Synthesis and Antifungal Activity of Novel Quinazolin-4(3H)-one Derivatives

A novel group of 6-iodoquinazolin-4(3H)-one derivatives was prepared starting from 6-iodo-2-ethoxy-4H-3,1-benzoxazin-4-one (3) via action of various nitrogen nucleophiles such as primary and secondary amines, hydrazine hydrate, and its derivatives. The 3-amino-2-hydrazinyl-6-iodoquinazolin-4(3H)-one (15) was used as a key starting material to prepare new heterocyclic compounds. The structures of all synthesized compounds were inferred from the infrared, mass spectral, and ¹H NMR spectral data as well as elemental analysis. The fungicidal activities of the target compounds were preliminarily evaluated.     

Access to the 2,3-dihydropyridazin-3-one and as-triazino[3,4-a]phthalazine ring systems from 4-aryl-2-oxo-butanoic acids

A novel series of 2,3-dihydropyridazin-3-ones 15 were synthesized via condensation between hydrazines and 4-(p-chlorophenyl)-2-hydroxy-2-(2-oxo-2-substituted ethyl)butanoic acids 8 which in turn were prepared by the reaction of substituted benzylpyruvic acids 6 with methyl alkyl(aryl) ketones 7. Dehydration of 8b-d by a mixture of glacial acetic acid and hydrochloric acid afforded 4-(p-chorophenyl)-2-(substituted phenacyl)-2-butenoic acids 10. Condensation reaction of 10 with hydrazines gave type 15 compounds in good yields. Also, a new series of as-triazino[3,4-a]phthalazines 20 was obtained from the reaction of substituted benzylpyruvic acids 6 with hydralazine to give the hydralazones 19 which underwent dehydrative cyclization reaction with PPA to afford 20. Structure assignments are based on ¹H, ¹³C nmr and ir spectra.     

Utilization of 2-ethoxymethylene-3-oxobutanenitrile in the synthesis of heterocycles possessing biological activity

2-Ethoxymethylene-3-oxobutanenitrile is a versatile trifunctional reagent that allows the introduction of a three-carbon moiety to amine-substrates. The reaction of the title compound with hydrazines has been studied leading to appropriate substituted pyrazoles 4-11. Reactions with other dinitrogen nucleophiles were studied giving access to a set of fused pyrimidines 13. All types of compounds displayed biological activity against bacteria, filamentous fungi and tumour HeLa cells, but not for yeasts. Pyrazole 10 and pyrimidine 13d have been found to possess the broadest activity.     

Synthesis and Molluscicidal Activity of Phosphorus-Containing Heterocyclic Compounds Derived from 5,6-Bis (4-bromophenyl)-3-hydrazino-1,2,4-triazine

Novel N¹-(phosphoryl moiety)-N²-(1,2,4-triazin-3-yl)hydrazines 4, 6, 8, 9 and 12, iminophosphorane 3, iminophosphane 5, 1,2,4-triazinyldiazaphospholine 7, 1,2,4,3-triazaphospholinotriazines 2, 10, 11, and 1,2,4-triazino[3,2-c][1,2,4,5] triazaphosphine 13 have been obtained via treatment 5,6-bis(4-bromophenyl)-3-hydrazino-1,2,4-triazine (1) with various polyfunctional phosphorus reagents by stirring at room temperature or refluxing for long time in tetrahydrofuran. Structures of these compounds have been deduced upon the basis of elemental and spectral data. Molluscicidal activity of the prepared compounds against Biomphalaria Alexandrina snails (the intermediate host of Schistosoma mansoni) showed considerable activities.     

3-O-乙酰基熊果酸3-乙酰基-2-[(未)取代苯基]-2,3-二氢-1,3, -噁二唑-5-甲酯的合成及其抗炎活性研究

熊果酸与氯乙酸乙酯反应制得熊果酸乙氧甲酰基甲酯(2), 2与水合肼反应得到熊果酸甲酰肼甲酯(3), 3与羰基化合物反应得到一系列酰腙4a～4g, 再将4a～4g与乙酸酐作用, 环合得到3-O-乙酰基熊果酸3-乙酰基-2-[(未)取代苯基]-2,3-二氢-1,3,4-噁二唑-5-甲酯(5a～5g). 15个新化合物均未见文献报道, 其结构经¹H NMR, IR, MS加以确证, 并进行了药理结果筛选. 结果表明, 部分化合物具有良好的抗炎活性. 其中, 化合物5a (40 mg•kg^－1), 5d (40 mg•kg^－1), 5g (40 mg•kg^－1)与熊果酸相比, 具有更强的疗效.     

Synthesis and reactions of 4H-3,1-benzoxazin-4-one derivative bearing pyrazolyl moiety as antimicrobial and antioxidant agents

Ring opening of 4-aryl-2-phenyloxazol-5-one 1 with 2-aminobenzoic acid in acetic acid and n-butanol gave compounds 2 and 3, respectively. The 4H-3,1-benzoxazin-4-one derivative 4 was synthesized by refluxing of compound 2 in acetic anhydride. Then it reacted with different nitrogen nucleophiles such as hydrazine hydrate, phenylhydrazine, cyclohexylamine, piperidine, ethylenediamine, ethanolamine, semicarbazide hydrochloride, cyanoacetohydrazide and methyl glycinate hydrochloride to give compounds 5–14 in order to study the behavior of these nucleophilic reagents on the performed ring system. All the structures of the newly prepared compounds were characterized by their IR, ¹H-, 13C-NMR and MS spectral data. Some of the synthesized compounds were screened for their antimicrobial and antioxidant activities. Compound 5 showed remarkable activity upon this screening.     

Regioselectivity and regiospecificity of benzoxazinone (2-isopropyl-4H-3,1-benzoxazinone) derivatives toward nitrogen nucleophiles and evaluation of antimicrobial activity

A novel group of 6-iodoquinazolin-4(3H)-one derivatives was prepared. The reaction of the benzoxazinone 3 with various nitrogen nucleophiles such as formamide and hydrazine hydrate and also the reaction of the isopropylquinazolinone 4 with hydrazonyl chloride have been shown to proceed with a high degree of regioselectivity at C(2). Spiro heterocycles have been found to play fundamental roles in biological processes and have exhibited diversified biological activity and pharmacological and therapeutical properties; thus reaction of acetohydrazides 10a–c afforded the spiro compounds 11a–c. The acetohydrazide derivative 7 reacted with carbon electrophiles such as acetylacetone, ethyl acetoacetate, acid chlorides, and benzaldehyde to give some interesting heterocyclic compounds 12–16, respectively. The structures of all the synthesized compounds were inferred by infrared, ¹H NMR, and mass spectra as well as elemental analyses. The antimicrobial activities of some of the synthesized products were preliminarily evaluated.     

Synthesis of Benzo[b]thiophene Substituted Carbamates,Ureas, Semicarbazides,and Pyrazoles and Their Antimicrobial and Analgesic Activity

2-Azidocarbonyl-3-chlorobenzo[b]thiophene 3 was obtained from 3-chloro-benzo[b]thiophene-2-carbonyl chloride 1 and 3-chloro-benzo[b]thiophene-2-carboxy hydrazide 2 . The compound 3 on Curtius rearrangement with various alcohols, amines, and hydrazines afforded the corresponding carbamates 4a–b , ureas 5a–j , and semicarbazides 6a–g , respectively. Compound 2 was also utilized for the synthesis of pyrazoles 7a–c by treatment with various chalcones. The structures of the newly synthesized compounds were elucidated on the basis of IR, ¹ H NMR, and mass spectral data and have been screened for antimicrobial and analgesic activities.     

Synthesis,antioxidant and antitumor activities of some of new cyclobutane containing triazoles derivatives

Abstract

Thiosemicarbazides (2a–e) were obtained by the interaction of furan-2-carboxylic acid hydrazide (1) with five different isothiocyanate (RNCS) derivatives. By addition of KOH to the reaction medium, ethyl, allyl, phenyl and benzyl, p-tolyl substituted 1,2,4-triazoles (3a–e) were obtained. 3a–e were dissolved in dry acetone containing K₂CO₃ in the presence of 2-chloro-1-(3-methyl-3-mesitylcyclobutyl) ethanone (4) to give 3,4,5-trisubstituted 1,2,4-triazole sulfanyl compounds containing a cyclobutane ring (5a–e). The structures of the final compounds were confirmed by elemental analyses, FT-IR, ¹H-NMR and ¹³C-NMR. The antioxidant and antitumor properties of the synthesized compounds were also investigated. Three of the triazole derivatives with p-tolyl, benzyl and phenyl substituents (5c–e) displayed good antioxidant and antitumor activity in comparison to the standards.     

Reactivity of 6-anisyl-5-cyano-4-oxo-2-thioxo-1,2,3,4-tetrahydro-pyrimidine to wards some electrophiles and nucleophiles

The title compound was subjected to react with some electrophiles and nucleophiles, such as alkyl halides, ethyl chloroacetate or amines, hydrazines etc. The resulting compounds were used in further syntheses for the purpose of obtaining some new types of heterocycles with possible biological and pharmaceutical activities.     

Synthesis and Herbicidal Activity of α-Amino Phosphonate Derivatives Containing Thiazole and Pyrazole Moieties

A series of novel α-amino phosphonate derivatives containing the thiazole and pyrazole moieties 3 were synthesized by the Mannich-type reaction of substituted pyrazole-aldehyde 1, 2-amino-5-ethoxycarbonyl-4-methyl-thiazole 2, and dialkyl phosphites or triphenyl phosphite in the presence of a Lewis acid such as magnesium perchlorate as the catalyst under solvent-free conditions. Their structures were clearly confirmed by spectroscopy data (IR, ¹H NMR, ³¹P NMR, MS) and elemental analysis. The results of a preliminary bioassay (in vitro) indicated that some of the title compounds 3 possessed moderate herbicidal activities against dicotyledonous plants (Brassica campestris L) or monocotyledonous plants (Echinochloa crus-galli) at the concerntration of 100 mg/L.

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.     

Acetylene mit Elektronendonator und Elektronenakzeptorgruppen

Acetylenes having both electrondonating and electronaccepting groups ( 1 ) may be obtained in good yield from the correspondingly substituted olefines via bromination and elimination of HBr. The reaction of the acetylene aldehyde 1a with proton acids yields, after rearrangement of the primary adducts, the β-substituted acrylamides. Addition of nucleophiles leads to the β-disubstituted α.β-unsaturated carbonyl compounds. With hydrazines one obtains pyrazoles and pyrazolones. The acetylenes 1 undergo [2+2]-, [2+3]- and [2+4]-cycloaddition reactions.     

Reaction of metallo S-alkyl N-cyanodithioiminocarbonates and alkyl N-cyanocarbamates with hydrazine. A novel preparation of 5-amino-3-mercapto-1,2,4-triazole

Metal salts of S-alkyl-N-cyanodithioiminocarbonates 7 react as electrophiles with hydrazine hydrate to form 5-amino-3-mercapto-1H-1,2,4-triazole 1 . The novel 4-cyanothiosemicarbazide 9 is proposed as the intermediate which cyclizes to the aromatic triazole. The rate determining step is addition of hydrazine to the iminocarbonate and is second order. Other nucleophiles such as substituted hydrazines and amines failed to react. Exchange of either or both sulfurs with oxygen leads to decomposition or mixtures of products.     

Synthesis and Transformations of Ethyl (Z)-2-(2,3-dihydro-1,3-dioxo-1H-isoindol-2-yl)-3-(dimethylamino)propenoate

Ethyl (Z)-2-(2,3-dihydro-1,3-dioxo-1H-isoindol-2-yl)-3-(dimethylamino)propenoate was prepared in one step from ethyl (2,3-dihydro-1,3-dioxo-1H-isoindol-2-yl)acetate and bis(dimethylamino)-tert-butoxymethane and treated with various amines and hydrazines to afford the corresponding amino substituted products. Reactions of the titled compound with N,N'-, C,N-, and C,O'-ambident nucleophiles in refluxing acetic acid furnished the corresponding fused pyrimidinones, quinolizinones, and pyranones.     

N‐tert‐butoxycarbonyl‐N‐substituted hydrazines in SNAr displacements. Synthetic pathways to N‐1‐substituted anthrapyrazoles,aza‐anthrapyrazoles and aza‐benzothiopyranoindazoles

The synthesis of several N‐tert‐butoxycarbonyl(Boc)‐protected‐N‐substituted hydrazines has been accomplished. The use of these protected hydrazines in S_NAr substitutions leads to products in which the most nucleophilic nitrogen displaces the leaving group. Treatment of these compounds with trifluoroacetic acid readily removes the Boc‐protecting group and the intermediates readily undergo cyclizations to yield N‐1‐substituted aza‐benzothiopyranoindazoles, anthrapyrazoles and aza‐anthrapyrazoles. Side chain buildup was employed in the synthesis of several aza‐anthrapyrazoles.     

Utilization of 2-substituted 3, 1-benzoxazin-4-ones in synthesis of some quinazoline annulated derivatives

Abstract

In this study, a new series of quinazoline and their annulated derivatives have been synthesized. A number of quiazolinone derivatives substituted at position-3 were prepared from 3, 1-benzoxazinone by the treatment of 3,1-benzoxazinone with different nitrogen nucleophiles such as, hydrazine hydrate, phenylhydrazine, ethanolamine, and cyano acetohydrazide afforded the quinazolinone derivatives 7–11. The reaction of hydrazide derivative 5 with aromatic aldehydes gave the Schiff’s bases derivative 16a–c. Some of the synthesized compounds were tested against the breast cancer cell line (MCF-7). The structures of all the newly synthesized compounds were established based on IR, ¹H, ¹³C NMR, mass spectral data, and elemental analyses.     

