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.     

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.     

A Novel synthesis of 6-hydroxyalkyl-and 6-hydroxy-aralkyl-6H-dibenz[c,e][1,2]oxaphosphorin 6-Oxides

A new strategy for the synthesis of 6-hydroxyalkyl- and 6-hydroxyaralkyl-6H-dibenz[c,e][1,2]oxaphosphorin 6-oxides 3 was achieved by the reaction of 2-(2-hydroxyphenyl)phenylphosphonic acid ( 1 ) with various carbonyl compounds 2 . The desired products 3 were obtained in acceptable yields.     

Practical Synthesis of 6-Chloro-dibenzo[c.e][1,2]oxaphosphorine

The title P-heterocycle 3, a versatile intermediate in synthesis, was prepared by two independent methods. The first involves an environmentally friendly version of an old protocol starting from 2-phenylphenol (1) and phosphorus trichloride. Their interaction could be accomplished at 50 °C under solventless conditions. Cyclization of the intermediate (2) so obtained could be realized best under microwave conditions at 150 °C in the presence of ZnCl₂. This method offers advantages over the traditional ones. According to another approach, the chloro-dibenzooxaphosphorine (3) was obtained by the novel reaction of 6H-dibenzo[c.e][1,2]oxaphosphorine-6-oxide (4) with phosphorus trichloride in boiling chloroform. Efficiency of the syntheses was demonstrated by converting the crude product 3 to a more stable phosphonic amide (6) that was stable enough to be isolated.

Silica-supported tungstic acid (STA): A recyclable catalyst for the synthesis of 1H-indazolo [1,2-b]phthalazine-trione and spiro-triazolo[1,2-a]indazole-tetraone derivatives under solvent-free condition

Abstract

An efficient one-pot synthesis of 1?H-indazolo[1,2-b]phthalazine-trione and spiro-triazolo[1,2-a]indazole-tetraone derivatives via three-component condensation reaction of phthalhydrazide or 4-phenylurazole, aldehydes or isatins and dimedone in the presence of a catalytic amount of silica-supported tungstic acid (STA), as a heterogeneous solid acid catalyst under solvent-free conditions is presented. This ecofriendly protocol offers several advantages such as a cost-effective procedure with excellent yields, short reaction time, simple workup, recovery and reusability of catalyst with broad scope of usable substrates. This has made the protocol sustainable and economic.     

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.     

"一锅法"合成N-链烯基-(2R,3R)-O,O-二乙酰酒石酰亚胺

本文报导一种由(2R,3R)-二乙酰酒石酸酐合成N-ω-链烯基二乙酰酒石酰亚胺的简单有效的"一锅合成法", 并使总产率有大幅度的提高。     

Synthesis of new dibenzo[c.e][1,2]oxaphosphorine 2‐oxide containing diols based on diethanolamine

Different approaches were applied to obtain new diol compounds based on dibenzo[c.e][1,2]oxaphosphorine 2‐oxide (DOPO, 1 ) and diethanolamine (DEolA). Of four processes investigated, a four‐step synthesis of 1 containing propionic acid amide of DEolA proved to be the most efficient one. In addition, the intramolecular amine salt of the DOPO derivative with a ring‐opened structure was obtained by reinvestigation of the reaction of DOPO with DEolA and paraformaldehyde. The Atherton–Todd reaction of 1 and DEolA was investigated as well. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:146–153, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20763     

One-pot synthesis of oxygen and nitrogen-bridged calix[2]arene[2]triazines

A simple and powerful one-pot reaction method was developed for the synthesis of heteracalixaromatics. In the presence of a base, one-pot macrocyclic condensation reaction between cyanuric chloride and 1,3-phenylene diols and diamines proceeded effectively under very mild conditions to afford a number of functionalised oxygen and nitrogen-bridged calix[2]arene[2]triazines in 33–54% yields. The method was applied in a multigram-scale (14.4 g) preparation of tetraoxacalix[2]arene[2]triazine.     

