Phosphorylation of N‐Silylpyrroles with Phosphorus Tribromide

Phosphorylation of N‐trimethylsilyl‐ and N‐dimethyl‐tert‐butylsilylpyrroles with phosphorus tribromide in pyridine proceeds selectively at position 3 of the pyrrole ring. Removal of the trialkylsilyl protecting group has furnished the first representatives of N‐unsubstituted 3‐phosphorylated pyrroles. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:93–96, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20416     

A convenient synthesis of 2‐(1H‐1,2,4‐triazol‐1‐yl)‐2H‐1,4‐benzothiazine derivatives

A series of 2‐(1H‐1,2,4‐triazol‐1‐yl)‐2H‐1,4‐benzothiazines were designed and synthesized by condensation of 1,2,4‐triazole‐substituted ω‐bromoacetophenones and o‐aminothiophenols with the aid of K₂CO₃ under mild conditions with moderate to high yields. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:332–336, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20434     

Synthesis of 1‐(phenylsulfanyl/phenoxy)‐3H‐naptho[1,2,3‐de]quinoline‐2,7‐diones

A convenient method is devised to synthesize 1‐(phenylsulfanyl/phenoxy)‐3H‐naptho[1,2,3‐de]quinoline‐2,7‐dione analogs in high yield for the first time by condensation of 2‐bromo‐N‐(9,10‐dixo‐dihydro‐anthracen‐1‐yl)‐acetamide with benzenethiol/phenol using potassium carbonate. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:221–227, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20399     

Diastereoselective addition of hypophosphorous acid to N‐(R)‐α‐methylbenzyl‐substituted schiff bases

The addition of hypophosphorous acid to an azomethine bond of N‐(R)‐α‐methylbenzyl Schiff bases of a variety of aldehydes led to the formation of N‐(R)‐α‐methylbenzylamino‐(S)‐methanephosphonous acids in 100% diastereoselectivity. This fact allows us to suggest the probable mechanism of the Strecker‐like reaction between hypophosphorous acid, an aldehyde, and (R)‐α‐methylbenzylamine. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:35–37, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20406     

A novel stereoselective synthesis of (2Z)‐2‐arylsulfanylallylic alcohols by tin–lithium exchange of (E)‐α‐stannylvinyl sulfides

Tin–lithium exchange reaction of (E)‐α‐stannylvinyl sulfides 1 with n‐butyllithium gave (Z)‐α‐arylsulfanylvinyllithiums 2 , which reacted with aldehydes or ketones 3 to afford stereoselectively (2Z)‐2‐arylsulfanylallylic alcohols 4 in good to high yields. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:639–643, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20487     

Stereoselective synthesis of trisubstituted alkenes containing (Z)‐allylthio units from the acetates of Baylis–Hillman adducts

A series of trisubstituted alkenes containing (Z)‐allylthio moieties as key structural units, that is, sodium (Z)‐allyl thiosulfates, symmetrical di(Z‐allyl) sulfides, and di(Z‐allyl) disulfides, unsymmetrical diallyl sulfides were prepared in moderate to good yields via chemical transformations from the acetates of Baylis‐‐Hillman adducts. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:188–198, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20394     

An efficient and green method for the synthesis of N‐phosphoramino o‐hydroxylphenyl α‐aminophosphonic monoesters

An efficient and green method to the synthesis of N‐protected o‐hydroxylphenyl α‐amino‐alkylphosphonic monoesters is described. It consists of the three‐component Mannich‐type reaction of phosphoramides, carbonyl compounds (aldehydes or ketones), and 2‐chlorobenzo[1,3,2] diox‐aphospholes under solvent‐free and catalyst‐free conditions, followed by hydrolysis. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:596–601, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20483     

Oxidation of diethyl N‐sulfinylphos‐phoramidates

It is reported that the diethyl N‐sulfinylphosphoramidate ( 1a ) is oxidized with iodoso‐ and/or iodoxybenzene as well as with organic peroxides, to give diethyl N‐sulfonylphosphoramidate ( 7a ). The latter was generated in situ at low temperature and trapped with dialkyl phosphoramidates, affording the N,N′ bis(dialkyl phosphor)sulfamides 3a–c . The oxidation of 1a with cumene peroxide in the presence of 2,2‐dimethyl‐propan‐1‐ol ( 9 ) produced the diethylphosphor‐N‐[2,2‐dimethylpropyl]sulfamate ( 10a ). © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:530–536, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20474     

On the reaction of bis(phosphothioyl)disul‐fanes with hydroxamic acids,part I: Ionic versus radical reaction pathways

Among sodium N‐alkyl‐4‐chlorobenzo‐hydroxamates treated with bis(phosphothioyl)disul‐fanes >P(S)SSP(S)< (where >P(S) is phosphorothioyl, phosphonothioyl, and phosphinothioyl), only the N‐methyl one yields quantitatively the respective O‐phosphothioyl derivatives exhibiting complete inversion of configuration at phosphorus in a reaction whose products are inert toward dithiophosphate arising in the reaction. For branched N‐alkyl benzohydroxamates, products of a SET process predominated. The mechanism of the title reaction is discussed. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:271–282, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20423     

N‐functionalized azolin‐2‐ylidene‐palladium‐catalyzed heck reaction

Novel 1,3‐dialkylimidazolidinium, 1,3‐dialkyl‐3,4,5,6‐tetrahydropyrimidinium, and 1,3‐dialkyl‐1H‐4,5,6,7‐tetrahydrodiazepinium hexafluorophosphates ( 1a–c, 2a–c ) as N‐heterocyclic carbene precursors have been synthesized and characterized. The incorporation of saturated N‐heterocyclic carbenes into palladium precatalysts gives high‐catalyst activity in the Heck coupling of aryl bromide substrates in aqueous media. The complexes were generated in the presence of Pd(OAc)₂ by in situ deprotonation of 1,3‐dialkylazolinium salts 1, 2 . © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:82–86, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20415     

MnCl2‐Promoted synthesis of quinoxaline derivatives at room temperature

MnCl₂ efficiently catalyzes the condensation of o‐phenylenediamine derivatives with 1,2‐diketones at room temperature to afford the corresponding quinoxaline derivatives in high yields. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:218–220, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20401     

Synthesis,structure, and biological activity of novel 4,5‐disubstituted thiazolyl urea derivatives

Novel 1‐(2,4‐dichlorophenyl)‐3‐[4‐aryl‐5‐(1H‐1,2,4‐triazol‐1‐yl)thiazol‐2‐yl] urea derivatives were synthesized by the reaction of 2‐amino‐4‐sustituted phentyl‐5‐(1H‐1,2,4‐triazol‐1‐yl) thiazoles with 2,4‐dichloro‐1‐isocyanatobenzene. Structures of the title compounds were confirmed by the elemental analysis, ¹H NMR, and single crystal X‐ray diffraction analysis. Biological evaluation showed that some of them possess promising antitumor activities. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:2–6, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20375     

Efficient synthesis of 2‐substituted thieno[2,3‐d]pyrimidin‐4(3H)‐ones via an iminophosphorane

The carbodiimides 4 , obtained from reactions of iminophosphorane 3 with aromatic isocyanates, were reacted with secondary amines to give 2‐dialkylamino‐5‐ethyl‐6‐methyl‐thieno[2,3‐d]pyrimidin‐4(3H)‐ones 6 in the presence of catalytic amount of EtONa. Reactions of 4 with phenols or ROH in the presence of the catalytic amount of K2CO₃ or RONa gave 2‐aryloxy‐ or 2‐alkoxy‐5‐ethyl‐6‐methyl‐thieno[2,3‐d]pyrimidin‐4(3H)‐ones 6 in satisfactory yields. The effects of the nucleophiles on cyclization have been investigated. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:266–270, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20424     

A facile synthesis of new 1,2‐dihydro‐2λ5‐[1,3]oxazolo[5,4‐d][1,3,2]diazaphosphinine derivatives starting from 2‐benzoylamino‐3, 3‐dichloroacrylonitrile

Easily accessible 2‐benzoylamino‐3,3‐dichloroacrylonitrile, when treated successively with primary amines, phosphorus pentachloride, sulfur dioxide, and various N‐ or S‐nucleophiles, furnishes the corresponding derivatives of 1,2‐dihydro‐2λ⁵‐[1,3]oxazolo[5,4‐d][1,3,2]diazaphosphinine, a novel fused heterocycle. The structure of the compounds obtained is unequivocally confirmed by spectroscopic methods and X‐ray diffraction analysis. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:506–511, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20470     

1,3,6‐Azadiphosphacycloheptanes: A novel type of heterocyclic diphosphines

The novel type of seven‐membered cyclic diphosphines, namely 1,3,6‐azadiphosphacycloheptanes, has been synthesized by condensation of 1,2‐bis(phenylphosphino)ethane, formaldehyde, and primary amines (aniline, p‐toluidine, benzylamine, and 5‐aminoisophthalic acid) as a mixture of rac‐ and meso‐stereoisomers. The structures of rac‐stereoisomers of N‐tolyl and N‐(3′,5′‐dicarboxyphenyl)‐substituted diphosphines were investigated by X‐ray crystal structure analyses. The stereoisomers of N‐(3′,5′‐dicarboxyphenyl)‐substituted compound were separated at a preparative scale, and their platinum(II) dichloride complexes were obtained. The corresponding meso‐isomer readily forms P,P‐chelate complex with [PtCl₂(cod)], whereas the rac‐stereoisomer forms oligomeric complex. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:125–132, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20397     

