Trisubstituted 1,3,5-Triazines. 6. Synthesis of 2,4,6-Tris(acetonyl)-1,3,5-triazine

Acylation of 2,4,6-tris(tert-butoxycarbonylmethyl)-1,3,5-triazine with acetic anhydride in the presence of lithium hydride with subsequent removal of the tert-butoxycarbonyl groups with trifluoroacetic acid leads to 2,4,6-tris(acetonyl)-1,3,5-triazine, the cyclic analog of -cyanoacetone. The special spectral features of this compound compared with triazines obtained previously are discussed.     

The structure of 2,4,6-tris[di(tert-butoxycarbonyl)methylidene]-hexahydro-1,3,5-triazine

The structure of 2,4,6-tris[di(tert-butoxycarbonyl)methylidene]hexahydro-1,3,5-triazine was studied by quantum chemistry, NMR and IR spectroscopy, and X-ray diffraction. This compound exists exclusively in the hexahydro-1,3,5-triazine form both in solution and in the solid phase, although due to the loss of the aromatization energy, this structure should be less stable than a 1,3,5-triazine structure. The formation of strong intramolecular hydrogen bonds confirmed by NMR and IR spectroscopy and X-ray diffraction data may be a main reason for stabilization of the hexahydro-1,3,5-triazine isomer. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1022–1026, June, 2006.     

Synthesis of substituted 2-amino-4,6-bis(nonafluoro-tert-butyl)-1,3,5-triazines

A procedure was developed for the synthesis of substituted 2-amino-4,6-bis(nonafluoro-tert-butyl)-1,3,5-triazines from 2-chloro-4,6-bis(nonafluoro-tert-butyl)-1,3,5-triazine and aliphatic and aromatic amines. The data of¹⁹F NMR spectroscopy are indicative of the presence of a barrier to internal rotation. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1568–1572, August, 1999.     

Nucleophilic Substitution Reactions of 2,4,6-Tris(trinitromethyl)-1,3,5-triazine. 3. Reaction of 2,4,6-Tris(trinitromethyl)-1,3,5-triazine with Azides and Hydrazine

As a result of nucleophilic substitution of the trinitromethyl groups in 2,4,6-tris(trinitromethyl)-1,3,5-triazine, the corresponding monoazido and diazido derivatives have been synthesized. The reaction of the starting triazine with hydrazine acetate in the presence of trifluoroacetic acid leads to 1-acetyl-2,2-bis[4,6-bis(trinitromethyl)-1,3,5-triazin-2-yl]hydrazine.     

Nitromethyl derivatives of 1,3,5-triazine. Synthesis and properties

The destructive nitration of 2,4,6-tris[di(carboxy)methylene]hexahydro-1,3,5-triazine and its esters has been investigated. A first representative of the nitromethyl derivatives of 1,3,5-triazine, viz. 2,4,6-tris(nitromethyl)-1,3,5-triazine, has been synthesized.Deceased.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Institute of Chemical Physics in Chernogolovka, Russian Academy of Sciences, Chernogolovka 142432. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1254–1259, September, 1997.     

Synthesis of new 2H,4H-benzopyrano[3,4-b]yridine-1,3,5-trione derivatives via carbon suboxide

The new 2H,4H-[1]benzopyrano[3,4-b]pyridine-1,3,5-trione derivatives 10a-f were prepared in the following three steps: first the preparation of new N-(tert-butoxycarbonyl)-3-amino-2H-1-benzopyran-2-one derivatives 5a-f by reaction of coumarin-3-carboxylic acids and diphenylphosphorylazide, then hydrolysis of 5a-f with gaseous hydrogen chloride to give the corresponding amines 7a-f , and finally the preparation of 10a-f by reaction of 7a-f and carbon suboxide in the presence of a Lewis acid.     

Heterocyclic ketones in the pfitzinger reaction

By the reaction of isatin with heterocyclic ketones (N-tert-butoxycarbonyl derivatives of pyrrolidin-3-one, piperidin-4-one, piperidin-3-one, 1,2,3,4-tetrahydroquinolin-4-one, 8-azabicyclo[3.2.1]octan-3-one, tetrahydropyran-4-one, tetrahydrobenzopyran-4-one) in the presence of KOH (the Pfitzinger reaction) were synthesized quinoline-4-carboxylic acids [4,3]fused with the respective heterocycles. These acids were involved in the reactions with diazomethane and amines at the carboxy group leading to methyl esters and amides, respectively. The esters obtained reacted with hydrazine hydrate affording the acid hydrazides, which entered in the condensation with benzaldehyde to form phenylhydrazones. The esters and amides containing N-tert-butoxycarbonyl fragment lost the tert-butoxycarbonyl group easily to form the secondary amines dihydrochlorides, the [4,3]fused quinoline-4-carboxylic acid derivatives.     

Thermodynamic stability of 2,4,6-tris(nitromethyl)-1,3,5-triazine: an experimental and theoretical study

The molecular geometries and electronic structures of 2,4,6-tris(nitromethyl)-1,3,5-triazine isomers were investigated by the density functional method DFT/B3LYP/6-311++G** to elucidate the structural factors responsible for the stability of these systems. It was shown that a characteristic feature of the nitromethyl tautomer (1) of 2,4,6-tris (nitromethyl)-1,3,5-triazine consists in nonvalence interactions between an oxygen atom of nitro group and a carbon atom of triazine ring, which are probably due to Coulomb attraction between them. The tautomer with the 2,4,6-tris (nitromethylene)-hexahyrdo-1,3,5-triazine structure (2) is stabilized trough direct polar conjugation between the amino and nitro groups at the double bond. Structural strain of the molecule with the 2,4,6-tris(aci-nitromethyl)-1,3,5-triazine structure (3) is the reason for its thermodynamic instability. X-ray data indicate that the compound under study exists in the triazine tautomeric form 1 and the distances between oxygen atoms of nitro group and carbon atom of the triazine ring are shortened. NMR data suggest the existence of triazine in the nitromethyl form 1 in acetonitrile and acetone and a tautomeric equilibrium between the nitromethyl and nitromethylene forms in a more polar solvent (DMSO). The results obtained suggest a Coulomb-type stabilization of the 2,4,6-tris(nitromethyl)-1,3,5-triazine molecule in the gas phase, in the crystal, and in nonpolar solvents.     

A Convenient Mannich-Type One-Pot Synthesis of Pyrimido[6,1-b][1,3,5]thiadiazines

Summary. 3-(Het)aryl-2-cyanoprop-2-enethioamides easily reacted with primary amines and excessive formaldehyde under mild conditions to afford pyrimido[6,1-b][1,3,5]thiadiazine derivatives in moderate yields. Furthermore, 2-cyano-2-cyclohexylideneethanethioamide reacted in the similar Mannich-type manner to give spiro-conjugated pyrimido-1,3,5-thiadiazines. The structure of 3,7-dibenzyl-8-(fur-2-yl)-3,4,7,8-tetrahydro-2H,6H-pyrimido[6,1-b][1,3,5]thiadiazine-9-carbonitrile was determined by X-ray diffraction analysis.     

Reaction of 4,6-bis(tert-butyl)-2,2,2-trichlorobenzo[d]-1,3,2-dioxaphosphole with phenylacetylene. ipso-Substitution of the tert-butyl group

The reaction of 4,6-bis(tert-butyl)-2,2,2-trichlorobenzo[d]-1,3,2-dioxaphosphole with phenylacetylene follows the mechanism of ipso-substitution of the tert-butyl group that is in para-position relative to the endocyclic O atom of the heterocycle, predominantly yielding 8-(tert-butyl)-2,6-dichloro-2-oxo-4-phenylbenzo[e]-1,2-oxaphosphorinine (NMR data). The structure of its hydrolysis product, 8-(tert-butyl)-6-chloro-2-hydroxy-2-oxo-4-phenylbenzo[e]-1,2-oxaphosphorinine, was proved by X-ray diffraction analysis.     

Trisubstituted 1,3,5-triazines. 2. Synthesis of 1,3,5-triazines from 2,4,6-tris[di(tert-butoxycarbonyl)methylene]hexahydro-1,3,5-triazine

A study was carried out on electrophilic addition and hydrolytic dissociation of 2,4,6-tris[di(tert-butoxycarbonyl)methylene]hexahydro-1,3,5-triazine. Chloro, bromo, and methyl derivatives of tris[di(tert-butoxycarbonyl)methyl]-1,3,5-triazine were synthesized for the first time as well as 2,4,6-tris-(tert-butoxycarbonylmethyl)-1,3,5-triazine. For Communication 1, see ref. [1]. N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow and Institute of Chemical Physics, Russian Academy of Sciences at Chernogolovka, 142432 Chernogolovka, Moscow Oblast. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1404–1407, October, 1998.     

