Stereochemicai study of 7-aryl-1,7,8,8a-tetrahydro-3(2H)indolizinones by1H and13C NMR

Stereochemistry of 7-aryl-1,7,8,8a-tetrahydro-3(2H)-indolizinones was studied by¹H and¹³C NMR. Complete assignment of¹H NMR signals and analysis of¹H-¹H coupling constants were performed using the iterative PANIC program. Values of³ J _6,7,³ J _7,8endo, and⁴ J _5,7 allow one to unambiguously identify the correspondingexo- andendo-stereoisomers. For stereoisomers with exo-orientation of H(7), complete assignment of¹³C NMR signals was performed on the basis of analysis of the¹³C-¹H coupling constants using two dimensional heteronuclear shift-correlating spectroscopy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 591–593, March, 1996.     

Unexpected dimerization of 5,7-dimethyl-2-trifluoromethyl-8-azachromone induced by hydrogen sulfide

Depending on the reaction conditions, the reaction of 5,7-dimethyl-2-trifluoromethyl-8-azachromone with hydrogen sulfide afforded cyclic and linear dimers with the S-S bond. The regio- and stereochemistry of the reaction products were determined by ¹H and ¹³C NMR spectroscopy.     

2-取代硫醚-5-(5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶基)-1,3,4-噁二唑/噻二唑类化合物的合成及生物活性

以5-氨基-1H-1,2,4-三唑-3-羧酸乙酯为起始原料, 设计合成了11个新型的2-取代硫醚-5-(5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶基)-1,3,4-噁二唑类化合物(5)和6个新型的2-取代硫醚-5-(5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶基)-1,3,4-噻二唑类化合物(8). 通过¹H NMR, MS和元素分析对所合成的化合物进行了结构表征. 初步的生物活性测试结果表明, 所合成的化合物均表现出不同程度的除草及杀菌活性, 其中化合物5k和8f的活性最好, 在50 mg/L浓度下对水稻纹枯病菌的抑制率达90%以上.     

Synthetic approaches to 5,7- and 5,8-dimethoxyquinoline. Sonochemical dehalogenation of substituted 2,4-dichloroquinolines. Use of the 2D COLOC spectrum for the NMR assignment of 5,8-dimethoxyquinoline

Summary Sonochemical dehalogenation of 2,4-dichloroquinoline is very facile. However, with 5,7-dimethoxy-2,4-dichloroquinoline the reaction proceeds stepwise to provide the title dimethoxyquinolines which cannot be prepared via theSkraup reaction. The¹³C NMR chemical shift assignments for 5,8-dimethoxyquinoline are presented. These were made by utilising the coupling connectivities from the bridgehead carbons in the 2D COLOC spectrum.

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Synthese von 5,7- und 5,8-Dimethoxychinolin. Sonochemische Dehalogenierung von substituierten 2,4-Dichlorochinolinen. NMR-Spektroskopische Zuordnung von 5,8-Dimethoxychinolin mittels eines COLOC-Experiments

Zusammenfassung 2,4-Dichlorchinoline können sonochemisch leicht dehalogeniert werden. Mit 5,7-Dimethoxy-2,4-dichlorchinolin verläuft die Reaktion in mehreren Schritten zu den Titelverbindungen, die mittelsSkraup-Reaktion nicht hergestellt werden können. Das¹³C-NMR-Spektrum von 5,8-Dimethoxychinolin wurde, ausgehend von den Brückenkopfkohlenstoffatomen, mit Hilfe eines COLOC-Experiments zugeordnet.

     

An NMR study of quaternary ammonium salts of 5,7-dimethyl-1,3-diazaadamantan-6-one

The temperature dependence of the ¹H NMR spectra of quaternary ammonium salts of 5,7-dimethyl-1,3-diazaadamantan-6-one in D₂O was examined. The molar ratio of the ketone and hydrate forms was determined.     

Nitropyrazoles

The structures of substitutedN-aminonitropyrazoles and 1- and 2-amino-4-nitro-1,2,3-triazoles as well as the site of protonation of 1-aminopyrazole were determined based on the¹H,¹³C, and¹⁵N (¹⁴N) NMR spectra. The¹³C NMR spectra were recorded under conditions of¹³C-{¹H,¹⁴N} triple resonance. Effects of substituents in the pyrazole ring on the¹³C and¹⁴N chemical shifts were studied. The¹³C,¹H and¹⁵N,¹H spin-spin coupling constants, obtained using techniques of [¹H]¹³C and [¹H]¹⁵N polarization transfer (SPT, INEPT), were measured, fully assigned, and discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2181–2186, November, 1995.For Part 8, see Ref. 1.     

Molecular structure of di-aryl-aldimines by multinuclear magnetic resonance and X-ray diffraction

The complete ¹H, ¹³C and ¹⁵N NMR analyses for a series of 25 diaryl-aldimines containing phenyl, pyridyl, pyrazolone and furanyl moieties are described herein. Detailed evaluation of substituent chemical shift and coupling constant effects showed that interaction between the lone pair of the pyrazolone carbonyl group or the nitrogen of 2-substitued pyridines with the aldimine hydrogen increases the value and shifts the resonance signal for this hydrogen to high frequency, in the ¹H NMR spectra. The X-ray crystal structure analysis of pyrazolone substituted aldimines evidenced the planarity of the aryl groups which are conjugated with the CN double bond. In the case of the N-(2-pyridinemethylene)-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one, two rotamers were observed in the same unit cell.     

2D-NMR: Part VI. 2D-INADEQUATE spectral analysis and crystal structure of tricyclo[7.3.1.02,7]tridecane

2-Hydroxy-13-oxo-tricyclo[7.3.1.0^2,7]tridecane derivatives can be obtained by reaction of cyclohexanone with alcohols under alkaline conditions. The unambiguous assignment of all signals of the¹H-NMR- and¹³C-NMR-spectrum is possible by 2D-¹H-¹³C-shift correlation and 2D-INADEQUATE. Compound1 crystallizes in space group P2₁/n witha=8.518 (1),b=14.789 (2),c=19.321 (2) Å, =94.91 (1)°,Z=8,D _c =1.22 Mg cm^–3. The structure refined toR=0.100 andR _w =0.097 for 1719 observed reflections. Two independent molecules form centrosymmetric hydrogen-bonded dimers.Part V:Haslinger E.,Kalchhau-ser H.,Robien W.,Steindl H., Monatsh. Chem.115, 597 (1984).     

Reaktivität der Pyrrolpigmente, 2. Mitt.: Deprotonierung von 3-Pyrrolin-2-onen

Deprotonation of 3,4-dimethyl-3-pyrrolin-2-on (1) int-butyl alcohol/potassiumt-butoxide solutions takes place on the N atom, as shown by¹H/²H exchange andpK _a determinations of1 (pK=17.1), 1,3,4-trimethyl-3-pyrrolin-2-one (pK _a =17.6), and 3,4-dimethyl-5-methoxy-2_H-pyrrole (pK _a =16.7). The SCF-MO approximation MINDO/3 indicates, however, that in the gas phase deprotonation of1 should occur at the C atom.

1.Mitt.:Ribó, J. M., Trull, F., Mh. Chem.110, 201 (1979).     

Oxidation of 1-hydrazino-3,3-dimethyl-3,4-dihydroisoquinoline. X-ray,spectroscopic, and quantum-chemical study of the structure of 3,3-dimethyl-3,4-dihydroisocarbostyryl azine

3,3-Dimethyl-3,4-dihydroisocarbostyryl azine (2) has been synthesized by oxidation of l-hydrazino-3,3-dimethyl-3,4-dihydroisoquinoline (1). The crystal and molecular structures of compound 2 were determined. It has been established that in the solid state, compound2 exists as an azine tautomer. The IR, electronic, and NMR spectral data indicate that in solution the tautomeric form of2 does not change. A possible mechanism of the oxidation of1 to2 is suggested.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2468–2474, December, 1995.The authors are grateful to Professor V. F. Zakharov (Russian University of People's Friendship) for recording the¹H NMR spectra.     

