메뉴 건너뛰기




Volumn 63, Issue 25, 1998, Pages 9399-9405

Synthesis and chiroptical properties of dendrimers elaborated from a chiral, nonracemic central core

Author keywords

[No Author keywords available]

Indexed keywords

BENZOIC ACID DERIVATIVE; DENDRIMER;

EID: 0032509282     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo981508b     Document Type: Article
Times cited : (27)

References (49)
  • 2
    • 0030767579 scopus 로고    scopus 로고
    • For a recent discussion of the chirality of dendrimer systems, see: (a) Peerlings, H. W. I.; Meijer, E. W. Chem. Eur. J. 1997, 3, 1563. (b) Thomas, C. W.; Tor, Y. Chirality 1998, 10, 53. (c) Seebach, D.; Rheiner, P. B.; Greiveldinger, G.; Butz, T.; Sellner, H. Top. Curr. Chem. 1998, 197, 125.
    • (1997) Chem. Eur. J. , vol.3 , pp. 1563
    • Peerlings, H.W.I.1    Meijer, E.W.2
  • 3
    • 0031931653 scopus 로고    scopus 로고
    • For a recent discussion of the chirality of dendrimer systems, see: (a) Peerlings, H. W. I.; Meijer, E. W. Chem. Eur. J. 1997, 3, 1563. (b) Thomas, C. W.; Tor, Y. Chirality 1998, 10, 53. (c) Seebach, D.; Rheiner, P. B.; Greiveldinger, G.; Butz, T.; Sellner, H. Top. Curr. Chem. 1998, 197, 125.
    • (1998) Chirality , vol.10 , pp. 53
    • Thomas, C.W.1    Tor, Y.2
  • 4
    • 0000491602 scopus 로고    scopus 로고
    • For a recent discussion of the chirality of dendrimer systems, see: (a) Peerlings, H. W. I.; Meijer, E. W. Chem. Eur. J. 1997, 3, 1563. (b) Thomas, C. W.; Tor, Y. Chirality 1998, 10, 53. (c) Seebach, D.; Rheiner, P. B.; Greiveldinger, G.; Butz, T.; Sellner, H. Top. Curr. Chem. 1998, 197, 125.
    • (1998) Top. Curr. Chem. , vol.197 , pp. 125
    • Seebach, D.1    Rheiner, P.B.2    Greiveldinger, G.3    Butz, T.4    Sellner, H.5
  • 5
    • 20644451148 scopus 로고    scopus 로고
    • note
    • We define "conformational order" as the presence of stable secondary structure within the branch segments of the polymer.
  • 12
    • 33748224868 scopus 로고
    • The examples in ref 5 exhibit rotations that increase with increasing numbers of chiral termini. However, in the following system, due to dense packing on the surface occurring due to hydrogen bonding, optical activity decreased as the number of amino acid termini present on poly(propylene imine) dendrimers was increased: Jansen, J. F. G. A.; Peerlings, J. H. W. I.; de Brabander-Van den Berg, E. M. M.; Meijer, E. W. Angew. Chem., Int. Ed. Engl. 1995, 34, 1206. Dyes encapsulated in the poly(propylene imine) system with an optical rotation of zero exhibited a small induced circular dichroism which could be the result of the achiral pockets adopting chiral, nonracemic conformations: Jansen, J. F. G. A.; de Brabander-van den Berg, E. M. M.; Meijer. E. W. Recl. Trav. Chim. 1995, 114, 225.
    • (1995) Angew. Chem., Int. Ed. Engl. , vol.34 , pp. 1206
    • Jansen, J.F.G.A.1    Peerlings, J.H.W.I.2    De Brabander-Van Den Berg, E.M.M.3    Meijer, E.W.4
  • 13
    • 20644460734 scopus 로고
    • The examples in ref 5 exhibit rotations that increase with increasing numbers of chiral termini. However, in the following system, due to dense packing on the surface occurring due to hydrogen bonding, optical activity decreased as the number of amino acid termini present on poly(propylene imine) dendrimers was increased: Jansen, J. F. G. A.; Peerlings, J. H. W. I.; de Brabander-Van den Berg, E. M. M.; Meijer, E. W. Angew. Chem., Int. Ed. Engl. 1995, 34, 1206. Dyes encapsulated in the poly(propylene imine) system with an optical rotation of zero exhibited a small induced circular dichroism which could be the result of the achiral pockets adopting chiral, nonracemic conformations: Jansen, J. F. G. A.; de Brabander-van den Berg, E. M. M.; Meijer. E. W. Recl. Trav. Chim. 1995, 114, 225.
    • (1995) Recl. Trav. Chim. , vol.114 , pp. 225
    • Jansen, J.F.G.A.1    De Brabander-van Den Berg, E.M.M.2    Meijer, E.W.3
  • 25
    • 20644435279 scopus 로고    scopus 로고
    • note
    • Hydrogenolysis of the secondary benzyloxy group competes with deprotection of the benzyl groups and is minimized by using Raney-Ni.
  • 27
    • 20644470254 scopus 로고    scopus 로고
    • note
    • In the absence of DMF, the alkylation efficiency decreases significantly.
  • 28
    • 20644444268 scopus 로고    scopus 로고
    • note
    • All dendrimers gave satisfactory combustion analysis and monodisperse GPC traces.
  • 30
    • 20644444049 scopus 로고    scopus 로고
    • note
    • Fragmentation at this benzylic position was also observed in the mass spectrum of central core 2.
  • 31
    • 0026909675 scopus 로고
    • 1 relaxation time measurements of PAMAM dendrimers have revealed that internal segment density increases with increasing generation: Meltzer, A. D.; Tirrell, D. A.; Jones, A. A.; Inglefield, P. T. Macromolecules 1992, 25, 4549. Further studies:
    • (1992) Macromolecules , vol.25 , pp. 4549
    • Meltzer, A.D.1    Tirrell, D.A.2    Jones, A.A.3    Inglefield, P.T.4
  • 42
    • 20644434080 scopus 로고    scopus 로고
    • note
    • 1-6 exhibit their most intense UV absorptions bands at 250-260 nm; however, 4-6 also exhibit a less intense absorption band at 308, 308, and 282 nm, respectively. Dendrimers 7-9 exhibit the most intense bands at 246 nm with a weaker absorption at 260-270 nm. These electronic differences are not solely responsible for the difference in optical rotatory power that is observed because the additional bands at longer wavelength in 4-6 should lead to a slight increase in rotation which is not observed.
  • 43
    • 20644441281 scopus 로고    scopus 로고
    • note
    • Since the terminal esters are electronically different than the tribenzoyl core, an interaction of these chromophores would be expected to generate a more complex Cotton effect than is observed.
  • 45
    • 20644457050 scopus 로고    scopus 로고
    • note
    • 3 implemented in Macromodel 5.0.
  • 47
    • 20644466978 scopus 로고    scopus 로고
    • note
    • Such variation of rotation values with solvent is not unusual. For an example of a solvent-induced reorientation of dipoles that reverses the sign of an ORD curve, see ref 18c.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.