Amine exchange reactions of 3-<Emphasis Type="Italic">tert</Emphasis>-butyl-6-(methylsulfanyl)-1,2,3,4-tetrahydro-1,3,5-triazine hydroiodide with amino acids

3-tert-Butyl-6-(methylsulfanyl)-1,2,3,4-tetrahydro-1,3,5-triazine hydroiodide enters into the amine exchange reaction with glycine and β-alanine in aqueous solution. The final exchange products are [4-(methylsulfanyl)-5,6-dihydro-1,3,5-triazin-3-ium-1(2H)-yl] acetate and 3-[4-(methylsulfanyl)-5, 6-dihydro-1,3,5-triazin-3-ium-1(2H)-yl] propanoate, respectively, crystallizing together with t-butylamine hydroiodide from aqueous or aqueous alcoholic solutions as ion associates, which also can be detected in solution in DMSO-d ₆. [4-(Methylsulfanyl)-5,6-dihydro-1,3,5-triazin-3-ium-1(2H)-yl] acetate can be extracted directly from the reaction mixture after carrying out the amine exchange in aqueous isopropanol or 95% ethanol, as well as by “recrystallization“ of its associate with tert-butylamine hydroiodide from aqueous isopropanol.     

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.     

The Reactions of 6-(tert-Butyl)-3-hydrazino-1,2,4-triazin-5(2H)-one with Carbonyl Compounds

The reaction of 6-(tert-butyl)-3-hydrazino-1,2,4-triazin-5(2H)-one with acetone and benzaldehyde yields the corresponding hydrazones. In the presence of thionyl chloride the benzaldehyde hydrazone is converted to 3-(tert-butyl)-6-phenyl-1,2,4-triazolo[4,3-b]-1,2,4-triazin-2(1H)-one and this can also be formed via the acylation of the starting hydrazinotriazinone using benzoyl chloride.     

Reactions of 3,5-di(tert-butyl)-1,2-benzoquinone with terminal acetylenes in the presence of phosphorus trichloride. ipso-Substitution of the tert-butyl group

The reactions of 3,5-di(tert-butyl)-1,2-benzoquinone with aryl-and alkylacetylenes in the presence of phosphorus trichloride afford 4-aryl(alkyl)-8-tert-butyl-2,6-dichloro-2-oxo-2H-benzo[e][1,2]oxaphosphinines as the major ipso-substitution products of the tert-butyl group by the chlorine atom. 4-Aryl(alkyl)-6,8-di(tert-butyl)-2,5-dichloro-2-oxo-and 4-aryl(alkyl)-6-tert-butyl-2,8-dichloro-2-oxo-2H-benzo[e][1,2]oxaphosphinines were obtained as the minor products. The structures of the stable representatives of this series were confirmed by X-ray diffraction. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1836–1845, September, 2007.     

A general approach toward the synthesis of 8-acylamidopyrazolo[1,5-a]-1,3,5-triazines

An expedient synthesis of 8-acylamidopyrazolo[1,5-a]-1,3,5-triazines was developed by treating 8-amino-4-[N-(4-aminophenyl)-N-(methyl)amino]pyrazolo[1,5-a]-1,3,5-triazine with various acyl chlorides following by the displacement of the so-formed N-(methyl)-N-[4-(acylamido)phenyl]amino leaving group with various amines. Applications to high-throughput synthesis are suggested.     

