A convenient synthesis and crystal structure of disubstituted 1,2,3-triazoles having ether functionality

Abstract

A series of 27 ether-linked 1,4-disubstituted 1,2,3-triazoles (8a–8z₁) has been synthesized by 1,3 dipolar cycloaddition of 1-substituted-4-(prop-2-yn-1-yloxy)benzene (3a–3c) and aromatic azides (5a–5c, 7a–7f). The synthesized compounds were explicated by FTIR, ¹H NMR, ¹³C NMR and HRMS techniques. The structures of synthesized triazoles 8c (CCDC 1840219) and 8f (CCDC 1840220) were also confirmed by X-ray crystallography.     

Stereoselective Synthesis of (Z)-1-Benzhydryl-4-cinnamylpiperazines via the Wittig Reaction

A synthetic method of producing (E)- and (Z)-isomers of 1-benzhydryl-4-cinnamylpiperazines in a specific ratio from corresponding benzhydrylpiperazine is described. Of the three compounds synthesized (5a–c), the ratio of E/Z-isomers remained around 15:85. The key intermediates, 1-benzhydryl-4-(2,2-dimethoxyethyl)piperazine derivatives (3a–c), were prepared by nucleophilic substitution reaction of benzhydrylpiperazines (2a–c) with chloroacetaldehyde dimethylacetal in good yield (up to 88%). Hydrolysis of 3a–c gave the corresponding aldehydes 4a–c, which when subjected to the Wittig reaction followed by column purification to afford 1a–c (E-isomers) and 6a–c (Z-isomers) in pure form. The isolated compounds were characterized by NMR and mass spectral analysis.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

[1,3]Dioxolo[5,6][1]benzothieno[2,3-c]-quinolin-6(5H)-ones

Summary The reaction of 3,4-methylenedioxycinnamic acid (1) with thionyl chloride resulted in the formation of 7-chlorothieno[2,3-f]-1,3-benzodioxole-6-carbonyl chloride (2) and cinnamoyl chloride (3). Subsequent reaction of the former withp-substituted anilines led to the formation of 7-chloro-N-(p-substituted phenyl)-thieno[2,3-f]-1,3-benzodioxole-6-carboxamides (4a–c) which on photocyclization afforded 2-substituted [1,3]dioxolo[5,6][1]benzothieno[2,3-c]quinolin-6(5H)-ones (5a–c) in fairly good yields and high purity. The structures have been confirmed by IR,¹H NMR, and analytical methods.Accepted for presentation at the Hong Kong International Symposium on Heterocyclic Chemistry (August 13–16, 1995)     

Synthesis and spectral properties of substituted 4-chlorooxazoloquinolines

Summary The treatment of a mixture of linearly and angularly annelated 2-substituted oxazolo[4,5-f]quinolones (5a–c) and oxazolo[5,4-g]quinolones (6a–c) and similarly the treatment of 2-substituted oxazolo[5,4-f]quinolones (7a–c) and oxazolo[4,5-g]quinolones (8b,c) with POCl₃ afforded substituted 4-chlorooxazolo[4,5-f]quinolines (9a–c) and 2-substituted 4-chlorooxazolo[5,4-f]quinolines (10b,c), respectively. Spectral characteristics of the synthesized derivatives (¹H and¹³C NMR, IR, UV, and MS) are discussed.Dedicated to Prof.Fritz Sauter on the occasion of his 65th birthday     

Spectral Assignment of Phenanthrene Derivatives Based on 6H-Dibenzo[C,E][1,2] Oxaphosphinine 6-Oxide by NMR and Quantum Chemical Calculations

Abstract

Organophosphorus compounds such as 6H-dibenzo[c,e][1,2]oxaphosphinine 6-oxide (DOPO, 1) and its derivatives are important and versatile compounds for a broad field of applications. However, a thorough spectral assignment is often subordinate to its chemical properties. This article presents and unambiguously attributes the ¹H and ¹³C NMR spectra of DOPO (1), selected products yielded from the Atherton–Todd reaction (2–4), DOPO-HQ (5) as well as sulfur derivatives (6–7) via a set of 1D- and 2D-NMR experiments. The complex P-C and P-H coupling patterns are discussed and compared with the derivatives possessing different chemical environments around the phosphorus atom. In addition, we compared our results with density functional theory calculations. Even though the prediction of NMR data of organophosphorus compounds via molecular modeling is limited, this study presents a method that yields good results for this class of heterocycles. This knowledge should help to quickly assign NMR spectroscopic data of other DOPO (1) derivatives and can be extrapolated to organophosphorus compounds in general.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: NMR Spectra of Compounds 1-7 (Figures S1 - S15).     

Untersuchungen über Chinone, 9. Mitt. Über Acetylderivate vonp-Indazolchinonen

Summary Acetylation of the indazolquinones1a (6-anilino-),b (6-p-toluidino-),c (6-N-methylanilino-),g (6- or 5-methylthio-), andk (benz[f]-) by heating with acetic anhydride yields the 2-acetylindazolquinones4a, b, c, g, andk. Reductive acetylation of the quinones1c, g, h/h ₁(6/5-methyl),k and — for structure elucidation — their 1-N- (2c) and 2-N- (3c, 3e)-methyl derivatives with acetic anhydride, zink powder, and sodium acetate gives the 1-acetyl-(7c, g, h/h ₁,k), resp. 1-methyl- (8c), and 2-methyl- (9c, e) diacetoxyindazoles. In case of1k, two diacetyl derivatives were isolated in addition to the already known triacetyl derivative7k, regardless of the conditions chosen. Acetylation of the intermediate product of the reaction from phenylthio-benzoquinone with diazomethane also yields a triacetyl-hydroquinone (7f). UV/Vis, IR, and¹H NMR spectroscopy were used for structure determination. Comparison of the UV/Vis spectra of the acetyl derivatives4 with those of1, 2, 3, and of compounds7 with those of analog substituted indazols shows that the acetyl group is located in position 2 with compounds4 and in position 1 with compounds7. By means of¹H NMR spectra the position of the acetyl group can be determined by the effect of the carbonyl group on the proton in position3.

     

Synthesis of Some New Triphenylphosphanylidenes,Alkylphosphonates, and Heterocycles of Pyrazole Derivatives and Their Antimicrobial Activity

Abstract

The reaction of 5(4H)-pyrazolone with phosphorus ylides afforded new triphenylphosphanylidene alkanone derivatives. Moreover, its benzylidene derivative reacted with Wittig–Horner reagents to give the corresponding dialkoxyphosphoryl, alkyl phosphonate, and heterocyclic products. Treatment of pyrazole-4-carbaldehyde with Wittig–Horner reagents and trialkyl phosphites gave the respective alkyl phosphonate adducts. Mechanisms accounting for the formation of the new products are discussed. The biological activity of some of the newly synthesized compounds was also examined.     

SYNTHESE DU FOSTEDIL (4-(2-BENZOTHIAZOLYL) BENZYLPHOSPHONATE DE DIETHYLE) A PARTIR D'IMIDATES N-ACYLES

Fostedil (diethyl 4-(benzothiazol-2-yl) benzylphosphonate) 7 has been synthesized efficiently by treatment of 2-(4-bromomethylphenyl) benzothiazole 6 with triethylphosphite. The latter (6) has been prepared by bromation of benzothiazole 3c. N-acylimidates 1(a–d) react with 2-aminobenzenethiol 2 to lead to the corresponding benzothiazoles 3(a–d) after elimination of primary amide 5. The structure of these products have been unequivocally confirmed by means of IR, ¹H, ¹³C, and ³¹P NMR spectroscopy and mass spectra.     

Syntheses and Antimicrobial Activity of Some Novel 6‐Substituted Dibenzo[d,f][1,3,2]dioxaphophepin‐6‐oxides,Sulfides, and Selenides

6‐Substituted‐dibenzo[d, f][1,3,2]dioxaposphepin‐6‐oxides, sulfides, and selenides (5a–i, 6a–d, and 7a–d) were synthesized by reacting 2,2′‐biphenol (1) with phosphorus tribromide in the presence of triethylamine at 0–30°C and subsequent reaction of the monobromide (2) with different Grignard reagents (3) at room temperature. The products (4) were converted to corresponding oxides, sulfides, and selenides (5a–i, 6a–d, and 7a–d) by oxidation with H₂O₂ at room temperature and refluxing with sulfur and selenium respectively. The chemical structures of all the products were confirmed by analytical, IR, NMR (¹H, ¹³C, and ³¹P), and mass spectral data. Most of these compounds exhibited moderate antimicrobial activity.     

Aldehyde-functionalized dithienylethenes with extended π-systems as versatile building blocks for NIR photochromic materials

A series of aldehyde-functionalized dithienylethenes 1b, 1c, 2b and 2c with extended π-conjugated systems have been synthesized by Wittig reaction. Their structures are confirmed by ¹H NMR, ¹³C NMR and HRMS (ESI). As expected, investigation on their photochromic properties indicates that dithienylethenes 1b, 1c, 2b and 2c have good photochromic behaviors with excellent fatigue resistance upon irradiation with UV or visible light. The DFT calculations further validate the differences in their photochromic properties in solution. Furthermore, they can be utilized as versatile building blocks to construct novel near-infrared photochromic materials.     

Synthesis and Characterization of New Chalcone Derivatives from cis-Bicyclo[3.2.0]hept-2-en-6-one

A series of chalcone derivatives (3a–k) were prepared via the reaction of cis-bicyclo[3.2.0]hept-2-en-6-one (1) with the respective arylaldehydes (2a–k) and were then characterized by Fourier transform infrared (FT-IR), ¹H NMR, ¹³C NMR, and elemental analyses.     

Synthesis and Characterization of Aminophosphines,Bis(amino)phosphine Derivatives,and Their Molybdenum(0) Complexes

Functionalized bis(amino)phosphines of the type PhP(NHR)₂ ( 1a–c ) and aminophosphines of the type Ph₂PNHR ( 2a–c ) have been synthesized by treating PhPCl₂ or Ph₂PCl with corresponding primary amines of H₂N-R where R = -CH₂SO₃H, -C₆H₄SO₃H, and benzo-15-crown-5. The molybdenum(0) complex of the aminophosphine ( 3 ) has been obtained by reacting cis-[Mo(CO)₄(bipy)] with aminophosphine ( 2c ). The synthesized aminophosphines, bis(amino)phosphines, and the molybdenum(0) complex have been characterized by IR, ¹H NMR, ³¹P NMR, and MS spectroscopic techniques and by elemental analysis.     

Synthesis and Spectral Characterization of Some Novel Thiazolyl-Pyrazoline Derivatives Containing 1,2,3-Triazole Moiety

Abstract

A series of novel 3-aryl-5-(2-aryl-1,2,3-triazol-4-yl)-1-(4-aryl-2-thiazoyl)-pyrazolines 6a–6r were synthesized using 2-aryl-4-formyl-1,2,3-triazoles 1a,b as the starting materials. Thus, reacting 1a,b with 1-arylethanones 2a–2c gave 1-aryl-3-(2-aryl-1,2,3-triazol-4-yl)-2-propen-1-ones 3a–3f. The reaction of the latter with thiosemicarbazide afforded 3-aryl-5-(2-aryl-1,2,3-triazol-4-yl)-1-thiocarbamoyl-pyrazolines 4a–4f, which condensed with 2-bromo-1-arylethanones 5a–5c to afford the target compounds 6a–6r. The chemical structures of the compounds were verified by means of their IR, ¹H NMR, ESI-MS spectroscopic data, and elemental analysis.

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.

GRAPHICAL ABSTRACT     

Convenient and efficient Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions catalyzed by 1,3,4-trisubstituted-1,2,3-triazolium iodide and palladium salt systems

A series of 1,3,4-trisubstituted-1,2,3-triazolium iodide salts (4a–c) were synthesized via a three-step reaction sequence. Corresponding anilines (1a–c) were converted to azides (2a–c) which were then treated with phenylacetylene with “Click” chemistry to access 1,4-disubstituted-1,2,3-triazoles (3a–c). Subsequent methylation of 1,4-disubstituted-1,2,3-triazoles (3a–c) yielded 1,3,4-trisubstituted-1,2,3-triazoliumiodide salts (4a–c) in appreciable yields. All the synthesized compounds were characterized by ¹H and ¹³C NMR, ATR–IR spectroscopic techniques and elemental analyses. Additionally, the structure of 1-(4-chlorophenyl)-4-phenyl-1,2,3-triazole (3b) was confirmed by single crystal X-ray diffraction analysis. The catalytic activity of 4a–c in a catalytic system consisting of 1,3,4-trisubstituted-1,2,3-triazoliumiodide salt/palladium(II) acetate/base were investigated toward Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions. The Suzuki–Miyaura cross-coupling reactions were carried out under mild reaction conditions with good to excellent yields, whereas Heck–Mizoroki cross-coupling reactions were performed at elevated temperature with moderate yields. Further, in situ method skips the synthetic procedure of preparing the palladium(II) complexes and hence is more economical and less tedious.     

Aluminum chloride–catalyzed C-alkylation of pyrrole and indole with chalcone and bis-chalcone derivatives

The AlCl₃-catalyzed alkylation of pyrrole (2) with chalcone (1a–i) at a ratio of 8:1 in the presence of 10 mol% AlCl₃ gave the solely 2-alkyl pyrroles (3a–i) at room temperature for 12 in good yields. The same reaction was performed with pyrrole (2) and chalcone at a ratio of 1:3 in CH₃CN at rt for 3 h to achieve 2,5-dialkyl pyrroles (4a–f). In addition, the reaction of the pyrrole (2) and indole (7) on 1,4-phenylene bis-chalcones (5a–g) at the ratio of 8:1 at rt for 24 h gave the double-addition products 6a–g and 8a–g in good yields, respectively. The structure of the products was confirmed by ¹H and ¹³C NMR spectroscopy and elemental analysis.     

DIBUTADIENYL PIPERAZINE,DIBUTADIENYL HOMOPIPERAZINES AND BUTADIENYL-SUBSTITUTED PIPERIDINES FROM MONOSUBSTITUTED HALODIENES

Compounds 3a–k were obtained from the reactions of compounds 1a–k with homopiperazine (2) in CH ₂ Cl ₂ . Compounds 1a–b, 1d–f, and 1h–l gave compounds 5a–b, 5d–f, and 5h–l with 2-methylpiperazine (4) in dichloromethane. Compounds 7c and 9c were obtained from the reactions of compound 1c with 4-ethoxycarbonyl piperazine (6) and 4-piperidinol (8) in CH ₂ Cl ₂ . Compounds 1a and 1f gave compounds 11a and 11f with 4-methylpiperazine (10), and compound 13f was obtained from the reactions of compound 1f with 4-methylpiperidine (12) in CH ₂ Cl ₂ .     

Synthesis and characterization of oxazine bearing pyridine scaffold as potential antimicrobial agents

A series of novel compounds 1-((1-(4-(2H-benzo[e][1,3]oxazin-3(4H)-yl)phenyl)ethylidene)amino)-6-((benzylidene)amino)-2-oxo-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitriles (7a–o) were synthesized by a sequence of multistep reactions. IR, ¹H NMR, ¹³C NMR, and mass spectral techniques were used to confirm the structures newly synthesized compounds. Antimicrobial activity of the title compounds (7a–o) was studied against strains of bacteria (Staphylococcus aureus and Streptococcus pyogenes, Escherichia coli and Pseudomonas aeruginosa) and fungi (Candida albicans, Aspergillus niger and Aspergillus clavatus) by serial dilution method. Compounds 7f and 7k exhibited significant antimicrobial activity.     

Poly-Diels-Alder Addition with a Bisoxazole as Bisdiene and a Bismaleinimide as Bisdienophile

Abstract

The poly-Diels-Alder addition between the new bisdiene 1,4-bis(5-methoxy-2-oxazolyl)benzene (4) and N,N′-hexamethylene-bis[2-(2,5-dihydro-2,5-dioxo-pyrrole-1-yl) acetamide] (7) is described. The structure of the resulting polyadduct 12 was proved by ¹H NMR spectroscopy with the aid of the low-molecular-weight model compounds 1,4-bis(1,3-dihydro-7-hydroxy-1,3-dioxo-2-phenyl-pyrrolo[3,4-c] pyridine-4-yl)benzene (9) and N,N'-hexamethylene-bis[2-(1, 3-dihydro-7-hydroxy-6-methyl-1,3-dioxo-4-phenyl-pyrrolo [3,4-c]pyridine-2-yl)acetamide] (11). The reaction proceeds via the aromatization of the primarily formed cycloadducts. Polyadduct 12 shows a number average degree of polymerization P_n of about 11 – 12 (M_n = 8500 ? 9200 g/mol), calculated from ¹H NMR endgroup signals.     

Synthesis and stereoselectivity of a new type of unsaturated phosphonates

A series of unsaturated phosphonates 2, 3, 4 with structures similar to that of abscisic acid (ABA) were synthesized by the Wittig‐Horner reactions of bisphosphonylmethane 1 with β‐substituted propenals, propargyl aldehydes or α,β‐unsaturated methyl ketones. Compounds 5 were prepared by the Michaelis‐Becker reactions of ω‐bromodienes 7 with sodium phosphites. Compounds 7 were obtained by the phase transfer Wittig reactions of ω‐bromobutylphosphonium salt 6 with β‐substituted propenals. The structures of all new compounds prepared were characterized by ¹H NMR, ³¹P NMR, IR spectra, and elemental analysis or MS. The stereochemistry of the Wittig reactions was studied. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:261–266, 2000     

An Efficient Synthesis of 1,5-Thiadiazepines and 1,5-Benzodiazepines by Microwave-Assisted Heterocyclization

A novel and efficient method for the synthesis of substituted thiazepines and diazepines has been developed. A simple one-pot reaction of chalcones 1a–f with 1-amino-2-mercapto-5-phenyl-1,3,4-triazole and o-phenylenediamine in the presence of a catalytic amount of sodium acetate under microwave irradiation gave 2-(3,8-diphenyl-7,8-dihydro[1,2,4]triazolo[3,4-b][1,3,4]thiadiazepin-6-yl)phenoles 2a–f and 2-(2-phenyl-2,3-dihydro-1H-1,5-benzodiazepin-4-yl)phenoles 3a–f, respectively. The structure of all the synthesized compounds was elucidated on the basis of elemental analysis, IR, ¹H and ¹³C NMR, and mass spectral data.