摘要:

Investigations of the Products of Isocyanates with HydroxylamineThe reactions of isocyanates with hydroxylamine give rise to several compounds according to the different conditions involved when starting with the primary reaction products, the hydroxy‐ureas. The pure compounds have been isolated. An interesting reaction ofN‐phenyl‐N′‐phenylcarbamoyloxyurea with sodium hydroxide has been observed. This compound is converted to 3‐hydroxy‐1, 5‐diphenylbiuret under condi

ISSN:0018-019X    

DOI:10.1002/hlca.19830660402

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

AbstractIn the presence of 2 mol‐equiv. of AcONa, both triglycosylborane1and dicyclohexylglycosylborane2readily react with bromine chloride generatedin situfrom bromide andN‐chlorosuccinimide (NCS) to give the bromo‐sugar3(75 and 60%, resp.). The use of the BH3‐THF/bromide/NCS/2 AcONa procedure permits the rapid, face‐specific synthesis of6(58% uptake of bromine) and face‐selective synthesis of8/9(71% uptake of bromine), from vinyl ether derivatives5and7, respectively. The dicyclohexylborane/bromide/NCS/2 AcONa procedure leads to the fast and quantitative conversion of11to the bromosugar12(91%). Hydroboration‐transmetallation sequences give access toC‐mercuriated carbohydrates13(71%) and14(78%). The bis(glycosyl)mercury derivative13is spontaneously cleaved by reaction with one equivalent of bromide/chloramine‐T/aqueous HCl‐solution to give3(87%) and14(76%). Hydrostannylation of acetylenic sugar15gave the (E)‐stannylvinyl derivative16as the major product. This latter precursor16is spontaneously cleaved by the bromide/chloramine‐T/aqueous HCl‐solution reagent to give th

ISSN:0018-019X    

DOI:10.1002/hlca.19830660403

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

AbstractDiazotization of α‐amino acids in 48:52 (w/w) hydrogen fluoride/pyridine along with excess of potassium halide results in the corresponding α‐halocarboxylic acids in good to excellent yields(Table 1

ISSN:0018-019X    

DOI:10.1002/hlca.19830660404

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

AbstractThe potassium 2‐substituted bicyclo[2.2.1]hept‐5‐en‐2‐alkoxides derived from alcohols2–9at 30° in hexamethylphosphoric triamide (HMPA) afford 1‐(3′‐cyclopentenyl)‐2‐alkanones10–19viaheterolytic C(1), C(2)‐allylic bond cleavage in the substrate alkoxide followed by intramolecular protonation of the resulta

ISSN:0018-019X    

DOI:10.1002/hlca.19830660405

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Hydroxyphenyl‐1‐methylpyridinium‐iodide as Potential Reactivators of Acetylcholinesterase Poisoned with Organophosphorus Compounds.It was our aim to reactivate acetylcholinesterase poisoned with sarin.We synthesized 2‐(o‐hydroxyphenyl)‐1‐methylpyridinium‐iodide (9), 2‐(p‐hydroxyphenyl)‐1‐methylpyridinium‐iodide (19) and 4‐(o‐hydroxyphenyl)‐1‐methylpyridinium‐iodide (14) as potential reactivators. All substances showed moderate toxicity against mice; their reactivity pote

ISSN:0018-019X    

DOI:10.1002/hlca.19830660406

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Syntheses of Some Alkyl‐, Cycloalkyl‐ and Aryl‐(4‐aminophenyl)‐sulfonesSyntheses of (4‐aminophenyl)‐alkyl, ‐cycloalkyl and ‐aryl sulfones2were achieved both by alkylation of 4‐(acetylamino)‐benzenesulfinic acid (7) to the corresponding acetanilides9followed by hydrolysis and by oxidation of the appropriate (4‐nitrophenyl)‐sulfides11to (4‐nitrophenyl)‐sulfones1wi

ISSN:0018-019X    

DOI:10.1002/hlca.19830660407

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

AbstractConverging data obtained in biochemical and pharmacological bioassays for opiate activity are presented for five new enkephalin‐like peptides. The main structural features of the analogues, the synthesis of which is described in detail, were the presence ofD‐alanine orD‐serine in position 2,p‐nitrophenylalanine in position 4 and of a freeC‐terminal carboxylic function. Confirming our previous observations [1], the substitution of phenylalanine byp‐nitrophenylalanine enhanced the overall opiate activity but decreased the selectivity towards m̈/δ‐receptor sites. Tyrosyl‐D‐alanyl‐glycyl‐p‐nitrophenylalanyl‐adamantylalanine was particularly potent in all assays while tyrosyl‐D‐seryl‐glycyl‐p‐nitrophenylalanyl‐leucyl‐threonine was very selective in the bioassays on isolated tissues and moderately selective in the binding assay. These results will have to be taken into account in future photoaffinity labelling and quantitative struct

ISSN:0018-019X    

DOI:10.1002/hlca.19830660408

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

AbstractPhotolysis (λ = 254 mm, THF) of the diepoxyenone (E)‐1at −78° leads to the 2,8‐dioxabicyclo[3.2.1]oct‐3‐ene intermediate3(51%). At ambient temperature3undergoes an unexpectedly rapid electrocyclic opening to the triketone2in quantitative yield. Compound3seems likely to be the intermediate in the acid‐catalyzed rearrangement of (

ISSN:0018-019X    

DOI:10.1002/hlca.19830660409

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Reactivity‐structure correlations for anisole and eleven of its substituted derivatives established from bromination rate constants in liquid SO2, unlike observations in water, show the reaction to be highly sensitive to substituent effects, (ρ H 2O+= −7.1; ρ SO 2+= −10.51). This result is ascribed to the solvation of the methoxy group which decreases the conjugation ofpara‐substituted (ρ O+= −9.70) compared to that ofortho‐substituted derivatives (ρ P+= −8.86). The highly solvated transition state lies far from reactants on the reaction coordinate and the positive charge developed

ISSN:0018-019X    

DOI:10.1002/hlca.19830660410

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Zero‐current Ion‐transport Studies and Potentiometric Measurements on Membranes Containing Chromoionophores for Li+and UO 22+Non‐macrocyclic ionophores for Li+and UO 22+have been substituted with a diphenylmaleimide unit. In membranes the obtained chromoionophores induce the same ion‐selectivity and ion‐transport behavior as the unsubsti

ISSN:0018-019X    

DOI:10.1002/hlca.19830660411

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY