摘要:

AbstractEquilibrium constants (K) and thermodynamic parameters for the charge‐transfer complexes between diiodine and Δ3‐4‐S‐methyl‐5,5‐dimethylimidazolidine‐2‐thione (1), 2‐S‐methyl‐5,5‐dimethylimidazolidine‐4‐thione (2), and Δ1‐Δ3‐2S‐methyl‐4‐S‐methyl‐5,5‐dimethylimidazolidine (3) have been determined in CH2Cl2by UV‐Visible spectroscopy. Depending on the solvent polarity, compound2exists as a Δ1or Δ2tautomer; both the tautomers are present in CH2Cl2. Compounds1and2act as good donors (K = 11,000 ± 800 and 640 ± 21 dm3mol−1, 25°C, respectively) owing to the presence of a thioamidic group in the molecule, whereas in compound3, the N‐coordination causes a strong reduction of the formation constant (K = 14.6 ± 0.8 dm3mol−1, 25°C). The high difference between the stability constants of1and2has been ascribed to an intramolecular hydrogen bonding between NH and the bonded iodine, which can be possible only for1. Additional spectroscopic data (FT‐Raman, NMR) enables a deeper unde

ISSN:1042-7163    

DOI:10.1002/hc.520050502

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractLow‐temperature1H,13C, and119Sn NMR spectroscopic techniques were used to probe the nature of cuprates derived from Me3SnLi, CuCN, or CuBr · Me2S. In THF, addition of Me3SnLi and CuX (X = Br or CN) gives aggregated [Me3SnCu · LiX]n. When the ratio of stannyl anion to cuprous cation is 2 : 1, mixtures of (Me3Sn)3Cu2Li, (Me3Sn)2CuLi · LiX, and (Me3Sn)3CuLi2are formed. This behavior is unlike either homo trialkylsilycyanocuprates, which form (R3Si)2Cu(CN)Li2at 2 : 1 ratios of silyl anion to cuprous ion, or mixed trialkylstannyl‐ or trialkylsilyl‐cuprates, which exist as (R3M)Cu(R′)(CN)Li2(M = Si or Sn and R′ = Me or Bu). (R3Sn)3CuLi2is the major species when the stannyl anion to cuprous cation ratio reaches 3 : 1. On the other hand, the analogous magnesium cuprates are discrete species in solution and possess differentia

ISSN:1042-7163    

DOI:10.1002/hc.520050503

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractHeterocyclic compounds, including benzimidazolones, naphthimidazolone, benzoxazolones, benzothiazolone, quinazolinone, benzoxazinone, quinazolinedione, and imidazopyridinone were synthesized in good yields by sulfur‐assisted carbonylation of aromatic amines with carbon monoxide (1 atm) at room temperature, with subsequent oxidation using molecular oxygen (1 atm, RT). The present method is characterized as a simple procedure carried out under quite mild condition

ISSN:1042-7163    

DOI:10.1002/hc.520050504

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractBoth diaminofurazan5(DAF) and diaminoazofurazan6(DAAF) were converted to 5‐(4‐amino‐1,2,5‐oxadiazol‐3‐yl)‐1H‐[1,2,3]triazolo[4,5‐c][1,2,5]oxadiazol‐3‐yl‐1H‐[1,2,3]triazolo[4,5‐c][1,2,5]oxadiazolium inner salt8(AMOTO) (25 and 91%) in oxidations with iodobenzene diacetate and to dinitroazoxyfurazan13(DNAF) (4 and 15%) in oxidations with a mixture of ammonium persulfate and hydrogen peroxide in concentrated sulfuric acid. The intermediacy of diaminoazoxyfurazan7was supported by its conversion under similar treatment to DNAF (60%). Further oxidation by ammonium persulfate converted AMOTO8to 5,5′[azobis‐(1,2,5‐oxadiazole‐4,3 ‐ diyl)]bis[1H(1,2,3)triazolo ‐ [4,5‐c][1,2,5]oxadiazolium]bis(inner salt)10. Diazidofurazan19(tentative assignment) was obtained from DAF5by tetrazotization followed by treatment with sodium azide. Aminoazido‐azofurazan16was obtained from diazotized DAAF by treatment with sodium azide and was converted to AMOTO8by an elimination of nitrogen at 25°C. Similar treatment converted tetrazotized DAAF to diazidoazofurazan9and 5‐(4‐azido‐1,2,5‐oxadiazol‐3‐yl) ‐ 1H ‐[1,2,3]‐triazolo[4,5‐c][1,2,5]‐oxadiazolium inner salt15(AZOTO) after evolution of nitrogen. Aminofurazan‐2‐ONN‐azoxyazidofurazan17(AAAF) was obtained from diazotized diaminoazoxyfurazan7by treatment with sodium azide. Excellent calcul

ISSN:1042-7163    

DOI:10.1002/hc.520050505

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractWittig reagents (1a–c) react with N‐(phenylsulfonyl)‐1,4‐benzoquinone monoimine2ato give adducts3a,4a, and4b. On the other hand, the reactions of2bwith the same ylides (1a–c) yield the new products3b,6a, and6b, respectively. Mechanisms accounting for the formation of the new products are discussed and the probable structures of the products are presented, based on compatible analytical and spec

ISSN:1042-7163    

DOI:10.1002/hc.520050506

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe (N→B)phenyl[iminodiacetate‐O,O′,N]borane1is stable to hydrolysis, and the fact that the N‐H proton has been shown to be more acidic than the α‐protons to the carbonyl groups has led to the syntheses of N‐substituted boron heterocycles. Thus, the reactions of compound1with 2,2,6,6‐tetramethylpiperidine and aryl halides led to the syntheses of (N→B)phenyl[N‐arylaminodiacetate‐O,O′,N]boranes2–9, which were, in turn, hydrolyzed to afford the corresponding N‐arylaminodiacetic acids10–17. All compounds studied in this work were characterized by1H,13C, and11B (for boron compounds) NMR, inf

ISSN:1042-7163    

DOI:10.1002/hc.520050507

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe reactions of acetone with tellurium tetrachloride have been studied with the aid of proton, carbon‐13, and tellurium‐125 NMR spectroscopy. In the absence of a proton scavenger, such as sodium hydrogen carbonate, at ambient temperature, a 2 : 1 ratio of acetone to tellurium tetrachloride quickly forms mainly acetonyl tellurium trichloride. At higher temperatures and after longer periods, the initially formed acetonyl tellurium trichloride is converted to 2‐methyl‐4‐oxo‐2‐penten‐1‐yl tellurium trichloride through an acidcatalyzed aldol condensation. In the presence of sodium hydrogen carbonate, the condensation reaction is prevented, and an equilibrium mixture of acetonyl tellurium trichloride and bis(acetonyl) tellurium dic

ISSN:1042-7163    

DOI:10.1002/hc.520050508

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractO‐Phenyl chloromethyldithio‐ and chloromethylselenothiophosphonic acids, formed by the reaction of O‐phenyl chloromethyl‐(chloro)thiophosphonate with hydrogen sulfide or hydrogen selenide, respectively, in the presence of Et3N, react in situ with alkyl thiocyanates and bis(thiocyanato)methane, yielding 2‐alkylithio‐4,5‐dihydro‐4‐thioxo‐4‐phenoxy‐1,3,4‐thia‐(selena)azaphospholes and 2,4‐dithioxo‐4‐phenoxy‐1,3,4‐thia(s

ISSN:1042-7163    

DOI:10.1002/hc.520050509

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractFour thiophene derivatives have been obtained unexpectedly from the reaction of N‐phenylacetyithiobenzamides with P4S10in boiling carbon disulfide. The structure of one of these was established by X‐ray crystallogra

ISSN:1042-7163    

DOI:10.1002/hc.520050510

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

Abstract1‐Lithio‐1‐(diethoxyphosphoryl)methyl methyl sulfide1‐Liwas reacted with diphenyl disulfide in a tetrahydrofuran solution to give predominantly diethyl methylthio(phenylthio)methylphosphonate2accompanied by a small amount of diethyl bis‐(phenylthio)methyl phosphonate3. The latter was the main product when the reaction was performed in the absence of the solvent. The formation of3was explained through the desulfenylation of the transiently formed diethyl methylthiobis(phenylthio)methylphosphonate4with lithium benzenethiolate and confirmed by31P NMR measurements at low te

ISSN:1042-7163    

DOI:10.1002/hc.520050511

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY