Preparation of Partially Hydrogenated 4,6‐Dimethyldibenzothiophenes

The synthesis of three key intermediates of the hydrogenation pathway in the hydrodesulfurization of 4,6‐dimethyldibenzothiophene (4,6‐DM‐DBT; 1 ) is described. The hydrogenated derivatives 1,2,3,4‐tetrahydro‐4,6‐dimethyldibenzothiophene (= 4,6‐dimethyl‐1,2,3,4‐tetrahydrodibenzothiophene; 4,6‐DM‐TH‐DBT; 2 ), 1,2,3,4,4a,9b‐hexahydro‐4,6‐dimethyldibenzothiophene (= 4,6‐dimethyl‐1,2,3,4,4a,9b‐hexahydrodibenzothiophene; 4,6‐DM‐HH‐DBT; 3 ), and dodecahydro‐4,6‐dimethyldibenzothiophene (= 4,6‐dimethylperhydrodibenzothiophene; 4,6‐DM‐PH‐DBT; 4 ) were prepared by direct hydrogenation of 1 . The reactions were carried out in continuous and batch reactors by using metal sulfide as well as noble‐metal catalysts. The influence of the reaction conditions on the formation of the products and the distribution of their stereoisomers was studied in detail. The isomers of the main products were isolated and characterized by NMR, GC/MS/MS, and X‐ray crystal‐structure diffractometry.     

Synthesis of certain substituted pyrimidines as potential schistosomicidal agents

A convenient route is reported for the synthesis of seven new pyrimidine derivatives namely: 2-bromometh-yl-4,6-dimethoxypyrimidine ( 3 ), 2-dibromomethyl-4,6-dimethoxypyrimidine ( 4 ), 2-acetoxymethyl-4,6-dimeth-oxypyrimidine ( 5 ), 2-hydroxymethyl-4,6-dimethoxypyrimidine ( 6 ), 4,6-dimethoxypyrimidine-2-carboxaldehyde ( 7 ), 2-acetoxymethyl-6-methoxy-3,4-dihydropyrimidin-4-one ( 8 ) and 2-hydroxymethyl-3,4-dihydro-6-methoxy-pyrimidin-4-one ( 9 ).     

Reaction of dichloronitrobenzofuroxanes with amines and their derivatives

Reactions of 4,6-dichloro-5,7-dinitrobenzofuroxane and 4,6-dichloro-5-nitrobenzofuroxane with some aliphatic amines were studied. In the reaction of 4,6-dichloro-5,7-dinitrobenzofuroxane with 2,2-dimetoxyethylmethylamine the monosubstituted product was formed for the first time. In the reactions of 4,6-dichloro-5-nitrobenzofuroxane with amines substitution only of one chlorine atom takes place.     

Synthesis of 2,2′-bipyrimidine derivatives

A new total synthesis of 2,2′ -bipyrimidine derivatives by the direct condensation of 2-amidinopyrimidinebenzenesulfonate with dicarbonyl compounds is described. The following 2,2′-bipyrimidines have been prepared: 5-ethyl-4,6-dihydroxy-2,2′-bipyrimidine; 5-ethyl-4,6-dichloro-2,2 -bipyrimidine; 4,6-dihydroxy-2,2′ -bipyrimidine; 5-ethyl-4,6-dimethoxy-2,2′ -bipyrimidine.     

Investigation of the HDS kinetics of dibenzotiophene and its derivatives in real gas oil ??

Summary The hydrodesulfurization (HDS) of dibenzothiophene (DBT), 4-methyl-dibenzothiophene (4 M-DBT), 4,6-dimethyldibenzothiophene (4,6 DM-DBT) and 4,6-diethyldibenzothiophene (4,6 DE-DBT) as real gas oil components on NiMo/Al₂O₃ catalyst was investigated. On the basis of the first order rate constants of HDS of the individual sulfur compounds calculated by both integral and differential evaluations the reactivities of the investigated compounds decreased in the order DBT >> 4 M-DBT > 4,6 DE-DBT ? 4,6 DM-DBT. Additionally, results showed that product inhibition during HDS does not take place.     

Carbenoid reactions of 2-halomethyl-4,6-dimethyl-s-triazines

Reactions of lithium, sodium, and potassium salts of 2,4,6-trimethyl-s-triazine (1) with 2-halomethyl-4,6-dimethyl-s-triazine (2) (X = Cl, Br) in glyme have been studied and found to give 1,2-bis(4,6-dimethyl-s-triazin-2-yl)ethane (3), 1,2-bis(4,6-dimethyl-s-triazin-2-yl)ethene (5), 1,2,3-tris(4,6-dimethyl-s-triazin-2-yl)cyclopropane (6), 1,2,3-tris(4,6-dimethyl-s-triazin-2-yl)propane (7), and 1,2,3,4-tetrakis(4,6-dimethyl-s-triazin-2-yl)butane (8). It is proposed that product 3 is formed primarily via an S(N)2 reaction, whereas the remaining products are formed primarily via carbenoid reactions that are enumerated.     

Development of a novel molecularly imprinted polymer for the retention of 4,6-dimethyldibenzothiophene

Several molecularly imprinted polymers (MIPs) for the retention of 4,6-dimethyldibenzothiophene (4,6-DMDBT) were prepared. The first was a polymer prepared non-covalently with methacrylic acid and ethylene glycol dimethacrylate polymerized in the presence of 4,6-DMDBT. After extraction of 4,6-DMDBT, the selectivity of the imprinted polymer was evaluated by HPLC and compared to a non-imprinted control polymer prepared without 4,6-DMDBT. The imprinted polymer retained 4,6-DMDBT slightly longer than the control polymer. The second polymer was prepared using nickel (II)-methacryloylhistidinedihydrate monomer which was combined with 4,6-DMDBT, and polymerized with ethylene glycol dimethacrylate. This is a novel use of this monomer for retention of sulfur-containing organic compounds. Selectivity for 4,6-DMDBT was much greater in this polymer compared to the first, and retention in acetonitrile was more than three times greater on the imprinted polymer compared to a control polymer. Results indicate the potential use of this novel MIP for the removal of organosulfur compounds from fuel.

Vicarious nucleophilic amination of five-membered 4,6-dinitrobenzoheterocycles

Russian Chemical Bulletin - Reactions of isomeric 4,6-dinitro-1- and 4,6-dinitro-2-phenylindazoles, as well as 4,6-dinitro-2-phenylbenzo[b]furan, with various aminating agents were studied under...     

Brombenzimidazole

Zusammenfassung 4-Brom-, 5-Brom- und 4,6-Dibrom-benzimidazol wurden synthetisiert und ihre UV-Spektren aufgenommen. Die Darstellung des 4,6-Dibrom-benzimidazols gelang durch Erhitzen von 2-Amino-4,6-dibromacetanilid oder 4,6-Dibrom-N,N-diacetyl-o-phenylendiamin auf höhere Temperaturen. Die Bromierung von 2-Nitroanilin und 2-Methyl-5-brombenzimidazol wurde näher untersucht.

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4-Bromo-, 5-bromo- and 4,6-dibromobenzimidazole have been prepared and their ultraviolet absorption spectra recorded. The synthesis of the latter was achieved by heating of either 2 amino-4,6-dibromoacetanilide or 4,6-dibromo-N,N-diacetyl-o-phenylenediamine to higher temperatures. The bromination of 2-nitroaniline and 2-methyl-5-bromobenzimidazole has been investigated.

     

Synthesis of 4,6-dimethyl-2-thioxo-1,2-dihydropyridine-3-carbonitrile by condensation of cyanothioacetamide with acetaldehyde and 1-(prop-1-en-2-yl)piperidine

Three-component condensation of cyanothioacetamide with acetaldehyde and 1-(prop-1-en-2-yl)-piperidine afforded 4,6-dimethyl-2-thioxo-1,2-dihydropyridine-3-carbonitrile which was alkylated with alkyl halides to obtain substituted 2-alkylsulfanyl-4,6-dimethylpyridine-3-carbonitriles, (3-amino-4,6-dimethylthieno-[2,3-b]pyridin-2-yl)(4-cyclohexylphenyl)methanone, and 2,2′-[ethane-1,2-diylbis(sulfanediyl)]bis(4,6-dimethylpyridine-3-carbonitrile).     

Synthesis and biological activity of new hybrids compounds derived from benzofuroxanes and polyene antibiotics

Hybrid compounds based on 4,6-dichloro-5-nitrobenzofuroxan, 7-chloro-4,6-dinitrobenzofuroxan, 5,7-dichloro-4,6-dinitrobenzofuroxan, and polyene antibiotics (amphotericin B and nystatin) have been prepared for the first time. They have exhibited biological activity comparable to that of starting antibiotics. Activity of the compound derived from 5,7-dichloro-4,6-dinitrobenzofuroxan and nystatin towards Trichophyton mentagrophytes is 4 times higher than that of nystatin.     

Reaktionen des 4,6-Dichlor-5-formylpyrimidins

Zusammenfassung Bei der Methanolyse des 4,6-Dichlor-5-formylpyrimidins (I) tritt neben dem 4,6-Dimethoxy-5-formylpyrimidin (III) auch das 4-Methoxy-6-hydroxy-5-formylpyrimidin (IV) als Reaktionsprodukt [in Verhältnis 11] auf. Das Aldoxim V des 4,6-Dichlor-5-formylpyrimidins ist instabil und geht in das 4-Chlor-5-cyano-6-hydroxypyrimidin (VI) über. Beide Reaktionen werden mit Hilfe möglicher Zwischenprodukte erklärt. Hingegen führt Methanolyse des Dimethylacetals von I in guter Ausbeute zum 4,6-Dimethoxy-5-formylpyrimidin (III). Das 4,6-Dichlordimethylacetal (II) wird durch aufeinanderfolgende Sulfanilamidolyse, Methanolyse und Hydrolyse in das Acetal des 4-Sulfanilamido-6-methoxy-5-formylpyrimidins (IX) verwandelt. Die gleiche Reaktionsfolge wird auch mit dem cyclischen Acetal 5-(2-Dioxolano)-4,6-dichlorpyrimidin zu XII durchgeführt.

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During methanolysis of 4.6-dichloro-5-formylpyrimidine (I) 4-methoxy-6-hydroxy-5-formylpyrimidine (IV) is formed as well as 4,6-dimethoxy-5-formylpyrimidine (III) in a ratio of 11. The aldoxime V of 4,6-dichloro-5-formylpyrimidine is not stable and is converted into 4-chloro-5-cyano-6-hydroxypyrimidine (VI). Both reactions are interpreted by considering possible intermediates. On the other hand, methanolysis of the dimethylacetal of I affords a good yield of 4,6-dimethoxy-5-formylpyrimidine (III). The 4,6-dichlorodimethylacetal (II) is converted into the acetal of 4-sulfanilamido-6-methoxy-5-formylpyrimidine (IX) by sulfanilamidolysis followed by methanolysis and hydrolysis. The same series of reactions has also been applied to the cyclic acetal of 5-(2-dioxolano)-4,6-dichloropyrimidine to give XII.

