The Synthesis and Reactions of N-Hydroxy-3-Arylsydnone-4-Carboxamide Oximes

N-Hydroxy-3-arylsydnone-4-carboxamide oximes (7) were prepared from the corresponding 3-arylsydnone-4-carbohydroximic acid chlorides (6) and hydroxylamine in high yield. The chemical reactivity of compound (2) is somewhat different from 3-arylsydnone-4-carboxamide oximes (2) in that the former compounds reacted with both aromatic and aliphatic aldehydes in the presence of acid catalyst to give 3-aryl-4-(5-aryl-1,2,4-oxadiazol-3-yl)sydnones (5) and 3-aryl-4-(5-alkyl-1,2,4-oxadiazol-3-yl)sydnones (3).     

Reactions of 4-Aryl-1,2,4-triazolidine-3,5-dithione with Some Electrophilic Reagents

Reaction of 4-aryl-1,2,4-triazolidine-3,5-dithiones in an alkaline medium with chloroacetic acid and its derivatives, as well as with -bromo ketones, results in their conversion to 4-aryl-1,2,4-triazole-3,5-bis(sulfides). The aminomethylation in a neutral medium leads to the formation of 1-(aminomethyl)-4-aryl-1,2,4-triazolidine-3,5-dithiones.     

The Reaction of 4-Formylsydnone and Methyl Ketones

In the presence of base, 3-subslituted 4-fonnyl- and 4-acetylsydnones decarbonylated to afford the corresponding 3-substituted sydnones. The Claisen-Schmidt reaction occurred between 3-substituted 4-for-mylsydnones and methyl ketone (such as 4-acetylsydnones, acetone and acetophenone) in dilute basic solution or electrogenerated basic (EGB) solution.     

Reactions of 3-(4-Aryl-2-thiazolyl)- and 3-(2-Benzothiazolyl)-2-iminocoumarins with N-Nucleophiles

The reaction of 3-(4-aryl-2-thiazolyl)- and 3-(2-benzothiazolyl)-2-iminocoumarins with N-nucleophiles was studied. This reaction gives 2-N-substituted 3-(4-aryl-2-thiazolyl)- and 3-(2-benzothiazolyl)iminocourmarins. N-Nucleophiles such as arylamines, heterocyclic amines, and hydrazine derivatives undergo this reaction.     

Preparation of 3-Aryl-4-(5-ARYL-Δ2-1,2,4-Oxadiazolin-3-YL)Sydnones and their Conversion into 3-ARYL-4-(5-ARYL-1,2,4-Oxadiazol-3-YL)Sydnones

3-Aryl-4-(5-aryl-Δ²-1,2,4-oxadiazolin-3-yl)sydnones (5) were synthesized in high yields by the reaction of 3-arylsydnone-4-carboxamide oximes (prepared from the corresponding 3-arylsydnone-4-carbonitriles) with aromatic aldehydes in the presence of acid catalysts. No reaction occurred when aliphatic aldehydes were used. The oxadiazolin-3-ylsydnones (5) were easily converted into the corresponding 3-aryl-4-(5-aryl-1,2,4-oxadiazol-3-yl)sydnones by N-bromosuccinimide oxidation. The 3-arylsydnone-4-carbonitrile oxides were synthesized in good yields by N-bromosuccinimide oxidation of the corresponding 3-arylsydnone-4-carboxaldehyde oximes.     

3-Substituted Sydnone Derivatives. Structures of 3-Cyclohexylsydnone and of Two Forms of 3-(3-Pyridyl)sydnone

The crystal and molecular structures of three sydnone derivatives are reported. The compound 3-cyclohexylsydnone crystallizes in space group C2/c of the monoclinic system with sixteen molecules in a cell of dimensions a = 19.326 (3), b = 9.471 (2), c = 20.005 (4)Å, β = 106.85(1)°. The structure has been refined to a final value of 0.0581 for the conventional R-factor based on 2222 independent observed intensities. Form I of 3-(3-pyridyl)sydnone crystallizes in space group P2/n of the monoclinic system with eight molecules in a cell of dimensions a = 7.317(2), b = 9.283 (2), c = 20.891 (6) Å, β = 99.61(2)°. The structure has been refined to a final value of 0.0514 for the conventional R-factor based on 1208 independent observed intensities. Form II of 3-(3-pyridyl)sydnone crystallizes in space group P2₁/c of the monoclinic system with eight molecules in a cell of dimensions a=9.073 (2), b = 22.267 (5). c = 7.494(2)Å, β = 112.15 (2)°. The structure has been refined to a final value of 0.0462 for the conventional R-factor based on 1330 independent observed intensities. Each of the three structures contains two crystallographically independent molecules in the cell. In the case of 3-cyclohexylsydnone, one of the independent molecules exhibits disorder around the exocyclic bond at N(3). A comparison of bond lengths indicates that the (electron donating) cyclohexyl group brings about enhanced electron density in the N(3)-C(4) bond, and possibly in the N(3)-N(2) bond. All three structures studied here exhibit intermolecular hydrogen bonding involving C(4)-H(4)…O(6) interactions. Although there are no stacking interactions in the cyclohexyl derivative, there is evidence for such interactions in the 3-pyridyl derivatives.     

