Substituted 2-methyl- and 2-methyleneindolines. 3. Nitroamino-5,6-disubstituted 2-methyl- and 2-methyleneindolines

A method is developed for the synthesis of 5,6-disubstituted nitroamino- and nitromethylamino-2-methyl- and-2-methyleneindolines. These are starting compounds for the synthesis of 2-methyleneindolines condensed with some heterocycle.See [1] for Communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1495–1499, November, 1990.     

2-Substituted imidazoles. 3. Metallation of 1-methyl-2-phenyl- and 1-methyl-2-(furyl-2)imidazoles

1-Methyl-2-phenylimidazole reacts with butyllithium to give 5-lithium substituted products. On the other hand, 1-methyl-2-(furyl-2)imidazole is metallated under the same conditions exclusively on the furan ring and primarily in the 3 position. The introduction of triethylamine into the reaction mixture, or replacement of butyllithium by lithium 2,2,6,6-tetramethylpiperidide leads to the formation of a lithium derivative substituted at the 5-position of the furan ring exclusively.For Communication 2, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 61–66, January, 1992.     

Nitroimidazoles. V . Synthesis of 1-methyl-2-(2-methyl-4-thiazolyl)nitroimidazoles

Reaction of readily available 2-methyl-4-formylthiazole ( 1 ) with glyoxal and ammonia gave 2-(2-methyl-4-thiazolyl)imidazole ( 2 ). Nitration of 2 with a mixture of nitric acid-sulfuric acid at 100° yielded 2-(2-methyl-4-thiazolyl)-4,5-dinitroimidazole ( 3 ) as the sole reaction product, while nitration at 65° afforded 2-(2-methyl-4-thiazolyl)-4-(or 5)-nitroimidazole ( 4 ). N-Methylation of compound 4 in the presence of base gave 1-methyl-2-(2-methyl-4-thiazolyl)4-nitroimidazole ( 6 ), whereas N-methylation with diazomethane afforded 1-methyl-2-(2-methyl-4-thiazolyl)-5-nitroimidazole ( 5 ). N-Methylation of compound 3 yielded 1-methyl-2-(2-methyl-4-thiazolyl)-3,5-dinitroimidazole ( 7 ) in high yield.     

Substituted 2-methyl- and 2-methylenindolines

Methods were developed to convert 1,2,3,3-tetramethyl-6-hydroxyindoline into coumarin dyes, in which the amino group is in the indoline system. The structure of the products was indicated by ¹H and ¹³C NMR spectroscopy.Communication 4, see ref. [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1614–1616, December 1992.     

Substituted 2-methyl- and 2-methyleneindolines. 6. Adducts of dialkylphosphites with 1,3,3-trimethyl-2-methyleneindoline. Reagents for synthesizing 5-substituted 2-methyl- and 2-methyleneindolines

The readily formed addition products of dialkylphosphites and 1,3,3-trimethyl-2-methyleneindoline have been used to synthesize 1,2,3,3-tetramethyl-3H-indolium salts and their derivatives substituted in the benzene ring. In most cases the protecting phosphorus group can be readily removed by adding mineral acids.For Communication 5, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1049–1054, August, 1993.     

Steric interactions in 2-substituted imidazoles. The molecular structure of 1-methyl-2-phenylimidazole and 1-methyl-4-phenylimidazole

The crystal and molecular structures are reported for two isomeric imidazoles: 1-methyl-2-phenylimida-zole ( 1 ) and 1-methyl-4-phenylimidazole ( 2 ). In molecule 2 the phenyl ring is rotated by 7.3° from the het-erocyclic plane due to steric interactions. The steric congestion is much more severe in 1 , with the adjacent methyl and phenyl substituents mininizing nonbonded interactions via a 32.3° rotation of the phenyl ring and a 0.159 Å displacement of the methyl carbon from the heterocyclic plane.     

Enantioselective catalysis XXIII. Aminoalcohol assisted decarboxylation of 2-carboxy-2-methyl-1-tetralone leading to enantioenriched 2-methyl-1-tetralone

Summary Catalytic amounts of enantiopure aminoalcohols assist the decarboxylation of 2-carboxy-2-methyl-1-tetralone to 2-methyl-1-tetralone affording enantiomeric excesses of up to 35%. A rapid screening of the efficiency of various potential inductors of enantioselectivity has been carried out using circular dichroism spectroscopy.

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Enantioselektive Katalyse, 23. Mitt. Bildung von optisch angereichertem 2-Methyl-1-tetralon durch aminoalkoholunterstützte Decarboxylierung von 2-Carboxy-2-methyl-1-tetralon

Zusammenfassung Katalytische Mengen von enantiomerenreinen Aminoalkoholen beschleunigen die Decarboxylierung von 2-Carboxy-2-methyl-1-tetralon. Es werden Enantiomerenüberschüsse von bis zu 35% erzielt. CD-Spektroskopie erlaubt eine schnelle Abschätzung der Effizienz von Aminoalkoholen und anderen Verbindungen als Katalysatoren für asymmetrische Reaktionen.

     

Heteroorganic furan derivatives. 61. Trimethyl(5-methyl-2-furyl)silane and trimethyl(5-methyl-2-furyl)germane

The transformations of trimethyl(5-methyl-2-furyl)silane and trimethyl(5-methyl-2-furyl)germane were studied upon vapor-phase oxidation by atmospheric oxygen on a V-Mo-Ag-O catalyst. Under these conditions, trimethyl(5-formyl-2-furyl)-silane and trimethyl(5-formyl-2-furyl)germane are formed albeit in only 5–7% yield. This low yield is a consequence of the thermal instability of the starting compounds and the aldehydes formed. The oxidation of 2-methyl-5-tert-butylfuran was studied under comparable conditions. The corresponding aldehyde was obtained in 30% yield. A scheme was proposed for the catalytic oxidation of 5-substituted 2-methylfurans.For Communication 60, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 22–24, January, 1987.     

Chemistry of 2-hetarylbenzimidazoles. 8. Synthesis and properties of 1-methyl-2-(5′-methyl-2′-selenienyl)benzimidazole

1-Methyl-2-(5-methyl-2-selenienyl)benzimidazole was synthesized and subjected to electrophilic-substitution reactions: nitration, bromination, sulfonation, chloromethylation, formylation, and acylation. The substituent usually enters the 4 position of the selenophene ring, but nitration with acetyl nitrate leads to a mixture of 5-nitro and 4-nitro derivatives. Oxidation of 2-selenienylbenzimidazole with potassium permanganate leads to the 5-carboxy derivative, while oxidation with selenium dioxide leads to the 5-hydroxymethyl and 5-formyl derivatives.See [1] for Communication 7.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1636–1639, December, 1987.     

Research on the chemistry of 2-hetarylbenzimidazoles. 4. Oxidation of 1-methyl-2-(5′-methyl-2′-hetaryl)benzimidazoles

The methyl group in 1-methyl-2-(5-methyl-2-hetaryl)benzimidazoles (hetaryl = furyl and thienyl) was oxidized. It was found that a salt of a carboxylic acid, which in an acidic medium loses carbon dioxide to give 1-methyl-2-(2-furyl)-benzimidazole, is formed when 1-methy1-2-(5-methyl-2-furyl)benzimidazole is treated with an aqueous solution of potassium permanganate. The carboxy derivative of thiophene is considerably more stable. Oxidation by means of selenium dioxide leads to the corresponding 5-formyl derivative. The structures of the compounds obtained were confirmed by data from the IR and PMR spectra.See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1089–1091, August, 1982.     

Synthesis of alkylphenanthrenes from naphthylalkylidenemalonodinitriles. A route to 1-methyl-, 2-methyl-, and 1,2-dimethylphenanthrene

The study has been carried out to evaluate the feasibility of synthesis of 1-methyl-, 2-methyl-, 1,2-dimethyl-, and 1-ethyl-2-methylphenanthrene through the annulation of the naphthalene system with the exploitation of the dicyanovinyl moiety of 2-naphthylalkylidenemalonodinitriles as an active electrophile in cold solutions of concentrated sulfuric acid. 2-(2-Naphthyl)propanal (3), 1-(2-naphthyl)propan-2-one (9), 3-(2-naphthyl)butan-2-one (14), and 3-(2-naphthyl)pentan-2-one (19) had been condensed with malonodinitrile to afford 2-naphthylalkylidenemalonodinitriles which were then cyclised to give 4-amino-1-methylphenanthrene-3-carbonitrile (5), 4-amino-2-methylphenanthrene-3-carbonitrile (11), 4-amino-1,2-dimethylphenanthrene-3-carbonitrile (16), and 4-amino-1-ethyl-2-metylphenanthrene-3-carbonitrile (21). The nitrile function has been removed from the aminonitriles, with the exception of 21, through hydrolysis and decarboxylation in alkaline ethanolic solutions under elevated pressure (∼3 MPa) and temperature 220-230°C to give the respective 4-amino-methylphenanthrenes. Diazotisation of the phenanthreneamines and the reaction with hypophosphorus acid has lead to the methylphenanthrenes in moderate yields (50-52%).     

1H NMR assignments for t-2-deuterio-r-1-methyl-1-phenylcyclopropane and c-2-deuterio-r-1-methyl-1-phenylcylclopropane. A literature correction

The synthesis and ¹H NMR spectra of the cis and trans monodeuterated isomers of 2-deuterio-1-methyl-1-phenylcyclopropane have been previously reported. We have prepared one of the isomers, c-2-deuterio-r-1-methyl-1-phenylcyclopropane, by a different, stereospecific, route. We now wish to correct the original ¹H NMR assignments which were in error.     

Substituted 2-methyl-and 2-methyleneindolines 4. Hetaryl-condensed 2-methyl- and 2-methyleneindolines with a linear structure

Methods have been developed for the synthesis from amino-substituted indolines of first linear trinuclear hetaryl-condensed2-methyleneindolines having quinolone, quinoline, quinoxaline, and benzmidazole fragments. The structure of the obtained compounds was confirmed by ¹H and ¹³C NMR spectra.For communication 3, see [1]Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1331–1335, October, 1992.     

Vinylhydroquinone. IV. Preparation and polymerization behavior of 2-methyl-5-vinylhydroquinone derivatives

As in the case of vinylhydroquinone (I), its alkyl-substituted derivative, 2-methyl-5-vinylhydroquinone (II) was found to copolymerize with methyl methacrylate by tri-n-butylborane in cyclohexanone at 30°C. II was prepared from the O,O′-bisether compound, 2-methyl-5-vinyl-O,O′-bis(1′-ethoxyethyl)hydroquinone (III). The monomer reactivity ratios (M₂ = II) were determined to be r₁ = 0.37 and r₂ = 0. No homopolymerization proceeded under the same conditions. Ordinary free-radical initiators, such as azobisisobutyronitrile and benzoyl peroxide, were not effective in the homopolymerization of II. 1:1 Copolymers were obtained from II and maleic anhydride by using tri-n-butylborane as an initiator. The copolymers exhibited no definite melting range and decomposed at 370–375°C endothermally (DSC). The polymerization behavior of III was also investigated. Although tri-n-butylborane did not initiate the homopolymerization of the monomer, azobisisobutyronitrile was capable of initiating the homopolymerization and copolymerization of III. The monomer reactivity ratios (M₁ = styrene) were determined to be r₁ = 0.83 and r₂ = 0.18. The ratios gave the following Q and e values; Q = 0.15 and e = ?2.2.     

Acylation of benzimidazole by the regel-buechel method. 2. Deacylation and dissociation of 1-methyl-3-acyl-2-(1′-methyl-2′-benzimidazolyl)-4-benzimidazolines

With excess acyl halide 1-methyl-3-acyl-2-(1-methyl-2-benzimidazolyl)-4-benzimidazoline is converted to an unstable 1-methyl-3-acyl-2-(1-methyl-3-acyl-4-benzimidazolin-2-yl)benzimidazolium chloride, which undergoes intramolecular redox cleavage with the formation of 1,1-dimethyl-2,2-dibenzimidazolyl and an aldehyde and dissociates at the C-C bond that connects the benzimidazolium and benzimidazoline fragments into a carbene yield and a 1-methyl-3-acylbenzimidazolium chloride.See [1] for communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 339–342, March, 1987.     

Behavior of propargyl- and allylpropargyl-ammonium salts in aqueous alkaline medium. Synthesis of 2-methyl-2-phenylbenz[f]isoindolinium and 2-methyl-2-phenylisoindolinium salts

Methylphenylpropargyl-(3-phenylpropargyl)-ammonium bromide salts are cyclized almost quantitatively under base-catalysis conditions with the formation of 2-methyl-2-phenylbenz[f]isoindolinium bromide. The allyl analog is subject to rearrangement-decomposition, to a Stevens rearrangement, and to nucleophilic substitution, the cyclic product being obtained in low yield. Methylphenylpropargyl-(3-vinylpropargyl)ammonium bromide is mainly cyclized, but the 3-isopropenylpropargyl analog of this salt is subject to cyclization and subsequent decomposition under analogous conditions.Part 225 of the series on Investigations on Amines and Ammonium Compounds, see [1] for part 224.DeceasedTranslated from Khimiya Geterotsklicheskikh Soedinenii, No. 1, pp. 68–72, January, 1995.     

