Showing papers in "Phosphorus Sulfur and Silicon and The Related Elements in 1998"
TL;DR: Some new pyran 3,8, pyrano[2,3-b]pyridine 4, 5, 6, 7, 8, 9, 10 and 14 derivatives have been developed.
Abstract: Some new pyran 3,8; pyrano[2,3-b]pyridine 4; pyrano[2,3-d] pyrimidine 5,6,7 and 9; pyridine 10–14 derivatives have been prepared. The structure of all the new compounds have been established on the basis of elemental analyses and spectroscopic data. All the synthesized compounds have been screened for their antibacterial activity. Pyranopyrimidinethione 7 and pyridinethione 10 exhibited a good antibacterial activity compared with the standard antibiotic Gentamycin.
80 citations
TL;DR: The N-P+−S phosphenium cations 1, 2 and 3 have been prepared by treatment of the respective precursor chlorophosphines4, 5 and 6 with the stoichiometric quantity of AlCl3 in CH2C12 solution.
Abstract: The N-P+−S phosphenium cations1, 2 and 3 have been prepared by treatment of the respective precursor chlorophosphines4, 5 and 6 with the stoichiometric quantity of AlCl3 in CH2C12 solution. The cations 3 are noteworthy that they are the first aliphatic phospheniurn cations featuring a P-S bond. That the values of 31P chemical shifts of phosphenium cations 3 are larger than those of aliphatic N-P+−N and N-P+−Cl cations characterize a relative inferior π-donor ability of RS group to R2N group and to Cl. The exo conformation of group at sulfur to dialkylamino group in 3 is proposed on the rare steric effect on 31P chemical shifts of substitutes at sulfur.
60 citations
TL;DR: In this article, Dietyl alkylphosphonates were efficiently and rapidly prepared in good yields from trialkylphosphates and alkyls halides under short microwaves irradiations.
Abstract: Diethyl alkylphosphonates are efficiently and rapidly prepared in good yields (75–99%) from trialkylphosphates and alkyl halides under short microwaves irradiations.
43 citations
TL;DR: In this article, the phosphorylation reaction of 5-arylmethylidene and 1-morpholinocyclopentenes with various phosphorus (III) and (V) halides was studied.
Abstract: The phosphorylation reaction of 5–arylmethylidene–1–morpholinocyclopentenes with various phosphorus (III) and (V) halides was studied. It was shown that the enamines react with phosphorus (III) halides giving stable halo– and dihalophosphines which are key substances for further synthesis. Hydrolysis of the phosphorylated enamines does not afford the expected phosphorylated ketones, decomposition being observed in acidic media.
32 citations
TL;DR: In this paper, the conformations of cycloadducts and cycloaddition reaction mechanism were described and different regioselectivities when different 1,5-benzoheteroazepines reacted with asymmetric 2-diazo-1-phenyl-1,3-butandione.
Abstract: 2,3-Dihydro-1,5-benzothiazepines and 2,3-dihydro-1H-1.5-benzodiazepines reacted with α -carbonylketenes, generated from 2-diazo-1,3-diphenyl-1,3-propanedione and 2-diazo-1-phenyl-1,3-butandione by heating, to give [2+4] cycloadducts 4a,5,6,12-tetrahydro-1H-1,3-oxazino [3,2-d] [1,5]-benzothiazepin-1-ones and 4a,5,6,12-tetrahydro-1H,7H-1,3-oxazino [3,2-d][1,5]-henzodiazepin-1-ones. The cycloaddition reactions showed different regioselectivities when different 1,5-benzoheteroazepines reacted with asymmetric 2-diazo-1-phenyl-1,3-butandione. The conformations of cycloadducts and cycloaddition reaction mechanism were described.
30 citations
TL;DR: In this paper, a range of α-chlorinated epoxyphosphonates has been prepared by epoxydation of α -halo-genated vinylphosphonsates with an excess of MCPBA.
Abstract: A range of α-chlorinated epoxyphosphonates has been prepared by epoxydation of α-halo-genated vinylphosphonates with an excess of MCPBA. The thermal rearrangement and the reactions of these new phosphonates with magnesium halides that lead to β-halogeno α-keto-phosphonates are described.
28 citations
TL;DR: In this paper, a series of 5-(Z)-arylidene-2-amino-4-imidazolidinones were synthesized via two different routes, which showed broad spectrum of activity against a wide range of different human cell lines of nine tumor subpanels causing both cytostatic and cytotoxic potency.
Abstract: A series of 5-(Z)-arylidene-2-amino-4-imidazolidinones 16–34, 5-(Z)-arylidene-2-(2-carboxyphenylamino)-4-imidazolidinones 35–41, 5-(Z)-arylidene-3-aminomethyl-2-thioxo-4-imidazolidinones 42–55 and 5-(Z)-arylidene-3-aminomethyl-2-methylmercapto-4-imidazolidinones 56–67 have been synthesized via two different routes. Conformational analysis and antitumor activities have been studied. The antitumor activity of these compounds showed broad spectrum of activity against a wide range of different human cell lines of nine tumor subpanels causing both cytostatic and cytotoxic potency.
28 citations
TL;DR: In this paper, it was shown that 3-formyl chromones with benzyl carbamate and triphenyl phosphite in acetic acid lead to the corresponding diphenyl chromone-3-[α(-N-benzyloxycarbonyl)amino]-methanephosphonates 2 in high yields.
Abstract: Reactions of 3-formylchromones with benzyl carbamate and triphenyl phosphite in acetic acid lead to the corresponding diphenyl chromone-3-[α(-N-benzyloxycarbonyl)amino]-methanephosphonates 2 in high yields. Deprotection of the Z-substituted diphenyl esters 2 by means of acetic hydrogen bromide solution and the subsequent hydrolysis by means of 20% aq. HCI, lead to the final chromone-3-(α-amino)methanephosphonic acids 4. Attempts of synthesis of the corresponding chromone-2- aminophosphonic derivatives by this way, have failed. On the other hand, chromone-2-(α-amino)methanephosphonic acid (6) was successfully obtained by an addition of tris(trimethylsilyl) phosphite to the aldimine, which was formed from the 2-formylchromone.
24 citations
TL;DR: In this paper, the synthesis of novel benzothienopyridines, benothienoquinoline, benzothiamoxazines and benzothiensopyrimidines utilizing 2-methyl-5,6,7,8-tetrahydro-4H-3,1-benzothienoxazine-4-one are reported.
Abstract: Synthesis of novel benzothienopyridines, benzothienoquinoline, benzothienoxazines and benzothienopyrimidines utilizing 2-methyl-5,6,7,8-tetrahydro-4H-3,1-benzothienoxazine-4-one are reported. The structure of these compounds were confirmed by micro-analyses, IR, 1H-NMR and mass spectrometry. Preliminary biological studies of some compounds showed a promising radioprotection and antineoplastic activities.
23 citations
TL;DR: In this article, a bridged bis-phenols react with diethylphosphite to give bis-phosphates, which are easily transformed by LDA, in good yields, to bis-ortho hydroxy aryl phosphonates.
Abstract: Commercially available bridged bis-phenols react with diethylphosphite to give bis-phosphates, which are easily transformed by LDA, in good yields, to bis-ortho hydroxy aryl phosphonates. These new monomers are of great relevance for the synthesis of novel macrocycles and for thermal resistant polycondensates containing phosphonate moieties.
23 citations
TL;DR: A brief survey of a method of classification of chalcogene-rich CHalcogenides is given in this article, where the anionic patterns of the compounds are either considered as isostructural derivatives of noble gas fluoride and interhalogene basic fragments or are due to high symmetric square sheets and primitive cubic networks.
Abstract: A brief survey of a method of classification of chalcogene-rich chalcogenides is given. The anionic patterns of the compounds are either considered as isostructural derivatives of noble gas fluoride and interhalogene basic fragments or are due to high symmetric square sheets and primitive cubic networks. With the increasing number of precise investigations on new compounds the underlying principle of the classification becomes more evident. Small deviations, nearly always observed in the structures, can often be explained by electronic requirements.
TL;DR: Methyltriphenylphosphonium tetrahydroborate as mentioned in this paper is a stable quaternary phosphonium borohydride which is able to reduce aldehydes, ketones, acyl chlorides, and azides efficiently in CH2Cl2 αβ-Unsaturated carbonyl compounds are reduced selectively via 1,2-reduction.
Abstract: Methyltriphenylphosphonium tetrahydroborate as a stable quaternary phosphonium borohydride is introduced. This compound is able to reduce aldehydes, ketones, acyl chlorides, and azides efficiently in CH2Cl2 αβ-Unsaturated carbonyl compounds are reduced selectively via 1,2-reduction. The effect of Lewis acids upon the mode and the rate of the reaction of epoxides and acetophenone are also described. This reagent is also able to bring about reductions effectively in the absence of solvent.
TL;DR: In this paper, 1H and 31P NMR spectroscopy in the presence of homochiral t−butyl(phenyl)phosphinothioic acid as chiral solvating agent.
Abstract: α-Hydroxy-, α-acetoxy-. α-chloroacetoxg, α-azido-, α-phthalimidooxy-, and α-aminooxy-phosphonates are investigated by 1H and 31P NMR spectroscopy in the presence of homochiral t−butyl(phenyl)phosphinothioic acid as chiral solvating agent. The 31P NMR shift differences for the diastereomeric complexes of α-hydroxyphosphonates are large (0.10 -0.30 ppm) and allow the determination of their enantiomeric excess and the cautious assignment of their absolute configuration.
TL;DR: In this paper, 3-allyl-5-(Z)-arylidene-2-(alkylmercapto)hydantoins 8a-f have been synthesized from the direct condensation of the aromatic aldehydes 7a−f with 3-al-l-2-thiohydantoin (6), which in turn was prepared from the reaction of glycine and allyl isothiocyanate.
Abstract: 3-Allyl-5-(Z)-arylidene-2-thiohydantoins 8a-f were synthesized from the direct condensation of the aromatic aldehydes 7a–f with 3-allyl-2-thiohydantoin (6), which in turn was prepared from the reaction of glycine and allyl isothiocyanate. The alkylation of 8a–f with alkyl bromides 9a, b gave 3allyl-5-(Z)-arylidene-2-(alkylmercapto)hydantoins 1a–1, S-Glycosylation and S-ribosylation took place on the reaction of 8a–f with pyranosyl bromides 11a, b and furanosyl bromide (15) under anhydrous alkaline conditions. The S-nucleoside structure, and not that of the N-nucleoside isomer, has been selected for the products. This structure has been confirmed from a model study of the coupling of 8a with α-D-glucose pentaacetate (13) and α-D-ribose tetrabenzoate (16) under Lewis acid conditions. The compounds do not display any antiviral and antitumoral activity.
TL;DR: In this article, the synthesis of several heterocyclic compounds was studied based on elemental analyses and spectral data studies. But none of the structures were established based on spectral data.
Abstract: Styryl thienyl ketone and Styryl furyl ketone 2a, b reacted with thiocyanoacetamide(1) to give the dihydropyridinethiones 3a, b which used as starting material for the synthesis of several heterocyclic compounds. Reaction with several halogeno-esters, halogeno-ketones and chloroacetamide gave 2-S-alkoyl pyridines 5a-d, 10a-d, 13a, b and 19a, b thieno[2,3-c] pyridines 6a, b, 11a, b 14a, b and 20a-d, pyrido[2′,3′,4:5]thieno[2,3-c]pyndazines 8a, b and pyrido[2′.3′:-4,5]thieno[2,3-d]pyrimidinones 15a, b 16a, b and 17a, b. Structures were established based on elemental analyses and spectral data studies.
TL;DR: In this paper, N-substituted nitrodiene 3a was obtained from the reaction of la with p-phenylendiamine and benzidine gave the compounds 5a-b.
Abstract: Mono(thio)substituted nitrodienes 1a-b give the compounds 7a and 7b cohen treated with piperazine. S, N-substituted nitrodiene 3a was obtained from the reaction of la with p-phenylendiamine. Under the same conditions the compounds la-b and benzidine give the compounds 5a-b. The compounds la-b from the reaction with aniline in ether yielded 9s-b. Mono(thio)substituted nitrodienes la-b give 11a-b by the reaction with piperidine in ether. 13a-c are prepared by the reaction of compounds la-c with morpholine.
TL;DR: In this article, the lithium phosphanides LiPHR (R = Ph, 2,4,6-Me3C6H2 (Mes)) are oxidised by benzophenone in THF at room temperature to give the cyclooligophophophosphanes (PPh)n (n = 4, 5, 6) and (PMes)n(n = 3 (1), 4 (2)) by X-ray structure determination.
Abstract: The lithium phosphanides LiPHR (R = Ph, 2,4,6-Me3C6H2 (Mes)) are oxidised by benzophenone in THF at room temperature to give the cyclooligophosphanes (PPh)n (n = 4, 5, 6) and (PMes)n (n = 3 (1), 4 (2)). Compounds 1 and 2 have been characterised by X-ray structure determination. In the solid state, the P4 ring in 2 is puckered (torsion angle P-P-P-P 41.04(3)°). The reduction product, LiOCHPh2 (3), was characterised by IR and NMR spectroscopy (1H, 13C, 7Li) and X-ray structure determination. LiOCHPh, is hexameric in the solid state and forms a slightly distorted hexagonal prism composed of alternating Li and O atoms.
TL;DR: In this article, a variety of chiral diferrocenyl dichalcogenides have been newly prepared, some of which have been shown to be asymmetric in synthesis.
Abstract: Our recent studies on asymmetric synthesis using chiral organochalcogen (S, Se, Te) compounds are presented. A variety of chiral diferrocenyl dichalcogenides have been newly prepared, some of which...
TL;DR: In this article, the first alkylation of amidophosphocavitands has been performed, where the substitutions at the phosphorus atoms are different substituents at different positions.
Abstract: Cyclophosphorylation of tetrapropylcalyxresorcin[4]arene by phosphorous amides gave P(III)-phosphocavitands, modification of which resulted in a series of P(V)-phosphocavitands with different substituents at phosphorus atoms. The first alkylation of amidophosphocavitands has been performed.
TL;DR: An original synthesis of two aminoalkylidenebisphosphonates is described by first preparing the intermediate hydroxyalkylIDenebisPhosphonate which are transformed into amines via the azides.
Abstract: Bisphosphonates are interesting therapeutic agents in the management of bone diseases and since several years our laboratory has been developing the chemistry of 1,1-bisphosphonates. This paper describes an original synthesis of two aminoalkylidenebisphosphonates by first preparing the intermediate hydroxyalkylidenebisphosphonates which are transformed into amines via the azides.
TL;DR: In this paper, the E-isomer of both types of phosphonates could be isolated in a pure form, and the corresponding corresponding-phosphonates with 6c (∼50%) and -[2, 1-b]-fused pyrido-derivative 12 were obtained in high yields.
Abstract: 2-Benzylidenecyanomethyl-1,3-benzothiazole (1) reacts with trialkyl phosphites (6) to give a mixture of the corresponding-phosphonates 9 (E & Z) with 6a, b or 16c (E & Z) with 6c (∼50%) and -[2,1-b]-fused pyrido-derivative 12 (∼20%), meanwhile, with dialkyl phosphonates 7 affords only the phosphonates 16 (E & Z) in high yields (∼80%). Only E-isomer of both types of phosphonates could be isolated in a pure form. α-Benzil monoxime (22) reacts with 6 to give oxazaphospholes 23, and with 7 to give α-hydroxyamino phosphonates 25.
TL;DR: Alkyl and aryl trifluoromethylselenides are easily obtained from triflooromethynyl trimethylsilane and diselenides or selenocyanates.
Abstract: Alkyl and aryl trifluoromethylselenides are easily obtained from trifluoromethyl trimethylsilane and diselenides or selenocyanates as well as from sodium trifluoromethanesulfinate and diselenides or selenenyl chlorides, via trifluoromethaneselenosulfonates.
TL;DR: In this article, the reaction mechanisms to account for formation of compounds 7a-d, 8a, b and 19 were also postulated, based on compatible elementary and spectroscopic results.
Abstract: Reactions of dialkyl phosphites (DAP, 1a, b) and trialkyl phosphites (TAP, 2a, b) with the α,β-unsaturated nitriles (3a, b and 4a, b) as well as with anils (5a and 6) derived from aromatic aldehydes (vanillin and/or piperonal) are reported. Structures of the new phosphonate products (cf. 7,8,15,16 and 17) were based upon compatible elementary and spectroscopic results Tervalent phosphites (TAP, 2a, b) and triphenylphosphine convert vanillin-oxme (5b) into 4-hydroxy -3-methoxybenzonitrile (19). Possible reaction mechanisms to account for formation of compounds 7a-d, 8a, b and 19 were also postulated.
TL;DR: In this paper, the structural assignment of the prepared compounds were based on microanalytical and spectroscopic evidences, and some prepared compounds are tested in vitro for their antitumor and radioprotective activities.
Abstract: Some novel pyridothienoxazine (5); pyridothienopyrimidines (6), (8), (9), (14); pyridothienoimidazole (16); isothiazolopyridine (17), and pyridoisothiazolopyrimidines (18–20) were synthesized. The structural assignment of the prepared compounds were based on microanalytical and spectroscopic evidences. Some prepared compounds were tested in vitro for their antitumor and radioprotective activities. Compounds (7), (12), (17) and (19) showed significant activities against EAC cells, at a concentration of 250μg/ml; while the isothiazolopyridine (17) exhibited radioprotective activity.
TL;DR: In this article, the synthesis of isomeric free acids from Li[HN(S)PR2] and R′2P(O)Cl, as well as of their K and Na salts, are presented.
Abstract: The synthesis of isomeric (SPMe2)(OPPh2)NH 1 and (OPMe2)(SPPh2)NH 2 from Li[HN(S)PR2] and R′2P(O)Cl, as well as of their K and Na salts, are presented. The compounds were characterized by means of IR and multinuclear NMR spectroscopy. The crystal and molecular structure of both free acids was determined using X-ray diffractometry. Compound 1 crystallizes in monoclinic space group P21/n, a = 16.798(6) A, b = 17.526(8) A, c = 18.095(7) A, β =114.72(2)°, Z = 12, and the unit cell contains three independent molecules. Compound 2 crystallizes in orthorhombic space group Fdd2, a = 1.5.072(7) A, b = 43.078(6) A, c = 9.912(8) A, Z = 16. In both compounds the molecular units are associated into polymeric chains through N-H-O [1.96 A (mean) in 1, and 1.8 A in 2] hydrogen bonds, which involve only the oxygen atom of each molecule. The conformation of the SPNPO system is discussed.
TL;DR: Condensation of 2-(2,2-dicyano-1-methylvinyl)thiophene (2) with phenylhydrazine furnished the corresponding 2-(1-phenyl hydrazonoethyl)-thienyl) compound as discussed by the authors.
Abstract: Condensation of 2-(2,2-dicyano-1-methylvinyl)thiophene (2) with phenylhydrazine furnished the corresponding 2-(1-phenylhydrazonoethyl)-thiophene (4). Compound (4) was obtained also via reaction of (1) with phenylhydrazine. Reaction of (2) with amines gave 2-(2,2-dicyano-1-ethylamino or benzylamino- 1 methylethyl)thiophene (5a,b). Treatment of (2) with elemental sulfur yielded directly the cyclised product 2-(5-amino-4-cyano-3-thienyl)thiophene (6). On the other hand refluxing (2) in pyridine with carbon disulfide gave the pyridine-1,3-dithione derivative (7). Condensation of (2) with phenyl isocyanate and/or phenyl isothiocyanate afforded 6-amino-4-(2-thienyl)-1,2-dihydro-2-oxo- 1-phenylpyridine-5-carbonitrile (9) and/or 5-(2-thienyl)-2,7-dithioxo-3,8-N-phenyl-1,2,3,7,8-pentahydropyrido[2,3-d]pyrimidine-4-imine (11). Also the dicyano derivative (2) when reacted with cinnamonitrile (12) afforded the 2-(3-amino-2,4-dicyano-5-arylphenyl)-thiophenes (15a-d). Conversion of (15b) into the polyazanaphthalene (17...
TL;DR: Bis(triphenylphosphine)(tetrahydroborato) zinc complexes have been used for the efficient reduction of varieties of organic compounds in THF or under solvent free conditions.
Abstract: Bis(triphenylphosphine)(tetrahydroborato)zinc and (triphenylphosphine)(tetrahydroborato) zinc complexes have been used for the efficient reductions of varieties of organic compounds in THF or under solvent free conditions. Selective reduction of aldehydes, ketones, α,β-unsaturated carbonyl compounds, and acyl chlorides to their corresponding alcohols and aryl, alkyl, aroyl, and sulfonyl azides to their corresponding mines and amides are described. Bis(triphenylphosphine)(tetrahydroboratro)zinc complex shows promising shelf stability and is much more stable than its mono triphenylphosphine analogue. The reducing ability of the two complexes is more or less the same.
TL;DR: In this article, the use of halomethylarenes and aromatic alcohols into aldehydes, and selective selective oxidation of sulfides have been elaborated, and their synthesis is briefly discussed and their analogs used as oxidants or as catalyst for hydrogen peroxide oxidation.
Abstract: Useful oxidative conversions of halomethylarenes and aromatic alcohols into aldehydes, oxidation of aldehydes, ketones and their azomethine derivatives into carboxy esters, phenols, nitriles and carboxylic acids, epoxidation of low reactive vinylbenzenes, ketone regeneration from ketazines, and selective oxidation of sulfides have been elaborated. Selenium compounds such as selenium(IV) dioxide, selenoxides, seleninic and peroxyseleninic acids, diselenides, benzisoselenazolones and their analogs used as oxidants or as catalyst for hydrogen peroxide oxidation are presented and their synthesis is briefly discussed.
TL;DR: In this article, the synthesis of 4-alkyl-1-trityl-1phospha-2,6,7-trioxabicyclo[2.2] octane tetrafluorobo-rates (alkyl group = Me, 4; Et, 5; r-Bu, 6) is described.
Abstract: The syntheses of 4-alkyl-1-trityl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane tetrafluorobo-rates (alkyl group = Me, 4; Et, 5; r-Bu, 6) are described. Compounds 4, 5 and 6 in the presence of base (pyridine, DBU) or base (pyridine, DBU) plus H2O undergo Arbuzov ring opening reactions to give pyridinium salts or a mixture of hydrolyzed products and pyridinium salts, respectively. The configurations of the products are addressed by means of NMR spectroscopic and X-ray crystallographic studies. The acyclic trityl salts [(RO)3 CPh,]+BF4(R = Et, 7; neopentyl, 8) were also prepared and their reactions with base or base plus H2O were carried out for comparison with the reactions of the polycyclic trityl salts.
TL;DR: In this paper, two phosphonated compounds bearing a mercaptan group have been prepared: HSCH2CO2 (CH2)2S(CH 2)3PO(OEt)2 (I) and HSCH 2CO2(CH2S) 3PO(Ot) 2 (II).
Abstract: Two phosphonated compounds bearing a mercaptan group have been prepared. These thiols are: HSCH2CO2 (CH2)2S(CH2)3PO(OEt)2 (I) and HS(CH2)3PO(OEt)2 (II). Both originate from diethyl allylphosphonate. (I) with mercaptoethanol and thioglycolic acid and (II) with thioacetic acid. (I) is obtained in two steps, firstly by addition of mercaptoethanol on diethyl allylphosphonate and secondly by esterification of the previous compound with thioglycolic acid (total yield 70%). In the same manner, (II) is obtained by addition of thioacetic acid followed by hydrolysis by KCN in methanol (total yield 90%).