Sulfurization of polymers. 6. Poly(vinylene polysulfide), poly(thienothiophene), and related structures from polyacetylene and elemental sulfur

Polyacetylene obtained by the dehydrochlorination of polyvinyl chloride in the NaOH—DMSO system undergoes sulfurization with elemental sulfur at 120—300 °C to liberate hydrogen sulfide and to form electroconducting (0.7·10^–12—5.8·10^–15Sm nm^–1) and paramagnetic (1.5·10¹⁷—1.7·10¹⁹sp g^–1, g = 2.0035—2.0045, H= 0.44—0.66 mT) dark powders with a metallic luster. Their IR spectra and comparison with the samples of sulfurized polyethylene show that sulfurized polyacetylene contains poly(vinylene polysulfide), poly(thienothiophene), and related structures. The polymers afford the cathode discharge capacity of lithium batteries up to 950 mA h g^–1(in the first cycle) and stable cycling at a level of 500—300 mA h g^–1(25 cycles).     

Reaction of 4,5-diamino-3-methyl-1-phenylpyrazole with 3-dimethylaminopropiophenones. Synthesis of new 4-aryl-6-methyl-8-phenyl-2,3-dihydropyrazolo[3,4-b]diazepines and 4-aryl-8-methyl-6-phenyl-2,3-dihydropyrazolo[4,3-b]diazepines

New 4-Aryl-6-methyl-8-phenyl-2,3-dihydropyrazolo[3,4-b]diazepines and 4-aryl-8-methyl-6-phenyl-2,3-dihydropyrazolo[4,3-b]diazepines were obtained from the reaction of 4,5-diamino-3-methyl-1-phenylpyrazole 1 with one equivalent of the 3-dimethylaminopropiophenones 2 in absolute ethanol. The structures of 4-aryl-6-methyl-8-phenyl-2,3-dihydropyrazolo[3,4-b]diazepines 3 and 4-aryl-8-methyl-6-phenyl-2,3-dihydropyrazolo[4,3-b]diazepines 4 were determined by detailed nmr measurements.     

Synthesis of 2,3-dioxo-2,3-dihydro-4-methyl-6-chloro-1H-pyrrolo[2,3-b]pyridine and its 1-α-L-arabinopyranoside

A new type of isatin analog-2,3-dioxo-2,3-dihydro-4-methyl-6-chloro-1H-pyrrolo[2,3-b]pyridine — was obtained by oxidation of 4-methyl-6-chloro-1H-pyrrolo(2,3-b]pyridine. Condensation of L-arabinose with 4-methyl-6-chloro-2,3-dihydropyrrolo[2,3-b]pyridine and subsequent acetylation and dehydrogenation gave 1-(2,3,4-tri-O-acetyl--L-arabinopyranosyl)-4-methyl-6-chloropyrrolo[2,3-b]pyridine, which served as the starting compound for the synthesis of 1--L-arabinopyranosyl-4-methyl-6-chloropyrrolo[2,3-b]pyridine. Oxidation of 1-(2,3,4-tri-O-acetyl-L-arabinopyranosyl)-4-methyl-6-chloropyrrolo[2,3-b]pyridine gave 1-(2,3.4-tri-O-acetyl--L-arabinopyranosyl)-2,3-dioxo-2,3-dihydro-4-methyl-6-chloropyrrolo [2,3-b]pyridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1083–1086, August, 1977.     

Saturated heterocycles, 75. Preparation of tetracyclic thiophene derivatives with bridgehead nitrogen. Synthesis of polymethylenethieno[2,3—d]dihydropyrrolo-, tetrahydropyrido- and tetrahydroazepino[1,2—a]pyrimidin-4-ones and -4-thiones

