Theses supervised by Prof. Dr. Yaşar Dürüst
17 theses · Bolu Abant İzzet Baysal University, Akdeniz University
Synthesis of various cyclic azomethine imines, nitrones and the investigation of their 1,3-dipolar addition reactions
1,3-Dipolar cycloaddition reactions can be regarded as one of the versatile method for the synthesis of five membered heterocycles. Pyrazolidinone and isoxazolidine containing heterocycles have been comprehensively studied for a long time since they are found in the structure of naturally occuring products and bioactive compounds. Also, it is known that isoxazoles constitute a useful heterocyclic ring system in preparing new biologically active molecules. In order to reach these heterocycles, in this PhD dissertation, various dipolarophiles have been utilized in the cycloaddition reaction of both azomethine imines and nitrones. The outcomes of present study were divided into four parts; In the first part, N,N-cyclic azomethine imines were prepared according to the literature method and characterized. Then, they were subjected to undergo cycloaddition reaction with benzothiophene 1,1-dioxide to give benzothiophenedioxide fused pyrazolidinones. Secondly, we investigated 1,3-dipolar cycloaddition of both phenylsulfonylacrylonitriles and (E)-3-(2-hydroxyphenyl)-2-(phenylsulfonyl)acrylonitrile with N,N-cyclic azomethine imines. These attempted 1,3-DC reactions unexpectedly gave same cycloaddition products regioselectively. In the third part, we aimed to synthesize aldehydes bearing isoxazole unit to furnish the precursors of new N,N-cyclic azomethine imines. Then, N,N-azomethine imines were synthesized by the use of newly prepared aldehydes and characterized. Followed their cycloaddition reaction were investigated under microwave irradiation by using some electron poor or rich dipolarophiles, namely, dimethylacetylenedicarboxylate, phenylvinyl sulfone and N-vinylimidazole. Lastly, new nitrones were prepared by utilizing isoxazole containing aldehydes and characterized, followed by their 1,3-dipolar cycloaddition reactions were carried out with phenyl vinyl sulfone and N-vinylimidazole to yield both isoxazole and isoxazolidine containing cycloaddition products.
Hammett correlations of iminic protons and carbons of some chromenone Schiff's bases
The aim of this work is to carry out DFT calculations on some selected chromenone (benzopyranone) Schiff bases which are substituted on the imine nitro-gen by a para substituted phenyl ring or other aromatic groups like 2-thienyl, thiazo-le, oxazole, pyrrole etc.. This ring will bear both electron withdrawing such as NO2, CN, SO3H, COOR, and electron releasing groups such as methyl, OH, OCH3, NMe2 . A density functional theory (DFT) calculations related to optimization energy, NMR chemical shifts of imine hydrogen, hydrogen attached to the number 2 carbon in chromenone pyran ring and carbon chemical shifts of the iminic carbon and num-ber 2 carbon of chromene ring are also carried out. Throughout this research work, various Hammett correlations between che-mical shift values calculated by using Gaussian 03 software and web-based prog-rams like NMR DB and Avogadro and Hammett substituent constants have been established and interpreted.
Synthesis and structural identification of some new benzothiadiazine-related derivatives
The aim of this work is to synthesize some new 4H-1,2,4-benzothiadiazine 1,1-dioxide derivatives with a new aproach and identify their structures by means of spectral and physical data. This research work has been constructed primarily based on the synthesis of some 3-aryl-4H-1,2,4-benzothiadiazine-1,1-dioxide derivatives and then determina-tion of their structures. Novelty of the chemistry can be described as follows; ben-zothiadiazine 1,1-dioxide derivatives exhibit various important biological activities and some of them are currently being used as medicines containing benzothiadiazi-ne 1,1-dioxide skeleton. For this reason, major purpose is to obtain these compo-unds by incorporating chloromethyl oxadiazoles by means of microwave irradiation or otherwise classical methods. The new compounds to be obtained will be elucida-ted by means of spectroscopic and physical methods. In summary, within this work, despite the difficulties encountered during the experiments, we succesfully synthesized 8 new benzothiadiazine-1,1-dioxide deri-vatives carrying 1,2,4-oxadiazolylmethyl group at 4-position of the benzothiadiazine ring. Synthesis of amidoximes and chloromethyl oxadiazoles as starting materials were carried out and their nucleophilic substitution reaction with benzothiazines dioxides were performed leading to target N-substituted products. All of these compounds are new and original and they are considered to make a remarkable contribution to the literature of synthetic organic chemistry. It is strongly possible that the compounds are potentially bioactive due to having the main skeleton and substituents. But, unfortunately, at the moment, we were not able to conduct a bioactivity screening of the compounds due to the low amounts of them and, in addition, regarding unrecoverable from DMSO-d6 NMR solutions.