Novel routes to aminophosphonic acids: Interaction of dimethyl H‐phosphonate with hydroxyalkyl carbamates

It was found that the reaction of dimethyl H‐phosphonate ( 1 ) with 2‐hydroxyalkyl‐N‐2′‐hydroxyalkyl carbamates at 135°C includes several chemical reaction steps: (i) chemical transformations of 1‐methyl‐2‐hydroxyethyl‐N‐2′‐hydroxyethyl carbamate ( 2 ) and 2‐methyl‐2‐hydroxyethyl‐N‐2′‐hydroxyethyl carbamate ( 3 ); (ii) transesterification of dimethyl H‐phosphonate with 2 and 3 , and with secondary hydroxyl‐containing compounds that are formed during the course of the chemical transformation of 2‐hydroxyalkyl‐N‐2′‐hydroxyalkyl carbamates; (iii) hydrolysis of 1 and dialkyl H‐phosphonates, formed via transesterification of 1 with secondary hydroxyl‐containing compounds. The interaction was studied by means of ¹H, ¹³C, ³¹P NMR, and FAB mass spectroscopy. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:119–124, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20404     

A new class of sulfur‐linked bis‐1,2,3‐selenadiazoles, 1,2,3‐thiadiazoles,and 2H‐diazaphospholes

Novel sulfur‐linked bis‐heterocycles, bis‐1,2,3‐selenadiazoles 4 , 1,2,3‐thiadiazoles 5 , and 2H‐diazaphospholes 7 , were synthesized from bis(2‐oxo‐2‐phenylethanone)sulfide 2 by adopting a simple and well‐versed methodology. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:261–265, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20425     

Synthesis of phosphonic acid containing thiadiazole

A series of phosphonic acid, 1,3,4‐thiadiazol‐2‐amine‐N‐alkyl have been synthesized by the reaction of 2‐amine thiadiazole, different aldehydes (or ketone), and phosphorous acid via the melting method or the solvent method. These compounds have been characterized by IR, ¹H NMR, ³¹P NMR, and elemental analysis. Results showed that compounds were reacted via the solvent method in better yields. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:140–143, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20395     

Comparison of the reactivity of N‐(p‐toluenesulfonyl)‐sulfinimidoyl fluorides and chlorides toward triphenylphosphine

The path of the reaction of aryl‐N‐(p‐toluenesulfonyl)‐sulfinimidoyl fluorides and triphenylphosphine is highly dependent on the order of the reactants addition. Addition of triphenylphos‐phine to aryl‐N‐(p‐toluenesulfonyl)‐sulfinimidoyl fluorides results in the formation of triphenyl(aryl‐thio)phosphonium salts of N,N′‐bis(p‐toluenesul‐fonyl)aryl‐sulfinamidines and triphenyldifluorophosphorane. By changing the reagent addition order, we obtained triphenyldifluorophosphorane, P,P,P‐triphenyl‐N‐(p‐toluenesulfonyl)‐phosphine imide, and diaryl disulfides. The outcome of the reaction aryl‐N‐(arenesulfonyl)‐sulfinimidoyl chlorides and triphenylphosphine does not depend on the order of addition of the reactants. P,P,P‐Triphenyl‐N‐(arenesulfonyl)‐phosphine imides, triphenyldichloro‐phosphorane, and diaryl disulfides were formed as a result. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:66–71, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20408     

Microwave‐assisted synthesis of some 1,2,4‐triazol‐5‐one derivatives

A series of 3‐alkyl(aryl)‐4‐(p‐hydroxy‐phenyl)‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones 2 were obtained from the reaction of alkyl (aryl) ester ethoxycarbonyl hydrazones 1 with p‐hydroxy aniline. The reaction of 1 with 1,4‐diamino benzene (1:1) to afford 3‐alkyl(aryl)‐4‐(p‐aminophenyl)‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones 3 . The reaction of 3 with benzaldehyde gave 3‐alkyl(aryl)‐4‐(4′‐benzilidenamino)‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones 4 . All of the above reactions occurred under microwave heating and conventional methods. Their structures were confirmed by ¹H NMR, ¹³C NMR, IR, and elemental analyses. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:38–42, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20381