Lead tetraacetate oxidation of phenylhydrazones of 3-benzoylazoles. Synthesis of azoacetates and their conversion into indazoles

Lead tetraacetate (LTA) oxidation of (E)- and (Z)-phenylhydrazones of 3-benzoyl-5-phenyl-1,2,4-oxadiazole, 3-benzoyl-5-phenylisoxazole, and 3-benzoyl-4-methyl-1,2,5-oxadiazole has been studied. Conversion of azoacetate products into 3-(azol-3-yl)-substituted indazoles has been achieved by reacting them with aluminium chloride in benzene at room temperature.     

Well-Defined Aminophenolate Zinc and Magnesium Complexes as Excellent Inhitiators for the ROP of Lactides

A series of molecular homo and heteroleptic zinc and magnesium compounds with aminophenolate ligands [(µ,η²-L²)ZnEt]₂ ( 1 ), [(η²-L²)Zn(µ-BnO)]₂ ( 2 ), [Zn(η²-L²)₂] ( 3 ), [Zn(η²-L³)₂] ( 4 ), [Mg(η²-L³)₂] ( 5 ) (L²-H = N-[methylene(2-hydroxy-3,5-di-tert-butylphenyl)]-N-methyl-N-cyclohexylamine, L³-H = N-[methylene(2-hydroxy-3,5-di-tert-butylphenyl)]-N-methyl-N-methyl-1,3-dioxolaneamine) have been prepared and characterized. The homoleptic complexes 3–5 are most probably a mixture of diastereoisomers that in solution show an interesting dynamics which plays an important role in their catalytic behavior. The complexes 2 – 5 are efficient initiators in ring-opening polymerization (ROP) of lactides to produce polymers with desired molecular weight and narrow polydispersity.     

High specific activity tritium labelling of some sigma-1 receptor agonists

The high specific activity tritiation of (+)-SKF-10,047 (1) and N,N-dimethyltryptamine (4) is described. [N-allyl-³H] (+)-SKF-10,047 (3) was prepared by Lindlar catalyst tritiation of (+)-N-propargylnormetazocine (2) and [N-methyl-³H] N,N-dimethyltryptamine (6) was synthesized by the alkylation of N-methyltryptamine (5) with [³H] methyl iodide. Both sigma-1 synthetic agonist 3 and endogenous agonist 6 have been useful in studying this receptor.     

Reactions of N-heteroarylformamide oximes and N-heteroarylacetamide oximes with N,N-dimethylformamide dimethyl acetal. Synthesis of 2-methyl-s-triazolo[1,5-x]azines and N-methylcyanoaminoazines

N-Heteroarylformamide oximes 3 (R ? H) were converted with N,N-dimethylformamide dimethyl acetal (DMFDMA) into N-heteroaryl-N-methylcyanoamino compounds 5 , as the main products. In some instances N-heteroarylcyanoamino compounds 4 , cyanoimino compounds 7 , and some other products, such as 9 and 10 were also formed. On the other hand, N-heteroarylacetamide oximes 3 (R ? CH₃) were cyclized under the same reaction conditions into 2-methyl-s-triazolo[1,5-x]azines ( 6 ). N-Heteroarylacetamide O-methyl oximes 11 and 12 were prepared from the corresponding acetamidines 2 (R ? CH₃) and O-methylhydroxylamine.     

Studies on the synthesis of heterocyclic compounds. III. Preparation of some pyrazolo[3,4-C] [1,5]benzodiazocin-10(11H)one derivatives

Starting from the readly available N-melhyl-N-(1-phenyl-3-R-pyrazol-5-yl)-2-nitrobenzamides (1a,b), the pyrazoles, 4-aeetyl substituted 2a,b, were prepared in high yield. Reduction of 2a gave the amino derivative 4a, which was eyclized to the desired pyrazolo[3,4-c][1,5]benzodiazo-cin-10(11H)one (5a). Compound 2b afforded 5b directly. Compound 5b was also prepared by the action of phosphorus oxychloride on N-methyl-N-(1,3-diphenylpyrazol-5-yl)-2-acetamido-benzamide (6b).     

Reaction of 6-chloro-2-[1-methyl-2-(N-methylthiocarbamoyl)]-hydrazinoquinoxaline 4-oxide with dimethyl acetylenedicarboxylate

The reaction of 6-chloro-2-(1-methylhydrazino)quinoxaline 4-oxide 4a with methyl or phenyl isothiocyanate gave 6-chloro-2-[1-methyl-2-(N-methylthiocarbamoyl)hydrazino]quinoxaline 4-oxide 7a or 6-chloro-2-[1-methyl-2-(N-phenylthiocarbamoyl)hydrazino]quinoxaline 4-oxide 7b , respectively, whose reaction with dimethyl acetylenedicarboxylate afforded 6-chloro-2-[N-methyl-N-(5-methoxycarbonylmethylene-3-methyl-4-oxo-2-thioxoimidazolidin-1-yl)]aminoquinoxaline 4-oxide 8a or 6-chloro-2-[N-methyl-N-(5-methoxycarbonylmethylene-4-oxo-3-phenyl-2-thioxoimidazolidin-1-yl)]aminoquinoxaline 4-oxide 8b , respectively.     

One-pot tandem ring-opening polymerization of N-sulfonyl aziridines and “click” chemistry to produce well-defined star-shaped polyaziridines

An effective approach for fast synthesis of well-defined star-shaped poly(2-methyl-N-tosylaziridine)s was developed by one-pot tandem ring-opening polymerization (ROP) of N-sulfonyl aziridines with trimethylsilyl azide (TMSN₃) and “click” reaction with alkynes. Azido terminated polyaziridines (α-N₃-PAzs) could be achieved via ROP of N-sulfonyl aziridines with TMSN₃ in the presence of organic superbases. The catalytic efficiency of organobases, including 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA), was evaluated, and all of them except TBD afforded “living”/controlled ROP of 2-methyl-N-tosylaziridines (TsMAz). Star-shaped polyaziridines were then fastly synthesized by the one-pot tandem strategy. During the reaction process, PMDETA catalyzed ROP first, then was triggered to be a ligand by adding CuBr for “click” reaction. Well-defined 3- and 4-arm star P(TsMAz)s were successfully prepared, and subsequently desulfonylated to give star-shaped polypropylenimines (PPIs). PPI stars exhibited intrinsic photoluminescence properties from the polyamine arms.     

Preparation of 2-[1-Phenyl-1H-pyrazol-5-yl]benzoic Acids from Dilithiated C(α),N-Phenylhydrazones and Methyl Hydrogen Phthalate

Select C(α),N-phenylhydrazones were dilithiated with excess lithium diisopropylamide to their dianion-type intermediates followed by condensation with methyl hydrogen phthalate. The resulting C-acylated hydrazones were not isolated but acid cyclized directly to afford new substituted 2-(1-phenyl-1H-pyrazol-5-yl)benzoic acids.     

Nitrogen-15 nuclear magnetic resonance spectroscopy. N?H proton exchange reactions of urea and substituted ureas

Proton-coupled nitrogen-15 NMR spectra of urea, N-methylurea, N,-N′-dimethylurea, N-methyl-N′-benzylurea and N-phenylurea have been obtained at natural abundance level in neutral, basic and acidic solutions at 25°C. Base-catalyzed N? H proton exchange of the ? NH₂ group of N-methylurea in water was found to be 1.5 times faster than that for the -NH- group, while the corresponding acid-catalyzed exchange is 7.5 times faster. Comparison of urea and N,-N′-dimethylurea in water shows urea to be 10 times faster in base but 2 times slower in acid. The ratio of the base-catalyzed N? H proton exchanges of the two -NH- groups of N-methyl-N′-benzylurea in dimethyl sulfoxide is close to unity, whereas the CH₃NH- group exchanges 4 times faster in acid. Similarly, the C₆H₅NH- group of N-methyl-N′-phenylurea exchanges 50 times faster than the CH₃NH- group in base and about 3 orders of magnitude slower in acid. The results are rationalized by consideration of steric and electronic effects.     

Some reactions of 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido) acetic acids

In situ generated 2,4-diaryl substituted münchnones from 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido)acetic acids react with acetic anhydride in the presence of 2-nitromethylene thiazolidine, which is most likely acting as a base, and unexpectedly undergo a Dakin–West type reaction and a concurrent autoxidation reaction leading to the formation of (E)-1-(N,4-dimethylbenzamido)-1-(4-fluorophenyl)prop-1-en-2-yl acetate, 4-substitutedphenyl-N-methyl-N-(4-substitutedbenzoyl) benzamides and p-substituted benzoic acids. In addition, a novel and efficient access to N-acyl urea derivatives is described by the reaction between 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido)acetic acids and cyclohexyl, isopropyl carbodiimides in the presence of a base. The structures of all new products were identified on the basis of NMR and IR spectra, along with X-ray diffraction data and HRMS measurements.     

The Rates of Diazomethane Formation from Methylnitrosoamides. The stability of diazomethane solutions towards aqueous alkalis

The rate of hydrolysis of N-methyl-N-nitrosoamides by aqueous alkalis varies greatly. Methylnitrosourea (1) is hydrolyzed rapidly by aqueous KOH-solutions at low temperatures to give a high yield of diazomethane. Under similar conditions, N,N′-dimethyl-N,N′-dinitroso-oxamide (3) is hydrolyzed more slowly, but also gives a good yield of diazomethane. N,N′-Dimethyl-N,N′-dinitrosoterephthal-amide (4) , and (N-methyl-N-nitroso)-4-amino-4-methyl-2-pentanone (5) are less easily hydrolyzed by aqueous KOH-solutions. N-Methyl-N-nitroso-p-toluenesulfonamide (2) was the least reactive out of those tested. The hydrolysis of diazomethane in toluene with aqueous bases follows first order kinetics. The hydrolysis rate is greatly influenced by the concentration and strength of the base and temperature.     

Internal rotation around the isopropyl-nitrogen bond and stable conformations of S-methyl-N,N-di-isopropyldithiocarbamate,dichlorotin(IV) bis(N,N-di-isopropyldithiocarbamate) and related compounds

Temperature dependent proton magnetic resonance spectra of dichloro- and dimethyltin(IV) bis(N,N-di-isopropyl-dithiocarbamate) ( 1 and 2 , respectively), dimethylchlorotin(IV) N,N-di-isopropyldithiocarbamate ( 3 ), dimethyltin(IV) bis(N-isopropyldithiocarbamate) ( 4 ), S-methyl-N,N-di-isopropyldithiocarbamate ( 5 ) and S-methyl-N-isopropyldithiocarbamate ( 6 ) were measured in halogenated hydrocarbons or CS₂. The internal rotation around the isopropyl–nitrogen bond of 1, 2, 3 and 5 is restricted below ?30°C, and that of 4 and 6 below ?70°C; 1, 2 and 3 exist as only one conformer in dichloromethane, while 5 exists as two rotational isomers with respect to the isopropyl–nitrogen bond with a mole ratio of about 2·7:1·0 in CS₂ below ?30°C. At this temperature, 6 exists as two stereoisomers in CS₂ with a mole ratio of about 1·2:1·0, although there is no stereoisomer in 4 . From these results, possible conformations of the compounds at low temperature are proposed and the assignments of each proton signal are described.     

New and convergent synthesis of saflufenacil

A new, practical, and hundred-gram scale synthesis of saflufenacil, a protoporphyrinogen oxidase (PPO) inhibitor herbicide, is described. The key intermediate N-methyl-N-isopropyl sulfamide ( 12 ) is obtained from sulfuryl chloride isocyanate, t-butanol, and N-methyl-N-isopropylamine in 74.8% yield over 3 steps. Saflufenacil is prepared in 48.6% yield over 8 steps and 98.7% purity (HPLC).     

Aktivierte Chinone: O- versus C-Addition von Phenolen; eine neue,regiospezifische Synthese von Xanthonen,Thioxanthonen und N-Methyl-9-acridonen

Activated quinones: O- versus C-addition of phenols. New regiospecific syntheses of xanthones, thioxanthones and N-methyl-9-acridones The acid catalyzed reaction of phenols with activated quinones, e.g. 2-methoxycarbonyl-1, 4-benzoquinone or 2-acetyl-1, 4-benzoquinone, leads to substituted biphenylderivatives (C, C-addition) as has been previously described [1]. O, C-Addition of phenols has now been achieved by using 2-methoxypyridin or 4-dimethyl-aminopyridin [4] as basic catalysts. The resulting substituted diphenylethers can serve as convenient starting materials for regiospecific syntheses of substituted xanthones, especially for 1, 4-dimethoxyxanthones. Arylthiols and N-methyl-N-arylamines also react readily with activated quinones to give substituted di-aryl-thioethers and N-methyl-N, N-diarylamines respectively; both types of compounds are convenient materials for regiospecific syntheses of substituted thioxanthones and N-methyl-9-acridones.     

ORGANISCHE PHOSPHORVERBINDUNGEN 85.1 HERSTELLUNG,EIGENSCHAFTEN UND BIOLOGISCHE WIRKUNG VON N-AMINOGLYPHOSATE UND AZAGLYPHOSATE

Abstract

The synthesis and the chemical, physical and spectral properties of N-aminoglyphosate ethylester (hydrazino-N′-carbethoxymethyl-N′-methylphosphonic acid) 4a, H₂OPCH₂N(NH₂)CH₂CO₂C₂H₅, of hydrazino-N′-carbethoxymethyl-N′-methyl-P-methylphosphinic acid 4b, CH₃(HO₂)PCH₂N(NH₂)-CH₂CO₂C₂H₅, and of azaglyphosate ethylester (hydrazino-N-carbethoxymethyl-N-methyl-phosphonic acid 9, H₂O₃PCH₂NHNHCH₂CO₂C₂H₅, are described. 4a, 9 and 10 exhibit plant growth regulating properties.     

Preparation,X-ray crystal structure and 13C- and 1H-NMR study of 1-methyl-2-(N-methyl-N-phenylglycyl)-3-(N-methylanilino)indole

Reaction of N-methylaniline with 40% glyoxal yields 1-methyl-2-(N-methyl-N-phenylglycyl)-3-(N-methylanilino)indole ( 1a ) as the main product together with 1-methyl-3-(N-methylanilino)indole ( 1b ). The reaction appears to be general for aromatic secondary amines since N-ethylaniline and N-phenylbenzylamine yield the corresponding indoles. The structure of 1a has been verified by single crystal X-ray diffraction. Compound 1a (C₂₅H₂₅N₃O) crystallized in the triclinic space group Pl? with cell dimensions a = 10.085(3)Å, b = 10.371(3)Å, c = 11.908(5)Å, α = 74.2(3)°, β = 74.7(3)° and γ = 60.7(2)° with Z = 2. The complete ¹H and ¹³C nmr assignment of indoles 1a and 1b was achieved from two-dimensional HETCOR and COSY spectra with the aid of homonuclear and heteronuclear double resonance experiments.     

Etude du couplage 2J(N15?H) en série hétérocyclique. Application à la détermination des constantes d'équilibres prototropiques rapides

The fast tautomeric equilibrium of (N¹⁵)-4-phenylisoxazolin-5-one ( 2 ) has been investigated by a study of ²J(N¹⁵? H₃) coupling. Comparison of the observed values for 2 and for the two fixed forms (N¹⁵)-2-methyl-4-phenylisoxazolin-5-one ( 3 ) and (N¹⁵)-4-phenyl-5-methoxyisoxazol ( 4 ) indicates a considerable amount of enolic type structure for 2 in basic media.     