Çeşitli heterohalkasal yapılar taşıyan yeni aza(tiyo) taç eterlerin sentezi ve karakterizasyonu
The coverage of this study is basically related to the synthesis various crown ethers containing nitrogen and sulfur atoms. Because many of these compounds are highly effective extractants for metal ions. Due to this feature, they found application in different areas. On the other hand, five membered heterocyclic compounds are one of the important part of 1,3-dipolar cycloaddition chemistry due to their importance in pharmaceutical chemistry, organic and bioorganic medicinal chemistry. In this regards, the biological effects and industrial uses of these macrocyclic compounds have encouraged us to synthesize macrocyclic compounds with 1,2,4-oxadiazoles and 1,2,3-triazoles which are not previously reported. The outcomes of this study were discussed in four parts; In the first part of this work, we have focused on the synthesis of the benzotriazacrown ether and then it was reacted with the 3-p-phenylsubstituted- 5-chloromethyl-1,2,4-oxadiazoles. Moreover, dibenzodiazacrown carrying 1,2,4-oxadiazole moieties were obtained. In the second part, novel benzodiazacrown ethers carrying chloro/azido methyl 1,2,4-oxadiazoles were synthesized with different stages. In addition, commercially obtained benzo-15-crown-5 was formylated according to the published literature procedure. Then, starting from this formylated crown, chloro/azido-methyl 1,2,4-oxadiazoles bearing benzocrown ethers were obtained in six different sections. In the third section, 1,3-dipolar cycloadditions of the azamacrocycles carrying acetylenic side chain with 5-azidomethyl-1,2,4-oxadiazoles were accomplished in two protocols. First part contains the synthesis of the novel azamacrocycles carrying acetylenic side chain and then these dipolarophilic novel molecules have undergone cycloaddition with the different p-phenyl substituted 5-azidomethyl 1,2,4-oxadiazoles. Finally, in addition to all parts in this thesis, a novel azathiacrown and dibenzocrown ethers carrying aldoxime and nitrile groups were obtained.
Bazı münknon türevlerinin elektonca eksik alkenlerle reaksiyonları
This thesis general describes a variety of reactions of 1,3-oxazolium-5-oxides, commonly known as Münchnones which are a special class of azomethine ylides with electron-deficient dipolarophilic reagents. In this regard, a series of pyrroles, N-benzoyl benzamides, p-substituted benzoic acids and N-acyl ureas have been obtained. These compounds are important heterocycles, widely present in natural and many pharmaceutical compounds. There are many synthetic methods to prepare pyrrole derivatives in the literature. Among them, 1,3-dipolar cycloaddition reaction of Münchnones with alkynes and alkenes are versatile. The purpose of this dissertation is to study the reactions of mesoionic Münchnone derivatives with electron deficient alkenes. The outcomes of these compounds were discussed in three parts; In the first part, the cycloaddition reaction of in situ generated Münchnones from N-acyl amino acids with benzo[b]thiophene 1,1-dioxide is described. The accompanying deoxygenation of sulfone moiety gave rise to the benzothiophene fused pyrrole derivatives. In order to rationalize the entire reaction, the transformation of sulfide into sulfone group which is the anticipated product was carried out by means of m-chloroperbenzoic acid oxidation. The second part of this work was involved in the synthesis of (E)-1-(N,4-dimethylbenzamido)-1-(4-fluorophenyl)prop-1-en-2-yl acetate, 4-aryl-N-methyl-N-(4-substitutedbenzoyl)benzamides and p-substituted benzoic acids by the reaction of in situ generated Münchnones from 2-(4-substitutedphenyl)-2-(N-methyl-N-p-substitutedbenzamido)acetic acids with acetic anhydride in the presence of 2-nitromethylene thiazolidine. A plausible Dakin-West type mechanisms for these reactions were proposed. The last part of this thesis, a novel efficient route leading to N-acyl urea derivatives was described by the reaction between Münchnone precursors with carbodiimides in the presence of a base.
Bazı sidnon türevlerinin elektronca yoksun alken ve alkinlerle 1,3-dipolar halka katılma reaksiyonları
One of the most versatile method for the construction of five membered heterocyles is 1,3-dipolar cycloaddition reactions. Sydnones, a well-defined class of mesoionic compounds that can provide an easy access to a variety of heterocyclic systems containing especially pyrazole and pyrazoline ring, They are generally found in the core structure of many drugs and alkaloids. In order to construct new pyrazole (or pyrazoline)-based heterocyles, various electron deficient dipolarophiles have been attempted in the cycloaddition reaction of sydnones throughout this Ph.D. dissertation study. The outcomes of the study were disscussed in four parts; In the first part, N-aryl sydnone derivatives as the precursor of azomethine imine were succesfully synthesized according to reliable literature method and characterized. Then, reactivity of acetylenic dipolarophile, 1-(prop-2-ynyl)-1H-indole, with N-aryl sydnones was investigated and reaction proceeded to give cycloadducts with lack of regioselectivity that is resulted from the nature of electon-withdrawing or donating substituents on the aromatic ring of sydnone. The second section covers the synthesis of new cyclopropyl-(1-substituted phenyl)-(1H-pyrazol-3-yl)methanols as the result of the complete regioselective cycloaddition reaction of acetylenic alcohol, namely 1-cyclopropylprop-2-yn-1-ol with N-aryl sydnone derivatives. The third part of this study involves the synthesis of new fused tricyclic cycloadducts bearing pyrazoline ring, namely, 2-(4-substituted phenyl)-3,3a-dihydro-2H-[1]benzothieno[3,2-c]pyrazole 4,4-dioxides via reaction of benzo[b]thiophene 1,1-dioxide with N-aryl sydnones in moderate yields. The synthesis of corresponding cycloadducts took place in completely regioselective manner. In the last part of the present work, treatment of secondary heterocyclic enamine, 2-nitromethylenethiazolidine, with N-aryl sydnones gave rise to unusual decomposition of sydnone ring by the possible release of acetolactone in intermediate step and underwent diazocoupling reaction instead of 1,3-dipolar cycloaddition. To the best of our knowledge, there is no reported study comprising such kind of decomposition of sydnones leading diazocoupling products.
Bazı yeni benzensulfonil substitue izoksazolidin bileşiklerinin sentezi ve kütle spekrumlarının incelenmesi
ABSTRACT SYNTHESIS AND MASS SPECTROMETRY OF SOME NEW BENZENESULFONYL SUBSTITUTED ISOXAZOLIDINES ALTU?, Cevher M.Sc., Department of Chemistry Supervisor : Prof. Dr. Yaşar DÜRÜST December 2004, 119 pages In this work, the 1,3-dipolar cycloaddition (1,3 DC) reactions of some nitrones including a new one to the dipolarophile phenylvinyl sulfone are described. To our best knowledge of literature survey, nine new isoxazolidine compounds have been synthesized. Purification of the title compounds have been performed by means of flash column chromatography on silica gel.Also much attention was focused on the fragmentation ways of the cycloadducts, namely benzenesulfonyl substituted isoxazolidines, in electron impact mass spectrometry and the routes leading to described fragmentations were interpreted in terms of stability and substituents existing on the isoxazolidine ring. The structures of benzenesulfonyl substituted isoxazolidines were elucidated by means of İR, NMR (1H, 13C), MASS spectra and physical 111characteristics (melting points and Rf values). The stereochemistry of the isoxazolidine ring was determined by n.O.e experiments and was found to be trans configuration according to the groups on C-3 and C-4 carbons. Regiochemistry is also determined as to have been formed only 4- regioisomers but not 5-regioisomers based on the J coupling constants in 1H- NMR and n.O.e data. Keywords: 1,3-Dipolar cycloaddition, nitrones, isoxazolidine. IV
Nitril oksitlerin 1,3-dipolar halka katılma tepkimeleri ile yeni azaheterohalkaların sentezi
1,3-Dipolar cycloaddition reactions are among the most powerful and direct approaches for the synthesis of five membered organic molecules. During the past several decades, nitrile oxides are becoming increasingly important in providing intermediates for the synthesis of complex molecules, including natural products and bioactive compounds. Syntheses of novel azaheterocycles are the focus of this dissertation through 1,3-dipolar cycloaddition of nitrile oxides. The results and discussion sections of this thesis are divided into four parts:Part 1 describes an efficient intermolecular 1,3-dipolar cycloaddition of a variety of nitrolic acids which are precursors of nitrile oxides with phenyl- and methyl vinylsulfone. This transformation produces stable 4,5-dihydroisoxazole-containing stereo- and regioselective cycloadducts.Part 2 is mainly consisted of the investigation of a novel tricyclic oxadiazol-tetrahydropyrrolo-oxadiazole structure via a reaction of alkylidene-2-pyrrolidines with nitrolic acids. A plausible mechanism for this reaction is proposed, which suggests nitrosation of the enamine by the nitrous acid that is liberated from the nitrolic acid......
Amidoksimlerin n-sübstitüye tiyoüre bileşikleriyle halka kapanması reaksiyonları
The major aim of this work is to try the cyclo condensation reactions ofamidoximes and N-substituted thioureas under the effect of catalysts. For thispurpose, first amidoximes were synthesized according to the literatureprocedures. The amidoximes were then reacted with N-substituted thioureas togive triazole-thione compounds. When KF/Al2O3 catalyst system was used inDMF medium a different and new type of heterocyclic ring; oxatriazine wasobtained.Another section of the work involved in the synthesis of some new SRderivatives of mercaptothiadiazole compounds. RX type compounds, some ofwhich were synthesized in this work were used to react withmercaptothiadiazole compounds. In addition, one sample reaction was carriedout to obtain an organosulfur-mercury compound by the action of mercury (II)chloride with mercaptothiadiazole compound.All of the compounds newly synthesized were identified by means of spectralmeasurements (IR,NMR,MS) and physical constants (e.g. melting points, Rfvalues) and in this regard, this work is an important contribution to the syntheticorganic chemistry.Keywords:Amidoxime,thiourea,triazole-thione,mercaptothiadiazole,oxatriazine, spectroscopy,chromatography
Beş ve altı üyeli oksijen, azot, ve fosfor içeren hetero halkalı bileşiklerin sentezi
The aim of this work is the synthesis of 2,4-disubstituted-2,3-dihydro-1,3,5,2-oxadiazaphosphole-2-oxides and 2,3-disubstituted-1,3,2-oxazaphospholidine-2-oxide , its thionated analog, heterocycles by the ring closure reactions of mono amidoximes with phenylphosphonyldichloride. Heterocyclic systems that include a phosphorus linked to an oxygen and nitrogen atom have been reported to have anti-tumor alkylating, anti-hypertensive , biocatalysts, catalyse the enantioselectiveaminolysis of lactones activities. For this purpose, first, amidoximes as starting compounds were synthesized according to the literature procedures. The amidoximes were then reacted with phenylphosphonyldichloride to give 2,4-disubstituted-2,3-dihydro-1,3,5,2-oxadiazaphosphole-2-oxide heterocycles and 2-anilinoethanol to give 2,3-disubstituted-1,3,2-oxazaphospholidine-2-oxide.All of the compounds newly synthesized were identified by means of spectral measurements (IR, NMR, MS) and physical constants (e.g. melting points, Rf values) and in this regard, this work is an important contribution to the synthetic organic chemistry.
Fenantrolinyum n-ilidlerin 1,3-dıpolar halka katılma tepkimelerinin incelenmesi
In this study, 1,3-dipolar cycloadditions reactions of (Z) substituted arylidene oxazolones to phenanthrolinium N-ylides were carried out for the first time. In the first stage of the work a number of substituted arylidene oxazolones as dipolarophilic structures were prepared according to the literature procedures. Some of them are novel compounds and not reported previously. Both electron-withdrawing and electron-releasing groups were selected on the starting arylidene oxazolones. In the second part, the 1,3-dipolar cycloaddition reaction of phenanthrolinium ylides prepared from phenanthroline and phenacyl bromide with (Z)-substituted arylidene oxazolones afforded novel aryl substituted spiro[oxazole-4,10?-pyrrolo[1,2-a][1,10]phenanthrolin]-5-ones, regioselectively. Totally, 15 novel aryl substituted spiro oxazolo [1,10] phenanthrolines including three chiral centers were obtained. The structures and stereochemical configurations of new aryl substituted spiro oxazolo [1,10] phenanthroline were elucidated by means of IR, NMR, 2D NMR, MASS, single crystal X-Ray Diffraction spectra and physical characteristics (melting points and Rf values).
1,2,4-oksadiazol halkası içeren bazı yeni azidlerin sentezi ve halka katılma tepkimeleri
In this work, in the first step, we aimed to obtain a number of 5-chloromethyl 1,2,4-oxadiazoles starting from p-substituted aromatic monoamidoximes. Then, 5-azidomethyl 3-aryl substituted 1,2,4-oxadiazoles were easily prepared from the reaction of chloromethyl 1,2,4-oxadiazoles and sodium azide in DMSO. To our best knowledge of literature survey, both a great number of chloromethyl oxadiazoles and all the azidomethyl oxadiazoles are novel heterocyclic compounds not known yet. As the major part of this work, 1,3-dipolar cycloaddition reactions of these novel 3-aryl substituted 5-azidomethyl 1,2,4-oxadiazoles with the dipolarophiles like N-phenyl maleimide, phenyl vinyl sulfone and some bicylic olefinic dipolarophiles which were easily synthesized from furan-maleic anhydride and furan-N-phenyl maleimide reactions were performed to afford bicylic and tricyclic cycloaddition products which might be expected to exhibit biological activity. These cycloadducts are the members of substituted 1,6-dihydropyrrolo-[1,2,3] triazoles, substituted-4-phenylsulfonyl-4,5-dihydro-[1,2,3] triazoles and 8,8a-hexahydro-4,8-epoxyfuro-[1,2,3] triazoles. The structures of all the cycloadducts were elucidated by means of IR, NMR (1H, 13C), MASS spectra and physical characteristics (melting points and Rf values).
Nitriliminlerin çeşitli dipolarsevenlerle 1,3-dipolar halka katılmalarından potansiyel biyoaktif heterohalkalı bileşiklerin sentezi
1,3-Dipolar cycloadditive methodology occupies a prominent place due to its versatility in the construction of complex heterocylic systems. Pyrazole and pyrazoline containing heterocycles have been intensively synthesized for many years by the nitrilimine cycloaddition reactions with dipolarophilic compounds since the pyrazole or pyrazoline rings are the core structure of many natural products and drugs. For this reason, this Ph.D. dissertation study comprises the synthesis of potential bioactive pyrazoline derivatives by means of nitrilimine cyloaddition reactions. The outcomes of nitrilimine cyloaddition reactions were discussed in five parts;In the first part, as the precursors of nitrilimines, wide range of aryl aldehyde hydrazones and hydrazonyl chlorides were efficiently prepared according to the modified literature methods and characterized.The second part of the work was involved in the synthesis of novel biscycloadducts, namely, aryl substituted dihydro bispyrrolo[3,4-c]pyrazole-4,6-diones, by the reaction of C,N-diarylnitrilimines with bismaleimide derivatives in excellent yields. It should be noted herein that the reaction was absolutely stereoselective and no other regioisomeric product was observed.In the third part, the effect of the substituent groups on para positions of phenyl ring attached to azomethine carbon of biscycloadducts to the absorption maxima values of UV-VIS spectra was investigated by measuring their ultraviolet absorption spectra and by the correlating them with Hammett sigma para constants. Some significant correlation results have been obtained.Fourth part covers the synthesis of novel dihydropyrrolo[3,4-c] pyrazole-4,5-diones by nitrilimine cycloaddition reactions with chiral (R)-N-(1-phenylethyl)maleimide. Regiocontrolled cycloaddition reactions gave rise to formation of either single regioisomer or mixture of regioisomers in some cases.Last part of the thesis was devoted to the investigation of reactivity of nitrilimines with 2-methyl-2-vinyloxirane since there is no reported cycloaddition reaction of nitrilimines to the alkenes bearing epoxide moiety as far as we searched the literature. The reaction took place in regioselective manner and the formation of two diastereomers resulted in each reaction which differs only by the rotation of single bond between oxirane and pyrazoline ring, thus, novel 2-methyl-2-oxiranyl substituted dihydropyrazoles were obtained in low diastereoselectivity.
Yeni potansiyel biyoaktif N-substitue (1,2,4-oksadiazol-İl metil), 1,2,4-oksadiazol-5(4H)-on ve 1,2,3,5-oksatiyadiazol-2-oksitlerin sentezi
This research study presents a simple and practical synthesis of N-substituted oxadizolones with respect to a variety of 5-chloromethyl-1,2,4-oxadiazoles. In order to achieve this synthetic sequence, first we prepared arylsubstituted 1,2,4,-oxadiazol-5-ones(or thiones) and 1,2,3,5-oxathiadiazol-2-oxides starting from the substituted aromatic amidoximes using CDI, TCDI, and SOCl2. To our best knowledge of literature survey, some of 1,2,4-oxadiazol-5-ones(or thiones) and all of the 1,2,3,5-oxathiadiazol-2-oxides are novel heterocyclic compounds and not known yet. As the major part of this work, we have been focused to obtain N-(1,2,4-oxadiazolylmethyl)-3-substituted phenyl- [1,2,4]-oxadiazol-5(4H)-ones (and thiones) starting from monosubstituted [1,2,4]-Oxadiazol-5(4H)-ones (and thiones) and 5-chloromethyl-1,2,4-oxadiazoles using K2CO3 in the reaction medium of DMF. The structures of all end products were elucidated by means of IR, NMR (1H,13C), LC-MS spectra and single crystal X-Ray Diffraction, and physical data (melting points and Rf values). Since the title compounds carry both oxadiazole and oxadiazolone, oxathiadiazole-S-oxide moieties we strongly believe that these compounds would show some remarkable bioactivities against various bacteria species and tumor cells. Therefore, we are getting prepared to examine these activities in collaboration with well-equipped international laboratories in the near future.
