Platinum(II) complexes of 2-alkoxy-dibenzo[c.e][1,2]oxaphosphorines

2-Alkoxy-dibenzo[c.e][1,2]oxaphosphorines were prepared by the reaction of chloro-dibenzooxaphosphorine with alcohols and were converted to the cyclic phosphonates by oxidation and to the corresponding phosphonous boranes by reaction with borane-dimethylsulfide. Interaction of the alkoxy-dibenzooxaphosphorines with dichlorodibenzonitrileplatinum led to bis(dibenzooxaphosphorino)dichloroplatinum complexes exhibiting the P-ligands in the cis disposition. Relative energetics for the prepared cis and the theoretically possible trans isomers of the complexes along with their stereostructures were investigated by quantum chemical calculations.     

New [ e ]-Fused Caffeines: A Simple Synthesis of 3-Substituted [1,2,4]Triazolo[4,3- e ]purines

 A convenient synthesis of 3-substituted [1,2,4]triazolo[4,3-e]caffeines by oxidative cyclization of 8-arylmethylenehydrazinocaffeines with bromine in acetic acid in presence of sodium acetate is described.     

Syntheses of dibenzo[b,e][1,4]dioxin derivatives via iron complexes, and further functionalizations via directed metallation

Double nucleophilic aromatic substitution reactions between (cyclopentadienyl)(η⁶-1,2-dichlorobenzene)iron(1 + ) salts and substituted 1,2benzenediols have been carried out under mild conditions to prepare [η⁶-dibenzo[b,e][1,4]dioxin]iron(1 + ) complexes functionalized in the 1- or 2-position with an alkyl, aldehyde, carboxylic acid, methoxycarbonyl, carboxamide, or hydroxy group. 3-Methyl- and 4-methyl-(η⁶-1,2-dichlorobenzene)iron complexes were treated with substituted 1,2-benzenediols to effect functionalization of both aromatic rings of the heterocycle. The dibenzodioxin ligands were liberated routinely by irradiation with ultraviolet light. Directed deprotonation of the free functionalized dibenzodioxins with an alkyllithium reagent followed by quenching with a variety of electrophiles yielded further derivatives, including two new isoindolone systems.     

Synthesis, IR spectral studies and quantum-chemical calculations on 1,2-dihydronaphto[1,2-e]oxazine-3-thiones and 3,4-dihydrobenzo[e][1,3]oxazine-2-thione

2-Hydroxy-1-naphthaldehyde (1) was reacted with substituted anilines to afford 1-(substituted phenyliminomethyl)naphthalen)-2-ols (2). The reduction of these imines by NaBH₄ gave 1-((substituted phenylaminomethyl)naphthalen)-2-ols (3) which were cyclized with thiophosgene to give corresponding 2-substituted phenyl-1,2-dihydronaphto[1,2-e]oxazine-3-thiones (4). 3-p-Tolyl-3,4-dihydrobenzo[e][1,3]oxazine-2-thione (8) was also obtained by the same way. The structures of these new compounds were determined by ¹H NMR, IR spectroscopic data and elemental analyses. AM1, PM3 and ab initio (at Hartree–Fock level with 3-21G basis set) methods were used to study the molecular geometry of the compounds. A complete infrared spectral analysis of the oxazines has been performed in this paper. Observed frequencies of the molecules were compared with calculated normal mode analysis which was carried out on the basis of RHF/3-21G method. Assignments of vibrational bands (in the range of 1760–400 cm⁻¹) have been performed by taking into account the results of the ab initio vibrational analysis. The mechanism of the cyclization reaction between (3a) and thiophosgene was studied by the semi-empirical AM1 and ab initio (RHF) calculations.     

Bis(dibenzo[c.e][1,2]oxaphosphorino)dichloroplatinum Complexes

Reaction of a series of P-amino and P-cycloalkoxy dibenzo[c.e][1,2]oxaphosphorines (1), (3) and (5) with cis-bis(benzonitrile)dichloroplatinum(II) afforded the title bis(dibenzooxaphosphorino) complexes (2), (4) and (6), respectively. In the case of chiral P-substituents, the complexes (4) and (6) were obtained in homo and heterochiral forms. Stereospecific ¹J(¹⁹⁵Pt–P) couplings found in the ³¹P-n.m.r. spectra of the products (2), (4) and (6) suggested the cis orientation of the identical substituents.     