The following tetracyclic ring systems and their derivatives have been synthesized for pharmacological investigations: Trimethylenethieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-one and -4-thione (1 a, 5 a); Tetramethylenethieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-one and -4-thione (1 b, 1 j, 5 b); Pentamethylenethieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-one and-4-thione (1 c, 5 c); Trimethylenethieno[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-one and -4-thione (1 d, 5 d); Tetramethylenethieno[2,3—d]tetrahydropyrido[1,2,—a]pyrimidin-4-one and -4-thione (1 e, 5 e); Pentamethylenethieno[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-one and -4-thione (1 f, 5 f); Trimethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-one and -4-thione (1 g, 5 g); Tetramethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-on and -4-thione (1 h, 5 h); Pentamethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-one and -4-thione (1 i, 5 i); Tentamethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-one (7 b); Pentamethylenethieno-[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-one (7 c).Compounds1 a–i were synthesized from 2-amino-3-ethoxycarbonyl-4,5-polymethylenethiophene2 a–c with the corresponding lactim ethers (3 a–c) in chlorobenzene in the presence of polyphosphoric acid (PPA). Compounds7 b and7 c were obtained in the reaction of -amino acid esters2 b and2 c with 2-bromopyridine (6). The thione derivatives (5 a–i) were prepared from compounds1 a–i with phosphorus(V) sulphide.Part 74:Szabó J, Fodor L, Szcs E, Bernáth G, Sohár P (1984) Pharmazie 39: 347.     

Synthesis of 1H-pyrrolo[2,3-b]phenoxathiin-2,3-dione

The title compound was obtained using the Sandmeyer reaction starting from 2-aminophenoxathiine. A new synthesis of N-methylpyrrolo[2,3-b]phenoxathiin-2,3-dione was also presented. Chemical and spectral data supporting the structure of the newly synthesized compounds were given. The isatin analogue, 1-methylpyrrolo-[2,3-b]phenoxathiin-2,3-dione-10, 10-dioxide, could not be obtained.Faculty of Chemistry, Organic Chemistry Department, University of Bucharest, 90–92 Panduri Road, Romania. Faculty of Pharmacy, Organic Chemistry Department, University of Medicine and Pharmacy Carol Davila, Bucharest, Romania. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 396–399, March, 1998.     

Sulfurization of polymers. 4. Poly(4,5,6,7-tetrathiono-4,5,6,7-tetrahydrobenzothiophene-2,3-diyl) and related structures based on polystyrene and elemental sulfur

Polystyrene was exhaustively sulfurized with elemental sulfur at 190--370 °C to liberate hydrogen sulfide and to form black lustrous powders (the sulfur content was up to 67%) possessing conductivity (10^–7--10^–6 S cm^–1 upon doping with I₂), paramagnetic properties ((3.4--13)·10¹⁹ sp g^–1, g = 2.0040--2.0046, H = 0.36--0.47 mT), and redox properties. The use of these polymers as active cathode materials in lithium batteries allows their repeated cycling at a specific discharge capacity of up to 330 mA h g^–1. The data of elemental analysis and differential scanning calorimetry, the IR and ESR spectra, the conductivities, and the character of electrochemical activity of the polymers synthesized are consistent with poly(4,5,6,7-tetrathiono-4,5,6,7-tetrahydrobenzothiophene-2,3-diyl) and related structures.     

Synthesis and transformations of 3-(1H-pyrrol-1-yl)thieno[2,3-b]pyridines

Reactions of 2,5-dimethoxytetrahydrofuran with 3-aminothieno[2,3-b]pyridines afford a number of substituted 3-(1H-pyrrol-1-yl)thieno[2,3-b]pyridines. The possibility of the reaction and the yield of the product are determined by the character of a substituent in position 2 of thieno[2,3-b]pyridine. The Curtius rearrangement of 2-acylazido-3(1H-pyrrol-1-yl)thieno[2,3-b]pyridines yields 4,5-dihydropyrido[3",2":4,5]thieno[2,3-e]pyrrolo[1,2-a]pyrazin-4-ones. The molecular and crystal structures of ethyl 4-methoxymethyl-6-methyl-3-(1H-pyrrol-1-yl)thieno[2,3-b]pyridine-2-carboxylate were determined by X-ray diffraction analysis.     

Heterocyclizations in the pyrido[2,3-b]pyrazine series

In this paper, we report the results of heterocyclizations in the pyrido[2,3-b]pyrazine series to give the pyrido[2,3-e] or [3,2-e]pyrrolo[1,2-a]pyrazine. The Clauson-Kaas reaction on 2,3-diaminopyridine is investigated; regioselectivity on the 3-amino group is shown by ¹H- and ¹³C-nmr. Synthesis and reactivity of the original pyrazino[2,3-g]indolizine series is also reported.     

Unambiguously confirmed structure of 2-phenacylidene-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one and 3-phenacylidene-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one

To determine the structures of two isomeric products, 2-phenacylidene-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one (2) and 3-phenacylidene-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one (3) obtained by condensation of 2,3-diaminopyridine (1) with ethyl benzoylpyruvate [1–3], these compounds were hydrolyzed to give 2-methyl-4H-pyrido[2,3-b]pyrazin-3-one (4) and 3-methyl-1H-pyrido[2,3-b]pyrazin-2-one (5) , respectively [4,5]. Both hydrolysates 4 and 5 were hydrogenated to afford 2-methyl-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one (6) and 3-methyl-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one (7) . The latter compound was identical with an unequivocally synthesized compound providing proof for the structures of all these compounds.     

Pyrylium[2,3-b]indole salts

2-Ketoindoline and 1-methyl-2-ketoindoline condense with hydroxymethylene ketones in the presence of hydrogen chloride to give pyrylium[2,3-b]indole chlorides, which can be converted to 5-(3-oxindolyl)-²-pyrazolines by reaction with phenylhydrazine and to 5-(3-oxindolyl)-²-isoxazolines by reaction with hydroxylamine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1030–1032, August, 1972.     

The synthesis of 5,6-dihydro-6-methylthiazolo-[2,3-b] [1,3] benzodiazepines, 2,3,10,11-tetrahydro-10-methyl-1H-cyclopenta[4,5] thiazolo[2,3-b] [1,3] benzodiazepine,and 7,8,9,10,12,13-hexahydro-13-methylbenzothiazolo[2,3-b] [1,3]-benzodiazepine via 1,3,4,5-tetrahydro-5-methyl-2H-1,3-benzodiazepine-2-thione

Catalytic reductive scission of 4-methylcinnoline (V) with Raney nickel afforded o-amino-β-methylphenethylamine (IV) in 57% yield. Treatment of IV with carbon disulfide followed by thermal cyclization of the product furnished 1,3,4,5-tetrahydro-5-methyl-2H-1,3-benzodiazepine-2-thione (III). Reaction of III with ethyl chloroacetate, ethyl 2-bromohexanoate, ethyl 2-chloroacetoacetate, 2-bromo-2′-methoxyacetophenone, and 2-bromoacetophenone provided a series of substituted 5,6-dihydro-6-methylthiazolo[2,3-b][1,3]benzodiazepines. Condensation of III with 2-chlorocyclopentanone and 2-chlorocyclohexanone gave 2,3,10,11-tetrahydro-10-methyl-1H-cyclopenta[4,5]thiazolo[2,3-b][1,3]benzodiazepine and 7,8,9,10,12,13-hexahydro-13-methylbenzothiazolo[2,3-b][1,3]benzodiazepine, respectively. Structure assignments are discussed. None of the compounds possessed appreciable biological activity.     

Synthesis and structure of novel derivatives of thieno[2,3-b]thiocine. An unusual product of intramolecular cycloaddition of 2-homomethallylthio-5-methyl-3-thiophenecarbonitrile oxide

9-Methyl-3,3a,4,5-tetrahydro-6H-thieno[2,3-b]thiocino[4,5-c]isoxazole and 9-hydroxyimino-2-methyl-7-methylene-6, 7,8,9-tetrahydro-5H-thieno[2,3-b]thiocine have been prepared for the first time by the oxidation of 2--alkenylthio-3-thiophenecarbaldoximes with NaOCl. X-ray structural investigations of thieno[2,3-b]thiocine and 2-homomethallylthio-5-methyl-3-thiophenecarbaldoxime have been carried out.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1262–1266, July, 1993.     

