摘要:

AbstractA convenient synthesis of 1‐(8‐phosphonomethoxy‐3,6‐dioxaoctyl) uracil, cytosine, adenine, and guanine nucleotide analogues26,28,30, and32by Mitsunobu coupling of the nucleobases with suitably functionalized alcohol derivative24is described. The antiviral activity of this series of compounds against herpes simplex virus (HSV) types 1 and 2 and human cytomegalovirus is r

ISSN:1042-7163    

DOI:10.1002/hc.520050512

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractIn order to look for novel antitumor drugs and virucides with high activity and low toxicity, a series of amino acid linked phosphoryl nitrogen mustard derivatives have been synthesized. The structures of all compounds prepared were confirmed by1H NMR,31P NMR, IR, MS spectroscopy, and elemental analyses. In the case of dl‐α‐amino acid derivatives, the presence of multiple chiral centers in the target products leads to the generation of diastereoisomers, which can be detected by spectroscopic and analytical (TLC) methods. Preliminary bioassays indicate that some of compounds5have high inhibitory activities against some tumor cells and tobacco mosaic virus (TMV). In addition, some of them display certain herbicidal activities and significant fungicidal activities against wheat leaf

ISSN:1042-7163    

DOI:10.1002/hc.520050513

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe cubic arsaalkyne tetramer2reacts at room temperature with ethyl triflate to give the As‐ethylated arsonium salt4. A similar reaction of2with benzyl triflate (generated in situ via PhCH2Cl/AgOTf) gives the As‐benzylated salt5. Low‐temperature protonation of2with FSO3H/SO2produces a mixture of arsonium ions6and7resulting from mono‐ and diprotonation. The NMR characteristics of the resulting arsonium ions are discussed and compared with those of the corresponding phosphonium ions derived from the tetraphosphacubane3. The FAB mass spectrum of4and its decomposition products (FAB‐CAD‐MS/MS) are als

ISSN:1042-7163    

DOI:10.1002/hc.520050514

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractSynthesis of several 6‐substituted‐1,2,4,8,10,11‐hexachloro‐12H‐dibenzo[d,g][1,3,2]dioxaphosphocin 6‐oxides and their IR,1H,13C, and31P NMR and mass spectral analyses are described. Observation of geminal coupling [2J(H,H)=16.0 Hz]between bridged methylene protons(12‐CH2)suggested their non‐equivalence and is consistent with a boat‐chair form which may be in conformational equilibrium with either a boat‐boat or a distorted and extended bo

ISSN:1042-7163    

DOI:10.1002/hc.520050515

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractA variety of diazo compounds was added to the parent vinylboronic ester derived from pinacol. The reactivity of some substituted 1‐alkenylboronic esters is also briefly examined. The nonisolated primary adducts spontaneously rearrange via a 1,3‐boron migration and lead to 1‐borylated‐2‐pyrazolines. The structure of one of these compounds has been established by X‐ray diffracti

ISSN:1042-7163    

DOI:10.1002/hc.520050516

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThree compounds (1,2, and3) containing 1,3,2‐oxathiaphospholane and 1,3,2‐dithiaphospholane rings were subjected to structural studies by the X‐ray method. Compounds1and3attain a half‐chair conformation, whereas, for compound2, an envelope conformation of the five‐membered heterocyclic ring was found in the solid state. For all three compounds, a site occupation of some structural elements in a unit cell was

ISSN:1042-7163    

DOI:10.1002/hc.520050517

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractPotassium carbonate mediated methanolysis of optically active 1,3‐oxathiolane‐2‐thiones (5‐membered cyclic xanthates) took place under very mild conditions to give optically pure 1,2‐episulfides. Also, methanolysis of 4‐[1‐(methanesulfonyloxy)alkyl]‐1,3‐oxathiolane‐2‐thiones and 2,4‐dialkyl substituted 1,3‐oxathiolane‐2‐thione gave 2,3‐

ISSN:1042-7163    

DOI:10.1002/hc.520050518

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe title compound2has been synthesized and its structure has been determined by X‐ray analysis. The following crystal data were found: monoclinic, P21, a = 9.936(4), b = 18.009(3), c = 10.418(3) Å, and β = 107.22(3)°. Two molecules of the compound (two oxathiaphospholane anions and two dicyclohexylammonium cations) are present in the independent part of the unit cell. The absolute configuration at the phosphorus atom is established as Rp. The ionic character of2is discussed. In the crystal lattice of2, a hydrogen‐bonding system

ISSN:1042-7163    

DOI:10.1002/hc.520050519

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractIon‐molecule reaction pathways between H2SiNH 2+and NH3have been examined by ab initio quantum chemical techniques using polarized split‐valence basis sets and including the effects of electron correlation and zero‐point energy corrections. The proton transfer (PT), hydrogen abstraction (HA), electron transfer (ET), and hydride transfer (HT) processes are thermodynamically unfavorable. The eliminative addition (EA) processes, in spite of their exothermicities, are also unfavorable, because they have activation barriers. The ammonia exchange (AE) process is most likely to occur among the reactions between H2SiNH 2+and NH3without an activation barrier. Therefore, H2SiNH 2+indicates apparent unreactivity toward NH3. This agrees well with the experimental result reported by Haller that SiH4N+apparently does not rea

ISSN:1042-7163    

DOI:10.1002/hc.520050520

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractSterically protected (E,E)‐3,4‐bis(2,4,6‐tri‐t‐butylphenylphosphinidene)dialkylcyclobutenes were isomerized to the corresponding (E,Z) derivatives in the presence of catalytic amounts of iodine. Similar iodine‐induced isomerizations were observed in the case of (E)‐ and (Z)‐2‐phenyl‐1‐(2,4,6‐tri‐t‐bu

ISSN:1042-7163    

DOI:10.1002/hc.520050521

出版商:VCH Publishers, Inc.    

年代:1994

数据来源: WILEY