Aminoacids in the synthesis of heterocyclic systems. The synthesis of methyl 2-acetylamino-3-dimethylaminopropenoate and 2-(N-methyl-N-trifluoroacetyl)amino-3-dimethylaminopropenoate and their application in the synthesis of heterocyclic compounds

Methyl (Z)-2-acetylamino-3-dimethylaminopropenoate (3) was prepared from N-acetylglycine (1), which was converted with N,N-dimethylformamide and phosphorus oxychloride into 4-dimethylaminomethylene-2-methyl-5(4H)-oxazolone (2), followed by treatment with methanol in the presence of potassium carbonate, into 3. The compound 3 was shown to be a versatile reagent in the synthesis of various heterocyclic systems. With N-nucleophiles, such as heterocyclic amines 4, either methyl 2-acetylamino-3-heteroarylaminopropenoates 5 or fused pyrimidinoncs 6 were formed, dependent on the reaction conditions and/or heterocyclic substituents: C-nuclcophiles with an active or potentially active methylene group, such as 1,3-dicarbonyl compounds 7, 8 and 9, substituted phenols 10a,b, naphthols 11, 12a-c, and substituted coumarin 13a, afforded substituted pyranones 20 and 22, and fused pyranones 21, 23–26. The nitrogen containing heterocycles 14–19 produced pyranoazines 27–31 and pyranoazole 32. In all of these systems the acetylamino group is attached at position 3 of the newly formed pyranone ring. The orientation around the double bond for methyl (Z)-2-(N-methyl-N-trifluo-roacetyl)-3-dimethylaminopropenoate (36) was established by X-ray analysis.     

Synthesis and characterization of group 12 complexes of N,N-methyl phenyl-N,N-butyl phenyl dithiocarbamate

Zn(II), Cd(II), and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate (L¹) and N-butyl-N-phenyl dithiocarbamate (L²) formulated as ML¹L² have been synthesized and characterized by elemental analysis, FT–IR, ¹H- and ¹³C-NMR spectroscopic techniques. Single-crystal X-ray structures of the Zn(II) and Hg(II) complexes are also reported. X-ray crystal structures revealed that in the zinc(II) complex, the dithiocarbamate is chelating and bridging, forming eight-member rings, while the Hg complex is monomeric with bidentate dithiocarbamate. In both complexes, the metals are in distorted tetrahedral geometry and the methyl and butyl groups of the dithiocarbamates exhibit compositional disorder between two positions.     

Diazo-Transfer Reaction with Diphenyl Phosphorazidate

Diphenyl phosphorazidate (DPPA) was used as the azide source in a one-pot synthesis of 2,2-disubstituted 3-amino-2H-azirines 1 (Scheme 1). The reaction with lithium enolates of amides of type 2 , bearing two substituents at C(2), proceeded smoothly in THF at 0°; keteniminium azides C and azidoenamines D are likely intermediates. Under analogous reaction conditions, DPPA and amides of type 3 with only one substituent at C(2) gave 2-diazoamides 5 in fair-to-good yield (Scheme 2). The corresponding 2-diazo derivatives 6–8 were formed in low yield by treatment of the lithium enolates of N,N-dimethyl-2-phenylacetamide, methyl 2-phenylacetate, and benzyl phenyl ketone, respectively, with DPPA. Thermolysis of 2-diazo-N-methyl-N-phenylcarboxamides 5a and 5b yielded 3-substituted 1,3-dihydro-N-methyl-2H-indol-2-ones 9a and 9b , respectively (Scheme 3). The diazo compounds 5–8 reacted with 1,3-thiazole-5 (4H)-thiones 10 and thiobenzophenone ( 13 ) to give 6-oxa-1,9-dithia-3-azaspiro[4.4]nona-2,7-dienes 11 (Scheme 4) and thiirane-2-carboxylic acid derivatives 14 (Scheme 5), respectively. In analogy to previously described reactions, a mechanism via 1,3-dipolar cycloaddition, leading to 2,5-dihydro-1,3,4-thiadiazoles, and elimination of N₂ to give the ‘thiocarbonyl ylides’ of type H or K is proposed. These dipolar intermediates with a conjugated C?O group then undergo either a 1,5-dipolar electrocyclization to give spirohetrocycles 11 or a 1,3-dipolar electrocyclization to thiiranes 14 .