Crystal and molecular structures of isomeric 2-morpholino-2-thiono-4-methyl-1,3,2-dioxaphosphinane and 2-morpholino-2-oxo-4-methyl-1,3,2-dioxaphosphinane

Two isomeric pairs of compounds, cis- and trans-2-morpholino-2-thiono-4-methyl-1,3,2-dioxaphosphinane ( 1A + 1B ) and 2-morpholino-2-oxo-4-methyl-1,3,2-dioxaphosphinane ( 2A + 2B ) were obtained and separated into the pure compounds by silica gel chromatography. Attempts at crystallization afforded 1A , 1B , and 2B . Each crystalline isomer was studied by the X-ray technique, and each crystal and molecular structures assigned. These studies revealed that 1B and 2B have exocyclic 4-CH₃ and sulfur (for 1B ) or 4-CH₃ and oxygen (for 2B ) in the diequatorial position (cis-geometry), while compound 1A possesses the 4-CH₃ group in equatorial position while sulfur is in an axial position (trans-geometry). For all the examined compounds, all the basic geometrical parameters, such as bond lengths, bond and torsion angles, and the deformation of a chair conformation of the six-membered heterocyclic rings, have been established. Such unambiguous assignment of cis-trans geometry in both pairs of 1 and 2 allowed us to confirm the stereoretentive PS → PO conversion by means of OXONE® and the stereoinvertive mechanism of formic-acid catalyzed hydrolysis of phosphorothiomorpholidates. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:271–279, 1998     

Conformational analysis of 2-methyl-1,3,2-oxaza- and 2-methyl-1,3,2-oxathiaborinane associates with water molecule

The structure and conformational behavior of 1: 1 molecular assotsiates of 2-methyl-1,3,2-oxazaand 2-methyl-1,3,2-oxathiaborinanes with water were studied ab initio in terms of HF/6-31G(d) and PBE/3z quantum-chemical approximations. The most stable complexes are formed via hydrogen bonding with the heteroatoms (oxygen and nitrogen or sulfur). Their conformational behavior implies equilibrium between sofa and half-chair conformers, and intermolecular hydrogen bond is retained in the course of ring interconversion. No associate with a dative O→B bond is formed.     

Kinetics and mechanism of formation of isomeric 1-methyl- and 2-methyl-5-vinyltetrazoles

The alkylation of 5-(β-dimethylaminoethyl)tetrazole (1) with dimethyl sulfate afforded 5-(β-dimethylaminoethyl)-1-methyltetrazole (2) and 5-(β-dimethylaminoethyl)-2-methyltetrazole (3). The exhaustive alkylation of compounds 2 and 3 at the terminal dimethylamino group gave 1-methyl-(4) and 2-methyl-5-(β-trimethylammonioethyl)tetrazole (5) methyl sulfates. The proton elimination from the α-methylene (with respect to the tetrazole cycle) groups of the quaternary ammonium cations of salts 4 and 5 by the action of a base leads to the corresponding zwitterions 4 ^± and 5 ^±, which in the rate-determining step undergo the cleavage of the nitrogen—carbon bond with the formation of 1-methyl-5-vinyl- (6) and 2-methyl-5-vinyltetrazole (7). The true constant of the transformation of zwitterion 4 ^± into tetrazole 6 is 21 times higher than that for the transformation of zwitterion 5 ^± into tetrazole 7.     

Molybdotellurates containing the 1-methyl-, 2-methyl- and 4-methyl imidazolium cations

Four molybdotellurates containing the 1-methylimidazolium, 2-methylimidazolium and 4-methylimidazolium cations have been synthesized and their structures: [2-H2-methyl-imz]6[TeMo6O24 ]·2H2O (2), [2-H2-methyl-imz]6[TeMo6O24 ]·2(2-H-methyl-imz)·2H2O (3) and [4-H2-methyl-imz]6[TeMo6O24 ]·Te(OH)6 (4) determined by X-ray diffraction methods. The protonated organic bases are bonded to the anion in the crystal by hydrogen bonds, except for (4) where the crystal structure consists of discrete [TeMo6O24]6– anions and Te(OH)6 units, both bonded to 4-methylimidazolium cations by hydrogen bonds. The hydrogen bonds were studied as a function of the unit charge of the oxygen atoms of the [TeMo6O24]6– anion. Distortions of the central octahedron of polyanions of formula [XMo6O24]n– (X=AlIII, MoVI, TeVI and IVII), and polyanions of formula [H6YMo6O24]n–, (Y=CoII, CuII, ZnII, CrIII, RhIII and PtIV) are discussed. 95Mo n.m.r spectroscopy of compounds [1-H2-methyl-imz]6[Te-Mo6O24]·Te(OH)6 (1), (2) and (4) indicates the existence of an octahedral oxygen atom arrangement around the molybdenum and a pH variation experiment, carried out with compound (1), confirmed the existence of hydrolytic processes of the compounds in aqueous solution. 125Te n.m.r. studies permitted identification of the Te atom in the [TeMo6O24]6– kernel in all compounds; the presence of two different Te(OH)6 moieties in compounds (1) and (4) was also detected. The similarity between the spectra of both compounds could indicate that (1) has the same structural arrangement as (4). Finally, the thermal behaviour and the thermal stabilities of the complexes as a function of the organic cation were studied.