Über die Basenfraktion eines stark schwefelhältigen Schieferöles

Zusammenfassung Aus der Basenfraktion eines stark schwefelhältigen Schieferöles ließen sich folgende Verbindungen unter Anwendung fraktionierter Destillation, präp. GLC, Adsorptionschromatographie auf Aluminiumoxid und Kieselgel isolieren: Pyridin, 2-, 3-, 4-Methylpyridin, 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-Dimethylpyridin, 2-Äthyl-4-methyl-, 2-Äthyl-6-methylpyridin, 2,3,6-,2,4,6-Trimethylpyridin, 2-Methylchinolin. Daneben wurden erstmalig auch schwefelhältige Stickstoffbasen aufgefunden: 5-Methyl-thieno-[3,2-b]-pyridin, 2,5-Dimethyl-thieno[3,2-b]pyridin, 6-Methyl-thieno[2,3—b]pyridin.

---

Basic components of a shale oil of high sulfur content

The following compounds were isolated from the base fraction of a shale oil of high sulfur content: Pyridine, 2-, 3-and 4-methyl-pyridine, 2.3- 2.4-, 2.5-, 2.6-, 3.4-and 3,5-dimethylpyridine, 2-ethyl-4-methyl-and 2-ethyl-6-methylpyridine, 2.3.6-and 2.4.6-trimethylpyridine, and 2-methylquinoline. For the first time some sulfur-containing nitrogen compounds have been detected: 5-methylthieno[3.2-b]pyridine, 2.5-dimethylthieno[3.2—b]pyridine, and 6-methylthieno[2.3-b]pyridine.

     

A convenient large scale synthesis of 2,6-dimethyl-4-(trimethylstannyl)pyridine

Reaction of phosphorus oxychloride with 2,6-dimethylpyridine N-oxide hydrochloride ( 1 ) gave a mixture of 2-(chloromethyl)-6-methylpyridine ( 2 ) and 4-chloro-2,6-dimethylpyridine ( 3 ). Treatment of this mixture with triethylamine converted 2 to the quaternary salt 4 which was separated by water extraction leaving 3 which was subsequently reacted with trimethylstannyl sodium to yield 2,6-dimethyl-4-(trimethylstannyl)pyridine ( 6 ).     

Formation of pyridines fromN-methylpyrimidinium iodide and enaminoesters

The reaction ofN-methylpyrimidinium iodide with enaminoesters yields a mixture of 3-ethoxycarbonyl-2-methylpyridine and 3,5-diethoxycarbonyl-2,6-dimethylpyridine. Mechanisms of the transformations of the pyrimidine ring found are suggested.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1318–1321, July, 1995.     

Synthesis of trialkyl derivatives of pyrrole and pyrrolidine

Summary 1-Furyl-3-methylaminoalkanes when hydrogenated in the vapor phase on Pt-asbestos, as a result of hydrogenolysis of the furan ring, are converted to 1-methyl homologs of pyrrole and pyrrolidine. At 220° we obtained the 1,5-dimethyl-, 1-methyl-5-ethyl-,1,4-dimethyl-, and 1-methyl-4-ethyl-2-n-propylpyrrolidines in 70% yield, while at 300° we obtained the 1,5-dimethyl-, 1-methyl-5-ethyl-, and 1-methyl-4-ethyl-2-n-propylpyrroles in 73–75% yield.     

Synthesis of 2-[3′-(trifluoromethyl)anilino] -5-hydroxynicotinic acid

2-[3′-(Trifluoromethyl)anilino]-5-hydroxynicotinic acid (2) was synthesized by two routes: a) by direct hydroxylation of 2-[3′-(trifluoromethyl)anilino]nicotinie acid (1) ; and b) by the following sequence starting from 2-chloro-3-methyl-5-nitropyridine (3) via 5-amino-2-chloro-3-methylpyridine (4) , 2-ehloro-5-hydroxy-3-methylpyridine (6) , 5-acetoxy-2-chloro-3-methylpyridine (7) , 5-acetoxy-2-chloronicotinie acid (8) , and 2-chloro-5-hydroxynicotinic acid (9). The correlation of 2 with one of the metabolites of 1 has been accomplished, and the identities of both compounds have been proven.     