The Reaction of 4-Formylsydnone with Nitroalkanes

Under various basic solutions and reaction durations, 3-substituted 4-formyIsydnones and nitroalkanes containing α-active hydrogen (e.g. nitromethane and nitroethane) are converted to β-nitroalcohols, nitroalkenes and dinitroalkanes. β-Nitroalcohols are obtained only by electrochemical reaction on an electrogenerated base (EGB). The mechanism of overall reaction steps in particular is discussed.     

Studies on the Preparation and Biological Activities of 3-(O-Methoxybenzyl)Sydnone Derivatives and 3-(Fluorophenyl)Sydnones

Two new sydnones; 3-(o-methoxybenzyl)sydnone(1) and 3-(o-melhoxybenzyl)-4-morpholinomethylsydnone(2) were synthesized from o-methoxybenzylamine and ethyl bromoacetat in moderate yields. 3-(o-,m-,p-Fluorophenyl)sydnones were prepared from the corresponding fluoroaniline and chloroacetic acid in higher yields with a conventional method. From the biological activity test, 1 shows significant response of coronary dilation test, collagen induced platelet aggregation inhibition, local anesthetic and moderate cardiotropic activity. In addition, 1 also leads to anticonvuls, muscle relaxation and behavior depression. But 2 only shows inhibition of collagen induced platelet aggregation and antiwrithing. 3-(p-Fluorophenyl)sydnone (5) shows significant response of coronary dilation, collagen induced platelet aggregation inhibition, moderate cardiotropic activity, antiwrithing and local anesthetic But 3-(o-Fluorophenyl)sydnone(3) and 3-(m-fluorophenyl)sydnone(4) only show coronary dilation and moderate cardiotropic activity.     

Sydnone Compounds. XX. The Synthesis and the Schmidt Reaction of 4-Formyl-3-Arylsydnone

A convenient method to prepare 4-formyl-3-arylsydone (I) from 3-arylsydnone by the Vilsmeier reaction in moderate yields (30%-76%) was carefully investigated. According to the Schmidt reaction, I reacts with sodium azide in concentrated sulfuric acid to produce 3-arylsydnone-4-carboxamide (II). But 3-arylsydnone-4-carhonitrile (III) is obtained, if dilute sulfuric acid was used instead. When III treates with concentrated sulfuric acid, II is obtained in good yield. The all possible reaction mechanisms are suggested.     

Carbon-13 NMR Studies of 3-Aryl-4-(5-aryl-Δ 2-1,2,4-oxadiazolin-3-yl)sydnones and 3-Aryl-4-(5-aryl-1,2,4-oxadiazol-3-yl)sydnones

The ¹³C NMR spectra of twelve 3-aryl-4-(5-aryl-Δ²-l,2,4-oxadiazolin-3-yl)sydnones and twelve 3-aryl-4-(5-aryl-l,2,4-oxadiazol-3-yl)sydnones have been measured and assigned by means of proton-noise decoupling and DEPT-experiments. The coupling constants were determined by means of gated decoupling, and NOE effects were observed by comparison of proton-decoupled and inverse-gated decoupled spectra. Differences shown by the oxadiazoline and the oxadiazole rings and the substitution effects are discussed.     