Synthesis of Benzo[c][2,7]Naphthyridines by One-Pot Multicomponent Reaction Using Ceric(IV) Ammonium Nitrate

A new, one-pot, three-component reaction for the synthesis of benzo[c][2,7]naphthyridines has been achieved from aromatic amines, aromatic aldehydes, and N-carbethoxy-4-piperidone in the presence of a catalytic amount of ceric ammonium nitrate in good yields at room temperature. The advantages of this procedure are mild reaction conditions, low toxicity, and the use of inexpensive reagents. Apart from milder and environmentally benign conditions, this method involves a simple, reliable approach to give good yields of the desired products and is compatible with a wide range of functional groups.     

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.     

p-TSA-catalyzed one-pot synthesis of novel 7-aryl-6H-benzo[h][1,3]dioxolo[4,5-b]xanthene-5,6(7H)-diones in ethanol

A one-pot, three-component reaction of aromatic aldehydes, 2-hydroxy-1,4-naphthoquinone, and 3,4-methylenedioxyphenol has been reported for the synthesis of novel 7-aryl-6H-benzo[h][1,3]dioxolo[4,5-b]xanthene-5,6(7H)-diones using environmentally benevolent para-toluene sulfonic acid (p-TSA) as the catalyst. This methodology provides a mild and fast route to diverse pyran derivatives in moderate to good yields.     

One-pot synthesis of 2-(dicyanomethylene)-1,2-dihydropyridine derivatives

The synthesis of 2-(dicyanomethylene)-1,2-dihydropyridine derivatives from the reactions of arylmethylidene derivatives of malononitrile dimers with 1,3-dicarbonyl compounds is described.     

Efficient three-step synthesis of benzo[e]imidazo[1,2-c][1,2,3]triazines

A novel three-step sequence toward benzo[e]imidazo[1,2-c][1,2,3]triazine derivatives is investigated. This pathway started from commercially available starting materials afforded 5a–h in good to excellent yields. In this method, we took the advantage of diazonium chemistry, which was followed by intramolecular N-N bond formation in the construction of N-rich cycles.     

3-(D-葡萄糖-1-基)-6-芳基-7H-1，2，4-三唑并[3，4-b][1，3，4]噻二嗪类化合物的合成及波谱研究

ω-溴代芳香基乙酮与3-(D-葡萄糖-1-基)-4-氨基-5-巯基-1，2，4-三唑反应 合成了一系列新颖的3-(D-葡萄糖-1-基)-6-芳基-7H-1，2，4三唑并[3，4-b[1，3 ，4]噻二嗪．用元素分析，IR，NMR，MS对其结构进行了表征，研究了其NMR波谱特 征，并以^1H-^1H COSY，^13C-^1H COSY，COLOC二维NMR技术对其^1H NMR，^13C NMR的谱峰进行了全归属     

Two routes to (11,12)-dihydrodibenzo[c,g][1,2]dithiocine

The title compound is made by two routes. One route features the separate introduction of two sulfur atoms and a double Pummerer reaction while the other route contains a direct introduction of both sulfur atoms using disulfur diimidazole.     

A new synthesis of dibenzo[b,g][1,5]naphthyridine-6,12(5H,1H)dione (epindolidione)

A new convenient synthesis of dibenzo[b,g][1,5]naphthyridine-6,12(5H,11H)dione starting from N-phenylglycine ethyl ester is described. Ester condensation of N-phenylglycine ethyl ester with diethyl oxalate followed by reaction with aniline under acid catalysis gave a mixture of diethyl dianilinomaleate and diethyl dianilinofumarate in 54% yield. Upon heating this mixture in a high-boiling inert solvent, 3-anilino-2-ethoxycarbonyl-4-quinolone was obtained in 72% yield. Final ring closure of the quinolone derivative using polyphosphoric acid gave the epindolidione.     

One-pot synthesis of substituted indolo[1,2-a]quinolines under transition-metal-free conditions

A simple and efficient one-pot synthesis of substituted indolo[1,2-a]quinolines under transition-metal-free conditions has been developed. When 2-fluorobenzaldehyde was treated with substituted 2-methylindoles in the presence of Cs₂CO₃, the desired products were typically obtained in good to excellent yields. This reaction sequence involves a nucleophilic aromatic substitution and a Knoevenagel condensation reaction. Our mechanistic investigation revealed that both reactions could proceed as an intermolecular reaction in the first step.