A proton magnetic resonance study of complexes of pyridine, 2-methylpyridine 3-methylpyridine, 4-methylpyridine,and 2,6-dimethylpyridine with borane and boron trifluoride

A variable temperature, proton magnetic resonance study has been made of complexes of pyridine, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, and 2,6-dimethylpyridine with borane and boron trifluoride. By lowering the temperature and slowing ligand exchange, separate resonance signals can be observed for bulk and complexed molecules of the base. A direct comparison of the complexing abilities of these ligands was made by studying them in pairs with borane or boron trifluoride. The complexing abilities, as estimated from the NMR data, decreased in the order: 4-MePy > 3-MePy > Py > 2-MePy > 2,6-MePy. This trend was interpreted in terms of steric effects and the basic strengths of these molecules towards boron trifluoride.     

Electrochemical synthesis and studies of substituted 2-thiopyridines

A series of substituted 2-alkyl(aryl-, hetaryl-)thiopyridines was prepared by cathodic electrolysis of thiols in the presence of 2-chloro-3-cyano-4-methoxymethyl-6-methylpyridine or 4-chloro-6-methyl-3-oxo-1H-furo[3,4-c]pyridine. The reaction of 3-cyano-4-methoxymethyl-6-methyl-2(1H)-thiopyridone with alkyl halides in the presence of KOH is regioselective and leads toS-alkyl derivatives. The advantages of electrosynthesis for the preparation of 2-alkylthiopyridines fused with 2(5H)-furanone and of 3-aminothieno [2,3-b]pyridines is demonstrated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2215–2219, December, 1994.     

Reaction of 1,1′-iminobis-2-butanols with sulfuric acid

Treatment of 1,1′-iminobis-2-butanols with 70% w/w sulfuric acid gives cis- and trans-2,6-diethylmorpholines, 3-ethyl-4-methylpyridine and unsaturated 3-ethyl-4-methylpiperidines. Hydrogenation of the unsaturated 3-ethyl-4-methylpiperidines gives cis- and trans-3-ethyl-4-methylpiperidines. With 50% w/w sulfuric acid cis- and trans-2,6-diethylmorpholines and a small amount of cis- and trans-2-ethyl-7-methyl-hexahydro-1,4-oxazepines are obtained.     

An alternate synthesis of 6-substituted-5-deazapteridines

A procedure for synthesis of 2,4-diamino-6-substituted-5-deazapteridines (pyrido[2,3-d]pyrimidines) is described. Condensation of 1-piperidino-1-propene with ethoxymethylenemalononitrile afforded an enamino malononitrile adduct, which when treated with ammonia yielded 2-amino-3-cyano-5-methylpyridine. Cyclization to 2,4-diamino-6-methyl-5-deazapteridine could be effected with guanidine. Similar condensation of piperidinopropene with ethyl methoxymethylenecyanoacetate followed by cyclization with hydroxylamine gave 2-amino-3-carbethoxy-6-methylpyridine 1-oxide. Reduction with phosphorus trichloride afforded the pyridine base, however, attempts to cyclize the amino ester to 2-amino-4-hydroxy-6-methyl-5-deazapteridine were unusccessful.     

Concise formal total synthesis of hybocarpone and related naturally occurring naphthazarins

A concise formal total synthesis of the cytotoxic bisnaphthazarin derivative hybocarpone has been completed through the development of routes to the synthetic precursor, 3-ethyl-2-hydroxy-5,7,8-trimethoxy-6-methyl-1,4-naphthoquinone. The oxidation of 3-ethyl-1,2,4,5,7,8-hexamethoxy-6-methylnaphthalene under Rapoport conditions gave 3-ethyl-2-hydroxy-5,7,8-trimethoxy-6-methyl-1,4-naphthoquinone in modest yields after basic hydrolysis. In addition, treatment of 3-ethyl-1,2,4,5,7,8-hexamethoxy-6-methylnaphthalene with boron tribromide provided access to the naturally occurring naphthazarin, boryquinone. The analogous oxidative demethylation of 3,6-dimethyl-1,2,4,5,7,8-hexamethoxynaphthalene and 3-ethyl-1,2,4,5,7,8-hexamethoxynaphthalene resulted in the synthesis of 2,5,7,8-tetrahydroxy-3,6-dimethyl-1,4-naphthoquinone (aureoquinone) and 3-ethyl-2,5,7,8-tetrahydroxy-1,4-naphthoquinone, respectively. An alternative selective synthetic route to 3-ethyl-2-hydroxy-5,7,8-trimethoxy-6-methyl-1,4-naphthoquinone was also developed utilizing an intramolecular Claisen condensation of methyl 2-butyryl-3,5,6-trimethoxy-4-methylphenylacetate with concomitant in situ aerial oxidation.     

Transformations of Perfluorinated 2-Alkyl- and 2,2-Dialkylbenzocyclobutenones in SbF<Subscript>5</Subscript> and SiO<Subscript>2</Subscript>-SbF<Subscript>5</Subscript>

Perfluorinated 2-methyl- and 2-ethylbenzocyclobutenones on heating in SbF₅ underwent isomerization into perfluoroindan-1-one and perfluoro(2-methylindan-1-one), while their reaction with SiO₂—SbF₅ gave perfluorinated 3-methyl- and 3-ethylphthalides, respectively. Perfluorinated 2-ethyl-2-methyl- and 2,2-diethylbenzocyclobutenones reacted with SbF₅ to produce perfluorinated 2-(but-2-en-2-yl)- and 2-(pent-2-en-3-yl)-benzoic acids, and their transformations in SbF₅ over SiO₂ afforded 5,6,7,8-tetrafluoro-1-oxo-3-trifluoromethyl-1H-isochromene-4-carboxylic acid and perfluoro(4-ethyl-3-methyl-1H-isochromen-1-one), respectively.     

Pulse radiolysis of pyridine and methylpyridines in aqueous solutions

The radicals formed from pyridine, 3-methylpyridine, 3,5-dimethylpyridine, 2,6-dimethylpyridine and 2,4,6-trimethylpyridine by attack of H, e^-_aq, OH and O^•- in acqueous solutions were investigated by pulse radiolysisin the pH-range 1–13.8. The UV-vis. absorption spectra as well as the formation and decay kinetics for the protonated and unprotonated forms of the methylpyridine radicals studied are presented. The pK_a-values for the OH-adducts were determined.     

Magnesium hydrides and the dearomatisation of pyridine and quinoline derivatives

Reactions of the β-diketiminato n-butyl magnesium complex, [HC{(Me)CN(2,6-(i)Pr(2)C(6)H(3))}(2)Mg(n)Bu], with a range of substituted pyridines and fused-ring quinolines in the presence of PhSiH(3) has been found to result in dearomatisation of the N-heterocyclic compounds. This reaction is proposed to occur through the formation of an unobserved N-heterocycle-coordinated magnesium hydride and subsequent hydride transfer via the C2-position of the heterocycle prior to hydride transfer to the C4-position and formation of thermodynamically-favoured magnesium 1,4-dihydropyridides. This reaction is kinetically suppressed for 2,6-dimethylpyridine while the kinetic product, the 1,2-dihydropyridide derivative, was isolated through reaction with 4-methylpyridine (4-methylpyridine), in which case the formation of the 1,4-dihyropyridide is prevented by the presence of the 4-methyl substituent. X-ray structures of the products of these reactions with 4-methylpyridine, 3,5-dimethylpyridine and iso-quinoline comprise a pseudo-tetrahedral magnesium centre while the regiochemistry of the particular dearomatisation reaction is determined by the substitution pattern of the N-heterocycle under observation. The compounds are all air-sensitive and exposure of the magnesium derivatives of dearomatised pyridine and 4-dimethylaminopyridine (DMAP) to air resulted in ligand rearomatisation and the formation of dimeric μ(2)-η(2)-η(2)-peroxomagnesium compounds which have also been subject to analysis by single crystal X-ray diffraction analysis. An unsuccessful extension of this chemistry to N-heterocycle hydrosilylation is suggested to be a consequence of the low basicity of the silane reagent in comparison to the pyridine substrates which effectively impedes any further interaction with the magnesium centres.     

Opening of the four-membered ring in perfluorinated 1-alkyl-2-phenyl- and 1-aryl-1,2-dihydrocyclobutabenzenes in the system I<Subscript>2</Subscript>-SbF<Subscript>5</Subscript>

Reactions of perfluorinated 1-phenyl-, 1-(2-ethylphenyl)-, 1-(4-ethylphenyl)-, 1-methyl-2-phenyl-, and 1-ethyl-2-phenyl-1,2-dihydrocyclobutabenzenes with iodine in antimony pentafluoride at 130°C, followed by hydroysis of the reaction mixture, resulted in the formation of perfluorinated 2-methyl-, 2-ethyl-2′-methyl-, 4-ethyl-2′-methyl-, 2-ethyl-, and 2-propylbenzophenones via opening of the four-membered ring in the initial cyclobutabenzene at the C¹–C² bond. The presence of hydrogen fluoride facilitates the process and promotes profound transformations leading to anthracene derivatives.     

2-Ethyl-3-hydroxy-6-methylpyridine nitroxy succinate as a multifunctional hybrid structure

Russian Chemical Bulletin - The effect of 2-ethyl-3-hydroxy-6-methylpyridine nitroxy succinate (1) on heart, brain, and liver tissues of experimental animals (C57/b1 mice) was studied by EPR. It...     

Ni[(C6H11O)2PS2]2与氮碱加合反应的研究

用光谱法研究了Ni[(C_6H_(11)O)_2PS_2]_2与咪唑,4-甲基吡啶,2,4-二甲基吡啶,2,2＇-联吡啶,乙胺,正丙胺,正丁胺和二乙胺的加合反应,测定了加合反应的平衡常数。平衡常数随着氮碱分子碱度增加而增大,随着氮碱分子空间位阻的增加而减小。讨论了几类氮碱加合反应平衡常数测定的处理方法。     

The synthesis of 4-benzylamino-6-methyl-1H-pyrrolo[3, 2-c]pyridine and 4-benzylamino-6-methyl-1H-pyrrolo[2, 3-b]pyridine

4-Benzylamino-6-methyl-1H-pyrrolo[3,2-c]pyridine ( 2 ) and 4-benzylamino-6-methyl-1H-pyrrolo[2,3-b]pyridine ( 3 ) were synthesized as deaza analogues of the anxiolytic agent 4-benzylamino-2-methyl-7H-pyrrolo[2,3-d]pyrimidine ( 1 ). The 1-deaza analogue (2) was prepared via a multi-step procedure from a pyrrole precursor, 1-benzyl-2-formylpyrrole ( 4 ) while the 3-deaza analogue 3 was synthesized from a pyridine precursor, 2-amino-3,6-dimethylpyridine ( 12 ).     

Crystal Forming Competition Between Some Pyridinium Trifluoroacetic Acetates

It is difficult to separate 4-methylpyridine (4-MP), 3-methylpyridine (3-MP) and 2,6-dimethylpyridine (DMP) which exist concurrently in tar oil distillation, because of their similar boiling points (4-MP, 145℃; 3-MP, 144℃;DMP, 144℃). Efforts have been made to separate 3-MP from the mixture of 4-MP and 3-MP by forming inclusion complex of 3-MP with hexadiyn, and with benzopinacol^[1]. And, trifluoroacetic acid (TFA) has been used to separate 4-MP from the mixture of methylpyridines by reactive distillation^[2]. Recently, TFA is used to separate 4-MP from the mixture by preferential co-crystallization. It is reported hereafter the crystal formation competition between some pyridinium trifluoroacetic acetates.     

4(3H)-Quinazolinones containing heterocyclic group in position 3

The corresponding 2,3-substituted 4(3H)-quinazolinones were obtained in the reactions of 2-methyl- and 2-phenyl-4-oxo-3,1-benzoxazines with 1-amino-1,2,4-triazole, 4-amino-2,3-dimethyl-1-phenyl-5-pyrazolone, 2-amino-5-ethyl-1,3,4-thiadiazole, 3-amino-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydroindazole, 1-amino-3-cyano-4,6-dimethyl-2-pyridone, and 1-amino-3-cyano-6-phenyl-4-trifluoromethyl-2-pyridone. The formation of N-benzolyanthranilamides in the reactions of 2-phenyl-4-oxo-3,1-benzoxazine with 2-amino-5-ethyl-1,3,4-thiadiazole and 1-amino-3-cyano-6-phenyl-4-trifluoromethyl-2-pyridones was exceptional. The structures of two of the products have been confirmed by X-ray crystallography.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 936–943, July, 2000.     

Reinvestigation of the synthesis of 5-arylamino-2-picolines

Reaction of 5-bromo- or 3-bromo-2-methylpyridine with o-nitroaniline gave the corresponding N-[2-methyl-5(or 3)pyridyl]-o-nitroanilines. Reduction to the corresponding amino derivatives and ring closure to 1-[2-methyl-5(or 3)pyridyl]benzotriazole allowed the structures to be confirmed and an earlier literature report to be corrected. Displacement of bromide by anthranilic acid from 5-bromo-2-methylpyridine and decarboxylation gave N-(2-methyl-5-pyridyl)aniline.