4 in relation to compounds3 are discussed.

     

Preparation of benzo[4,5]thiazolo[3,2-a]chromeno[4,3-d]pyrimidin-6-one derivatives using MgO-MgAl2O4 composite nano-powder

MgO-MgAl₂O₄ nanocomposite was prepared from the co-precipitation of Mg(NO₃)₂ and Al(NO₃)₃ salts, characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and fourier transform infrared spectroscopy (FTIR) techniques and evaluated in the synthesis of thirty five derivatives of benzo[4,5]thiazolo[3,2-a]chromeno[4,3-d]pyrimidin-6-ones (d₁-d₃₄) via the multi-component reaction of 4-hydroxycoumarins, aldehydes, and 2-aminobenzothiazole derivatives under solvent free condition. The catalytic activity of MgO-MgAl₂O₄ nanocomposite and the synthesis of the above mentioned compounds were investigated under thermal solvent free (times: 1.4–3 h; yields: 75–95%), ultrasonic irradiation (US) conditions (times: 1–2.5 h; yields: 69–97%) and using high-speed ball milling (HSBM) technique (times: 0.7–2.5 h; yields: 67–97%). In all cases, the products were obtained in excellent yields. Nuclear Magnetic Resonance (NMR) and MASS spectroscopy were used to characterize the structure of the desired product. The mechanism for the preparation of compounds d₁-d₃₄ was proposed and confirmed by ¹H NMR investigations.     

Zur Synthese von Homocamphenilansäure

Syntheses of the title compound and of some of its derivatives are described. Homocamphenilanic acid could not be obtained by aDiels-Alder reaction of cyclohexadiene with an appropriate dienophile but is easily accessible via homocamphene by hydroboration of this homoterpene and subsequent oxidation of the reaction product.

Anmerkung: Zur Verwendung der Vorsilbe Homo- im Zusammenhang mit Norbornanen siehe Lit. [13] und Fußnote in Lit. [12].     

Zur elektronischen Struktur von [Y9C4O]I8

On the Electronic Structure of [Y₉C₄O]I₈ The new [Y₉C₄O]I₈ structure exhibits striking similarities with layered structures of the well-known rare-earth metal carbide halides [M₂C]X₂ and [M₂C₂]X₂ (M = rare-earth metal, X = halide) which already have been studied concerning their electronic structures and conductivities. In contrast to the last compounds, [Y₉C₄O]I₈ formally contains one extra electron. This electron appears to be delocalized in various metallic orbitals. The oxygen atoms which are located in the bent sections in the metal double layers as well as the halide double layers in the structure are considered to act as barriers for electronic mobility. Therefore a one-dimensional metallic conductivity is expected to be dominant.     

Zur Synthese und Struktur von 8-Nitro-imidazo [1,2-a]pyridinen

Summary The title compounds were synthesized by reaction of nitroketene aminals with -chlorovinylcarbonyl compounds. The chloromethylene malononitriles1 react with nitromethylenimidazolin (2 a) and -benzimidazoles2 b to yield the 8-nitro-2,3-dihydroimidazo[1,2-a]pyridines3 and the 4-nitropyrido[1,2-a]-benzimidazoles6, both containing an amino group. Analogously, from the special 3-chloro-2-propeniminium salt7 and2 a the imidazopyridine derivative9 was formed. The 3-aryl-3-chloro-2-propeniminium salts10 were converted into the nitro-dihydroimidazo[1,2-a]pyridines11 and the pyrido[1,2-a]benzimidazole12 containing the aryl group by reaction with2 a and2 b, respectively. The structures were investigated by 2-dimensional¹H/¹³C-NMR-spectroscopy.

     

水中苯并[h]色烯衍生物的洁净合成

在三乙基苄基氯化铵(TEBA)存在下的水介质中，芳亚甲基丙二腈与1-萘酚发生 加成、环化反应生成2-氨基-3-氰基-4-芳基苯并[h]色烯．产物的结构通过元素分 析、红外光谱和核磁共振氢谱确证，该方法具有操作简单、产率高、环境友好的优 点．     

Synthesis and Crystal Structure of Ethyl （2-Amino-4-（2-chlorophenyl）-4H-benzo-[h]-chromene-2-yl） Formate

1 INTRODUCTION 2-Aminochromene is an important class of compounds as the main compounds of many natu- rally occurring products which can be used as cos- metics and pigments[1] and potential biodegradable agrochemicals[2～4]. Inorganic solid supports as c…     

Ring-contraction from benzo[b][1,4]thiazines to benzo[d]thiazolines induced by oxygen

An unexpected ring-contraction from benzo[b]pyrazino[1,2-d][1,4]thiazine-1,4-diones (6) to benzo[4,5]thiazolo[3,2-a]pyrazine-1,4-diones (7) has been developed. The preliminary mechanistic studies showed the transformation contained two independent steps: the first step is the formation of a Michael adduct upon the addition of the protic solvent, in the presence of base, to the C-2-C-3 double bond of compound 6, and the second step is a ring-contraction induced by oxygen via the migration of sulfur atom from C-2 to C-3 position. And its scope is also studied.     

Synthesis of a linear benzo[3]phenylene-[60]fullerene dyad

The synthesis of a new linear benzo[3]phenylene-[60]fullerene dyad 1 is achieved over 10 steps in 15% overall yield by using an efficient sequence combining a double cobalt(I)-mediated cyclotrimerization with a Bingel reaction.     

2—取代—1,7—二氧螺（4.4）壬—8—酮的合成研究

分别用Ｋ２ＣＯ３，１，５－二氮双环（４．３．０）壬－５－烯（ＤＢＮ）和四丁基氟化铵（ＴＢＡＦ）等碱催化３－（３－羟基丙基）－γ－丁烯酸内酯的分子内Ｍｉｃｈｅａｌ加成反应合成了２－取代－１，７－二氧螺（４．４）壬－８－酮