New class of diethyl substituted phosphoramidimidates and phosphonimidates: synthesis,spectral characterization and antimicrobial activity

Abstract

A series of new class of diethyl N-2-hydroxyethyl-N'-substituted phosphoramidimidates 6(a–e) and diethyl P-morpholino-N-substituted phosphonimidates 6(f–j) was synthesized. The precursor intermediates, diethyl substituted phosphoramidites 3(a–b) were prepared initially by a reaction of various amines 1(a–b) and diethyl phosphorochloridite (2) and then they were treated by in situ with aromatic/alkyl azides through Staudinger reaction to accomplish title products. Structures of all the synthesized compounds were characterized by spectroscopic data such as IR, NMR (¹H, 13C, ³¹P), mass, and elemental analyses. The synthesized compounds were screened for their in vitro antimicrobial activity to understand their biological potency. The biological screening results disclosed that compounds 6b, 6c, 6e, 6g, 6h and 6j having potent antimicrobial activity against all the tested pathogens.     

Synthesis and antitumor activity evaluation of some N-heterocycles derived from pyrazolyl-substituted 2(3H)-furanone

Pyrazolyl-substituted 2(3H)-furanone was allowed to react with different nitrogen nucleophiles such as hydrazine hydrate, ethylenediamine, ethanolamine, and anthranilic acid to give pyrrolone and benzoxazinone derivatives. The acid hydrazide 3 was reacted with some carbonyl compounds such as 4-chlorobenzaldehyde, chloroacetyl chloride, and acetic anhydride to give thiazolidinone, oxadiazole, and pyridazinone derivatives. Selected examples of the synthesized compounds were evaluated as anticancer agents against three types of carcinoma cell lines (HePG 2, HCT116, and PC3), using Doxorubicin as a reference drug. The result revealed that some of the new compounds showed high activities. Compound 6a was more potent than the standard drug. A docking study using MOE 2008.10 program was performed.     

Synthesis and antitumor evaluation of novel tetrahydrobenzo[4′,5′]thieno[3′,2′:5,6]pyrimido[1,2-b]isoquinoline derivatives

In the present study, a novel 8,9,10,11-tetrahydro-7H,14H-benzo[4′,5′] thieno[2′,3′:4,5]-1,3-oxazino[3,2-b]isoquinoline-7,14-dione 5 was prepared by condensation of 2-amino-3-carbethoxy-4,5,6,7-tetrahydrobenzothiophene with homophthalic anhydride under microwave irradiation, followed by alkaline hydrolysis and cyclization using acetyl chloride. Compound 5 was further allowed to react with different nitrogen nucleophiles to get new tetrahydrobenzothienopyrimido isoquinolinone derivatives. The structures of the prepared compounds were elucidated by IR, ¹H-NMR, ¹³C-NMR, and mass spectroscopy. The newly prepared compounds were tested in vitro against a panel of two human tumor cell lines, namely, hepatocellular carcinoma (liver) HepG2, and mammary gland breast MCF-7. Almost all the tested compounds showed satisfactory activity.     

Heterocyclic compounds from 4h‐3,1‐benzoxazin‐4‐one derivatives as anticancer agent

Behaviour of 2‐(4‐oxo‐4H‐benzo[d][l,3]oxazin‐2‐yl)‐benzoic acid (1) towards nitrogen nucleophiles namely, hydrazine hydrate, in different solvents, ammonium acetate, and o‐phenylenediamine has been investigated to give aminoquinazolin‐4‐one, benzotriazepinone, spiro‐type compound, and nitrogen bridgehead compounds 3‐5 , respectively. Also, reactivity of the aminoquinazolin‐4‐one 2 towards carbon elec‐trophiles such as ethyl acetoacetate, ethyl phenylacetate, ethyl chloroacetate, and aromatic aldehydes has been discussed. Reaction of Schiff s base 8 with sulfur nucleophiles namely o‐aminothiophenol and/or thio‐glycolic acid afforded Michael type adducts. Structural assignments, of products 1‐24 have been confirmed by elemental analysis and spectral data (¹H‐ and ¹³C ‐NMR and MS fragmentation). The bioassay indicates that some of the target compounds obtained have good selective anticancer activity.