新颖有机催化剂的合成及催化不对称直接Aldol反应研究

以N-苄氧羰基-(S)-脯氨酸和5-(1-氨基烷基)四氮唑(烷基: 甲基、乙基、2-苯基乙基)为原料, 经两步反应合成了3个新颖的有机催化剂: (S)-5-脯氨酰胺基甲基四氮唑(3a), (S,S)-5-(1-脯氨酰胺基乙基)四氮唑(3b)和(S,S)-5-(1-脯氨酰胺 基-2-苯基乙基)四氮唑(3c), 并首次将其用于催化丙酮和含吸电子基芳香醛的不对称直接aldol反应. 在室温条件下, 催化剂3b表现出较好的催化活性, 产物的ee值最高可达96%.     

Synthesis and Reactions of Some Novel Nicotinonitrile,Thiazolotriazole, and Imidazolotriazole Derivatives for Antioxidant Evaluation

The novel 2-(1H)-pyridone, the lead compound of the pyridone derivative 1, reacted with an electrophilic reagent (ethyl chloroacetate) to give the corresponding ester 2. Condensation of compound 2 with thiosemicarbazide and/or hydrazine hydrate afforded the mercaptotriazole and the corresponding acetic acid hydrazide derivatives 3 and 4, respectively. The latter compound reacted with ethyl acetoacetate, ethyl cyanoacetate, and maleic anhydride to give compounds 5, 6, and 7, respectively. Alkylation of compound 3 with methyl iodide or chloroacetic acid afforded methylsulfanyltriazole and thiazolotriazole derivatives 8 and 9, respectively. Compound 8 reacted with glycine to afford the imidazotriazole derivative 10. Both compounds 9 and 10 reacted with glucose and benzaldehyde to give compounds 11, 12, 13, and 14, respectively. Some of the prepared products were selected and subjected to screening for their antioxidant activity.     

Synthesis and Some Reactions of Quinoxalinecarboazides

Chlorination of ethyl(quinoxalin‐2(1H)one)‐3‐carboxylate 1 gave ethyl (2‐chloroquinoxaline)‐3‐carboxylate 2 ;thionation of 1 by P₂S₅ or 2 by thiourea yielded the same product 3 . Reaction of chloro compound 2 or thiocompound 3 with hydrazine hydrate gave pyrazolylquinoxaline 4 . The reaction of ester 1 with thiourea or hydrazine hydrate afforded pyrimido quinoxaline 5 or carbohydrazide 6 ; the reaction of 6 with carbon disulfide in basic medium followed by alkylation afforded oxadiazoloquinoxaline derivatives 7, 8a,b . Carboazide 9 was produced by reaction of 5 with nitrous acid. Compound 9 on heating in an inert solvent, with or without amines, in alcohols or hydrolysis in H₂O undergoes Curtius rearrangments to yield 10‐13 . Reaction of 13 with thiosemicarbazide gave triazoloquinoxaline 14 which on reaction with alkylhalides or hydrazine hydrate yielded 15a‐c while hydrolysis of 13 gave 3‐aminoquinoxalinone 16 which was used as an intermediate to produce 17‐20 .     

Synthesis,Pharmacological, and Biological Screening of Novel Derivatives of Benzodiazepines

A series of novel 4‐(substituted phenyl)‐2‐(thiophen‐2‐yl)‐2,3‐dihydro‐1H‐benzo[b][1,4]diazepine have been synthesized from 3‐(substituted phenyl)‐1‐(thiophen‐2‐yl)prop‐2‐en‐1‐one. 3‐(Substituted phenyl)‐1‐(thiophen‐2‐yl)prop‐2‐en‐1‐one was prepared by condensing 2‐acetyl thiophene with various aromatic aldehydes in the presence of 20% NaOH as base. Different 3‐(substituted phenyl)‐1‐(thiophen‐2‐yl)prop‐2‐en‐1‐one on cyclization with o‐phenylenediamine in the presence of NaOH as base resulted in 4‐(substituted phenyl)‐2‐(thiophen‐2‐yl)‐2,3‐dihydro‐1H‐benzo[b][1,4]diazepine derivatives. The structures of synthesized compounds are confirmed by IR, ¹H NMR, mass spectra, and elemental analysis. All the compounds have been screened for their antimicrobial, analgesic, and anti‐inflammatory activities.     

Synthesis and Antibacterial Assay of Some New Pyrenyl Pyridine Candidates

Russian Journal of General Chemistry - Novel polycyclic compounds, 1-pyrene-based pyridone derivatives, are synthesized by treatment of pyrenyl acetohydtazide with several arylidenemalononitriles...     

Synthesis and Some Reactions of 2,4,6-Cycloheptatrienethione

The synthesis of 2,4,6-cycloheptatrienethione ( 1 ) was accomplished by reaction of tropone and phosphorus pentasulfide. Although 1 proved to be extremely unstable in concentrated solution, its UV. spectrum was measured, the ε-values being determined indirectly by hydrolysis to tropone. The proof of structure rests on analytical data, conversion to tropone oxime on reaction with hydroxylamine and reaction with the sodium salt of malonitrile to give 2-amino-3-cyano-3aH-cyclohepta[b]thiophene ( 4 ) which rearranged on chromatography to give what is probably the corresponding 8H-compound ( 5 ). On dissolving 1 in 95% sulfuric acid, a large hypsochromic shift in the UV. spectrum was observed, which may be due to the mercaptotropylium ion.     

Synthesis and Reactions of Some New Thienopyrimidines

4-Methyl-6-mercapto-2-phenylpyrimidine-5-carbonitrile ( 1 ) was reacted with different halo compounds, namely ethylchloroacetate, chloroacetone, bromoacetanilide, p-chlorobromoacetanilide, and p -methoxy chloroacetanilide in ethanol in the presence of sodium acetate yielded the corresponding S-alkylated derivatives ( 2a-e ). The latter compounds underwent cyclization into thienopyrimidines ( 4a-e ) upon treatment with sodium ethoxide in ethanol. The reaction of ( 4a ) with hydrazine hydrate led to the formation of 5-amino-4-methyl-2-phenylthieno[2,3-d]pyrimidine-2-carbohydrazide ( 5 ). Compound ( 5 ) was reacted with a variety of reagents to produce other new thienopyrimidines as well as oxadiazolylthienopyrimidines ( 6, 11 ).     

Synthesis and Some Reactions of Polyols Formals

Synthesis of formals of some polyols such as dipentaerythritol, dietriol and diglycerin was proposed. Based on them, esters and carbamates were obtained.     

Synthesis,Structure, and One-electron Redox Reactions of Novel Benzodithiolium Salts

Abstract

Novel stable benzodithiolium salts have been synthesized and characterized by X-ray crystallographic analysis, which have been readily converted to the first isolable dithiolyl radicals by one-electron reduction.     

InCl3-Catalyzed,Three-Component Reactions for the Synthesis of Some Novel Functionalized/Annulated Barbituric Acids

Some novel 5-aminoalkylbarbituric acids and corresponding chromene derivatives were synthesized via a one-pot, three-component Mannich reaction starting from 1,3-dimethylbarbituric acid, arylaldehydes, and amines.     

Synthesis,Reactions, and Antimicrobial Evaluation of Some Polycondensed Thienopyrimidine Derivatives

Some novel indeno[2,1-b]thiophenes, indeno[1′,2′:4,5]thieno[2,3-d][1,2,3]triazines, indeno[1′,2′:4,5]thieno[2,3-d]pyrimidines, indeno[1′,2′:4,5]thieno[2,3-d][1,3]thiazolo[3,2-a]pyrimidines, and indeno[1′,2′:4,5]thieno[2,3-d][1,2,4]triazolo[4,3-a]pyrimidines 2–16 were prepared starting with 2-aminoindeno[2,1-b]thiophene-3-carboxylic acid amide ( 1 ). Furthermore, the antimicrobial evaluation of the prepared products showed that many of them revealed promising antimicrobial activity.     

Design,Synthesis, Antibacterial Evaluations and In Silico Studies of Novel Thiosemicarbazides and 1,3,4-Thiadiazoles

The emergence of drug-resistant bacterial strains continues to be one of the major challenges of medicine. For this reason, the importance of searching for novel structures of antibacterial drugs chemically different from the currently known antibiotics is still of great importance. In this study, we synthesized the thiosemicarbazide and 1,3,4-thiadiazole derivatives and tested them for antibacterial activity. In in vitro tests, we examined the activity of the synthesized substances against Gram-positive and Gram-negative bacteria strains. While all 1,3,4-thiadiazoles tested lacked significant activity, the antimicrobial response of the thiosemicarbazides was moderate and it was also dependent on the type and position of the substituent on the phenyl ring. The highest activity towards all Gram-positive bacteria strains was shown by all three linear compounds containing the trifluoromethylphenyl group in the structure. The MIC (minimum inhibitory concentration) values were in the range of 3.9–250 µg/mL. Additionally, we try to explain the mechanism of the antibacterial activity of the tested compounds using the molecular docking to DNA gyrase and topoisomerase IV, following previous reports on the molecular basis of the activity of thiosemicarbazides. Docking simulations allow the purposing dual mechanism of the antibacterial activity of the synthesized compounds through inhibition of topoisomerase IV DNA gyrase with the moderate prevalence of the topoisomerase pathway.     

Synthesis and Pharmacological Evaluation of Some Novel Imidazo[2,1-b][1,3,4]thiadiazole Derivatives

Synthesis of bis‐1,3‐{6′‐arylimidazo[2,1‐b][1,3,4]thiadiazol‐2‐yl}‐1,2,2‐trimethylcyclopentane ( 3 ), bis‐1,3‐{thiadiazolo[2′,3′:2,1]imidazo[4,5‐b]quinoxalinyl}‐1,2,2‐trimethylcyclopentane ( 5 ) has been achieved by the reaction of bis‐(5′‐amino‐1′,3′,4′‐thiadiazolyl)‐1,2,2‐trimethylcyclopentane with α‐haloketones, 2,3‐dichloroquinoxaline respectively. Bromination of compound 3 furnished bis‐1,3‐{5′‐bromo‐6′‐arylimidazo[2,1‐b][1,3,4]thiadiazol‐2‐yl}‐1,2,2‐trimethylcyclopentane ( 4 ). The structural assignment of these compounds was supported by IR, ¹H NMR and elemental analysis data. The antimicrobial, anti‐inflammatory and antifungal activities of some of the compounds have also been evaluated.     

Ferrocenecarboselenoic Acid: Synthesis and Some Reactions

The first ferrocenecarboselenoic acid was synthesized and characterized. The existence of tautomeric equilibrium between the selenol (FcCOSeH) and selenoxo forms (FcCSeOH) in polar solvents was proven by ¹H‐, ¹³C‐ and ⁷⁷Se‐NMR spectra. The selenoxo form exists predominantly in a polar solvent at low temperature below –70 °C. Treatment of this acid with lithium, sodium, and potassium hydrides and with rubidium and cesium fluorides gave the corresponding alkali metal ferrocenecarboselenoates in quantitative yields. Treatment with 4‐methylphenyl isocyanate at room temperature led to ferrocenoyl 4‐methylphenylcarbamoyl selenide FcCOSeC(O)NHC₆H₄Me‐4 in high yield. A similar reaction with phenyl isothiocyanate formed a mixture of FcCOSeC(S)NHPh and FcCOSeC(SH)=NPh in moderate to good yield. The carboselenoic acid readily reacted with piperidine to give piperidinium ferrocenecarboselenoate in good yield. Air oxidation of this selenoic acid afforded diferrocenoyl selenide as a major product along with diferrocenoyl diselenide. The structures of the selenide (FcCO)₂Se and diselenide (FcCOSe)₂ were examined by single‐crystal X‐ray analysis.     

Synthesis of Methyl p-Alkoxyphenylcarbamates and Some Their Reactions

Alkylation of methyl p-hydroxyphenylcarbamate with allyl bromide and 1,4-dibromobutane leads to formation of the corresponding methyl p-alkoxyphenylcarbamates. Reactions of methyl p-allyloxyphenylcarbamate with benzaldehyde, p-methoxybenzaldehyde, p-nitrobenzaldehyde, and p-chlorobenzaldehyde oximes in boiling ethanol in the presence of N-chlorobenzenesulfonamide sodium salt yields 3-aryl-5- (p-methoxycarbonylaminophenoxymethyl)-4,5-dihydroisoxazoles. Methyl p-(4-bromobutoxy)phenylcarbamate reacts with morpholine in benzene to give methyl p-(4-morpholinobutoxy)phenylcarbamate.     

Synthesis and Some Pharmacological Studies of New Benzenesulfonamide Derivatives

Summary.  New benzenesulfonamide derivatives containing pyrazole and oxadiazole moieties were prepared starting from sodium saccharin. The structures of the novel compounds were characterized by elemental analyses and spectroscopic methods. The new compounds are structurally related to the COX-2 inhibitor celecoxib (Celebrex^?). A pharmacological study of the pyrazoles revealed that several compounds possess higher analgesic and antiinflammatory activities than celecoxib, particularly 11 and 17. Most of the pyrazoles showed a significant increase in the sleeping time of thiopentone anaesthesized mice and also protected mice against the convulsive and lethal effects of pentylenetetrazole. Moreover, the ulcerogenic activity of those compounds showing a pronounced antiinflammatory effect was also studied. Received August 20, 2001. Accepted (revised) November 19, 2001