A study of nitrogen- and sulfur- containing heterocycles

The reaction of 3-amino-6-chloro-2-mercaptopyridine with phenacyl halides has been studied, and a number of 3-aryl-7-chloro-2H-pyrido-[2,3-b]-1,4-thiazines have been synthesized. Two types of intermediate compounds have been isolated: 2-amino-6-chloro-2-phenacyl-thiopyridines and 3-aryl-7-chloro-3-hydroxy-1,2-dihydropyrido[2,3-b]-1,4-thiazines.     

A study of nitrogen- and sulfur-containing heterocycles

The reduction of -cyanoacylurethanes in an aqueous medium in the presence of hydrochlorides of aromatic amines and Raney nickel has given -arylaminoacryloyl-and -alkyl--arylaminoacryloylurethanes which have been converted by heating with 10 % aqueous caustic alkalis into 1-aryl-and 5-alkyl-1-aryluracils.For Communication X, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 8, pp. 1088–1091, August, 1970.     

A study of nitrogen- and sulfur-containing heterocycles

The catalytic hydrogenation of N--cyanoacylureas and 1-alkyl-3--cyanoacylureas in the presence of hydrochlorides of aromatic amines has given N--arylaminoacryloyl-, 1-alkyl-3--arylaminoacryloyl-, N--alkyl--arylaminoacryloyl-, and 1-alkyl-3--alkyl--arylaminoacryloylureas. The action of N- -phenylaminoacryloyl- and 1-methyl -3- -phenylaminoacryloylureas of ethanolic hydrogen chloride has given uracil and 1-methyluracil.For Communication IX, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 6, pp. 847–850, June, 1970.     

A Carbon-13 and nitrogen-15 NMR study of some nitrogen heterocycles

A number of phenyl-substituted nitrogen heterocycles and the corresponding 2,6-diethylphenyl derivatives were examined by 13 C nmr in order to verify that the heterocyclic ring system was the same in both series. The heterocyclic ring carbon shifts did not differ substantially between the phenyl and 2,6-diethylphenyl derivatives for all systems except one, where substantial differences were also seen in the ¹⁵N chemical shifts. Acetylated derivatives were prepared to confirm the cyclization mode in this latter case.     

Investigation of nitrogen- and sulfur-containing heterocycles

Catalytic hydrogenation of cyanoacetyl-, -cyanopropionyl-, and cyanobutyrylurethanes in aqueous media in the presence of Raney nickel and the hydrochlorides of o- and p-toluidines, o- and p-alkoxyphenylamines, p-aminoacetophenone, ethyl p-aminobenzoate, and ethyl p-aminophenylacetate, and in the presence of sodium p-aminosalicylate and acetic acid gave the corresponding -arylaminoacryloyl(or -alkylacryloyl)urethanes, which were converted, without isolation in the pure state, to 1-aryl- and 1-aryl-5-alkyluracils by heating in dilute alkali solutions.See [1] for communication XXV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1280–1282, September, 1974.     

Investigation of nitrogen- and sulfur-containing heterocycles

The chlorine atom in 4-chloro-6,7-dihydro-8H-pyrimido[5,4-b][1,4-oxazin-7-ones is replaced by amine residues and mercapto and methoxy groups and can also be removed in the presence of Pd/C. Pyrimidooxazin-7-ones are alkylated in the 8 position, while, depending on the conditions, the 4-mercapto derivatives are alkylated either at the mercapto group or simultaneously at the mercapto group and in the 8 position.     

Investigation of nitrogen- and sulfur-containing heterocycles

The reaction of (3-amino-6-chloro-2-pyridylmercapto)oxalacetic ester with ammonia, benzylamine, morpholine, and piperidine yielded amides, while the reaction of the ester with hydrazine hydrate gave [2-(ethoxycarbonylmethylthio)-3-pyridyl]oxamic acid hydrazide. The benzylamide and morpholide of this acid were obtained by treatment of 2-chloro-6-hydroxy-6,7-di(ethoxycarbonyl)dihydropyridothiazine with the appropriate amines. The reaction of 2-mercapto-3-amino-6-chloropyridine with chlorooxalacetic ester in the presence of alkali yielded potassium [2-(ethoxycarbonylmethylthio)-3-pyridyl]oxamate.See [1] for communication XXI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1502–1505, November, 1971.     

Investigation of nitrogen- and sulfur-containing heterocycles

The reaction of 5-amino-4-chloro- and -4-methoxy-6~mercaptopyrimidines with 4-methoxy-, 4-amino-, and 2,4-diethoxyphenacyl chlorides has yielded 5-amino-4-chloro- and -4-methoxy-6-phenacylthiopyrimidines. The reaction of 2, 5-diamino-4-methyl-6-mercaptopyrimidine with 4-methoxyphenacyl chloride has yielded 2-amino-6-hydroxy-6-(4-methoxyphenyl)-4-methyl-5, 6-dihydropyrimido[4, 5-b]-1,4-thiazine, and that with 4-aminophenacyl chloride has yielded the corresponding 7H-pyrimido[4, 5-b]-1,4-thiazine.For part IV, see [1].     

Investigation of nitrogen- and sulfur-containing heterocycles

A number of derivatives of a new heterocyclic system — pyrimido[5,4-b][1,4]-7-oxazinone- were obtained by the reaction of substituted 5-hydroxy-6-aminopyrimidines with ethyl esters of-halocarboxylic acids.See [1] for communication XXIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1285–1288, September, 1972.     

Investigation of nitrogen- and sulfur-containing heterocycles

The corresponding N-(3-pyridyl)hydroxamic acid derivatives were obtained by reductive desulfuration of [2-(ethoxycarbonylmethylthio)-6-chloro-3-pyridyl]hydroxamic acid amide, benzylamide, and morpholide. The amides were synthesized by reaction of [2-(ethoxycarbonylmethylthio)-6-chloro-3-pyridyl]hydroxamic acid ester with diethylaminoethylamine and pyrrolidine. Heating of the ester and morpholide of [2-(ethoxycarbonylmethylthio)-6-chloro-3-pyridyl]hydroxamic acid with H₂SO₄ gives 2-chloropyrido[2,3-b] [1,4]thiazin-6-one.See [1] for communication XXVI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 676–678, May, 1973.     

Investigation of nitrogen- and sulfur-containing heterocycles

2-Mercapto-3-ureido-6-chloropyridine reacts with the ortho, meta, and para derivatives of phenacyl halides to give 2-phenacylthio-3-ureido-6-chloropyridines, which are readily cyclized to 6-arylpyrido[2,3-b][1,4]thiazines regardless of the presence or absence of a substituent in the meta and para positions of the benzene ring.See [1] for communication XXIX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 798–800, June, 1974.     

Investigation of nitrogen- and sulfurcontaining heterocycles

It is shown that 5-acetamido-6-carbethoxymethylmercaptopyrimidines (IV-VII) a r e formed by reaction of 5-amino-6-mercaptopyrimidines (I-IlI) with -chloro- and -chloro--methylacetoacetic esters in the presence of excess alkali, while 6-methyl-7-carbethoxy-pyrimidothiazines (XI-XIII) are formed in the absence of alkali; under similar conditions, hydroxyamino compounds VIII-X and 6-carbethoxymethylpyrimidothiazines XIV-XVI are obtained from I-III and -chloroacetoacetic ester. 6-Carbethoxy- and 7-carbethoxypyrimidothiazines XVII-XXI were synthesized from I-III and ethyl bromopyruvate, II, and chloroformylacetic ester, respectively.For Communication XV, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1423–1427, October, 1970.     

Investigation of nitrogen- and sulfur-containing heterocycles

The reaction of o-aminomercapto derivatives of pyrimidine, pyrazine, and pyridine, with -halo acid nitriles was investigated. The corresponding cyanoalkylthio heterocycles, which were converted to 6-amino derivatives of pyrimido[4,5-b]-, pyrazino[2,3-b]-, and pyrido-[2,3-b]-1,4-thiazines, were obtained. The structures of the substances obtained were confirmed by IR, UV, and PMR spectroscopy.See [10] for communication XXII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 944–948, July, 1972.     

Investigation of nitrogen- and sulfur-containing heterocycles

The synthesis of two-ring 1,4-thiazine systems was previously accomplished on the basis of the reaction of o-amino mercapto derivatives of pyridine and pyrimidine with dicarbonyl compounds — halo -keto esters and halo -diketones. In the present paper it is shown that the primary products of this reaction are S--keto-alkylmercapto derivatives, which are subsequently cyclized to the corresponding hydroxy amino compounds. The latter are converted to N-acylamino-S--carbethoxy (keto)alkylmercapto derivatives under the influence of an alkaline agent. The indicated compounds were isolated and characterized [2, 3].See [1] for communication 36.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 250–253, February, 1979.     

Investigation of nitrogen- and sulfur-containing heterocycles

5-Acylamino-6-acylmethylmercaptopyrimidines are formed by reaction of 5-amino-6-mercaptopyrimidines with halo--diketones in alkaline media, while 7-acylpyrimido[4,5-b]-[1, 4]thiazines are formed in close-to-neutral media.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 120–123, January, 1973.     