Yeni potansiyel biyoaktif 3-(3-sübstitüe fenil-1,2,4-oksadiazolil-5-metil)-1-imidazolidin-2,4-dionların ve 5-nitro-2-((3-sübstitüe fenil-1,2,4-oksadiazol-5-il)-1H-benzo[d]imidazollerin sentezi
This work is aimed to assemble of novel 3-(3-substituted phenyl-1,2,4-oxadiazolyl-5-methyl)-1-imidazolidine-2,4-diones (hydantoins) and, 5-nitro-2-((3-substituted-phenyl-1,2,4-oxadiazol-5-yl)methylthio)-1H- benzo[d]imidazoles. In order to achieve this, firstly, p-substituted aromatic monoamidoximes used for the synthesis of 3,5-disubstituted-1,2,4-oxadiazoles were synthesized from p-substituted benzonitriles. Then these amidoximes were used in order to prepare 5-(chloromethyl)-3-aryl-1,2,4-oxadiazoles. These chloromethyl oxadiazoles were easily reacted with heterocycles having N-H or S-H groups such as 1-methyl hydantoin and 5-nitro-2-mercaptobenzimidazole when bases such as potassium carbonate and NaOH, respectively, were used for removing protons on nitrogen and sulfur atoms. The reaction products of 5-(chloromethyl)-3-aryl-1,2,4-oxadiazoles with 1-methylhydantoin are N-substituted products; and with 5-nitro-2-mercaptoimidazole, S-substitution products were obtained and structurally determined by physical (melting points, Rf values) and spectroscopic data, namely, IR, NMR (1H-NMR and 13C-NMR) and LC-MS spectra. In addition, X-Ray diffraction data was used to resolve full structure. Since all of these novel compounds carry potent biactive groups like oxadiazole, hydantoin and sulfanyl-nitro-benzimidazole, we are planning to examine their bioactivity assays in collaboration with well-equipped international laboratories in the near future.
Yeni uracil ve o-benzosülfimid esaslı potansiyel biyoaktif heterohalkaların sentezi
The aim of this work is to synthesize a variety of N-(5-methyl-1,2,4-oxadiazolyl) substituted o-benzosulfimide, N,N?-(5-methyl-1,2,4-oxadiazolyl) disubstituted uracil, N,N?-(5-methyl-1,2,4-oxadiazolyl)disubstituted 5-amino uracil, and N,N?-(5-methyl-1,2,4-oxadiazolyl) disubstituted benzylidene pyrimidinedione. 1,2,4-Oxadiazole related scaffolds have been used for decades in composing a variety of heterocylic compounds with a remarkable potency of bioactivity. In order to perform this, firstly we have prepared, 5- chloromethyl 1,2,4-oxadiazoles from the p-substituted benzamidoximes, which were easily synthesized from the p-substituted benzonitriles. To our best knowledge of literature, N- oxadiazolylmethyl substituted O-benzosulfimide, N-oxadiazolylmethyl substituted uracil, N-oxadiazolylmethyl substituted 5-amino uracils, and N ?oxadiazolylmethyl substituted pyrimidines have not been reported so far. 5-Chloromethyl-1,2,4-oxadiazoles were reacted with the above mentioned benzosulfimide, uracil which have N-H, by using K2CO3 in DMF. These structures of all end products were elucidated by means of IR, NMR (1H, 13C), LC-MS spectra and physical data (melting points and Rf values). Since all of these novel compounds carry potent groups like oxadiazole, bioactivity assessment of these heterocyles are underway in due course.
1,2,4-oksadiazolilmetil grubu taşıyan bazı yeni sidnonların sentezi ve halkalı katılma tepkimeleri
In this work, the synthesis of 5-(chloromethyl)-1,2,4-oxadiazole substituted sydnones is firstly described. Then, 5-(azidomethyl)-1,2,4-oxadiazole substituted sydnones were easily synthesized from the reaction between 5-(chloromethyl)-1,2,4-oxadiazole substituted sydnones and sodium azide in acetone/water. To best our knowledge of literature, both 5-(chloromethyl)-1,2,4-oxadiazole and 5-(azidomethyl)-1,2,4-oxadiazole substituted sydnones are novel heterocyclic compounds not known yet. Also, the 1,3-dipolar cycloaddition reactions of these 5-(azidomethyl)-1,2,4-oxadiazole substituted sydnones with dipolarophiles such as N-phenylmaleimide, phenyl vinyl sulfone and phenyl propiolic acid were performed to afford products which might be expected to exhibit biological acitivity. The structures of these novel products were elucidated by means of IR, NMR (1H, 13C), Mass spectra, X-ray diffraction spectra and physical characteristics (melting points and Rf values).