Pseudo-four-component synthesis and in silico studies of 5-(5-hydroxy-3-methyl-1H-pyrazol-4-yl)-substituted 5H-chromeno[2,3-b]pyridines

Multicomponent reactions (MCRs) are important processes, in which more than three different reactants directly get converted into one new structure bearing most of the atoms of these reactants. It is a very powerful tool in drug discovery and combinational chemistry. A new pseudo-four-component synthetic approach to 5-(5-hydroxy-3-methyl-1H-pyrazol-4-yl)-substituted 5H-chromeno[2,3-b]pyridines with 68%–95% yields is reported. This MCR opens an efficient and convenient way to substituted 5H-chromeno[2,3-b]pyridines, which are promising compounds in medicinal chemistry and for the treatment of lung cancer through inhibition of aldo-keto reductase 1B10. A new consensus approach of molecular docking and molecular dynamics was applied for the investigation of interaction of synthesized 5H-chromeno[2,3-b]pyridines and aldo-keto reductase 1B10.     

[1,3]Dioxolo[5,6][1]benzothieno[2,3-c]-quinolin-6(5H)-ones

Summary The reaction of 3,4-methylenedioxycinnamic acid (1) with thionyl chloride resulted in the formation of 7-chlorothieno[2,3-f]-1,3-benzodioxole-6-carbonyl chloride (2) and cinnamoyl chloride (3). Subsequent reaction of the former withp-substituted anilines led to the formation of 7-chloro-N-(p-substituted phenyl)-thieno[2,3-f]-1,3-benzodioxole-6-carboxamides (4a–c) which on photocyclization afforded 2-substituted [1,3]dioxolo[5,6][1]benzothieno[2,3-c]quinolin-6(5H)-ones (5a–c) in fairly good yields and high purity. The structures have been confirmed by IR,¹H NMR, and analytical methods.Accepted for presentation at the Hong Kong International Symposium on Heterocyclic Chemistry (August 13–16, 1995)     

Cross-condensation of derivatives of cyanoacetic acid and carbonyl compounds. 2. One-pot synthesis of substituted 2-amino-7-methyl-5-oxo-4,5-dihydropyrano[4,3-b]pyrans in ethanol and ionic liquid [bmim][PF6]

The three-component reaction of 4-hydroxy-6-methylpyran-2(2H)-one with cyanoacetic acid derivatives and carbonyl compounds in EtOH or in the ionic liquid, viz., 1-butyl-3-methylimidazolinium hexafluorophosphate ([bmim][PF₆]), affords substituted 2-amino-7-methyl-5-oxo-4,5-dihydropyrano[4,3-b]pyrans. The yield of substituted pyrano[4,3-b]pyrans in [bmim][PF₆] is by 10—14% higher than that in EtOH.     

Acylation and Cyclodehydration of Benzofuran-, Benzothiophene-, and Indolyl-3-acetic Acid Arylamides. Synthesis of Novel Benzofuro[2,3-c]-, Benzothieno[2,3-c], and Indolo[2,3-c]pyrilium and Pyridine Derivatives

The acylation of benzo[b]furan-, benzo[b]thiophene, and indolyl-3-acetic acid arylamides using acetic anhydride in the presence of 70% perchloric acid occurs at the -position of the heterocycle to give 2-acetylbenzo[b]furan-, 2-acetylbenzo[b]thiophene, and 2-acetylindolyl-3-acetic acid arylamides. Depending on the amount of perchloric used in the reaction they undergo cyclodehydration to 3-arylamino-1-methylhetero[2,3-c]pyrilium salts and to N-aryl-1-methyl-3(2H)hetero[2,3-c]pyridones.     

