Pyridine-2(1H)-thione in Heterocyclic Synthesis: Synthesis of Some New Nicotinic Acid Ester,Thieno[2, 3-b]pyridine,Pyrido[3′, 2′: 4, 5]thieno [3, 2-d]pyrimidine,and Thiazolylpyrazolo[3, 4-b]pyridine Derivatives

Nicotinic acid esters 3a–c were prepared by the reaction of pyridine-2(1H)-thione derivative 1 with α-halo-reagents 2a–c. Compounds 3a–c underwent cyclization to the corresponding thieno[2, 3-b]pyridines 4a–c via boiling in ethanol/piperidine solution. Compounds 4a–c condensed with dimethylformamide-dimethylacetal (DMF-DMA) to afford 3-{[(N,N-dimethylamino)methylene]amino}thieno[2, 3-b]- pyridine derivatives 6a–c. Moreover, compounds 4a–c and 6a–c reacted with different reagents and afforded the pyrido[3′,2′:4, 5]thieno[3, 2-d]pyrimidine derivatives 10a–d, 11a–c, 12a,b, 14a,b, 17, and 19. In addition, pyrazolo[3, 4-b]pyridine derivative 20 (formed via the reaction of 1 with hydrazine hydrate) reacted with ethylisothiocyanate yielded the thiourea derivative 21. Compound 21 reacted with α-halocarbonyl compounds to give the 3-[(3H-thiazol-2-ylidene)amino]-1H-pyrazolo[3, 4-b]pyridine derivatives 23a–c, 25, and 27a,b.     

SYNTHESIS OF 15H-ISOQUINO[2′,3′:3,4]IMIDAZO[2,1-B]QUINAZOLINE-7,13,15-TRIONES AND 14H-ISOQUINO[2′,3′:3,4]IMIDAZO[2,1-B]BENZO[G]QUINAZOLINE-8,14,16-TRIONE AS NEW POLYCYCLIC FUSED-RING SYSTEMS

3-Thioxo-2H-imidazo[1,5-b]isoquinoline-1,5-dione (3) and 2-sub-stituted 3-thioxo-2H-imidazo[1,5-b]isoquinoline-1,5-diones (4a–l) were prepared from the reaction of 2-thiohydantoin (2) and 3-substituted 2-thiohydantoin (5a–l) with 2-formyl benzoic acid (1). Alkylation of 3 under an anhydrous basic conditions afforded 4a–i. The alkylation of 3 in aqueous basic solution afforded 3-(alkylmercapto)imidazo[1,5-b]isoquinoline-1,5-diones (7a,b). Reactions of the aromatic amino acids 9a,b and 12 with 7a afforded 2-(2H-1,5 dioxoimidazo[1,5-b]isoquinazolin-3-ylideneamino)benzoic acids (10a, b) and 3-(2H-1,5-dioxoimidazo[1,5-b]isoquinazolin-3-ylideneamino)2-naphthalenecarboxylic acid (13), which were then cyclyzed by heating in acetic anhydride to afford 15H-isoquino[2′,3′ :3,4] imidazo[2,1-b]quinazoline-7,13,15-triones (11a,b) and 14H-isoquino[2′,3′:3,4]imidazo[2,1-b]benzo[g]quinazoline-8,14,16-trione (14). Some of the new compounds were tested for their antitumor activities.     

One pot synthesis of ethyl carboxylate and acetyl selenolo[2,3-b]quinoline derivatives and their tetra/pentacyclic systems

Abstract

Ethylcarboxylate and acetyl selenoloquinoline derivatives were prepared in a one pot synthesis via reaction of sodium hydrogen selenide and 2-chloro-3-cyano-4-methylquinoline followed by reactions with ethyl chloroacetate and chloro acetone respectively which used as precursors to synthesize many of tetra and pentacyclic systems. A new series of pyrimido [4′,5′:4,5]selenolo[2,3-b]quinoline, thiazino[2’,3’:4,5]selenolo[2,3-b]quinoline, oxazino[2',3':4,5]selenolo[3,2-b]quinoline, pyrido[2′,3′:4,5]selenolo[2,3-b]quinoline, pyrido[2′,3′:4,5]selenolo[2,3-b]quinoline-2-substituted selenyl and selenolo[2′,3′:5,6]pyrido[2″,3″:4,5]selenolo[2,3-b]quinoline derivatives were prepared. Elemental analysis, IR, ¹H NMR, ¹³ Abdel-Hafez, S. H.; Gobouri, A. A.; Alshanbari, N. A.; Gad El-Rab, S. M. F. Synthesis of Novel Vitamin E Containing Sulfa Drug Derivatives and Study Their Anti-Bacterial Activity. Med. Chem. Res. 2018, 27, 2341–2352. DOI: 10.1007/s00044-018-2240-7.[Crossref], [Web of Science ®] , [Google Scholar]C NMR and mass spectra confirmed the structures of the newly synthesized compounds.     

