摘要:

AbstractThe Diels‐Alder adducts of functionalized dienes withP‐chloro‐bis(trimethylsilyl)methylenephosphine can be aromatized, except in a few particular cases, thus opening a general route to functionalized phosphinines. The aromatization procedure differs with the substituents. Intermediates such as secondary cyclic phosphines could be characterized and even isolated. In some cases, aromatization and 1,5 sigmatropic shift of a trimethylsilyl group were observed and hydrogenolysis of the CSi bond

ISSN:1042-7163    

DOI:10.1002/hc.520020403

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe synthesis of diorganotin(IV) derivatives of thiosalicylic acid, of 3‐aza‐2‐thiosalicylic acid, and of several related compounds is reported. Their characterization by1H,13C, and119Sn NMR, Mössbauer, and mass spectrometry is described. The in vitro antitumor activity of selected derivatives against two human tumoral cell lines is dis

ISSN:1042-7163    

DOI:10.1002/hc.520020404

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe crystal and molecular structures of the title compounds were determined by X‐ray diffraction technique from diffractometer intensity measurements. It has been found that two homologous disulfides, bis(dimethoxythiophosphoryl) disulfide1and bis(dineopentoxythiophosphoryl) disulfide2, form different molecular and crystal structures with space groupsC2/candP&1macr;, respectively. These results were confirmed by31P CP MAS NMR studies, which showed that under favorable conditions the solid state NMR may lead to determination of the number of crystallographically unique phosphorus atoms. Moreover, the variation of the disulfide S–S bond length versus torsional P–S–S–P angles was

ISSN:1042-7163    

DOI:10.1002/hc.520020405

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractPentacoordinated hydrosilanes react with excess of aryl isocyanates to give isocyanurates under mild and neutral conditions. The catalytic species are the initially formedN‐silylformamides, which incorporate three equivalents of isocyanate, and then rearrange toN‐silylformamide and isocyanura

ISSN:1042-7163    

DOI:10.1002/hc.520020406

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe MNDO MO calculations were carried out for the formation of oxaphosphetanes from substituted ylides and aldehydes (Equations 2–4). It was found that the reactions proceed through a nearly planar cyclic four‐membered ring transition state (TS) in all cases studied and that phenyl substitution on phosphorus has little effect on the TS geometry. This finding is not in line with the TS models that have been proposed to explain the experimentally observed cis‐select

ISSN:1042-7163    

DOI:10.1002/hc.520020407

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractAzidophosphanes are versatile reactants in the Staudinger reaction. The azides Cl2PN3(1), (Et2N)ClPN3(2), and (Et2N)2PN3(3) react with phosphanes to give theN‐phosphanyl phosphazenes4–10. (Et2N)P(N3)2is oxidized by PhN3yielding (Et2N)P(N3)2NPh (11), which with PPh3yields the di‐ and triphosphazenes

ISSN:1042-7163    

DOI:10.1002/hc.520020408

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

Abstract2,4‐Dioxo‐1,2,3,4‐tetrahydroquinazolines were easily synthesized in excellent yields by sulfur‐assisted carbonylation of 2′‐aminobenzamides with carbon monoxide in the presence of a base, such as

ISSN:1042-7163    

DOI:10.1002/hc.520020409

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractTwo new diphosphazane ligands, PriN(PPh2)(PO2C6H4) (1) and PriN{P(O2C6H4)}2(3), have been synthesized and characterized by spectroscopic data. The structure of1has been confirmed by single crystal X‐ray diffraction. Crystal data: Monoclinic,C2/c,Z= 16,a= 34.149(5) Å,b= 9.717(6) Å,c= 29.439(5) Å, β = 125.11(2)°,V= 7991 Å3,R= 0.058,Rw= 0.061. This compound shows two different P–N bond lengths (1.654 (4) and 1.743(4) Å) and a P–N–P angle of 120.7(2)°. Variable temperature31P NMR measurements for1and3throw light on the nature of the conformers pres

ISSN:1042-7163    

DOI:10.1002/hc.520020410

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractCrystal structures of 1,3‐dichloro‐1,3‐diazetidine‐2,4‐dione (1) and the hitherto unknown compound 1,3‐bis(trimethylsilyl)‐1,3‐diazetidine‐2,4‐dione (2) have been determined by X‐‐ray crystallography:1: (CINCO)2,Mr= 154.94,T= 295 K, orthorhombic,Pbca,a= 7.699(1),b= 6.706(1),c= 10.598(2) Å,V= 547.2(2) Å3,Z= 4,dx= 1.881 g/cm3, μ = 10.9 cm−1,R= 3.14%,Rw= 2.82% (660 observations, 38 parameters).2: [(CH3)3SiNCO]2,Mr= 230.41,T= 100 K, monoclinic,I2/a,a= 20.257(2),b= 6.416(1),c= 21.260(3) Å, β = 101.29(1)°,V= 2709.7(6) Å3,Z= 8,dx= 1.130 g/cm3, μ = 2.4 cm−1,R= 4.86%,Rw= 4.39% (2375 observations, 151 parameters). In both compounds, the symmetry of the (XNCO)2framework (X = Cl, Si) was determined to be nearlyC2hwith trans configuration of the exocyclic X atoms. Extreme values were observed for the angles between the ring plane and the exocyclic N–X bonds: 32.5(1)° in1and 2.5(2)° and 0.8(2)° in2, respectively. Quantum chemical procedures at various levels of theory (ab initio SCF and semi‐empirical PM3) applied to1revealed the possible appearance of two isomers, a lower energy trans form and a higher energy cis form (approx. 2.4 kcal/mol above trans) differing mainly in the spatial arrangement of the chlorine atoms. The calculations excluded a planar heavy‐atom con

ISSN:1042-7163    

DOI:10.1002/hc.520020411

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractDicyclohexylammonium succinatotriphenylstannate, synthesized by condensing [(c‐C6H11)2NH2] [HO2C(CH2)2CO2] with (C6H5)3SnOH, has a zig‐zag structure consisting of polymeric chains in which planar triphenyltin cations (Σ C–Sn–C = 360.0(2)°) are axially linked by succinato dianions (Sn–O = 2.214(2) Å; O–Sn–O = 172.52(6)°); the dicyclohexylammonium cations surround the chain and are hydrogen‐bonded to the acyl oxygens of the ligand (N…O = 2.829(3) Å). The stannate is four‐coo

ISSN:1042-7163    

DOI:10.1002/hc.520020412

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY