A FACILE SYNTHESIS OF HETEROCYCLE SUBSTITUTED CHALCONE AND 5-NITROFURANYL OLEFIN DERIVATIVES

Reaction of heterocycle substituted telluronium salts with aroma-tic aldehydes under mild conditions gave corresponding chalcones.In thepresence of dibutyl telluride,2-bromomethyl-5-nitrofuran condensed easilywith aromatic aldehydes in THF to afford corresponding olefin derivativesas one-pot reaction.     

REACTIONS WITH 2-THIOHYDANTOIN DERIVATIVES: SYNTHESIS OF MANNICH BASES AND IMIDAZOTHIAZOLE DERIVATIVES

Abstract

5-Arylidene-2-thiohydantoins (la-c) and 5-arylazo-1-phenyl-2-thiohydantoins (7a, b) were condensed with formaldehyde and primary or secondary aromatic amines to give the corresponding Mannich bases (2a-f) and (8a, b) respectively, which could also be converted into the educts (la-c) and (7a, b) by boiling in ethanolic HCI. On treatment of (2a-f), (5a-c) and (8a, b) with an ethereal diazomethane the colourless cyclopropane products (3a-c) and yellow N-methyl substituted compounds (9, b) were isolated respectively. Alkylation of (2d-f) with methyl iodide and (la-e) with 3-chloropentane-2,4 dione gave the corresponding 2-alkylmercapto derivatives (5a-c) and (2a-c) respectively, the former of which on hydrolysis by boiling ethanolic HCI afforded the hydantoin derivatives (6a-c). Cyclization of (12a-c) using polyphosphoric acid resulted in the formation of imidazothiazole derivatives (13a-c). The structure of the isolated products were established by elemental analyses and spectral data studies.     

A FACILE SYNTHESIS OF N-DIETHOXYPHOSPHORYLFORMAMIDINES

Abstract

The convenient synthesis of N-phosphorylated formamidines, 3 based on the reaction c diethyl(ethoxymethylene)phosphoramidate, 1 with primary and secondary amines is described.     

HETEROCYCLES SYNTHESIS THROUGH REACTIONS OF INDOLIN-2-ONE DERIVATIVES WITH ACTIVE METHYLENE AND AMINO REAGENTS,PART 3, NOVEL AND FACILE ONE-STEP SYNTHESIS OF SPIROTHIOPYRAN-4- YL INDOLIDENE DERIVATIVES

Abstract

New spirothiopyran-4-yl indolidene derivatives have been synthesised via a facile one-step method. Structures and reaction mechanisms are also reported and supported by another synthetic route.     

A FACILE SYNTHESIS OF AMINO-IMINOMETHANESULFONIC ACID

Aminoiminomethanesulfonic acid was conveniently obtained by oxidation of aminoiminomethanesulfinic acid with H₂O₂ in a high yield and good purity.     

A FACILE METHOD FOR THE SYNTHESIS OF NOVEL PYRIDINONE DERIVATIVES VIA KETENE N,S-ACETALS

A simple and easy method is provided for the synthesis of the novel pyridinone derivatives (3a–e), (8a–c) and (10a–c) by the reaction of ketene acetals (2a–e), (7a–c) and (9a–c) with ethyl cyanoacetate respectively. Compounds (3b–d) reacted with triethyl orthoformate to afford the pyridinone derivatives (4-6) respectively. Compound 7a reacted with ethyl acetoacetate or diethyl malonate to give thiazolopyridinone derivative 11 or 12 respectively.     

Organoallylaluminum reagents promote easy access to trihalomethyl triazolyl homoallylic alcohols analogous to rufinamide

The results of allylation reactions employing allylaluminum reagents are described for 5-substituted (2,6-difluorobenzyl)-4-trifluoro(chloro)acetyl-1H-1,2,3-triazoles (1), in which the 5-substituents are H, Me, and Ph. The allylating reagents were generated in situ by the catalytic insertion of aluminum into allyl and crotyl bromides (2), in order to furnish a new series of twelve trihalomethyl triazolyl homoallylic alcohols (3) at yields of up to 94%. The excellent reactivity of these organoallyl reagents is highlighted as an economical alternative to the indium-mediated reactions to produce homoallylic alcohols, which are important building blocks in organic synthesis.     

REACTIONS WITH THIAZOLINONES: A NEW ROUTE FOR THE SYNTHESIS OF THIAZOLONYLPYRIDAZONE AND THIAZOLYLPYRAZOLONE DERIVATIVES

Abstract

2-Amino-1.1.3-tricyanoprop-l-ene (1) reacted with thioglycollic acid to afford the key compound for this study namely: 2-amino-I,I-dicyano-3(2-thiazolin-4-on-2-yl)prop-1-ene 2. 2 reacted with hydrazines to afford the thiazolylmethylaminopyrazole derivatives 3 and 4. The reaction of 2 with diazotised primary aromatic amines afforded coupling products which were cyclised to the hydrazothiazolonylpyridazine derivatives 7. The reaction with aromatic aldehydes gave the his-ylidene derivatives 8. Structures are assigned based on elemental and spectroscopic analysis.     

预测环加成反应区域选择性的一个简易方法

长期以来,我们一直在研究化合物的性能与结构关系的定量化问题,其目的是为了寻求一个定量确定反应物反应活性的简易方法。本文研究了一种确定环加成反应区域选择性的新方法。早在七十年代初期,对于环加成反应的区域选择性问题就有报导,可以通过分子轨道法等加以确定。但是,应用分子轨道法的计算程序过于繁琐,所以应用并不广泛。1989年,S.K.Pal提出了处理这个问题的一个方程,即可以通过活性中心原有的电负性进行推算。这种原有的电负性可以用Huheey方法计算,但是这种计算方法在应用中仍然是相当复杂     

CHEMOSELECTIVE REDUCTION OF AZIDES WITH SODIUM SULFIDE HYDRATE UNDER SOLVENT FREE CONDITIONS

Sodium sulfide hydrate has been employed for an efficient reduction of a variety of azides to the primary amines in good-to-excellent yields under solvent-free system and without perturbing many active functionalities such as ether, carbonyl, sulfonyl, and nitro.     

SYNTHESIS,REACTIONS AND BIOLOGICAL ACTIVITY OF PHOSPHORUS-CONTAINING DERIVATIVES OF CHROMONE AND COUMARIN

Chromone and coumarin derivatives exhibit a wide spectrum of biological activity, including spasmolytic, antiarrhythmic, cardiothonic, antiviral, and anticancer properties. Phosphorus-containing chromone and coumarin derivatives form a novel group of compounds, possessing remarkable cytotoxicity and alkylating and anticancer activity against selected tumor cell lines. Derivatives containing a phosphorus atom at position 2 of a γ-pyrone ring are known to be efficient antibacterial agents.

This review presents methods developed for the synthesis of derivatives of chromone and coumarin that contain a phosphonate moiety. Among them, the reaction of derivatives of 2-hydroxyacetophenone with phosphonic compounds is the one most frequently used. Some analogues were characterized by X-ray crystallography.     

END GROUP TRANSFORMATION OF POLYMERS PREPARED BY ATRP,SUBSTITUTION TO AZIDES

Polystyrenes, polyacrylates and poly(methyl methacrylate) prepared by atom transfer radical polymerization (ATRP) have predictable molecular weights, low polydispersities and well-defined halogen end groups. The halogen end groups have been substituted by other functionalities such as azides and amines. In order to predict the feasibility and selectivity of nucleophilic substitution reactions, the reactivities of the end groups of the different polymers were studied. First, model studies with benzyl halide (BzX), 1-phenylethyl halide (1-PEX), methyl 2-halopropionate (MXP), ethyl 2-bromoisobutyrate (EBiB) and 2-halopropionitrile (2-XPN) were performed. The models compounds were dissolved in DMF and after adding sodium azide (1.1 eq.), the reaction mixtures were stirred at 25°C. The relative magnitude of the rate constants for the reactions with the chlorinated substrates were found to be BzCl > MClP > 1-PECl ≈ 2-ClPN:22 > 6 > 1. Increased substitution at the carbon center decreased the rate of reaction, benzyl chloride reacted 22 times faster than 1-phenylethyl chloride. The brominated substrates reacted very fast. The rate constant of 1-PEBr, determined by competition experiments, was 4.5 times higher than the rate constant of benzyl chloride. Based on these results, the bromine end groups of different polymers were substituted under reaction conditions simular to those used for the model reactions. The end-functionalized polymers were characterized by ¹H-NMR, IR and MALDI-TOFMS.     