Microwave-assisted three component synthesis of novel bis-fused quinazolin-8(4H)-ones linked to aliphatic or aromatic spacer via amide linkages

Abstract

A novel series of bis(tetrahydro[1,2,4]triazolo[5,1-b]quinazolin-8-ones) and bis(tetrahydrobenzo[4,5]imidazo[2,1-b]quinazolinones) containing amide linkages were regionselectively prepared via a three-component reaction of bis(aldehydes) with dimedone and 3-amino-1,2,4-triazole (or 2-aminobenzimidazole) under conventional heating as well as under microwave irradiation.     

Synthesis of Polyfunctionally Substituted Pyrazolonaphthyridine,Pentaazanaphthalene, and Heptaazaphenanthrene Derivatives

6-aminopyrazolo[3,4-b]pyridine-5-carbonitrile (2) was used as a precursor for the synthesis of a variety of pyrazolo[3,4-b][1,8]naphthyridines (3, 4) and pentaazacyclopenta[b]naphthalenes (5–10, 13, 14) via the initial addition to either the cyano or amino group followed by cyclization. Also, a series of heptaazadicyclopenta[a,g]naphthalenes (15–17) and heptaazacyclopenta[b]phenanthrenes (18, 19) were obtained via the interaction of 4-(dibenzothiophen-2-yl)-1,5-dihydro-5-imino-3-methyl-1-phenyl-1,2,6,8,9-pentaazacyclopenta[b]naphthalen-6-ylamine (14) with different reagents. The structures of the synthesized compounds were established by elemental and spectral analyses.     

Facile synthesis and characterization of novel pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one and pyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidine incorporating 1,3-diarylpyrazole moiety

4-(3-(4-Hydroxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-6-phenyl-2-thioxo-1,2-di hydro-pyridine-3-carbonitrile (1) reacted with ethyl chloroacetate (2) in ethanolic sodium acetate solution to yield the corresponding ethyl (3-cyanopyridin-2-ylsulphanyl)acetate derivative 3. Intramolecular cyclization of compound 3 was achieved by its heating in DMF containing potassium carbonate to afford the corresponding ethyl 3-aminothieno[2,3-b]pyridine-2-carboxylate derivative 4 which reacted with hydrazine hydrate in refluxing pyridine to yield the starting material 3-aminothieno[2,3-b]pyridine-2-carbohydrazide derivative 7. Compound 7 reacted with different reagents such as triethylorthoformate, formic acid, acetic acid and acetic anhydride to afford the target molecules pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one derivatives 8–10, 12 and 13 in good to excellent yields. On the other hand, pyridine-2(1H)-thione derivative 1 reacted with hydrazine hydrate in refluxing pyridine to give the other starting material 3-amino-1H-pyrazolo[3,4-b]pyridine derivative 20 which reacted with acetylacetone under reflux to afford the target molecule pyrido[2′,3′:3,4]pyrazolo[1,5-a]-pyrimidine derivative 21 in a good yield. The structures of target molecules were elucidated using elemental analyses and spectral data.     

Synthesis of Some New Pyrazolo[3,4-b]Pyridlne and Pyrazolo[3,4-d]Pyrimidine Derivatives1

Several pyrazolo[3,4-b]pyridine (3,4) and pyrazolo-[3,4-d]pyrimidine (5-13) derivatives were prepared using 5-amino-l-(5-ethyl-5H-1,2,4-triazino[5,6-b]-indol-3-yl)-lH-pyrazole-4-carbonitrile (2) . The pyridine derivatives 3 and 4 were obtained by reaction of 2 with malononitrile and ethyl cyanoacetate, respectively, while pyrimidine analogs 5-13 were synthesized cither by a one-step or multi-step sequence.     

