Gadolinium triflate catalyzed alkylation of pyrroles: efficient synthesis of 3-oxo-2,3-dihydro-1H-pyrrolizine derivatives

Novel 2-alkylated pyrrole derivatives were synthesized regioselectively by Gd(OTf)₃ catalyzed addition reactions of pyrrole to substituted dimethyl 2-benzylidenemalonate derivatives under mild reaction conditions. 2-Alkylated pyrrole derivatives are used for the construction of the 3-oxo pyrrolizine skeleton. Intramolecular cyclization of alkylated pyrrole derivatives afforded new diastereoselective 3-oxo-2,3-dihydro-1H-pyrrolizine derivatives with good to high yields.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-β-haloethyl derivatives of bis(oxytriazene oxides) bearing the NCH<Subscript>2</Subscript>O fragment

Synthetic procedures towards 3-monosubstituted functional derivatives of 1-alkoxy-1-triazene 2-oxides were elaborated. Alkylation of the synthesized compounds with chloromethoxy derivatives of 3,3-bis(2-haloethyl)-1-hydroxy-1-triazene 2-oxides gave (2-chloro/ bromoethyl) derivatives of 1,2,3,6,7,8-hexaaza-5-oxa-3-alkoxyocta-1,6-diene 2,7-dioxides. 2-Iodoethyl-1,2,3,6,7,8-hexaaza-5-oxa-3-alkoxyocta-1,6-diene 2,7-dioxides were first synthesized by the reaction of the corresponding bromoethyl derivatives with NaI.     

Synthesis of 2,3-diformyl-5-ethylbenzofuran and its derivatives

A mixture of 3-formyl and 3-acetoxymethyl derivatives is formed in the oxidation of 2-carbethoxy-3-methyl-5-ethylbenzofuran with selenium dioxide. Reduction of the products with lithium aluminum hydride gives the corresponding 2,3-dihydroxymethyl derivatives, which are converted to 2,3-diformyl derivatives by successive oxidation by the Fetizon method and with manganese dioxide. The corresponding benzofuro[2, 3-d]pyridazines were synthesized by reaction of 2-carbethoxy-3-formyl-5-ethylbenzofuran with hydrazine hydrate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 893–895, July, 1982.     

Design and synthesis of new derivatives of 3H‐quinazolin‐4‐one as potential anticonvulsant agents

As a part of systematic investigation on synthesis and biological activities, some new derivatives of 2‐ethyl‐3‐(substituted benzothiazole‐2′‐yl)–[3H]‐quinazolin‐4‐ones 3 have been synthesized, and the structures of the compounds were confirmed by elemental analysis and spectral data. The newly synthesized derivatives are then screened for anticonvulsant activity by maximal electroshock method. J. Heterocyclic Chem., (2011).     

Synthesis and Reactivity of Enaminones: A Facile Synthesis of Thiophene and 1,3,4‐Thiadiazole Derivatives Incorporating a Thiazole Moiety

Several new heterocyclic compounds such as thiophene derivatives have been synthesized by the reactions of the versatile unreported 3‐mercapto‐2‐(4‐methyl‐2‐(tosylamino)thiazole‐5‐carbonyl)‐3‐phenylaminopropenal ( 7 ) with chloroacetonitrile, ethyl 2‐bromoacetate, and 1‐aryl‐2‐bromoethanone derivatives. Reaction of potassium salt intermediate 6 with hydrazonyl halides ( 14a , 14b , 14c ) to afford 1,3,4‐thiadiazole derivatives incorporating a thiazole moiety has been described. All newly synthesized compounds were elucidated by considering the data of both elemental and spectral analysis.     

1-(2'-苯基-1', 2', 3'-三唑-4'-甲酰基)-4-芳基氨基硫脲及其 环化产物的合 成

以2-苯基-1,2,3-三唑-4-甲酰肼为原料合成了几种新的1-(2'-苯基-1',2',3'-三唑-4'-甲酰基)-4-芳基氨基硫脲,在不同条件下环化,制得一系列新的1,3,4-噻二唑、1,3,4-恶二唑和1,2,4-均三唑衍生物。化合物的结构经元素分析、IR、^1HNMR和MS确证,并对其波谱性质进行了讨论。     

Some reactions of systems containing the imidazole ring

Behavior towards sodamide is compared for 3-benzyl- and 3-methyl substituted naphth [1, 2-d] imidazole and imidazo [4, 5-f] quinoline derivatives. The following are synthesized: 2-amino derivatives of 3-benzylnaphtho- [1, 2-d] imidazole(by direct animation), and of 3-benzylimidazo [4, 5-f] quinoline (ammonolysis of a 2-chloro substituted compound).     