InBr3 as a versatile and highly efficient catalyst for the synthesis of 3-allyl- and 3-benzylindoles

Indoles undergo smooth alkylation with allylic and benzylic alcohols in the presence of 10 mol % of InBr₃ under mild conditions to produce 3-allyl- and 3-benzyl indoles, respectively, in excellent yields and with high selectivity. This is the first example of the alkylation of indoles with benzylic alcohols using InBr₃ as an acid catalyst.     

IMINO DIELS-ALDER REACTIONS CATALYZED BY OXALIC ACID DIHYDRATE. SYNTHESIS OF TETRAHYDROQUINOLINE DERIVATIVES

Oxalic acid dihydrate is found to catalyze the Imino Diels-Alder reaction of schiff bases derived from substituted anilines with cyclopentadiene, results in the formation of Tetrahydroquinoline derivatives in moderate yields.     

A FACILE SYNTHESIS OF ARYL THIOCYANATES USING SODIUM PERBORATE

A simple and convenient synthesis of aryl thiocyanates in high yields using sodium perborate is described.     

SYNTHESIS AND REACTIONS OF HALO DERIVATIVES OF 4-ISOPROPYL-2H-1,4-THIAZIN-3-ONE

Abstract

Reaction of 4-isopropyl-2H-1,4-thiazin-3-one 1 (R [dbnd] i-Pr) with N-chloro- and N-bromosuccinimide occurred exclusively at the 6-position to give 6-chloro and 6-bromo derivatives of 1 (R [dbnd] i-Pr), respectively, in high yield, in sharp contrast to the 2-aroyloxylation by benzoyl peroxide or m-chloroperbenzoic acid reported earlier.² Reaction of 1 (R [dbnd] i-Pr) with methanesulfonyl chloride in the presence of aluminum chloride afforded an addition compound, 4-isopropyl-5,6-dichloro-1,4-tetrahydrothiazin-3-one. The 2-chloro derivative 6 of 1 (R [dbnd] i-Pr) was successfully prepared by hydrolysis of the 2-m-chloroben-zoyloxy derivative of 1 (R [dbnd] i-Pr) followed by treatment with thionyl chloride. Derivative 6 reacted readily under mild conditions with water, alcohols, thiols, ammonia and amines to give various 2-substituted compounds of 1 (R [dbnd] i-Pr). With phenol as a nucleophile, 1 (R [dbnd] i-Pr) reacted exclusively at the para position. Reaction at carbon atoms also occurred with N,N-dimethylaniline and 2,6-xylidine.     

质体醌类似物的合成研究——Ⅰ.不同侧链的质体醌类似物

本文通过对2,3-二甲基-1,4-苯醌与脂肪酸在过硫酸铵及硝酸银作用下发生的自由基烷基化反应,合成了九种新的具有不同长短侧链的质体醌类似物。其结构已经IR,UV,~1H NMR和MS证实。     

一些三唑类化合物的合成及其生物活性的研究

一些唑类化合物的广谱、高效、强内吸性杀菌作用和植物生长调节作用正受到人们广泛的关注。为筛选合成上简易,且有较高生物活性的化合物,作者设计了下列三类1,2,4-三唑和苯并1,2,3-三唑类化合物。其化学结构通式如下:     

香豆素类衍生物的合成

由人免疫缺陷病毒 ( HIV)感染引起的免疫缺陷综合症 ( AIDS)——艾滋病 ,是人类致命疾病之一。世界各国都在致力于寻找抗艾滋病药物 ,其中一个研究热点是通过大规模筛选寻找生物活性较强的小分子非肽类抑制剂 ,然后进行结构优化 ,以期找到新一代的抗艾滋病药物。香豆素类衍生物是一类具有抗病毒等许多生物活性的化合物 ,一直被人们所重视。 1 992年 ,从马来西亚热带雨林植物 Calophllum L anigerum中分离出具有抗艾滋病病毒活性的香豆素类化合物 Calanolides[1] 。同时 ,由于香豆素类化合物合成相对简单 ,生物利用度高 ,促使人们在这个…     

SYNTHESIS OF MELEZITOSE DERIVATIVES

The reactivity of melezitose hydroxyls is studied during tritylation in pyridine. Some novel derivatives of melezitose are prepared. An acetyl is transferred from the 4- to the 6-position after detritylation of 3 and 4. The structures of the products are proved by elemental analysis;¹H,¹³C, and¹H-¹H COSY NMR spectra;IR spectra; and fast-atom bombardment mass spectrometry.