Coupling and Cyclization of Sydnone Compounds

Cyclization were occurred via the coupling reactions of some mercuric chloride derivatives of sydnone with LiPdCl₃-CuCl₂. A unique six-membered ring, 3,3′-ethylene-4,4′-bissydnone, was obtained by the cyclization reation of 1,2-di[3-(4-chloromercuric)sydnonyl]ethane. However, the seven-membered 3,3′-trimethylene-4,4′-bissydnone and 1,3-di[3-(4-chloro)sydnonyl]-propane were obtained from the corresponding mercuric chlroide of sydnone. Onyl substitution reaction took place when 4,4′-di[3-(4-chloromercuric)sydnonyl]biphenyl, 4,4′-di[3-(4-chloromercuric)sydnonyl]benzene, di(p-[3-(4-chloromercuric)sydnonyl]-phenyl}methane and, di(p-[3-(4-chloromercuric)sydnonyl]phenyl]ether were treated using the same process.     

The 1,3-Dipolar Cycloadditions of 3-Arylsydnone-4-Carbonitrile Oxides with Nitriles

3-Arylsydnone-4-carbonitrile oxides (2), which are generated in situ by thermal dehydrochlorination of the corresponding hydroximic acid chlorides (1), undergo 1,3-dipolar cycloadditions with sydnone-4-carbonitriles (6) to give 3-aryl-4-[5-(3-arylsydnonyl)-1,2, 4-oxadiazol-3-yl] sydnones (9). These nitrile oxides (2) also react with alkyl- and arylnitriles to give 1,3-dipolar cycloaddition products.     

Preparation of 3-(3′-,4′-Hydroxyphenyl)sydnones

3-(3′-,4′-Hydroxyphenyl)sydnones were prepared by dealkylation of 3-(3′-,4′-alkoxyphenyl)sydnones with concentrated sulfuric acid at room temperature in a range of 59 to 86% yield.     

2-芳基-4-氧-4 H-吡喃酮[3,2-c]-9-溴喹啉类化合物的合成

黄酮类化合物广泛存在于埴物体中,具有广泛的生物活性,其研究发展很快,但对于氮杂黄酮类化合物的研究工作却甚少。含氮黄酮类化合物具有抗癌、抗菌、冠状动脉扩张等作用。但是,目前黄酮类药物仍存在以下问题:(1)黄酮类化合物结构繁多,生物活性极其广泛,但作用强度普遍较弱;(2)黄酮类化合物水溶性较低,影响药物的吸收与疗效。新型黄酮类化合物的合成仍有一定的意义。     

2-芳基-5-(5-苯基-2H-四唑-2-亚甲基)-1,3,4-噁二唑类化合物的研究

作者曾研究2-芳基-5-(2-苯基-4-喹啉基)-1,3,4-噁二唑类衍生物,并发现它们具有促进小麦发芽生长的功效。Juby和Shan等报道某些四唑类化合物具有消炎性     

3-Aryl- and 2,3-Diaryl-4-oxo-4,5,6,7-tetrahydroindazoles. 1. Reactions of Phenyl- and Tosylhydrazones of Dimedone and Cyclohexane-1,3-dione with Substituted Benzaldehydes

Sixteen 3-aryl-4-oxo-2-phenyl-4,5,6,7-tetrahydroindazoles were obtained from the reaction of the phenylhydrazones of dimedone and cyclohexane-1,3-dione with 3-bromo-, 4-bromo-, 4-chloro-, 4-fluoro-, 2-hydroxy-, 4-hydroxy-, 4-methoxy-, 2-nitro-, 3-nitro-, 4-nitro-, and 4-dimethylamino-benzaldehydes. The interaction of the tosylhydrazones of dimedone and cyclohexane-1,3-dione with the substituted benzaldehydes gave thirteen 3-aryl-4-oxo-4,5,6,7-tetrahydroindazoles. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1662–1668, November 2005.     

Condensation products of 1-aryl-4-hydrazinocarbonyl-2-pyrrolidinones with diketones

The reactions of 1-aryl-4-hydrazinocarbonyl-2-pyrrolidinones with 2,4-pentanedione and 2,5-hexanedione have been studied. It was found that heating the hydrazinocarbonyl compounds with 2,4-pentanedione gave 3,5-dimethylpyrazole compounds and with 2,5-hexanedione gave 1-substituted 2,5-dimethylpyrroles. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 229–232, February, 2008.     

The 1,3-Dipolar Cycloadditions of 3-Arylsydnone-4-Carbonitrile Oxides with Alkenes

3-Arylsydnone-4-carbonitrile oxides may undergo 1,3-dipolar cycloadditions with alkenes to produce the corresponding 3-aryl-4-(5-substituted-isoxazolin-3-yl)sydnones. The direct reaction of 3-arylsydone-4-carbohydroximic acid chlorides with alkenes may also give the same products, and with higher yield.