Synthesis, reactions and antimicrobial activities of 8-ethoxycoumarin derivatives

Condensation of 3-acetyl-8-ethoxycoumarin (3) with thiosemicarbazide gave ethylidenehydrazinecarbothioamide 5, which was transformed into the thiazolidin-4-one derivatives 6,7. Interaction of 3 with DMF/POCl(3) gave b-chloroacroline derivative 8. Treatment of 3 with malononitrile gave benzo[c]chromone and 2-aminobenzonitrile derivatives 9 and 10, respectively with respect to the reaction conditions. Condensation of 3-(2-bromoacetyl)-8-ethoxycoumarin (4) with o-phenylenediamine gave 3-(quioxaline-2-yl)-8-ethoxycoumarin hydrobromide (11), while 4 reacted with 2-aminopyridine to give chromenopyridopyrimidine derivative 12. Condensation of 4 with potassium thio-cyanate/methanol gave an unexpected derivative, 2H-chromeno-3-carboxy(methyl-carbonimidic)thioanhydride 16, which upon treatment with (NH(2))(2)·H(2)O gave 3-ethoxy-2-hydroxybenzaldehyde azine 19. Interaction of 4 with thiourea derivatives gave thiazole derivatives 20a-c. The structures of the newly synthesized compounds were confirmed by their spectra data. The newly synthesized compounds were also screened for their antimicrobial activity.     

2,2'-二苯并噁唑衍生物的合成和光性能研究

合成了16种2,2-二苯并(口恶)唑衍生物,测定了化合物的熔点、红外光谱、紫外吸收光谱、荧光发射光谱以及荧光量子产率,与1,4-二(苯并(口恶)唑1′,3′-基-2′)苯和1,4-二(苯并(口恶)唑-1′,3′-基-2′)乙烯衍生物进行了比较,讨论了它们之间光谱特性的差异.     

Synthesis,PM3‐Semiempirical,and Biological Evaluation of Pyrazolo[4,3‐c]quinolinones

A series of α,β‐unsaturated ketones containing quinolone moieties 2 , 3 , 4 , 5 , 6 were synthesized by condensation of 7‐methoxyquinoline‐2,4(1H,3H)‐dione ( 1 ) with different aryl aldehydes. Pyrazole derivatives 8 , 9 , 10 , 11 were also synthesized via refluxing of α,β‐unsaturated ketones 2 , 3 , 4 , 5 , 6 with hydrazine derivatives. Newly synthesized compounds were characterized by elemental analyses, spectral data, and screened for their antioxidant and antitumor activities. Geometrical optimizations of the molecular structures for different synthesized compounds were studied.     

Azasteroids. Synthesis by Diels-Alder Reaction between Maleimides, Citraconimide, and Triazolindiones and 1-(1-Trialkylsiloxyvinyl)-3,4-dihydronaphthalene Derivatives

Summary. 18-Nor-16-azaestrane derivatives with 8β, 13β, and 14β orientation were isolated from Diels-Alder reactions between maleimides or citraconimide and 1-(1-siloxyvinyl)naphthalene derivatives. (8RS)-13,14,16-Triazaestrane derivatives were synthesized from 1,2,4-triazolin-3,5-diones. The parent 11-oxo derivatives were obtained by desilylation, and they were transformed into 11-hydroxyimino derivatives. 3-Hydroxy derivatives, finally were synthesized by cleavage of the 3-methoxy group with BBr₃. During these transformations the stereochemistry of the steroidal skeleton was not changed. The stereochemistry of these “unnatural” steroids was elucidated by spectroscopic methods, and compared with results from calculations, and with the configuration of natural estrane derivatives. Finally, an improved method for the synthesis of the starting material, 6-methoxy-1-[(1-trialkylsiloxy)-vinyl]-3,4-dihydronaphthalene was developed.     

Synthese von Thieno[2,3—d]-1,2,3-triazin- und [1]Benzothieno [2,3—d]-1,2,3-triazin-Derivaten

The title substances, derivatives of two new heterocyclic ring systems, were synthesized by intramolecular cyclisations of diazonium compounds, prepared from derivatives of 2-amino-thiophene-3-carboxamide and of 2-amino-benzo[b]thiophene-3-carboxamide. By-reactions and substitution reactions are mentioned.     

Novel 1,4-benzothiazine derivatives: synthesis,crystal structure,and anti-bacterial properties

In order to develop relatively small molecules as pharmacologically active molecules, novel 1,4-benzothiazine derivatives with triazole and oxazolidinone were synthesized. In this study, a series of 1,2,3-triazolylmethyl-1,4-benzothiazine derivatives were developed by exploiting a click chemistry reaction using a CuI-catalyzed Huisgen [3 + 2] cycloaddition. Starting from 2-(substituted)-3,4-dihydro-2H-1,4-benzothiazi-3-one, a number of 1,4-benzothiazine derivatives were also synthesized using different alkylating agents to give a 4-(substituted)-2-(substituted)-3,4-dihydro-2H-1,4-benzothiazi-3-one in good yields. The crystal and molecular structure of compound oxazolidin-2-one in basic benzothiazine was established by single-crystal X-ray diffraction. The newly synthesized products were subjected to in vitro biological evaluation. The result indicated that the compounds show convincing antibacterial activities against different microorganisms. All structures of the synthesized compounds were elucidated on the basis of spectral analyses and chemical reactions.     