Hydrolysis of 7,7-Substituted Derivatives of 3-tert-Butyl-3,4-dihydro-2H-thiazolo-[3,2-a][1,3,5]triazin-6(7H)-one

Alkaline hydrolysis of 3-tert-butyl-7,7-bis(hydroxymethyl)-3,4-dihydro-2H-thiazolo[3,2-a][1,3,5]-triazin-6(7H)-one can occur in three directions: with cleavage of the tetrahydrotriazine ring, with cleavage of the thiazolidine ring, and also with opening of both rings. Depending on the process conditions, either the hydrolysis product corresponding to the first direction or the hydrolytic decomposition products corresponding to the second and third directions can be obtained in preparative quantities. Hydrolysis of 3,3′-di-tert-butyl-3′,4′-dihydro-2′ H-spiro[(perhydro-1,3-oxazine)-5,7′-thiazolo[3,2-a][1,3,5]triazin]-6′-one in (NH₄)₂CO₃ solution occurs in two steps: in the first step, cleavage of the tetrahydrotriazine ring occurs; and in the second step, opening of the perhydrooxazine ring occurs. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1089–1097, July, 2005.     

Heterocyclen, 48. Mitt.: Synthesen von substituierten 1,3,5-Triazinen und über eine neuartige Synthese substituierters-Triazolo[4,3-a] 1,3,5-triazine

Zusammenfassung Durch stufenweisen Austausch von Chloratomen im 2,4,6-Trichlor-1,3,5-triazin wurden verschiedene unsymmetrisch substituierte Derivate des 1,3,5-Triazins synthetisiert. Von einigen Hydrazinotriazinen ausgehend gelang die Synthese von substituiertens-Triazolo[4,3-a]-1,3,5-triazinen.

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By a successive replacement of the chlorine atoms in 2.4.6-trichloro-1.3.5-triazine it was possible to synthesize different unsymmetrically substituted derivatives of 1.3.5-triazine. Some hydrazino triazines were used as starting material for the synthesis of substituteds-triazolo[4.3-a]-1.3.5-triazines.

     

The chemistry of 4-hydrazino-7-phenylpyrazolo[1,5-a] -1,3,5-triazines

The reaction of 4-hydrazino-7-phenylpyrazolo[1,5-a]-1,3,5-triazine ( 4 ) with nitrous acid gave 8-phenyltetrazolo[1,5-e]pyrazolo[1,5-a]-1,3,5-triazine ( 5b ), which was determined by pmr and ir spectra to be in equilibrium with 4-azido-7-phenylpyrazolo[1,5-a]-1,3,5-triazine ( 5a ). The equilibrium between the tetrazolo ( 5b ) and azido ( 5a ) forms was studied by pmr and an attempt was made to determine if substituents in the pyrazole nucleus could sufficiently stabilize the tricyclic tetrazolo form ( 5b ) over the bicyclic azido form ( 5a ). Thermal degradation of 5 (a ? b) in an aprotic solvent gave 4-amino-7-phenylpyrazolo[1,5-a]-1,3,5-triazine ( 7 ), indicating the probability of a nitrene mechanism involved in the decomposition. Heating 5 in aqueous base gave both 7 and the “hydroxy” analog, 7-phenylpyrazolo[1,5-a]-1,3,5-triazin-4(3H)one ( 6 ), further substantiating the existence of a nitrene intermediate with a competing nucleophilic displacement of the azido group by a hydroxyl group. Cyclization of 4 with diethoxymethylacetate (DEMA) gave 8-phenyl-s-triazolo[4,3-e]pyrazolo[1,5-a]-1,3,5-triazine ( 8 ), which underwent thermal rearrangement to 8-phenyl-s-triazolo[2,3-e]pyrazolo[1,5-a]-1,3,5-triazine ( 9 ). Acid catalyzed ring opening of 9 with formic acid gave 3-N-formamido-5-phenyl-2(2-s-triazolyl)pyrazole ( 10 ). The failure of 10 to recyclize to 9 with the resultant loss of water, supported the theory that the rearrangement of 8 to 9 might occur simply as a concerted, thermally induced “anhydrous” rearrangement rather than via a covalently hydrated intermediate or a Dimroth type mechanism (in the base catalyzed rearrangement).     

Synthesis of SE- and TE-Containing Amino Acids: Useful Probes for Structural Studies of Proteins

ABSTRACT

The synthesis of (l)-Se-cystine, (l)-[⁷⁷Se]-cystine and (l)-Te-cystine in 4 steps from commercially available 2(S)-[(tert-butoxycarbonyl)amino]-3-hydroxy-propionate has been accomplished. [4-¹³C]Te-Met has been synthesized in a one pot reaction.