摘要:

AbstractAcid hydrolysis, under relatively mild conditions (3N HCl, 100°C), of a series of homo‐polymers ofN‐vinyl‐N‐methylacetamide, and copolymers thereof with vinyl acetate or methyl acrylate, afforded poly(N‐vinyl‐N‐methylamine), poly(N‐vinyl‐N‐methylamine‐co‐vinyl alcohol) and poly(N‐vinyl‐N‐methylamine‐co‐acrylic acid) in almost quantitative yield. A simple and practical route to poly(N‐vinyl‐N‐methylacetamide‐co‐acrylic acid) and poly(N‐vinyl‐N‐methylacetamide‐co‐vinyl alcohol) has been developed and some kinetic results relating to the hydrolysis step are given. The products were characterized by

ISSN:0165-0513    

DOI:10.1002/recl.19891080402

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe oxidation of cerium(III)‐exchanged zeolite NaY (exchange level 24‐91%) with aqueous hydrogen peroxide and oxygen has been studied. The fraction of Ce(IV) produced decreases with increasing Ce content of the zeolites. Hydrogen peroxide is catalytically decomposed by the Ce(III)/Ce(IV) redox couple with formation of an equilibrium level of a Ce(IV) hydroxide species. Oxidation with oxygen at temperatures higher than 400 K yields an oxycerium(IV) complex. The latter NaCe(IV)Y zeolite effects oxidative glycol cleavage of 2,3‐dimethyl‐2,3‐butanediol to acetone. Activation in oxygen restored its oxidizing capacity. Thus, the oxygen‐activated NaCe(IV)Y zeolite is a regenerable glycol‐cleaving oxidant. The H2O2‐oxidized NaCe(IV)Y is not active in glycol‐cl

ISSN:0165-0513    

DOI:10.1002/recl.19891080403

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

Abstract5,7‐Dimethyl[1,2,4]triazolo[1,5‐a]pyrimidine (dmtp) has been used as a ligand for nickel(II) and cobalt(II) chloride, bromide, iodide and triiodide. The halides yield compounds of compositiontrans‐[M(dmtp)2(H2O)4](H2O)2X2, the triiodides having the compositiontrans‐[M(dmtp)4(H2O)2](dmtp)2(I3)2. The IR spectra of he halides are all mutually isomorphous, differing from those of the triiodides. Spectroscopic properties agree with octahedrally coordinated metal ions with MN2O4and MN4O2chromophores, respectively. The crystal structures of two representative compounds,i.e.the nickel iodide and the nickel triiodide compounds, are described.[Ni(dmtp)2(H2O)4](H2O)2I2is triclinic,P−1,a8.175(1) Å,b8.263(3) Å,c9.628(2) Å), α 85.60(2)°, β 81.84(2)°, γ 82.06(2)°, Z 1,dc1.870 Mg.m−3,R0.084 based on 2516 reflections. Ni2+is octahedrally coordinated by two N(3)‐bonded dmtp ligands (trans‐oriented) with Ni‐N 2.080(6) Å) and four water molecules with Ni‐O 2.067(6) Å and 2.094(6) Å, respectively. The iodides and the remaining water molecules are retained in the lattice, through extensive hydrogen bonding. [Ni(dmtp)4(H2O)2](dmtp)2(I3)2is triclinic, P−1,a12.428(2) Å,b14.852(2) Å,c8.795(2) Å, α 103.27(2)°, (3 108.80(3)°, γ 89.73(2)°, Z 1,dc1.944 mg.m−3,R0.092 based on 3724 reflections. Ni2+is octahedrally coordinated by two water molecules in atransorientation with Ni‐O 2.13(1) Å and by four N(3)‐bonded dmtp ligands with Ni‐N 2.07(2) Å and 2.09(2) Å, respectively. The triiodide ions are linear with II bonds of 2.918(3) Å and 2.884(3) Å. The compound forms a lattice adduct w

ISSN:0165-0513    

DOI:10.1002/recl.19891080404

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe syntheses of (17O)phenol from (17O)water, (18O)phenol from (18O)water, (1‐13C)‐phenol and (4‐13C)phenol from (2‐13C)acetone and (2‐13C)phenol and (3‐13C)phenol from (1‐13C)‐acetone with high isotopic enrichment are described. The labelled phenols are converted into their corresponding L‐tyrosines by the bacteriumErwinia herbicola. A full analysis of the1H and13C NMR spectra of phenol and L‐t

ISSN:0165-0513    

DOI:10.1002/recl.19891080405

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractTwo different routes are described for the synthesis of the 2,2,2‐trifluoro‐l‐[2‐(dialkyl‐amino)phenyl]ethanones2and9and their hydrates3and10, respectively, via trifluoroacetylation of theN,N‐dialkylanilines1and via a Barbier reaction of 2‐fluorobenzaldehyde. These compounds were thermally converted into a mixture ofcis‐ andtrans‐pyrrolo‐ and pyrido[1,2‐a] [3,1]benzoxazines, (11:cis;12:trans). The structure of these compounds was proven by X‐ray analysis (11a) and1H NOE difference spectroscopy. Cyclization of (R)‐9b(R1= CH3) gave predominantly one enantiomer (12f, 70%) and in addition two diastereomers of17aand two of18a(total yield ≈︁ 17%), while cyclization of (S)‐9c(R1= CH2OCH3) gave a mixture of12g(18%), two diastereomers of17b(36%) and two diastereomers of18b(18%). The benzaldehyde19a(R3= H), acetophenone19d(R3= CH3), trifluoroacetophenones19b,c(R3= CF3) and benzophenone19e(R3= C6H5) reacted with Lawesson's reagent to yield exclusively thetrans‐pyrrolo[1,2‐a] [3,1]benzothiazines21a‐ein yields of 33‐77%. Reaction of19f(R1= CH3, R3= H),19g(R1= CH3, R3= CF3) and19h(R1= CH3, R3= CH3) with Lawesson's reagent resulted in th

ISSN:0165-0513    

DOI:10.1002/recl.19891080406

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractComplexation studies of alkali cations with a cyclic tetrasaccharide made up of (1 → 6)‐β‐D‐gluco‐pyranosyl residues, cyclogentiotetraose peracetate (CGD4Ac) by proton n. m. r. spectroscopy in deuterated acetone and nitromethane are described.The ligand affinity decreases in both solvent, from cesium to lithium as follows: Cs+∼ Rb+>K+>Na+>Li+, in agreement with the ligand cavity size (3.3 Å) calculated by molecular modelling.During complexation, a conformational change of the CGD4Ac ligand was observed, the gg conformer being predominent at the co

ISSN:0165-0513    

DOI:10.1002/recl.19891080407

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19891080409

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19891080411

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19891080413

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19891080414

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY