Studies in the field of 2,1,3-thia- and selenadiazoles

The reaction of benzo-2,1,3-thiadiazole with hydroxylamine sulfate in concentrated sulfuric acid at 150° C for 1–10 hr has been studied. It has been shown that under these conditions mixtures of different amounts of 4- and 5-aminobenzo-2,1,3-thiadiazoles are formed.For part LII, see [1].     

Investigations of 2,1,3-thia- and selenadiazoles

All three possible isomeric amines are obtained by the reaction of 4- or 5-methylbenzo-2,1,3-thiadiazoles with hydroxylamine sulfate in concentrated sulfuric acid. Under similar conditions, 5,6-dimethyl-4-aminobenzo-2,1,3-thiadiazole is obtained from 5,6-dimethylbenzo-2,1,3-thiadiazole.See [1] for communication LXIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 601–602, May, 1971.     

Studies in the field of 2,1,3-thia- and -selenadiazoles

The results of studies on 2,1,3-thiadiazole, benzo-2,1,3-thiadiazole, benzo-2,1,3-selenadiazole, and their derivatives by chemical, physicochemical, and physical methods give no grounds for assuming that they have a quinoid structure. These results permit the statement that these heterocycles containing quatervalent sulfur or selenium are typical heteroaromatic systems satisfying Hückel's (4n+2) rule.For part LV, see [1].     

Researches on 2,1,3-thia-and selenadiazoles

Chloromethylation of 4- and 5-chlorobenzo-2,1,3-thiadiazoles with dichlorodimethyl ether in the presence of anhydrous aluminum chloride gives 4-chloro-7-chloromethyl- and 5-chloro-4-chloromethylbenzo-2, 1,3-thiadiazoles respectively. Reductive scission followed by treatment with thionyl chloride converts them to 4-chloro-7-methyl- and 5-chloro-4-methylbenzo-2,1,3-thiadiazoles; Chlorination of the latter gives 4-methyl-5,7-dichlorobenzo-2,1,3-thiadiazole. Replacement of the chlorine in the chloromethyl groups gives 4-chloro-7-hydrosymethyl-,5-chloro-4-hydroxymethyl-, 4-chloro-7-cyanomethyl-,4-chloro-7-carboxymethyl-,5-chloro-4-carboxymethylbenzo-2,1,3-thiadiazoles. Reductive scission of 4-chlorobenzo-2,1,3-thidiazole followed by treatment with sodium selenite gives 4-chlorobenzo-2,1,3-selenadiazole.Part XLIII see [1].     

Investigations of 2,1,3-thia- and selenadiazole s

All of the possible isomeric monoaminobenzo-2,1,3-selenadiazoles are formed in the reaction of benzo-2,1,3-selenadizaole 4- or 5-irethyl-, or 5,6-dimethylbenzo 2,1,3-selenadiazoles with hydroxylaminesulfate in concentrated sulfuric acid.See [1] for communication LXV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 328–330, March, 1972.     

Investigations on 2, 1, 3-thia- and selenadiazoles

Nitration and nitrosation of 4-hydroxy-5-methyl-benzo-2, 1, 3-thiadiazole gives 4-hydroxy-5-methyl-7-nitro-and 4-hydroxy-5-methyl-7-nitrosobenzo-2, 1, 3-thiadiazoles. Oxidation of the latter, or of 4,7-diamino-5-methylbenzo-2,1,3-thiadiazole gives 5-methyl-4,7-dihydroxy-2, 1, 3-thiadiazole, forming derivatives with sodium bisulfite or hydroxylamine, and reduced by sodium dithionite to 5-methyl-4, 7-dihydroxybenzo-2, 1, 3-thiadiazole. The latter is also obtained by diazotizing 5-methyl-4-hydroxy-7-aminobenzo-2, 1, 3-thiadiazole, and decomposing the diazonium salt. Nitration of 4-ethoxybenzo-2, 1, 3-thiadiazole with sodium ethoxide gives 4-ethoxy-7-aminobenzo-2, 1, 3-thiadiazole, acetylated to 4-ethoxy-7-acetaminobenzo-2, 1, 3-thiadiazole.For Part XXXVII see [1].     

Investigations in the field of 2,1,3-thiadiazole and 2,1,3-selenadiazole

The action of sodiomalonic ester on 4-bromomethylbenzo-2,1,3-thiadiazole forms a malonate which is converted by acid hydrolysis into 4-(-carboxyethyl)benzo-2,1,3-thiadiazole. When this reaction is carried out with 5-bromomethylbenzo-2,1,3-thiadiazole, mono- and disubstituted malonic esters are formed the acid hydrolysis of which gives the corresponding acids. The nitration of 4-and 5-(-carboxyethyl)benzo-2,1,3-thiadiazoles forms, respectively, 4-(-carboxyethyl)-5,7-dinitrobenzo-2,1,3-thiadiazole and 5-(-carboxyethyl)4-nitrobenzo-2,1, 3-thiadiazole. The reaction of 4-bromomethylbenzo-2,1, 3-thiadiazole with potassium cyanide forms two products: 4-cyanomethylbenzo-2,1, 3-thiadiazole and 1,2-di(benzo-2,1, 3-thiadiazole-4-yl)-2-cyanoethane.For part LVIII, see [1].     

Researches on 2,1,3-thia- and selenadiazole XLV. Nitration of 4-hydroxy- and 4-ethoxybenzo-2,1,3-thiadiazoIe

Nitration of 4-hydroxybenzo-2,1,3-thiadiazole under conditions generally used for phenols, gave a high yield of 4-hydroxy-5-nitrobenzo-2,1,3-thiadiazole. The latter is readily reduced to 4-hydroxy-S-aminobenzo-2,1,3-thiadiazole which on treatment with orthoformic ester gives oxazolo [5,4-e]benzo-2,1,3-thiadiazole. 4-Ethoxybenzo-2,1,3-thiadiazole is nitrated under similar conditions, giving a high yield of a mixture of equal quantities of 4-ethoxy-S-nitro- and 4-ethoxy-7-nitrobenzo-2,1,3-thiadiazole.     

Researches on 2,1,3-thia- and selenadiazole XLV. Nitration of 4-hydroxy- and 4-ethoxybenzo-2,1,3-thiadiazoIe

Nitration of 4-hydroxybenzo-2,1,3-thiadiazole under conditions generally used for phenols, gave a high yield of 4-hydroxy-5-nitrobenzo-2,1,3-thiadiazole. The latter is readily reduced to 4-hydroxy-S-aminobenzo-2,1,3-thiadiazole which on treatment with orthoformic ester gives oxazolo [5,4-e]benzo-2,1,3-thiadiazole. 4-Ethoxybenzo-2,1,3-thiadiazole is nitrated under similar conditions, giving a high yield of a mixture of equal quantities of 4-ethoxy-S-nitro- and 4-ethoxy-7-nitrobenzo-2,1,3-thiadiazole.For Part XLIV see [1].     

Studies in the field of 2, 1, 3-thia- and -selenadiazoles

The thiadiazole ring activates a chlorine atom in the ortho or para positions with respect to the nitro group in the nucleophilic animation of chloronitrobenzo-2, 1, 3-thiadiazoles. The action of ammonia on a chlorobenzo-2, 1, 3-thiadiazole activated by a nitro group in ethylene glycol readily leads to the replacement of the chlorine by an amino group. The resulting aminonitrobenzo-2, 1, 3-thiadiazoles have been reduced to the corresponding diamines and these have been converted into pyrazine, quinoxaline, thiadiazole, and acetic acid derivatives.     

Studies in the field of 2, 1, 3-thia- and -selenadiazoles

The thiadiazole ring activates a chlorine atom in the ortho or para positions with respect to the nitro group in the nucleophilic animation of chloronitrobenzo-2, 1, 3-thiadiazoles. The action of ammonia on a chlorobenzo-2, 1, 3-thiadiazole activated by a nitro group in ethylene glycol readily leads to the replacement of the chlorine by an amino group. The resulting aminonitrobenzo-2, 1, 3-thiadiazoles have been reduced to the corresponding diamines and these have been converted into pyrazine, quinoxaline, thiadiazole, and acetic acid derivatives.For communication L, see [1],     

Investigation of 2, 1, 3-thia- and 2, 1, 3 selenadiazoles

The nitration of naphtho[1,2-d][2,1,3]thiadiazole under the conditions that are normally used for aromatic compounds gives a mixture of 6- and 9-nitronaphthothiadiazoles, which can be reduced to 6- and 9-amino derivatives, respectively. 6-Hydroxynaphthothiadiazole is obtained from 6-aminonaphthothiadiazole by the Sandmeyer reaction, while 8-hydroxynaphthothiadiazole is converted to the 8-amino derivative under the conditions of the Bucherer reaction. 4-Carboxy-5-(o-carboxyphenyl)-2,1,3-thiadiazole was obtained by the oxidation of naphtho[1,2-d][2,1,3]-thiadiazole with a potassium dichromate-dilute sulfuric acid mixture.See [1] for communication LXVI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1496–1502, November, 1972.     

An improved procedure for the nitration of benzo‐2,1,3‐selenadiazoles and their reduction to ortho‐phenylenediamines

A method for the nitration of benzo‐2,1,3‐selenadiazoles using nitric acid dissolved in a mixture of methanesulfonic acid and phosphorus pentoxide at room temperature is presented. The S_N2Ar displacement of fluoride that is observed when sulfuric acid is used as solvent is prevented and yields are high. Sodium nitrate could be used in place of nitric acid with no loss in yield. Following nitration, the 2,1,3‐selenadiazole ring is cleaved with hydriodic acid to afford a 3‐nitro‐ortho‐phenylenediamine. The method is applied to the multi‐gram preparation of 4‐fluoro‐3‐nitrobenzene‐1,2‐diamine.     

Aryleneazachalcogenenes. 2. Photoelectron spectra and electron structures of benzo-2,1,3-thia- and-selenadiazoles and their perfluoro derivatives

The He(I) photoelectron spectra of benzo-2,1,3-thia- and -selenadiazoles and their perfluoro derivatives were measured and interpreted on the basis of calculations by the MNDO method, the -fluoro effect, and an analysis of the vibrational structures and relative intensities of the bands. It was observed that replacement of the sulfur atom by a selenium atom leads to only slight changes in the ionization energies of the MO. This confirms the previous conclusion that replacement of one chalcogen by another has a small effect on the -electron structures of the molecules of these heteroaromatic compounds.See [1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 563–567, April, 1991.     

The mass spectra of some 2,1,3-benzothiadiazoline and 2,1,3-benzothiadiazine 2,2-dioxides

Although the behaviour of 1H, 2H-2,1,3-benzothiadiazoline 2,2-dioxide is similar to that of sulphoxides in the mass spectrometer in losing a molecule of SO₂, the 1,3-dimethyl derivative loses the radical SO₂H. In addition the radical CH₃SO₂ is lost in a one step process that must involve a methyl migration. The radical SO₂H is also lost from 2,1,3-benzothiadiazine 2,2-dioxides methylated in the 3-position and the hydrogen involved is shown to originate from this methyl group by deuterium labelling. The mass spectra of other 2,1,3-benzothiadiazine 2,2-dioxides are also discussed.     

Studies in the anthrapyridone field

It is shown that hydrogen chloride catalyzes the replacement of halogen in the reaction of halogenoanthrapyridines with aromatic amines. Cupric acetate, in the presence of potassium acetate at 80–120° C, does not catalyze the replacement of halogen in these substances. The replacement of the arylamino residues in position 6 of a number of 2, 6-diarylaminoanthrapyridines by alkylamine residues under the action of aliphatic amines, was noted.For part V, see [8].     

Studies in the quinone field

The condensation of p-benzoquinone with substituted N-benzyl-β-aminocrotonic esters has been studied. A series of derivatives of 1-benzyl-5-hydroxyindole containing various substituents in the benzene nucleus of the benzyl radical has been obtained.     

The polarized electronic spectra and electric field spectra of benzo-diazoles. I. 2,1,3-benzoselenadiazole

The analyses of the polarized spectra of the S₁ - S_o transition of 2,1,3-benzoselenadiazole (BSD) dispersed in two different host crystals: naphthalene and p-dichlorobenzene have yielded (1) the assignment of the S₁ state as B₂, and (2) the vibronic coupling activity by b₂ fundamentals. VibronicaUy induced intensity by b₂ fundamentals accounts for only a small fraction of the overall intensity, but the intensity of phonon sidebands amounts to about 80% of the total intensity. The phosphorescence spectrum and the singlet-triplet absorption have been observed. Electric field spectra have been used to (1) measure the change of dipole moments upon excitation: 1Δμ(S₁ - S_o)I = 3.35 D and IΔμ(T₁- S_o) I = 2.26 D, (2) establish the identity of low frequency bands (19 - 111 cm^?1) as phonon sidebands, and (3) probe the nature of vibronic activity.     

Studies in the field of anthrapyridone

A series of cyanines has been obtained by the reaction of 3-methy-l2-methylthioanthrapyridinium methosulfate (V) with compounds containing active methylene groups. Compound V was synthesized from N-methylanthrapyridone by the action of phosphorus oxychloride, treatment of the resulting 2-dichlorophosphonyloxy-3-methylanthrapyridinium chloride with thiourea, and the reaction of the N-methylanthrapyridine-2-thione with dimethyl sulfate.On the nomenclature used in this paper, see the note to the preceding paper [Translator's note].For part IV, see [6].