     

Synthesis and properties of some aryl-s-triazines

The synthesis and reactions of several substituted s-triazines were studied in attempts to prepare 4,6-bis(4-chlorophenyl)-s-lriazine-2-carboxylie acid ( 2 ) and 2-aldehyde ( 8 ). The 4,6-bis-(4-chlorophenyl)-s-triazine derivatives were surprisingly inert to a variety of reagents. 4,6-Bis-(4-chlorophenyl)-2-methyl-s-triazine ( 1 ) could not be oxidized with any of a variety of oxidants. On bromination 1 gave 4,6-bis(4-chlorophenyl)-2-dibromomethyl-s-triazine ( 4 ) which was resistant to hydrolysis but on oxidation with selenium dioxide gave 2 . Compound 2 was also prepared by the oxidation of 4,6-bis(4-chlorophenyl)-2-hydroxymethyl-s-triazme ( 7 ) with potassium permanganate. Other reagents did not oxidize 7 to 8 . 4,6-Bis(4-chloroanilino)-2-mcthyl-s-triazine ( 3 ) was also resistant to oxidizing agents. 2-Diazomethy1-4,6-dichloro-s-triazine ( 11 ) on reaction with 4-chloroaniline gave 4,6-bis(4-chloroanilino)-2-chloromethyl-s-triazine ( 12 ). All efforts to prepare 8 were unsuccessful.     

Synthesis of 4,6-disubstituted pyrimidines via Suzuki and Kumada coupling reaction of 4,6-dichloropyrimidine

A series of 4,6-disubstituted pyrimidines were synthesized via Suzuki and Kumada coupling reaction of 4,6-dichloropyrimidine.     

Synthesis of 2-thioxo-4,6-diphenyl-1,2-dihydronicotinonitrile via condensation of benzaldehyde with cyanothioacetamide and <Emphasis Type="Italic">p</Emphasis>-(1-styryl)morpholine

2-Thioxo-4,6-diphenyl-1,2-dihydronicotinonitrile has been prepared via condensation of benzaldehyde with cyanothioacetamide and N-(1-styryl)morpholine; alkylation of the product with alkyl halides has afforded substituted 2-alkylsulfanyl-4,6-diphenylnicotinonitriles and 3-amino-2-acyl-4,6-diphenylthieno[2,3-b]pyridines.     

Preparative synthesis of 4,6-dinitroanthranil

A preparative method for the synthesis of 4,6-dinitroanthranil by intramolecular cyclization of 2-azido-4,6-dinitrobenzaldehyde was developed.     

Synthesis of biologically active derivatives of D-glucosamine-4-phosphate and 1-thyminyl-D-glucosamine-4,6-disulfate

New 1-thyminyl-D-glucosamine-4-phosphate and 1-thyminyl-D-glucosamine-4,6-disulfate derivatives were synthesized. The 1-thyminyl-D-glucosamine-4,6-disulfate derivative showed antiviral activity against HIV.     

Reaction of N,N'-Di(methoxycarbonyl)-p-benzoquinonediimine with Meldrum's Acid and its Analogs

Reactions of 2,2-dimethyl-4,6-dioxo-1,3-dioxane (Meldrum's acid), 2,2-tetramethylene-4,6-dioxo-1,3-dioxane and 2,2-pentamethylene-4,6-dioxo-1,3-dioxane in the presence of MeONa gave rise instead of expectable products of Michael 1,4-addition the corresponding N,N'-di(methoxycarbonyl)-p-benzoquinonediimines substituted in the ring.     

Transamination of azomethines with o-alkylisoureas as a method for the synthesis of 1,2-dihydro-sym-triazines

The reaction of o-alkylisoureas with azomethines leads to the formation of 4,6-dialkoxy-2-aryl-1-N-amidino-1,2-dihydro-sym-triazines. 4,6-Dialkoxy-2-phenyl-1-N-(4,6-dihydroxy-2-pyrimidinyl)-1,2-dihydro-sym-triazines were obtained by cyclization of these compounds with malonic ester.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 995–996, July, 1976.     

Nucleophilic displacement of hydrogen in 4,6-dinitro--benzofuroxan and -benzofupazan. Synthesis of some novel 7-substituted 4,6-dinitro-benzofuroxans and -benzofurazans.

Formal hydride ion displacement readily occurs in 4,6-dinitro-benzofuroxan and -benzofurazan. This process provides a simple two-step synthesis of some new 7-substituted-4,6 dinitro derivatives.