Synthesis and Properties of 6-Amino-7-hetaryl-5-R-5H-pyrrolo[2,3-b]pyrazine-2,3-dicarbonitriles

We have established that when 5-chloro-6-[cyano(2,3-dihydro-1-R-benzo[d]azol-2-yl)methyl]-2,3-pyrazinedicarbonitriles are reacted with nucleophilic reagents (aliphatic and aromatic amines, hydrogen sulfide), annelation of the five-membered ring occurs on the [b] face of the pyrazine with formation of 6-amino-7-hetaryl-5-R-5H-pyrrolo[2,3-b]pyrazine-2,3-dicarbonitriles and 6-amino-7-(1H-benzo[d]imidazol-2-yl)thieno[2,3-b]pyrazine-2,3-dicarbonitrile respectively. Further heating with excess of acylating reagent leads to formation of a novel heterocyclic system 1H-benzo[4,5]imidazo[1,2-c]pyrazino[2',3':4,5]pyrrolo[3,2-e]pyrimidine. Reaction of vicinal dinitriles with hydrazine hydrate leads to the novel system 1H-pyrrolo[2',3':5,6]pyrazino[2,3-d]pyridazine.     

1,4-Cycloaddition reactions. II. Preparation of p-dioxino[2,3-g]furo[3,2-c] quinolines,p-dioxino[2,3-f] furo[3,2-c] quinolines,and [1,3] dioxolo[4,5-g] furo[3,2-c] quinolines from 2,3-dihydro-5-methylfuran and schiff bases

The boron trifluoride catalyzed 1,4-addition of 2,3-dihydro-5-methylfuran to N-(p-methoxy-benzylidene)-1,4-benzodioxan-6-amine (II) gave 2 pairs of epimers, 2,3,3a,4,5,8,9,11b-octahydro-4-(p-methoxyphenyl)-11b-methyl-p-dioxino[2,3-g]furo[3,2-c]quinoline (IIIa and b) and 2,3,7,8,8a,9.10,1la-octahydro-8-(p-methoxyphenyl)-11a-methyl-p-dioxino[2,3-f]furo[3,2-c]quinoline (IVa and b). When N-(p-methoxybenzylidene)-3,4-methylenedioxyaniline (V) was condensed with 2,3-dihydro-5-methylfuran in an analogous manner, a mixture of 2 epimers of 2,3,3a,4,5,10b-hexahydro-4-(p-methoxyphenyl)-10b-methyl[1,3]dioxolo[4,5-g]furo[3,2-c]quinoline (VIa and b) was isolated. Treatment of this mixture with sulfur afforded 6-(p-methoxyphenyl)-8-methyl-1,3-dioxolo[4,5-g]quinoline-7-ethanol (VIII). Structural assignments for all of the products were made from NMR spectra. None of the compounds possessed appreciable biological activity.     

A new one-step synthesis of 2,3-dihydro-5H-thiazolo[2,3-b]quinazolin-5-one and 3,4-dihydro-2h,6h[1,3]thiazino[2,3-b] quinazolin-6-one

2,3-Dihydro-5H-thiazolo[2,3-b]quinazolin-5-one and 3,4-dihydro-2H,6H[1,3] thiazino[2,3-b]-quinazolin-6-one have been synthesized in one step by the reaction of methyl anthranilate with ehloroalkyl isothiocyanates.     

The synthesis of 4-benzylamino-6-methyl-1H-pyrrolo[3, 2-c]pyridine and 4-benzylamino-6-methyl-1H-pyrrolo[2, 3-b]pyridine

4-Benzylamino-6-methyl-1H-pyrrolo[3,2-c]pyridine ( 2 ) and 4-benzylamino-6-methyl-1H-pyrrolo[2,3-b]pyridine ( 3 ) were synthesized as deaza analogues of the anxiolytic agent 4-benzylamino-2-methyl-7H-pyrrolo[2,3-d]pyrimidine ( 1 ). The 1-deaza analogue (2) was prepared via a multi-step procedure from a pyrrole precursor, 1-benzyl-2-formylpyrrole ( 4 ) while the 3-deaza analogue 3 was synthesized from a pyridine precursor, 2-amino-3,6-dimethylpyridine ( 12 ).