Reactions of 4-amino-1,3,5-dithiazine with ammonia and amines

It is shown that selective replacement of the sulfur atom in the 3 position by a nitrogen atom, which leads to 2,6-dimethyl-4-amino-3H-2,6-dihydro-1,3,5-thiadiazine, occurs when 2H,6H-2,6-dimethyl-4-amino-1,3,5-dithiazine is treated with ammonium hydroxide. Under the same conditions, amines cause profound destruction of 2H,6H-2,6-dimethyl-4-amino-1,3,5-dithiazine with the production of thiourea.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 652–655, May, 1982.     

Investigation of the structure of 2h,6h-2,6-dimethyl-4-amino-1,3,5-dithiazine by IR spectroscopy

It was established by IR spectroscopy that 2H,6H-2,6-dimethyl-4-amino-1,3,5-di-thiazine exists in the amino form in carbon tetrachloride at low concentrations.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1050–1053, August, 1981.     

PMR spectra and structures of 2H,6H-2,6-dimethyl-4-amino-1,3,5-dithiazine and its derivatives

An analysis of the PMR spectra of 2H, 6H-2, 6-dimethyl-4-amino-1,3,5-dithiazine, its acyl derivatives, and 2H, 3H, 6H-2, 6-dimethyl-4-amino-1,3,5-thiadiazine in various solvents and in the presence of Eu(FOD)₃ [tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimettyl-4,6-octanedionato)₃ europium] confirms the structure assigned to it and makes it possible to prefer a cis orientation of the methyl substituents in the half-chair conformation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 485–487, April, 1981.     

Divinyl sulfide. 15. Cycloaddition of divinyl sulfide and its 2-methyl derivatives to thiourea and N-monoalkyl- and N-monoarylthioureas

The heterocyclization of divinyl sulfide with N-monoalkyl- and N-monoarylthioureas and 2-vinyl propen-1-yl sulfide and di(propen-1-yl) sulfide with thiourea in the presence of equimolar amounts of inorganic acids leads to new nitrogen heterocycles 2H,6H-2,6-dialkyl-4-alkylamino- and 2H,6H-2,6-dialkyl-4-imino-5-N-phenyl-1,3,5-dithiazines in salt form. The action of bases on the diathiazine salts gives the corresponding 1,3,5-dithiazines. These heterocycles were found more sensitive to the action of nucleophiles causing ring opening than 1,3,5-dithiazines unsubstituted at the nitrogen atom.For 14, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 697–703, May, 1986.     

The effect of 6- and 7-substituents on the structure and tautomeric conversions of 3,3-dimethyl-1-(4,4-dimethylcyclohexa-2,6-dion-1-yl)-3,4-dihydroisoquinoline

The crystalline and molecular structure of 3,3-dimethyl-6,7-dimethoxy-1-(4,4-dimethylcyelohexa-2,6-dion-1-yl)-3,4-dihydroisoquinoline (I) have been determined. The effects of 6- and 7- substituents on the structure and tautomeric conversion of 3,3-dimethyl-1-(4,4-dimethylcyclohexa-2, 6-dion-1-yl)-3, 4-dihydroisoquinoline in solution have been studied by IR, electronic, x-ray electronic, and NMR spectroscopy and using quantumchemical calculations in the MNDO/H approximation. It was found that I exists in the enamine-diketone tautomeric form in the crystalline state and in solution. The 6- and 7- substituents cause a change in molecular conformation and a corresponding redistribution of electron density.Russian University of National Friendship, Moscow 117198. N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow 117000. Institute of Technical Chemistry, Ural Section, Russian Academy of Sciences, Perm' 614600. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 922–933, July, 1995. Original article submitted April 15, 1995.     

Free-radical addition of phenyl- and diphenylphosphines to 2-vinyl-1,3-dioxa-6-aza-2-silacyclooctanes

Conclusions Phenyl- and diphenylphosphines add to 2,6-dimethyl-2-vinyl-1,3-dioxa-6-aza-2-silacyclooctane upon the action of UV irradiation to form 2,6-dimethyl-2-[(2-phenylphosphino)ethyl)]-1,3-dioxa-6-aza-2-silacyclooctane and 2,6-dimethyl-2-[(2-diphenylphosphino)ethyl]-1,3-dioxa-6-aza-2-silacyclooctane, respectively.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2615–2616, November, 1985.     

Synthesis,structure, and tautomerism of 3a,7-dimethyl-4,6-diphenyl-2-ethynyl-7a-hydroxyperhydropyrrolo[3,2-c]pyridine

Isomeric [with respect to the fusion of the piperidine and pyrrolidine rings, as well as with respect to the mutual orientation of the substituents attached to the C₍₂₎ and C_(3a) carbon atoms] 3a, 7-dimethyl-4,6-diphenyl2-ethynyl-7a-hydroxyperhydropyrrolo[3,2-c]pyridines were isolated for the first time in the reaction of 3,5-dimethyl-2,6-diphenyl-4-piperidinone oxime with acetylene under the conditions of the Trofimov reaction under pressure. It was established that, in solutions, the isomers of this compound with an axial-equatorial fusion of the rings exist in the form of ring—chain tautomers.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 903–914, July, 1992.     

Synthesis and NMR spectral studies of some 2,6-diarylpiperidin-4-one O-benzyloximes

Variously substituted 2,6-diarylpiperidin-4-one O-benzyloximes were synthesized by the direct condensation of the corresponding 2,6-diarylpiperidin-4-ones with O-benzylhydroxylamine hydrochloride. All the synthesized compounds are characterized by IR, Mass and NMR spectral studies. NMR spectral assignments are made unambiguously by their one-dimensional (1H NMR and 13C NMR) and two-dimensional (1H-1H COSY, NOESY, HSQC and HMBC) NMR spectra. All the synthesized compounds are resulted as single isomer, i.e., exclusively E isomer (9-14). The conformational preference of 2,6-diarylpiperidin-4-one oxime ethers with and without alkyl substituents at C-3 and C-5 has also been discussed using the spectral studies. The observed chemical shifts and coupling constants suggest that compounds 8-13 adopt normal chair conformation with equatorial orientation of all the substituents while compound 14 contributes significant boat conformation along with the predominant chair conformation in solution. The effect of oximination on ring carbons, their associated protons, alkyl substituents and ipso carbons are studied. Every proton in the piperidone ring of the oxime ether is observed as distinct signal due to oximination. The order of chemical shift magnitude in compound 8 is H-2a>H-6a>H-5e>H-3e>H-3a>H-5a. For 9-12, the order is H-6a>H-5e>H-2a>H-3a>H-5a, for 13, H-6a>H-2a>H-5e>H-3a>H-5a and for 14, the order is H-2a>H-6a>H-5e>H-3a>H-5a while the 13C chemical shift magnitude for 8-14 due to oximination is C-2>C-6>C-3>C-5.     

Effect of geminal substituents on dehydrogenation of dihydro derivatives of nitrogen heterocycles. 2,3-dihydroperimidines and benzimidazolines

A study was carried out on the rate of hydride ion displacement from 1,3-dimethyl-2-R-2,3-dihydroperimidines and 1,3-dimethyl-2-R-benzimidazolines to 1,3,5-trinitrobenzene. In all cases, inhibition by the substituents at C(₂) is observed but this effect is much more pronounced in 2,3-dihydroperimidines than in benzimidazolines. An x-ray diffraction structural analysis of 1,3-dimethyl-2-phenyl-2,3-dihydroperimidine showed that the geometry of 2,3-dihydroperimidines causes steric blocking of the hydrogen atom at C(₂) by the geminal substituent and substituents at the nitrogen atom.Translated from Khimiya Geterotsiklicheskikh Saedinenii, No. 7, pp. 977–985, July, 1985.     

Study of oxidation reactions of 4H-selenopyrans

The oxidation of 4H-4R-2,6-diphenylselenopyrans was studied. This reaction was found to depend on the presence of substituents at C₍₄₎ of the heterocycle and the reaction conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 24–26, January, 1995.     

3,6,6-trimethyl-4-oxo-1-(2-pyridyl)-4,5,6,7-tetrahydroindazole in Schmidt reaction and Beckmann rearrangement conditions for the 4-hydroxyimino derivative

Treatment of 3,6,6-trimethyl-4-oxo-1-(2-pyridyl)-4,5,6,7-tetrahydroindazole with sodium azide in acids gives 3,7,7-trimethyl-5-oxo-1-(2-pyridyl)-5,6,7,8-tetrahydro(4H)pyrazolo[4,3-b]azepine. Heating 1-(2-pyridyl)-3,6,6-trimethyl- and 1-phenyl-6,6-dimethyl-4-hydroxyimino-4,5,6,7-tetrahydroindazoles in polyphosphoric acid gives 1-phenyl-5,6-dimethyl- and 1-(2-pyridyl)-3,5,6-trimethyl-4-aminoindazole respectively: The reactions of the latter with 4-dimethylaminobenzaldehyde gave the 4-(4-dimethylaminobenzalamino) derivative and with 2-formyldimedone the 4-(4,4-dimethyl-2,6-dioxocyclohexylidenemethylamino) derivative.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 830–834, June, 2000.     

N-heterocyclic phosphenium cations: syntheses and cycloaddition reactions

A series of trifluoromethanesulfonate (OTf) salts of N-heterocyclic phospheniums (NHP) bearing phenyl (1a), para-methoxyphenyl (1b), 2,6-diisopropylphenyl (1c) and mesityl (1d) substituents is reported. The compounds are made by a modification to a literature procedure that improves the overall yields for and by 15 and 23%, respectively. Two unwanted side-products in the synthesis of , the diammonium salt, [(2,6-iPr-C6H3)N(H)2CH2CH2N(H)2(2,6-iPr-C6H3)]Cl2 (4) and the bisphosphine (2,6-iPr-C6H3)N(PCl2)CH2CH2N(PCl2)(2,6-iPr-C6H3) (5), are crystallographically characterized, as is the intermediate cyclic chlorophosphine, C1PN(4-OMe-C6H4)CH2CH2N(4-OMe-C6H4) (3b). The phenyl-substituted NHP is fully characterized, including by X-ray crystallography, for the first time; this compound contains a short P-O contact of 2.1850(14) A. Cycloaddition reactions of with 2,3-dimethyl-1,3-butadiene give the expected spirocyclic phospholeniums, 7,8-dimethyl-1,4-diaryl-1,4-diaza-5-phopshoniaspiro[4.4]non-7-ene, as their OTf salts (6a-d), while reactions with N,N'-dimesityl-1,4-diaza-1,3-butadiene give, except in the case of , which is too bulky to react, the aza analogues, 1,4-dimesityl-6,9-diaryl-1,4,6,9-tetraaza-5-phosphoniaspiro[4.4]non-2-ene (7a, 7b and 7d). The sterically congested is in thermal equilibrium with and free diazadiene, and undergoes a substitution reaction with 2,3-dimethyl-1,3-butadiene to give .     

Products active on mosquitoes,IV: Synthesis and biological activity of 8-propargyloxy-3,7-dimethyl-2,6-octadienyl/6-octenyl ethers

Summary A series of 8-proparglyoxy-3,7-dimethyl-2,6-octadienyl and 8-propargyloxy-3,7-dimethyl-6-octenyl ethers were prepared from 8-hydroxygeranyl and 8-hydroxycitronellyl ethers, respectively. Almost all compounds showed high toxicity toCulex quinquefaciatus larvae at 1 mgl^–1 dose level.

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Gegen Mücken aktive Produkte, 4. Mitt.: Synthese und biologische Aktivität von 8-Propargyloxy-3,7-dimethyl-2,6-octadienyl/6-octenyl-ethern

Zusammenfassung Eine Reihe von 8-Propargyloxy-3,7-dimethyl-2,6-octadienyl- und 8-propargyloxy-3,7-dimethyl-6-octenyl-ethern wurden aus 8-Hydroxygeranyl- bzw. 8-Hydroxycitronellyl-ethern hergestellt. Fast alle Verbindungen zeigten hoch Toxizität gegenüber Larven vonCulex quinquefaciatus in einer Dosierung von 1 mgl^–1.

     

Synthesis of 6-hetaryl-substituted azulenes and their reactions with 2,6-diphenylpyrylium perchlorate

A method for the synthesis of 4,6,8-trimethyl- and 4,8-dimethyl-6-(2-thienyl, 2-benzothiazolyl) azulenes from 2,6-dimethyl-4-(methyl, 2-thienyl, 2-benzothiazolyl)-pyrylium perchlorates and cyclopentadienyllithium is described. The possibility of direct pyrylation of azulenes with 2,6-diphenylpyrylium perchlorate is demonstrated. Azulenes with a pyrylium ring in the 1 position were synthesized, and their behavior with respect to ammonium acetate was investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1045–1047, August, 1980.     

Conformation of 5,5-disubstituted 2,2-dimethyl-1,3-dioxanes

It was established by PMR spectral data that in solutions of derivatives of 5-acetoxymethyl-, 5-methyl-, and 5-hydroxymethyl-2,2-dimethyl-1,3-dioxanes with nitrogen-containing substituents (2,4-disubstituted 1,3,5-triazin-6-ylamino, benzamido, and nitro groups) with an N-C₍₅₎ bond the 1,3-dioxane ring exists in the chair conformation with primarily an axial orientation of the nitrogen-containing substituent. Depending on the nature of the substituents attached to the C₍₅₎ atom, the 1,3-dioxane ring may exist either in the stable chair conformation or may undergo rapid inversion of the chair-chair type at 20 °C.The author sincerely thanks A. I. Kol'tsov for his assistance in recording and interpreting the PMR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 468–473, April, 1985.     

Bromination of 4-aryl-3,5-dialkoxycarbonyl-2,6-dimethyl-1,4-dihydropyridines

4-Aryl-3,5-dialkoxycarbonyl-2,6-dimethyl-1,4-dihydropyridines are brominated by N-bromosuccinimide in methanol at room temperature at the methyl groups at positions 2 and 6 to form mono-, di-, tri-, and tetrabromo derivatives. When the N-unsubstituted bromomethyl-1,4-dihydropyridines are heated they are easily converted to tetrahydrofuropyridines, but in the case of the analogous N-substituted-1,4-dihydropyridines cyclization does not occur. The 2,6-bis(bromomethyl)-substituted products easily replace bromine under the influence of nucleophilic reagents.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1230–1235, September, 1991.     

Condensed Tetrazolo-1,3,5-triazines. 1. Synthesis of 5-Polynitromethyltetrazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]-1,3,5-triazin-7-one Salts

The aziridation of 2-R-4,6-bis(trinitromethyl)-1,3,5-triazines containing electron-donor substituents has been studied. It was found that the corresponding 4-azido-2-dialkylamino-6-trinitromethyl-1,3,5-triazines are formed when R = NMe₂, NEt₂. When R = O^–NMe₄ ⁺ a novel reaction route was discovered leading to the tetramethylammonium salt of 5-polynitromethyltetrazolo[1,5-a]-1,3,5-triazin-7-one which is formed as a result of azido-tetrazole and lactim-lactam tautomeric conversion. Denitration of this salt at the trinitromethyl group occurs with retention of the tetrazolo-1,3,5-triazine structure. An X-ray analysis was carried out for the denitration product which was the dipotassium salt of 5-dinitromethyltetrazolo[1,5-a]-1,3,5-triazin-7-one.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 259–266, February, 2005.     

Reaction of 4-methyl-1,2-phenylenediamine with acetoacetic ester

Depending on the reaction conditions, 4-methyl-1,2-phenylenediamine reacts with acetoacetic ester to form 4,7(or 8)-dimethyl-2,3-dihydro-1H-1,5-benzodiazepinones or 5(or 6)-methyl-1-isopropenylbenzimidazolones. During acid catalysis under mild conditions, the more basic diamine group initially reacts with acetoacetic ester to form ethyl 3-(2-amino-4-toluidino)-crotonate, which subsequently can be converted to the corresponding benzodiazepinone and 2,5-dimethylbenzimidazole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1556–1560, November, 1971.     

The catalytic conversion of homologs of 2-acetylfuran into trialkyltetrahydropyranes

Summary By hydrogenation in the vapor phase on a platinum catalyst at 200–210° we have formed from 2-acetyl-3-alkyl-5-methylfurans the 2,6-dimethyl-4-alkyltetrahydropyranes with yields of 40–45%.     

6,11-Dioxa-D-homoanalogs of steroids by reaction of 2-acetyl-2-cyclohexen-1-ones with 4-hydroxycoumarins

Unsubstituted 2-acetyl-2-cyclohexetz-1-one reacts with 4-hydroxycoumarin following the pattern of a Diels -Alder heterodiene condensation to form 12-methyl-6,11-dioxa-9-hydroxy-D-homo-1,3,5(10), 12-tetraene-7,17a-dione. In the case of 2-acetyl-5,5-dimethyl-2-cyclohexen-1-one, reaction with both 4-hydroxy- and 4,7-dihydroxycoumarin follows the pattern of a Michael addition with the formation of 3-(2-acetyl-5,5-dimethyl-3-oxocyclohexyl)-4-hydroxy-and 4,7-dihydroxy coumarin respectively. Dehydration of both types of adduct gives 6,11-dioxa-D-homoanalogs of steroids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 345–348, March, 1994.