Reaction of phosphorus pentachloride with 2,6-dichloro-4-phenylbenzo[ e ][1,2λ5]oxaphosphinine 2-oxide. Synthesis and steric structure of 2,2,6-trichloro-4-phenylbenzo[ e ][1,2λ5]oxaphosphinin-2-ylium hexachlorophosphate

2,2,2,6-Tetrachloro-4-phenylbenzo[e][1,2]oxaphosphinine and 2,2,6-trichloro-4-phenylbenzo[e][1,2λ⁵]-oxaphosphinin-2-ylium hexachlorophosphate were prepared by treatment of 2,6-dichloro-4-phenylbenzo[e][1,2λ⁵]-oxaphosphinine 2-oxide with phosphorus pentachloride. The structure of the latter compound was proved by means of X-ray diffraction analysis. Original Russian Text ? V.F. Mironov, E.N. Varaksina, D.A. Tatarinov, A.A. Shtyrlina, A.B. Dobrynin, I.A. Litvinov, 2008, published in Zhurnal Obshchei Khimii. 2008, Vol. 78, No. 2, pp. 210–215.     

Synthesis and complexation of novel dibenzo[<Emphasis Type="Italic">c.e</Emphasis>][1,2]oxaphosphorine-based P-ligands

The reaction of chloro-dibenzo[c.e][1,2]-oxaphosphorine with (L)-methyl prolinate gave the corresponding phosphorous ester-amide, while the interaction of the same starting material with half an equivalent of 2-methylaminothanol and (1S,2R)-(+)-ephedrine led to the corresponding bis(dibenzooxaphosphorine) derivatives that are bidentate P-ligands. The new P-ligands prepared were characterized as the corresponding P-borane and P-oxide derivatives. The P-ligands were utilized in the synthesis of novel Pt-complexes, which gave a species of PtCl₂P₂ type, while two others were seven-membered chelate ring complexes. Structures of the Pt-complexes were elucidated on the basis of stereospecific J _Pt–P couplings and quantum chemical calculations.     

Pyrazoles and Pyrazolo[4,3- e]pyrrolo[1,2- a]pyrazines, I. Synthesis and Antimicrobial Activity

The synthesis of the title compounds was achieved using 1-phenyl-5-(pyrrol-1-yl)-1H-pyrazole-3-carboxylic acid azide as starting material. The latter compound was allowed to react with alcohols and amines to afford the corresponding carbamates and urea derivatives. Alkaline hydrolysis of the carbamates gave the corresponding amine, which was acylated and/or aroylated to give amide derivatives. These and the urea derivatives were subjected to cyclodehydration to give the title compounds. Antibacterial and antifungal activities were observed for several derivatives.     

Platinum complexes of dibenzo[1,2]dithiin, dibenzo[1,2]dithiin oxides and related polyaromatic hydrocarbon ligands

The synthesis of platinum bisphosphine complexes of biphenyl- 2,2'-dichalcogenates and the oxides of dibenzo[1,2]dithiin and related ligand systems by oxidative addition to [Pt(PPh(3))(4)] is reported. We also describe the synthesis of a new compound, dibenzothiophen-4-yldiselenide and its simple platinum complex (obtained by oxidative addition). All complexes have been fully characterised, principally by using multinuclear NMR spectroscopy and in six cases by means of single-crystal X-ray diffraction studies. The majority are simple S/S or Se/Se complexes, however the addition of dibenzo[1,2]dithiin trioxide to [Pt(PPh(3))(4)] gives a bimetallic system, [Pt[2-[S(O)],2'-[S(O)(2)]-biphen}(PPh(3))](2), containing a central Pt(2)S(2)O(2) core in which the ligand behaves as a tridentate S,S,O donor.     

Mass spectral fragmentation mechanisms of some dibenzo[c,f][1,2] diazepines

The fragmentation mechanisms of 11H-dibenzo[c,f][1,2]diazepine (I), its 3,8-dichloro derivative (II), 3,8-dichlorodibenzo[c,f] [1,2]diazepin-11-one (III) and 3,8-dichloro-11H-dibenzo-[c,f][1,2]diazepin-N-oxide (IV) are discussed. The initial loss of molecular nitrogen is characteristic of I, II and III. Compound IV has a strong molecular ion, that competitively eliminates cither NO or Cl- and N₂O. The common radical ion, m/166 e present in the mass spectra of I, fluorene, 2-methyl-9,10-anthraquinone and 2-methylbenzo[c]cinnoline, appears to be formed in different states.     

Simple synthesis of quinolines and dibenzo[b,f][1,5]diazocines under microwave irradiation

Quinolines 3a–f, 5a–f, and dibenzo[b,f][1,5]diazocines 4, 6 were synthesized in the presence of 0.5 equiv. of diphenyl phosphate (DPP) under microwave irradiation. The obtained yield of 6,12-diphenyl-dibenzo[b,f][1,5]diazocine 4 was higher when using anhydrous DPP than when using HCl, H₃PO₄, and CH₃COOH.     

Eight-membered organosulfur heterocycles. Synthesis of dibenzo[d,g][1,3,6,2]dioxathiaphosphocin and dibenzo[d,g][1,3,6,2]dioxathiasilocin ring systems

The reaction of 2,2′-thiobisphenols with either phenylphosphonous dichloride or phosphorus trichloride followed by an alcohol gave derivatives of the dibenzo[d,g][1,3,6,2]dioxathiaphosphocin ring system. The analogous reaction of 2,2′-thiobisphenols with alkyl and aryl dichlorosilanes gave the heretofore unreported dibenzo[d,g][1,3,6,2]dioxathiasilocin ring system. The analytical and spectral data are reported.     

Syntheses of dibenzo[c,e][1,2]diselenin and related novel chalcogenide heterocyclic compounds

Reaction of 2,2′-dilithio-1,1′-binaphthyl with selenium followed by air oxidation gives a mixture of dinaph-thoselenophene and dimer and oligomers of 2,2′-diseleno-1,1′-binaphthyl. 2,2′-Dilithio-1,1′-biphenyl reacts with selenium to afford dibenzo[c,e][1,2]diselenin. Structures of the dimeric 2,2′-diseleno-1,1′-binaphthyl and dibenzo[c,e][1,2]diselenin have been confirmed by X-ray crystallographic analyses. Similar reaction of 2,2′-dilithio-1,1′-binaphthyl with sulfur or tellurium gives a mixture of dinaphthothiophene and dinaphtho[2,1-c:-1′,2′-e][1,2]dithiin or a mixture of dinaphthotellurophene and oligomer of 2,2′-ditelluro-1,1′-binaphthyl, respectively. Dibenzotellurophene and oligomer of 2,2′-ditelluro-1,1′-biphenyl are obtained from reaction of 2,2′-dilithio-1,1′-biphenyl with tellurium.     

The regulation of biothiol-responsive performance and bioimaging application of benzo[c][1,2,5]oxadiazole dyes

The different oxidation states of sulphur atom play a significant role on functional materials. In this work, a aryl-thioether and its sulphone substituted benzo[c][1,2,5]oxadiazole dyes were synthesized and utilized to determine thiol-containing amino acids. The result of selectivity experiments showed they detected the cysteine and homocysteine under physiological condition with negligible interference from other amino acids. In comparison to the thioether dye, the sulphone-based dye exhibited much faster response time for Cys and Hcy. However, the sulphone restricted its thiol-reactivity and bioimaging performance in living cells. By reducing the oxidation state of sulphur atom, we amazedly found that the sulfoxide-based dye still maintained high selectivity ultrafast response time for Cys/Hcy under physiological condition. It was worth mentioning that it also had high reactivity and good bioimaging performance that sulfone compounds did not have.     

Tetrazoles: XLVIII. 3H-Naphtho[2,1-e]-and 3H-Naphtho[1,2-e][1,2,4]triazepines from 5-Aryltetrazoles. Physical and Chemical Properties

Thermolysis of N-imidoyltetrazoles generated under conditions of phase-transfer catalysis from 5-aryltetrazoles and N-(2-naphthyl)benzimidoyl chloride yields 3H-naphtho[2,1-e][1,2,4]triazepines, and acid hydrolysis of the latter leads to formation of 3-arylbenz[e]indazoles. Acid hydrolysis of 3H-naphtho[1,2-e]-[1,2,4]triazepine gives the corresponding amino ketone.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 3, 2005, pp. 451–456.Original Russian Text Copyright © 2005 by Nikulin, Artamonova, Koldobskii.Dedicated to Full Member of the Russian Academy of Sciences V.I. Minkin on his 70th AnniversaryFor communication XLVII, see [1].     

new simple and one-pot synthetic routes to polyfunctionally substituted imidazo-[1,2-a]pyridines, pyrido[1,2-a]pyrimidines, pyrido-[1,2-a]-1,3-diazepines, and imidazo[1,2-a]pyrimidines

Reactions of arylidenemalononitriles with 2-nitromethylene-substituted imidazolidine, hexahydropyrimidine, and hexahydro-1,3-diazepine afforded the title derivatives. Reaction of 2-nitromethylenehexahydropyrimidine with benzylamine or n-butylamine and formalin in a molar ratio of 1:1:2 gave the hexahydro-1H-imidazo[1,2-c]pyrimidine derivatives. Treatment of 2-nitromethyleneimidazolidine and hexahydropyrimidine with secondary aliphatic amines and formalin in a molar ratio of 1:1:1 afforded the corresponding methylene bis-compounds. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1850–1853, December, 2005.