Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Electronic Resource  (20)
  • Physics  (13)
  • HPLC  (5)
  • Inorganic Chemistry  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Optical Resolution of [2,2]Paracyclophanes by High-Performance Liquid Chromatography on Tris(3,5-dimethylphenylcarbamates) of Celllulos and Amylose (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 841-845 
    Details
    ISSN: 0009-2940
    Keywords: Resolution, optical / Stationary phase, Chiral / Anylose carbamates / Celluslose carbamates / [3.2]Paracyclophanes, functionalized ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical resolution of 22 [2,2]paracyclophane derivatives was examined by high-performance liquid chromatography (HPLC) using tris(3,5-dimethylphenylcarbamates) of cellulose and amylose as chiral stationary phases. Most compounds were completely separated into enantiomers at least on one of the stationary phases. The preparation of hte new cyclophane derivatives 10, 11, 12, 14, 16, and 19 as wel as a new procedure for the synthesis of 4-fluoro-[2,2]paracyclophane (3) are described.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230432
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Nitro- und Allyloxy-substituierte helicale [2.2]Metacyclophane: Synthese, Circulardichroismus und Röntgen-Kristallstrukturanalysen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1585-1590 
    Details
    ISSN: 0009-2940
    Keywords: Charge transfer ; Circular dichroism ; Helical molecules ; [2.2]Metacyclophanes ; Structure-chiroptic relationships ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nitro- and Allyloxy-Substituted Helical [2.2]Metacyclophanes: Synthesis, Circular Dichroism and Crystal StructuresThe preparations of the title compound 3a, intraannularly nitro-functionalized, of the extraannularly substituted reference compound 3b, and of the sulfone 4 are described. Enantiomeric resolution of these helical phanes was accomplished on (+)-PTrMA and cellulose tris(3,5-dimethylphenyl)carbamate by HPLC. Racemization of the enantiomers of 3b is faster than that of the previously reported extraannularly substituted phanes. The crystal structure of 3a as well as that of the allyl ether 3d show severe distortions of the benzene rings; the CD spectrum of 3a is pointing at an intramolecular charge-transfer complex, an effect that cannot be evaluated from the CD spectrum of 3b.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240719
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Optical resolution of β-lactams on 1-phenylethylcarbamates of cellulose and amylose (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 122-124 
    Details
    ISSN: 0899-0042
    Keywords: 4-acetoxy-2-azetidinone ; antibiotics ; carbapenem ; HPLC ; chiral stationary phases ; cellulose tris(1-phenylethylcarbamate) ; amylose tris(1-phenylethylcarbamate) ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical resolution of six β-lactams was examined by HPLC using chiral stationary phases consisting of tris((R)-, (RS)-, and (S)-1-phenylethylcarbamate)s of cellulose and amylose. All β-lactams were optically resolved at least by one of the carbamates. Amylose tris((S)-1-phenylethylcarbamate) showed high optical resolving abilities for some β-lactams.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040210
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Dichloro-, dimethyl-, and chloromethylphenylcarbamate derivatives of cyclodextrins as chiral stationary phases for high-performance liquid chromatography (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 402-407 
    Details
    ISSN: 0899-0042
    Keywords: enantioseparation ; HPLC ; cyclodextrin ; phenylcarbamate ; chiral stationary phase ; optical resolution ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New dichloro-, dimethyl-, and chloromethylphenylcarbamate derivatives of cyclodextrins (CDs) were prepared and their enantiomeric recognition abilities were evaluated as chiral stationary phases (CSPs) in normal phase high-performance liquid chromatography (HPLC). The effects of the type of cyclodextrins, the nature and position of the substituents on the phenyl ring, binding mode and spacer on the chiral recognition were studied in detail. No marked change of chiral recognition abilities was established by reversing the binding side of CDs (i.e., by the narrower [primary] opening of the cone-shaped CD to silica gel with the wider [secondary] opening sides). This result indirectly proves the previously drawn conclusion about the minor role of inclusion phenomena in chiral recognition in this case. Nevertheless, chiral recognition of these CSPs toward some compounds critically depends on the type of CDs used. All CD derivatives described in this study show rather low enantiomeric resolving abilities compared with corresponding polysaccharide (cellulose and amylose) derivatives, although very high enantioselectivity of separation was observed for a few compounds, such as racemic flavanone and cyclopropanedicarboxilic acid dianilide. © 1996 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    Enantioseparation on 4-halogen-substituted phenylcarbamates of amylose as chiral stationary phases for high-performance liquid chromatography (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 9 (1997), S. 63-68 
    Details
    ISSN: 0899-0042
    Keywords: enantioseparation ; chiral stationary phase ; HPLC ; amylose phenylcarbamate ; chiral discrimination ; resolution ; enantiomer ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four 4-halogen-substituted phenylcarbamate derivatives of amylose were prepared and their chiral recognition abilities as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) were evaluated and compared with those of the corresponding cellulose derivatives. The amylose derivatives with fluoro, chloro, bromo, or iodo group at the four-position on the phenyl group were found to show higher chiral resolving ability than the corresponding cellulose derivatives. Among four amylose derivatives 4-fluoro- and 4-chlorophenylcarbamates showed an excellent chiral recognition ability. Especially, amylose tris(4-chlorophenylcarbamate) resolved (±)-1,2,2,2-tetraphenylethanol with a very high α value (α = 8.29). In order to obtain useful information concerning the chiral recognition mechanism of this resolution, we also performed enantioseparation of a variety of analogous racemic alcohols, and found that both the hydroxy and bulky triphenylmethyl groups of the racemate are essential for the effective chiral recognition. Chirality 9:63-68, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Resolution of enantiomers by HPLC on tris(4-alkoxyphenylcarbamate)s of cellulose and amylose (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 616-621 
    Details
    ISSN: 0899-0042
    Keywords: cellulose tris(4-isopropoxyphenylcarbamate) ; cellulose tris(3,5-dimethyl-4-methoxyphenylcarbamate) ; amylose tris(3,5-dimethyl-4-methoxyphenylcarbamate) ; optical resolution ; HPLC ; chiral stationary phase ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ten phenylcarbamate derivatives of cellulose and amylose having alkoxy groups such as ethoxy, isopropoxy, and isobutoxy at 4-position, and methyl groups at 3- and 5-positions and methoxy group at 4-position were synthesized and their chiral recognition abilities as stationary phases for high-performance liquid chromatography were investigated and compared to those with tris(4-methoxyphenylcarbamate)s of cellulose and amylose. In 4-alkoxy derivatives of cellulose, chiral recognition ability increased as the bulkiness of 4-alkoxy groups increased. 4-Isopropoxy and 4-isobutoxy derivatives showed high chiral recognition. On the other hand, chiral discrimination of amylose 4-alkoxy derivatives scarcely depended on the bulkiness of the alkoxy group, and 4-methoxy and 4-isopropoxy derivatives showed high chiral recognition. 3,5-Dimethyl-4-methoxyphenylcarbamates of cellulose and amylose possessed higher chiral recognition ability than the corresponding 4-methoxy derivatives. © 1993 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530050809
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Direct chromatographic separation of 2-arylpropionic acid enantiomers using tris(3,5-dimethylphenylcarbamate)s of cellulose and amylose as chiral stationary phases (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 1 (1989), S. 239-242 
    Details
    ISSN: 0899-0042
    Keywords: optical resolution ; HPLC ; chromatography ; antiinflammatory drug ; ibuprofen ; ketoprofen ; flurbiprofen ; tiaprofenic acid ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Direct optical resolution of antiinflammatory drugs such as ibuprofen, ketoprofen, flurbiprofen, and tiaprofenic acid were attempted by high-performance liquid chromatography using tris(3,5-dimethylphenylcarbamate)s of cellulose and amylose as chiral stationary phases. Although ibuprofen was not sufficiently resolved, the other three 2-arylpropionic acids were completely resolved by amylose tris(3,5-dimethylphenylcarbamate). Ibuprofen was resolved as anilide derivative.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530010310
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Poly(β-Amino acids). V. Synthesis and conformation of oligomeric α-isobutyl-L-aspartate (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 1911-1921 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-Isobutyl-L-aspartate oligomers, Z-(α-i-Bu-Asp)2n-OEt (n = 1-5), where Z = benzyloxycarbonyl and OEt = ethyl ester, were prepared stepwise, and their conformation in solution was investigated by optical rotation, circular dichroism (CD), and NMR spectroscopy. The oligomers up to hexamer existed only in a disordered form. An ordered structure began to appear at octamer and decamer in chloroform and 2,2,2-trifluoroethanol. The ordered structure was more favorable for N-unprotected oligomers, H-(α-i-Bu-Asp)2n-OEt, in comparison with the corresponding Z-(α-i-Bu-Asp)2n-OEt. The effects of oligomer concentration and temperature on the structure were slightly observed. The most likely ordered structure was a β form caused by intramolecular association.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.170170703
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Anionic copolymerization of optically active α-methylbenzyl methacrylate and trityl methacrylate. I. Reactivity of monomers (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 2917-2928 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The monomer reactivity ratios were determined in the anionic copolymerization of (S)- or (RS)-α-methylbenzyl methacrylate (MBMA) and trityl methacrylate (TrMA) with butyllithium at -78°C, and the stereoregularity of the yielded copolymer was investigated. In the copolymerization of (S)-MBMA (M1) and TrMA (M2) in toluene the monomer reactivity ratios were r1 = 8.55 and r2 = 0.005. On the other hand, those in the copolymerization of (RS)-MBMA with TrMA were r1 = 4.30 and r2 = 0.03. The copolymer of (S)-MBMA and TrMA prepared in toluene was a mixture of two types of copolymer: one consisted mainly of the (S)-MBMA unit and was highly isotactic and the other contained both monomers copiously. The same monomer reactivity ratios, r1 = 0.39 and r2 = 0.33, were obtained in the copolymerizations of the (S)-MBMA-TrMA and (RS)-MBMA-TrMA systems in tetrahydrofuran (THF). The microstructures of poly[(S)-MBMA-co-TrMA] and poly-[(RS)-MBMA-co-TrMA] produced in THF were similar where the isotacticity increased with an increase in the content of the TrMA unit.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.170170927
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Anionic polymerization and copolymerization of S-methyl thiomethacrylate (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 3705-3712 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: S-Methyl thiomethacrylate (methyl thiolmethacrylate, MTMA) was polymerized with a variety of anionic initiators such as n-BuLi, octylpotassium, PhMgBr, and Et2AlNPh2 in toluene and THF. Stereoregularity of the polymer (PMTMA) was determined from the 1H-NMR spectrum of poly(methyl methacrylate), which had been derived from PMTMA, because the α-methyl resonance in the 1H-NMR spectrum of PMTMA was not satisfactorily solved owing to the overlap of pentad signals. The 13C-NMR spectrum of PMTMA also showed the splitting due to pentad sequences. Stereoregularity of PMTMA was always low compared with that of poly(methyl methacrylate), which was prepared under the same reaction conditions. MTMA was much more reactive than methyl methacrylate and methacrylonitrile in the copolymerization with n-BuLi in toluene and in THF at -78°C. The lower stereoregulation of the polymerization of MTMA and the higher reactivity of MTMA were mainly ascribed to the higher resonance effect of MTMA.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.170171126
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...