BENZOQUINOLINES II. SYNTHESIS OF SOME NEW BENZO[h] PYRIMIDO [4′,5′:4,5]THIENO[2,3-b]QUINOLINE DERIVATIVES AND RELATED FUSED HEXACYCLIC SYSTEMS

Abstract

Reaction of 8-amino-7-(2 furyl)-5,6-dihydrobenzo[h]thieno[2,3-b]quinoline-9-carbonitrile (3a) with phenyl isothiocyanate, triethyl orthoformate, ethylenediamine and/or sodium azide afforded benzo[h]thieno[2,3-b]quinolines 4,7,20 and 25 respectively. Cyclization of thiourea derivative 4 furnished thioxopyrimidine derivative 5. The dithioxopyrimidine 6 was prepared by reaction of 3a with carbon disulfide. On treatment of 7 with hydrazine hydrate, 10-amino-7-(2-furyl)-11-imino-5,6,10,11-tetrahydrobenzo[h]pyrimido[4′,5′:4,5]thieno [2,3-b]quinoline (8) was obtained. Compounds 8,20 and 25 were used as key intermediates in the synthesis of the fused hexacyclic compounds 9–19, 21–24 and 26–28 respectively. 8-Amino-7-(2-furyl)-5,6-dihydrobenzo[h]thieno[2,3-b]quinoline-9-carboxamide (3b) was reacted with some reagents, namely triethyl orthoformate, benzaldehyde, carbon disulfide, phenyl isothiocyanate, and/or acetic anhydride to give the corresponding benzo[h]pyrimido [4′,5′: 4,5]thieno[2,3-b]quinolines 29, 30, 31, 32 and 34. Compound 29 underwent some sequence reactions to give 37–42. Some of the prepared compounds were tested in vitro for their antibacterial and antifungal activities.     

Studies on the Synthesis of New 3-(3,5-Diamino-1-substituted-pyrazol-4-yl)azo-thieno[2,3-b]pyridines and 3-(2-Amino-5,7-disubstituted-pyrazolo[1,5-a]pyrimidine-3-yl)azothieno[2,3-b]pyridines

Coupling the diazonium salt of 3-amino-2-cyano-4,6-dimethylthieno[2,3-b]pyridine 1 with malononitrile 2 gave 2-cyano-3-(hydrazonomalononitrile)-4,6-dimethylthieno[2,3-b]pyridine 3 which then reacted with hydrazine compounds 4a-4h to yield corresponding 2-cyano-3-(3,5-diamino-1-substituted-pyrazol-4-yl)azo-4,6-dimethylthieno[2,3-b]pyridines 5a-5h. The 2-cyano-3-(2-amino-5,7-disubstituted-pyrazolo-[1,5-a]pyrimidine-3-yl)azo-4,6-dimethylthieno[2,3-b]pyridines 7a-7f were obtained in good yield by the cyclocondensation reaction of 2-cyano-3-(3,5-diamino-pyrazol-4-yl)azo-4,6-dimethylthieno[2,3-b]pyridine 5a with the appropriate 1,3-diketones 6a-6f under acidic condition.     

Synthesis and characterization of N′-(11H-indeno[1,2-b]quinoxalin-11-ylidene)benzohydrazonamides as potential antimicrobial agents

Abstract

A series of new N′-(11H-indeno[1,2-b]quinoxalin-11-ylidene)benzohydrazonamides 3a–3j was synthesized in excellent yields from the reaction of N³-substituted benzohydrazonamides 1 and 2-(11H-indeno[1,2-b]quinoxalin-11-ylidene)malononitrile 2 in dichloromethane or with 11H-indeno[1,2-b]quinoxalin-11-one 4 in ethyl acetate at ambient temperature. The new compounds have been characterized and screened for biological activity. Some of them showed significant antibacterial and antifungal activities. In particular, compounds 3c and 3e showed interesting activities as antibacterial agents while compounds 3a 3c, 3e, 3g, and 3i showed high antifungal activities.     

微波辐射下合成5-(2-甲基/三氟甲基-苯并咪唑-1-亚甲基)-3-(苯基/p-取代苯基)-2H-1',2',4'-三唑[3,4-b]-1

分别采用微波辐射法和加热回流的常规方法, 将1-氨基-2-(2-甲基/三氟甲基-苯并咪唑-1-亚甲基)-5-巯基-1,3,4-三唑与α-溴代芳基乙酮3a～3e反应, 合成了一系列未见文献报道的1,2,4-三唑[3,4-b]-1',3',4'-噻二嗪类化合物4a～4e 和5a～5e. 微波辐射法具有反应时间短、产率高、副反应少等优点. 标题化合物经元素分析, IR, ¹H NMR, MS确证结构.     