3,3-二甲基-2-(3-甲基薁乙烯基)-3H-吲哚衍生物的合成

1-甲酰基薁-3-甲酸甲酯和2,3,3-三甲基-3H-吲哚衍生物发生缩合反应,合成了一系列3,3-二甲基-2-(3-甲基薁乙烯基)-3H-吲哚衍生物,收率48%～64%,其结构经~1H NMR,IR和元素分析表征.     

Synthesis of deoxy derivatives of lactose and their hydrolysis by beta-galactosidase from E. coli.

Methyl 2-deoxy-alpha-lactoside, methyl 3-deoxy-beta-lactoside, 1,5-anhydro-4-O-beta-D-galactopyranosyl-D-glucitol and the 2-deoxy and 2,3-dideoxy derivatives of 1,5-anhydro-4-O-beta-D-galactopyranosyl-D-glucitol have been synthesized by deoxygenation of lactose derivatives at appropriate positions. Cyclohexyl beta-D-galactopyranoside has also been synthesized. All derivatives proved to be substrates for the enzyme beta-galactosidase from E. coli, but the rate of hydrolysis of the substrate analogues was strongly dependent on the nature of the aglycone.     

Heterocyclic Synthesis Using Nitrilimines:Part 16. Synthesis of Some New Pyrazole and Spiropyrazoline Derivatives

1,3‐Dipolar cycloaddition of the nitrilimines with the 2‐propylidene‐3‐coumaranone afforded the corresponding pyrazole derivatives. Similar reactions of nitrilimines with 3‐ethylidene‐1‐indanone furnished spiropyrazoline derivatives. The spectral data of the synthesized compounds are in full agreement with its molecular structure.     

Synthesis and Reactivity of 3‐oxoprop‐1‐en‐1‐olate Derivative as a Building Block for the Synthesis of Azole and Azine Derivatives

Several new heterocyclic compounds such as 7‐substituted pyrazolo[1,5‐a ]pyrimidine ( 5a–e ) derivatives have been synthesized by the reactions of the versatile unreported sodium 3‐(4‐methyl‐2‐(4‐methylphenylsulfonamido)thiazol‐5‐yl)‐3‐oxoprop‐1‐en‐1‐olate (2) with amino heterocyclic ( 3a–e ) derivatives. Reaction of (2) with hydrazonyl halide ( 7a–d ) and hydroximoyl chloride ( 11a,b ) derivatives followed by reaction with hydrazine hydrate afforded pyrazolo[3,4‐d ]pyridazine and isoxazolo[3,4‐d ]pyridazine derivatives, respectively incorporating a thiazole moiety have been described. All newly synthesized compounds were elucidated by considering the data of both elemental and spectral analysis.     

Synthesis and Antimicrobial Activity of 1-Aryl-4-(arylimino)-6-iminohexahydro-1,3,5-triazine-2-thione Derivatives

Russian Journal of General Chemistry - A series of 6-imino-1-aryl-4-(arylimino)-1,3,5-triazinane-2-thione derivatives are synthesized by cyclization of 1-aryl-3-cyanoguanidine with aryl...     

Synthesis and some reactions of 3-chloro-2-(cyanomethylene)-1,2-dihydroquinoxalines

2,3-Dichloroquinoxaline and some of its derivatives have been reacted with malononitrile and ethyl cyanoacetate to yield a variety of 3-chloro-2-(cyanomethylene)- 1,2-dihydroquinoxaline derivatives. The reaction of 3-chloro-2-(dicyanomethylene)-1,2- dihydroquinoxaline (2e) with pyridine and its methyl derivatives led to the zwitterionic structures 6a-6c. The structures of the newly synthesized compounds were assigned by spectroscopic data and elemental analyses.     

Synthesis of function-oriented 2-phenyl-2H-chromene derivatives using l-pipecolinic acid and substituted guanidine organocatalysts

Organocatalytic domino oxa-Michael/aldol reactions between salicylaldehyde with electron deficient olefins are presented. We screened guanidine, 1,1,3,3-tetramethylguanidine (TMG) and l-pipecolinic acid as organocatalysts for this transformation. 3-Substituted 2-phenyl-2H-chromene derivatives are synthesized with high yields and with poor enantioselectivity (5-17% ee) using l-pipecolinic acid while TMG works well with cinnamaldehyde without using co-catalyst. These 3-substituted-2-phenyl-2H-chromene derivatives are further derivatized to synthesize triazole and biotin-containing chromene derivatives, to facilitate purification of protein targets.