Reaction of 3-benzylidene-2,4-pentanedione and 3-methoxymethylene-2,4-pentanedione with aroylhydrazines

Aroylhydrazines 2 reacted with 3-benzylidene-2,4-pentanedione ( 1 ) to give 1-aroyl-3,5-dimethyl-1H-pyrazoles 5 and benzaldehyde aroylhydrazones 6 . From the reaction of 3-methoxymethylene-2,4-pentanedione ( 7 ) with aroylhydrazines 2 the unknown N-aroyl-4-acetyl-1H-pyrazoles 9 were exclusively isolated in good yields.     

Structure elucidation and 13c NMR assignment of an 1,2,4-oxadiazole substituted pyrazole

The orientation of the substituent groups in an 1,2,4-oxadiazole substituted pyrazole, formed by reaction of a phenylnitrile oxide with an unsymmetrically substituted hydrazine is determined. One-dimensional methods as the selective INEPT and ¹³C{¹H} nOe experiments are used. Both techniques provide also an unambiguous assignment of the ¹³C nmr spectrum.     

Synthesis and stereochemistry of 2-benzylidene-4-carbethoxy-5-methyl-3-(2H)-furanones

The title products were obtained by Knoevenagel condensation between 4-carbethoxy-5-methyl-3-(2H)furanone and substituted benzaldehydes (or 4-chloroacetophenone). The configuration of the resulting compounds was investigated by ¹H nmr using the lanthanide shift reagent.     

Identification of 4,5-unsymmetrically substituted l-amino- and 1-(N-arylacetylamino)-1,2,3-triazoles by 13C-NMR

¹³C nmr chemical shifts are used for the structural assignment of isomeric 1-amino-1,2,3-triazoles and 1-(N-arylacetylamino)-1,2,3-triazoles unsymmetrically substituted with phenyl, methyl or hydrogen in the 4,5-positions of the triazole ring. A signal at 11 ± 0.6 ppm indicates a 4-methyl triazole derivative, whereas a signal at 7.9 ± 1 ppm indicates a 5-methyl triazole. A signal at 120 ± 0.5 ppm (C-5) indicates a hydrogen in the 5-position (unsubstituted triazole).     

N1-substituted 3,5-dimethoxy-4-halogeno-1H-pyrazoles: Synthesis and NMR study

The synthesis of 1-methyl- and 1-benzyl-3,5-dimethoxy-4-halogeno-1H-pyrazoles is described. Moreover, detailed nmr spectroscopic studies with the title compounds are presented. The highly shielded pyrazole C-4 atom in the corresponding 4-iodo congeners was found to have a ¹³C-chemical shift of only ?27 ppm.     

Synthesis and properties of 5-aroylamino-2H-1,2,4-thiadiazol-3-ones

5 -Aroylamino-2H-1,2,4-thiadiazol-3-ones 3 were obtained from the corresponding 1-aroyl-2-thiobiurets 2 by oxidative cyclization with bromine. 5 -Aroylamino-2H-1,2,4-thiadiazol-3-ones 3 can exist in two tautomeric forms a lactam form and a lactim form. On the basis of the ¹³C nmr spectra and additional experimental information, it has been established that the stable form, in which these compounds exist, is the lactam form.     

Synthesis and spectral properties of 2‐[(o‐ and p‐substituted)aminophenyl] ‐3H‐5‐[(o‐ and p‐substituted)phenyl]‐7‐chloro‐1,4‐benzodiazepines

A series of twelve new 2‐[(o‐ and p‐substituted)aminophenyl]‐3H‐5‐[(o‐ and p‐substituted)phenyl]‐7‐chloro‐1,4‐benzodiazepines, which have possible pharmacological properties has been obtained. The synthesis was carried out following six steps. The structure of all products was corroborated by ir, ¹H nmr, ¹³C nmr and ms. In addition for the compound 2‐(o‐chloroaminophenyl)‐3H‐5‐(o‐fluorophenyl)‐7‐chloro‐1,4‐benzodiazepine 7, its structure was confirmed by X‐ray diffraction.     

Cyclecondensation of 3-amino-1,2,4-triazole with substituted methyl cinnamates

The reaction of 3-amino-1,2,4-triazole ( 1 ) with substituted methyl cinnamates 2a-h leads selectively to the formation of 7-aryl-6,7-dihydro[1,2,4]triazolo[1,5-a]pyrimidin-5(4H)-ones 3a-h . The structure eluci dation of the products is based on ir, ¹H and ¹³C nmr measurements and X-ray diffraction.     

Reactions of Aliphatic Diazo Compounds: III. Reaction of Ethyl Diazoacetate with 1,3-Diarylpropenones

Ethyl diazoacetate adds to 1,3-diarylpropenones in a regioselective fashion to give intermediate 4,5-dihydro-3H-pyrazole derivative; 1,3-hydride shift in the latter leads to formation of isomeric ethyl 4-aryl- 5-aroyl-4,5-dihydro-1H-pyrazole-3-carboxylate and ethyl 4-aryl-3-aroyl-4,5-dihydro-1H-pyrazole-5-carboxylate at a ratio of 5:1. Thermolysis of these products is not stereospecific; as a result, three isomeric substituted ethyl cyclopropanecarboxylates and 2-pyranone derivative are formed.     

Synthesis of tetronic acid enamine. Dienamine derivatives from 3-(2H)furanones

The synthesis of 5-aryl (or alkyl) aminomethylene-3-(1-amino or 1-alkylaminoethylidene)-2,4-dioxo-(3H,5H)furans and 5-arylaminomethylene-3-(1-hydroxyethylidene)-2,4-dioxo-(3H,5H)furans (new 3-acetyltetronic acid derivatives) are described. The stereochemistry of these compounds from the ¹H nmr data is discussed.     

Synthesis of substituted 3‐phenyl‐6h‐pyrazolo[4,3‐d]isoxazoles from corresponding 4‐benzoyl‐5‐hydroxypyrazoles

Treatment of 1,(3)‐(di)substituted 4‐benzoyl‐5‐hydroxypyrazoles with phosphorus oxychloride affords the corresponding 4‐benzoyl‐5‐chloropyrazoles. Reaction of the latter with hydroxylamine leads to oximes, which can be cyclized to novel 3‐phenyl‐6H‐pyrazolo[4,3‐d]isoxazoles by treatment with sodium hydride in dimethyl formamide. Detailed nmr spectroscopic studies (¹H, ¹³C) with all obtained compounds are presented.     

Nitrogen bridgehead compounds. Part 72 Straightforward synthesis of 1,2,3,4-tetrahydrorutaecarpine and derivatives

In polyphosphoric acid, the Fischer indolization of 6-arylhydrazono-1,2,3,4,6,7,8,9-octahydro-11H-pyrido-[2,1-b]quinazolin-11-ones, obtained from 1,2,3,4,6,7,8,9-octahydro-11H-pyrido[2,1-b]quinazolin-11-ones by three pathways, afforded substituted 1,2,3,4,7,8-hexahydro-5H-13H-indolo[2′,3′:3,4]pyrido[2,1-b]quinazolin-5-ones in high yields. The structures of the 6-substituted octahydropyridoquinazolinones and hexahydroindo-lopyridoquinazolinones were characterized by uv, ¹H and ¹³C nmr data.     

Efficient synthesis in three steps and spectral determination of methyl‐5‐[(o‐, m‐, and p‐substituted‐phenylthio]‐2‐benzimidazolecarbamates

The preparation and spectral properties often novel methyl 5‐[(o‐, m‐, and p‐substituted)‐phenylthio]‐2‐benzimidazolecarbamates with possible pharmacological activity as antihelmintics is described; by condensation and cyclization between 5‐methylthioures sulfate chloroformic acid methyl ester and 3,4‐diaminophenyl‐substituted‐phenylthio ether dissolved in ethanol. The structures of all final products were corroborated by ir; ¹H‐nmr, ¹³C‐nmr and ms.     

The complete 1H and 13C chemical shift assignments of a cyclopropylpyrroloindole analog: Adozelesin

The ¹H and ¹³C nmr spectral assignments of [7bR]-N-[2-[(4,5,8,8a-tetrahydro-7-methyl-4-oxocyclo-propa[c]pyrrolo[3,2-e]indol-2(1H)-ylcarbonyl]-1H-indol-5-yl]-2-benzofurancarboxamide (Adozelesin) (1) are described. Complete and unambiguous assignments of the hydrogen and carbon spectra were made using a combination of conventional homonuclear and gradient-selected inverse-detected heteronuclear nmr experiments: double quantum filtered ¹H-¹H correlation spectroscopy (COSY), gradient-selected heteronuclear single quantum coherence spectroscopy (gs-HSQC), and gradient-selected heteronuclear multiple bond coherence spectroscopy (gs-HMBC). The enhanced sensitivity of these experiments allowed a smaller sample concentration and shorter spectral collection times for a full nmr analysis of this compound. The nmr data corroborates the published structure of this compound.     

Substituted γ-Lactones. 35 . Reduction of 4-aroyl-3-hydroxy-2(5H)-furanones

The reduction of 4-aroyl-3-hydroxy-2(5H)-furanons 1a-c was investigated using different reducing agents. Sodium borohydride reacts with type 1 compounds by loss of water to yield 4-(arylmethylene)-2,3(4H,5H)-furandiones 2a-c . Platinum or charcoal supported by pallodium chloride transforms 1a to 4-benzyl-3-hydroxy-2(5H)-furanone ( 3). Compounds 2a and 2b react with o-phenylenediamine to give 3-(E-(1′-hydroxymethyl-2′-aryl)ethenyl]-2-quinoxalinones 4a and 4b . The lactone 3 under the same conditions splits out formaldehyde and forms 3-(2′-phenylethyl)-2-quinoxalinone ( 6 ). The structure assignments of the novel compounds are based on elemental analysis and nmr as well as ir spectroscopic data.     

A facile synthesis and antimicrobial activity of 2,10‐dichloro‐6‐(aryloxy/thiophenoxy)‐4,8‐dinitrodibenzol[d,g][1,3,6,2]‐dioxathiaphosphocin‐ 6‐oxides

Novel 6‐substituted 2,10‐dichloro‐4,8‐dinitrodibenzo[d,g][1,3,6,2]dioxathiaphosphocin‐6‐oxides 4 were synthesized by reacting 5,5′‐dichloro‐3,3′‐dinitro‐2,2′‐dihydroxydiphenyl sulfide ( 2 ) with different aryl phosphorodichloridates, trichloromethylphosphonic dichloride and O‐2‐chloroethyl phosphoryldichloride (3) in the presence of triethylamine at 55–60°. Some of these compounds are prepared by reacting the monochloride, 2,6,10‐trichloro‐4,8‐dinitrodibenzo[d,g][1,3,6,2]dioxathiaphosphoein‐6‐oxide ( 5 ) in situ with substituted phenols and thiols. 5 is prepared by condensing 2 with phosphorus oxychloride. The ¹H nmr chemical shifts of the dibenzodioxathiaphosphocin moiety indicates the presence of more than one conformer in solution. However the presence of more than one conformer in each example cannot be entirely eliminated. Interestingly 4d on oxidation to 12‐sulphone by H₂O₂ in acetic acid medium yielded only 12‐sulphoxide 6a . The ir, ¹H, ¹³C, ³¹P nmr and mass spectral data are discussed. Some of these compounds were screened for antifungal activity against Curvularia lunata and Aspergillus niger and antibacterial activity on Bacillus subtilis and Klebsiella pneumoniae. A few of them possess significant activity.     

Synthesis and spectral properties of 2‐methylthio‐3H‐7‐[(o‐; m‐ and p‐substituted)phenoxy]‐4‐(p‐substituted‐phenyl)‐[1,5]benzodiazepines

A series of eleven new 2‐methylthio‐3H‐7‐[(o‐; m‐ and p‐substituted) phenoxy]‐4‐(p‐substituted‐phenyl)‐[1,5]benzodiazepines, which have potentially useful pharmacological activities, has been synthesized by condensing the 4‐[(o‐; m‐ and p‐R₁)phenoxy]‐1,2‐phenylendiamines with 3,3‐dimercapto‐1‐(p‐R₂‐phenyl)‐2‐propen‐1‐one. Afterward the lH‐[1,5]benzodiazepine‐2‐thiones obtained were treated with sodium hydride and methyl iodide. The structure of all products was corroborated by ir, ¹H nmr, ¹³C nmr and ms.     

Efficient synthesis and spectral determination of 11‐[(o‐ m‐ and p‐substituted)‐phenyl]‐8‐chloro‐3,3‐dimethyl‐2,3,4,5,10,11‐hexahydro‐1H‐dibenzo[b,e][1,4]diazepin‐1‐ones

A new synthesis to obtain eleven novel derivatives of 11‐[(o‐ m‐ and p‐substituted)‐phenyl]‐8‐chloro‐3,3‐dimethyl‐2,3,4,5,10,11‐hexahydro‐1H‐dibenzo[b,e][1,4]diazepin‐1‐ones with possible pharmacological activity in the central nervous system in two efficient steps has been developed. The final products were obtained by condensation and cyclization between 3‐[4‐chloro‐1,2‐phenylenediamine]‐5,5‐dimethyl‐2‐cyclohexenone with (o‐ m‐ and p‐substituted)benzaldehyde. The structure of all products was corroborated by ir, ¹H‐nmr, ¹³C‐nmr and high resolution in ms.     

A facile synthesis and spectral (ir, 1H, 13C, 31P nmr) studies of 2,10-dichloro-6-aryloxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-sulfides

The synthesis of new 2,10-dichloro-6-aryloxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-sulfides 4 was achieved in two steps with high yields from the simple materials 5,5′-dichloro-2,2′-dihydroxydiphenyl-methane (1) and thiophosphoryl chloride (2) which produced the key intermediate 2,6,10-trichloro-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-sulfide (3) . Treatment of 3 with substituted phenols under phase transfer catalytic (PTC) conditions led to members of 4 . Long range coupling [⁵J_(P,H) = 3.6 Hz] was observed between phosphorus and one of the bridged methylene protons in 4 . A ¹³C nmr analysis revealed ²J_(P,O,C), ³J_(P,O,C) ⁴J(P,O,C) and ⁵J(P,O,C) couplings. All ³¹P nmr chemical shifts for thirteen members of these new heterocycles are reported for the first time. The nmr data are not totally definitive to confirm a boat-chair as the major conformer for the central eight-membered dioxaphosphocin ring, but such a conformer is tentatively suggested as favored.     

Preparation and NMR spectra of substituted 2-phenyl-5,5-dialkylimidazolinones

Eighteen substituted 2-phenyl-5,5-dialkylimidazolinones 2 have been prepared by cyclizations of substituted 2-(N-benzoylamino)alkanamides 1. The cyclization of methylamides 1 proceeds at room temperature whereas primary amides are cyclized on boiling. The ¹H and ¹³C nmr spectra of the imidazolinones are presented and the changes in their spectra connected with their protonation in hexadeuteriodimethyl sulfoxide-trifluoroacetic acid mixtures are discussed.