An investigation of nitrogen- and sulfur-containing heterocycles

The reaction of 3-amino-6-chloro-2-mercaptopyridine with ortho-substituted phenacyl halides has been investigated. Two types of intermediate compounds have been isolated: 3-amino-6-chloro-2-(phenacylthio)pyridines and 2-aryl-2-hydroxy-1,2-dihydro-3H-pyrido[2,3-b][1,4]thiazines. Boiling 3-amino-6-chloro-2-mercaptopyridine with ortho-substituted phenacyl halides in ethanol has given 2-aryl-3H-pyrido[2,3-b][1,4]thiazines.For Communication XXVII, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1262–1265, September, 1973. Original article submitted March 15, 1972,     

Molecular orbital study of some heterocycles containing nitrogen and sulphur

A systematic study of 1, 2, 5-Thiadiazole (I), 2, 1, 3-Benzothiadiazole (II) and the recently synthesised Naphtho[2, 3-c]-1, 2, 5 thiadiazole (III) has been made using the Hückel molecular orbital theory (HMO). Stability and reactivity of these molecules as predicted by HMO calculations are in agreement with experimental observations. For (I) and (II) bond lengths are known and excellent agreement with theory has been shown. Spin densities calculated for the radical anion of (II) are in good agreement with experimental data. Bond lengths in (III) and its reactivity as well as the spin densities for its radical anion are predicted.

---

Zusammenfassung Es wurde eine systematische HMO-Studie von 1, 2, 5-Thiadiazol (I), 2, 1, 3-Benzothiadiazol (II) und dem kürzlich synthetisierten Naphto-[2, 3-c]-1, 2, 5-thiadiazol (III) durchgeführt. Die HMO -Berechnung der Stabilität und Reaktivität ist in Übereinstimmung mit den experimentellen Ergebnissen. Theoretische Bindungslängen für (I) und (II) und Spindichten für (II) sind ebenfalls in Übereinstimmung mit den Experimenten, Bindungslängen und Spindichten für (III) werden vorausgesagt.

---

Résumé Utilisant la méthode des orbitales moléculaires de Hückel (HMO) nous avons étudié systématiquement les 1, 2, 5-thiadiazole (I), 2, 1, 3-benzothiadiazole (II) et le naphto [2, 3-c] 1, 2, 5 thiadiazole (III) récemment synthétisé. La stabilité et la réactivité de ces molécules, telles que la théorie les prédit, sont en bon accord avec les données expérimentales. Les longueurs des liaisons de (I) et (II) sont connues et sont en bon accord avec la théorie. Les densités de spin calculées pour l'anion radicalaire de (II) sont en bon accord avec l'expérience. On prédit les longueurs de liaison et la réactivité de (III) ainsi que les densités de spin de son anion radicalaire.

     

Positive and negative electrospray ionization-collision-induced dissociation of sulfur- containing zwitterionic liquids

The mass spectrometric properties of several (1,2-dimethyl-1H-imidazol-3-ium-3-yl)-alkane-1-sulfonates (alkane=ethyl, propyl and butyl) are investigated in this study. These substances, named zwitterionic liquids (ZILs), were synthesized using classical transformations and analyzed in positive and negative electrospray ionization mode using collision-induced dissociation (0-50 eV). We have also performed regioselective deuterium labeling of the alkyl chain of 3-(1,2-dimethyl-1H-imidazol-3-ium-3-yl)-propane-1-sulfonates. Thus, the mass spectra of isotopically-labeled compounds were used for the confirmation of fragmentation pathways of ZILs. Briefly, the data obtained in this study show that the fragmentation of ZILs is dependent on the alkyl chain length between the imidazolium ring and the sulfonate group. In positive electrospray mode, the main fragments are the imidazolium ring containing even electron ions. On the other hand, in negative electrospray mode, sulfur-containing radical-anions are dominant.     

Gas-phase study of the chemistry and coordination of lead(II) in the presence of oxygen-, nitrogen-, sulfur-, and phosphorus-donating ligands

Using a pickup technique in association with high-energy electron impact ionization, complexes have been formed in the gas phase between Pb(2+) and a wide range of ligands. The coordinating atoms are oxygen, nitrogen, sulfur, and phosphorus, together with complexes consisting of benzene and argon in association with Pb(2+). Certain ligands are unable to stabilze the metal dication, the most obvious group being water and the lower alcohols, but CS(2) is also unable to form [Pb(CS(2))(N)](2+) complexes. Unlike many other metal dication complexes, those associated with lead appear to exhibit very little chemical reactivity following collisional activation. Such reactions are normally promoted via charge transfer and are initiated using the energy difference between M(2+) + e(-) --> M(+) and L --> L(+) + e(-), which is typically approximately 5 eV. In the case of Pb(2+), this energy difference usually leads to the appearance of L(+) and the loss of a significant fraction of the remaining ligands as neutral species. In many instances, Pb(+) appears as a charge-transfer product. The only group of ligands to consistently exhibit chemical reactivity are those containing sulfur, where a typical product might be PbS(+)(L)(M) or PbSCH(3)(+)(L)(M).