Tricyclic heteroaromatic ring systems III. Synthesis of 1H,6H-dipyrazolo[3,4-b:3′,4′-d]pyridin-3-ones

The reaction of hydrazines with substituted ethyl 4-chloro-1H-pyrazolo[3,4-b]pyridine-3-carboxylates leads to the formation of 1H,6H-dipyrazolo[3,4-b:3,4-d]pyridin-3-ones.

---

Tricyclische heteroaromatische Ringsysteme, III. Synthese von 1H,6H-Dipyrazolo[3,4,-b:3,4-d]pyridin-3-onen (Kurze Mitteilung)

Zusammenfassung Die im Titel genannten Verbindungen wurden durch die Reaktion von Hydrazinen mit substituierten Ethyl-4-chlor-1H-pyrazolo[3,4-b]pyridin-3-carboxylaten dargestellt.

     

Synthesis of Chiral Propargylamines,Chiral 1,2-Dihydronaphtho[2,1-b]furans and Naphtho[2,1-b]furans with C-Alkynyl N,N′-di-(tert-butoxycarbonyl)-aminals and β-Naphthols

Chiral phosphoric acid-catalyzed couplings of C-alkynyl N,N′-di-(tert-butoxycarbonyl)-aminals with β-naphthols led to chiral propargylamines in moderate to high yields with high to excellent enantioselectivity, in which the reactions underwent sequential chiral phosphoric acid-catalyzed in situ formation of N-(tert-butoxycarbonyl)-imines (N-Boc-imines) from the aminals, and 1,2-addition of β-naphthols to the N-Boc-imines. Chiral 1,2-dihydronaphtho[2,1-b]furans and naphtho[2,1-b]furans were prepared with satisfactory results when 10 mol% AgOAc and 20 mol% 2,6-lutidine or 1.2 equiv. of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were added to the resulting chiral propargylamines solution, respectively.     

Synthesis of New 2-[(Substituted-pyrazol-1-yl)carbonyl]-thieno[2,3b]pyridine Derivatives Using 1,3-Diketones,Alkylethoxymethylenes and Ketene Dithioacetals

The reaction of 3-amino-4,6-dimethyl-2-thieno[2,3-b]pyridine carbohydrazide ( 1 ) with appropriate 1,3-diketones 2a-2d in glacial acetic acid afforded 3-amino-2-[(3,5-disubstituted-pyrazo)-1-yl)carbonyl]-4,6-dimethylthieno[2,3-b]pyridines 3a-3d. 3-Amino-2-[(5-amino-3,4-disubstituted-pyrazol-1-yl)carbonyl]-4,6-dimethylthieno[2,3-b]pyridines 5a-5h were also prepared by treatment of carbohydrazide 1 with appropriate alkylethoxymethylenes and ketene dithioacetals 4a-4h , respectively.     

Synthesis of New 2-[(Substituted-pyrazolin-1-yl)carbonyl]-thieno[2,3-b]pyridine Derivatives

The reaction of 3-amino-4,6-dimethyl-2-thieno[2,3-b]pyridine carbohydrazide ( 1 ) with appropriate chalcones 2a-2d in the presence of acid catalyst produced the corresponding 3-amino-2-[(3,5-disubstituted-pyrazolin-1-yl)carbonyl]-4,6-dimethylthieno[2,3-b]pyridines 3a-3d . 3-Amino-2-[(3-substituted-pyrazolin-1-yl)carbonyl]-4,6-dimethylthieno[2,3-b]pyridines 7a, 7b were also obtained by the cyclization reaction of carbohydrazide 1 with Mannich base derivatives 6a, 6b under basic condition.     