NMR spectroscopic study of the (Z)/(E)-isomerism of 1-aryl-3-arylamino-2-propen-1-ones in solution and in the crystalline state

Summary ¹H,¹³C, and CP/MAS¹³C NMR spectra of sixp-substituted 1-aryl-3-arylamino-2-propen-1-ones in solution and in the solid state are reported and discussed. In the proteon-accepting solvent dimethylsulfoxide, electronegative substituents shift the isomeric equilibrium to the (E)-isomer. Bulky substituents promote crystallization of the (Z)-form.

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NMR-Spektroskopische Untersuchung der (Z)/(E)-Isomerie von 1-Aryl-3-arylamino-2-propen-1-onen in Lösung und im Kristallzustand (Kurze Mitt.)

Zusammenfassung ¹H-,¹³C- und CP/MAS-¹³C-NMR Spektren von sechsp-substituierten 1-Aryl-3-arylamino-2-propen-1-onen in gelöstem und festem Zustand werden berichtet und diskutiert. In protonenakzeptierendem Dimethylsulfoxid verschieben elektronegative Substituenten das Gleichgewicht zum (E)-Isomer. Große Substituenten begünstigen die Kristallisation in der (Z)-Form.

     

Simple Procedure for the Synthesis of 5,7-Diarylpyrido[2,3-d]pyrimidine Derivatives catalyzed by KF-Alumina

A simple KF/Al₂O₃-catalyzed reaction of 1,3-diaryl-2-propen-1-one and 2,6-diamino-4-hydroxylpyrimidine in ethyl alcohol gave aromatized 5,7-diarylpyrido[2,3-d]pyrimidine derivative by air oxidation. On the other hand, the unaromatized intermediate products were isolated under dry nitrogen successfully. A possible reaction mechanism with two pathways to lose water was proposed based on the further experimental results; one of them was confirmed by ¹H NMR spectra of isolated intermediate product.     

Determination of the structure of 7-diethylamino-4-(1,2,3-triazol-1-yl)-2H-1-benzopyran-2-one derivatives using two-dimensional heteronuclear chemical-shift correlated NMR techniques

¹H and¹³C NMR spectra of 7-diethylamino-4-(1,2,3-triazol-1-yl)-2H-1-benzopyran-2-one derivatives have been studied. The location of the substituent in the 1,2,3-triazole ring was determined by the 2D COLOC method. It was established that the H(3) and H(5) protons in the coumarin moiety experience anisotropic influence of the phenyl subsituent at the C(5) atom in the triazole ring.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1330–1332, July, 1994.     

1H and 13C NMR Spectra of 9H-Pyrimido[4,5-b]indoles

Based on analysis of ¹H and ¹³C NMR spectra of 9H-pyrimido[4,5-b]indole and its 4-phenyl-2-substituted derivatives, we have made assignments for the signals from the ¹H and ¹³C atoms of these compounds.     

Über das 4-Hydroxy-6,6-dimethyl-5,6-dihydro-2(1H)-pyridinthion bzw.-on und die entsprechenden Tautomeren

The tautomers, 4-hydroxy-5,6-dihydro-6,6-dimethyl-2(1H)-pyridinethione (1) and 6,6-dimethyl-2-thioxo-4-piperidone (2) resp., and 4-hydroxy-5,6-dihydro-6,6-dimethyl-2(1H)-pyridone (9) and 6,6-dimethyl-2,4-piperidinedione (10) resp. were synthesized by hydrolysis of 4-amino-5,6-dihydro-6,6-dimethyl-2(1H)-pyridinethiones (4, 5) and-ones (11, 12).1, 2 and9, 10 undergo an aminolysis in amines to the corresponding 4-aminodihydro-2(1H)-pyridinethiones4, 5 and-ones11, 12 resp.

     

Reactions of 5,7-dimethyl-2-polyfluoroalkyl-8-azachromones with N-nucleophiles

On treatment with ammonia, primary amines, and pyrrolidine, 5,7-dimethyl-2-trifluoromethyl-8-azachromone undergoes ring opening to give -aminovinyl ketones. The reactions with morpholine and piperidine proceed as addition to give 2-morpholino- and 2-piperidino-8-azachromanones. With ethylenediamine, diethylenetriamines, hydrazine hydrate, and hydroxylamine, this compound reacts similarly to 2-polyfluoroalkylchromones, yielding CF₃-containing dihydrodiazepines, pyrazoles, and isoxazoles with a 2-pyridone substituent.     

Umsetzungen von Metall- und Metalloidverbindungen mit mehrfunktionellen Molekülen, 16. Mitt.

The reaction of trimethylsilylcarbonamides with halogeno-diorganyl-boranes resp. trihalogenoboranes or organodihalogenoboranes gives monomeric resp. dimeric amidoboranes (borylcarbonamides) and derivatives of 4,8-diaza-1,5-dibora-2,6,9-trioxabicyclo[3.3.1]nonadienes. By reaction of the free acylamides with halogenoboranes in most cases the imide halides could be isolated as the only products. By reaction of the hydrochloride of bis(dimethylamino)-hydroxyborane withn-butyl-lithium followed by addition of the imide halides, the corresponding imidoylamines were formed.¹H,¹¹B, and¹⁹F-nmr spectra, mass spectra and characteristic ir group frequencies are reported.

15. Mitt.:W. Maringgele undA. Meller, Z. anorg. allg. Chem., im Druck.     

Proton NMR spectra and structure of chlorotin(IV) ternary complexes of 8-quinolinol and its 5,7 dichloro and 2 methyl-5,7 dichloro derivatives

The low temperature ¹H NMR spectra in d-chloroform of the ternary complexes bis-(8-quinolinato) tin(IV) dichloride, bis-(5,7 dichloro-8-quinolinato) tin(IV) dichloride, and bis-(2 methyl-5,7-dichloro-8-quinolinato) tin(IV) dichloride have been obtained. The spectra showed that for the three complexes, only two configurations were appreciably populated, their free energy differences being equal to 0.28, 0.08 and ?0.04 kcal/mol respectively. The proton chemical shifts, the ¹H-¹H coupling constants and some of the ¹H-¹¹⁹Sn coupling constants have been obtained for each complex in the two configurations. An approximate computation of chemical shifts, including aromatic ring magnetic anisotropies and electric effects from polar groups, allowed the identification of the two configurations as the cis-cis-trans and the cis-trans-cis (with respect to Cl, N and O atoms), the former being the more populated one.     

Simulation of 2D H homo- and H-C heteronuclear NMR spectra of organic molecules by DFT calculations of spin-spin coupling constants and H and C-chemical shifts

Simulation of 2D ¹H homo- and ¹H-¹³C heteronuclear NMR spectra of organic molecules are here suggested as a tool in the structure elucidation of organic compounds. DFT calculations of ¹H and ¹³C chemical shifts are performed on a sample compound, the ethyl ester of the exo-2-norbornanecarbamic acid, with the mPW1PW91 method using the 6-31G(d) basis set, following a full optimization of the geometry. Homo and heteronuclear spin-spin coupling constants are also calculated, providing full prediction of the common 2D ¹H-¹H COSY, 2D ¹H-¹³C HSQC, and 2D ¹H-¹³C HMBC.     

Structure of products of the reaction of 2-cyanoaziridine with carbonyl compounds

The structure of azimexone (3), the product of the reaction of 2-cyanoaziridine with acetone, was confirmed on the basis of¹H and¹³C NMR spectra. The formation of this product is accounted for by the -aziridinoalkylating action of an intermediate containing a good leaving iminoyloxy group. Similar reactions were observed for 1-chloromethylaziridine and a 1-aziridinylmethylammonium salt (6), but not for 1-methoxymethylaziridine (7) and 1-aziridinemethanol.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2136–2139, December, 1993.