Synthesis and Structure Elucidation of Pyrimidobenzimidazoles and Fused Derivatives II [1]. Dodecahydrobenzimidazo-[2,1-b]quinazolines and Decahydrobenzimidazo-[2,1-b]benzo[h]quinazolines [2]

Summary.  The cyclization reactions of trans-3a-hexahydro-2-benzimidazolamine with 2-alkylidene- and 2-benzylidenecyclohexanones and α-tetralones, respectively, yield mixtures of two isomeric condensates each. Thorough high resolution NMR analyses (¹H and ¹³C NMR, HH-COSY, gs-HSQC, gs-HMBC, 1D TOCSY, and 1D NOE difference spectra) revealed that the corresponding isomers are in all cases linearly fused diastereomeric 12α- and 12β-substituted trans-6aα-dodecahydrobenzimidazo[2,1-b]quinazolines and 7α-substituted trans-8aβ- and trans-8aα-decahydrobenzimidazo[2,1-b]benzo[h]quinazolines, respectively. The formation of corresponding angularly fused regioisomers was not observed so far. The stereochemistry and the tautomerism of some bases and their hydrochlorides as well as the regiospecific course of the cyclization reactions are discussed. Biological tests showed that the novel compounds don’t exert remarkable antibacterial and antimycotic effects. Received November 3, 1999. Accepted November 30, 1999     

Novel Synthesis of 2-(2-(3-Hydroxy-5-oxo-4-phenylthiophen-2(5H)-ylidene)-2-phenylacetamido)propanoic Acid Analogues and Their Anti-Inflammatory Properties

This article describes the reaction of 3,6-diphenyl-thieno[3,2-b]furan-2,5-dione 1 with different amino acids 2a–j in glacial acetic acid which afforded the 2-(2-(3-hydroxy-5-oxo-4-phenylthiophen-2(5H)-ylidene)-2-phenylacetamido)propanoic acid analogues 3a–j and also describes the reaction of 3,6-diphenyl-thieno[3,2-b]thiophene-2,5-dione 4 with different amino acids 5a–e in acidic medium to give 2-(2-(3-mercapto-5-oxo-4-phenylthiophen-2(5H)-ylidene)-2-phenylacetamido)propanoic acid analogues 6a–e. All the compounds have been screened for their anti-inflammatory activity against the carrageenan induced rat paw edema in albino rats. In the primary screening, some of the compounds exhibited appreciable activity.

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.     

Stereoselective synthesis of trans-3-functionalized-4-pyrazolo[5,1-b]thiazole-3-carboxylate substituted β-lactams: Potential synthons for diverse biologically active agents

Abstract

An efficient protocol for the stereoselective synthesis of pyrazolo[5,1-b]thiazole-3-carboxylate tethered β-lactam conjugates 8a–j from novel pyrazolo [5,1-b]thiazole-3-carboxylate substituted Schiff’s bases 6a–f is reported here. The reaction between various ketene precursors and novel Schiff’s bases 6a–f afforded exclusive formation of trans-β-lactams 8a–j. The substrate scope of this approach was investigated extensively by varying different groups (R, Z). All the novel compounds were characterized using various spectroscopic techniques, such as FT-IR, ¹H NMR, ¹³C NMR, elemental analysis, ¹³C NMR (DEPT-135), and mass spectrometry in representative cases. Single crystal X-ray crystallographic study of trans-ethyl 7-(1-(4-methoxyphenyl)-4-oxo-3-phenoxyazetidin-2-yl)-6-methyl-2-(methylthio)pyrazolo[5,1-b]thiazole-3-carboxylate 8a has confirmed the molecular structure and the stereochemical outcome. To the best of our knowledge, the synthesis of such types of Schiff’s bases and β-lactam conjugates has not been reported so far.     

Facile synthesis of some novel triazolo[3,4-b]thiadiazines and triazolo[4,3-b]tetrazines

4-Amino-5-ethyl-4H-1,2,4-triazole-3-thiol was used as a key intermediate for the synthesis of triazolo[3,4-b][1,3,4]thiadiazines, triazolo[4,3-b][1,2,4,5]tetrazines and Schiff’s base via reactions with various hydrazonoyl halides and salicyaldehyde, respectively. Moreover triazolyl-N-N′-triazole derivatives were prepared from reaction of Schiff’s base with various hydrazonoyl halides. The structures of all the newly synthesized heterocyclic compounds were established by considering elemental analysis and spectral data.     

Green Aspect for Multicomponent Synthesis of Spiro[4H-indeno[1,2-b]pyridine-4,3′-[3H]indoles]

An efficient, four-component reaction of isatin, 1,3-indanedione, ethyl acetoacetate, and ammonium acetate in ethanol/water (9:1) system furnished spiro[4H-indeno[1,2-b]pyridine-4,3′-[3H]indoles] at room temperature. Merits of the method are mild reaction conditions, simple workup procedure, and ambient temperature. The synthesized compounds exhibit excellent fluorescence properties.