Intramolecular remote functionalisation of steroids by benzophenone — Increased specificity by solvent-induced hydrophobic interactions

  • Anil K. Lala
  • A. P. Gokhale
Molecular Recognition


Proximity of reactant sites is one of the major factors that contributes to specificity and high reaction rates observed in enzyme catalysis. Enzymes achieve this proximity between the reactant sites by having high affinity for the substrate. Structural studies on enzyme-substrate complexes provide sufficient evidence in this context and indicate that weak bonding interaction are involved in formation of such complexes. We have exploited the hydrophobic interaction between cholesterol and benzophenone to carry out photoinduced remote functionalisation of cholesterol at specific sites. Thus, using polar solvents intramolecular hydrophobic interaction between cholesterol and benzophenone permitted exclusive functionalisation of ring D in cholesterol. The current study indicates that weak interactions between the reactants can be used to bring them in proximity and photochemical reactions can provide the method for functionalising even inert sites like C-H bonds.


Cholesterol benzophenone remote functionalisation enzyme model hydrophobic interactions 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Atassi M Z and Manshouri T 1993Proc. Natl. Acad. Sci. USA 90 8282CrossRefGoogle Scholar
  2. Baldwin J E, Bhatnagar A K and Harper R W 1970Chem. Commun. 659Google Scholar
  3. Beckett A and Porter G 1961Trans. Faraday. Soc. 57 1686CrossRefGoogle Scholar
  4. Breslow R 1980Acc. Chem. Res. 13 170CrossRefGoogle Scholar
  5. Breslow R 1988Cherntracts: Org. Chem. 1 333Google Scholar
  6. Breslow R and Baldwin S W 1970J. Am. Chem. Soc. 92 732CrossRefGoogle Scholar
  7. Breslow R, Baldwin S, Flechtner T, Kalicky P, Liu S and Washburn W 1973J. Am. Chem. Soc. 95 3251CrossRefGoogle Scholar
  8. Breslow R, Corcoran R J, Snider B B, Doll R J, Khanna P L and Kaleya R 1977J. Am. Chem. Soc. 99 905CrossRefGoogle Scholar
  9. Breslow R and Kalicky P 1971J. Am. Chem. Soc. 93 3540CrossRefGoogle Scholar
  10. Breslow R, Kitabatake S and Rothbard J 1978aJ. Am. Chem. Soc. 100 8156CrossRefGoogle Scholar
  11. Breslow R and Link T 1992Tetrahedron Lett. 33 4145CrossRefGoogle Scholar
  12. Breslow R, Maitra U and Heyer D 1984Tetrahedron Lett. 25 1123CrossRefGoogle Scholar
  13. Breslow R, Rothbard J, Herman F and Rodriguez M I 1978bJ. Am. Chem. Soc. 100 1213CrossRefGoogle Scholar
  14. Breslow R and Winnik M A 1969J. Am. Chem. Soc. 91 3083CrossRefGoogle Scholar
  15. Brockerhoff H and Ramsammy L S 1982Biochim. Biophys. Acta 691 227CrossRefGoogle Scholar
  16. Czarniecki M F and Breslow R 1979J. Am. Chem. Soc. 101 3675CrossRefGoogle Scholar
  17. Dugas H 1989Bioorganic chemistry. A chemical approach to enzyme action 2nd edn (New York: Springer-Verlag) p. 262Google Scholar
  18. Grieco P A and Stuk T L 1990J. Am. Chem. Soc. 112 7799CrossRefGoogle Scholar
  19. Kaufman M D, Grieco P A and Bougie D W 1993J. Am. Chem. Soc. 115 11648CrossRefGoogle Scholar
  20. Lala A K and Kumar E R 1993J. Am. Chem. Soc. 115 3982CrossRefGoogle Scholar
  21. Lee E, Lee H H, Chang H K and Lim D Y 1988Tetrahedron Lett. 29 339CrossRefGoogle Scholar
  22. Snider B B, Corcoran R J and Breslow R 1975J. Am. Chem. Soc. 97 6580CrossRefGoogle Scholar
  23. Stuk T L, Grieco P A and Marsh M M 1991J. Org. Chem. 56 2957CrossRefGoogle Scholar
  24. Walling C and Gibian M 1965J. Am. Chem. Soc. 87 3361CrossRefGoogle Scholar
  25. Walsh C 1979Enzymatic reaction mechanism (San Franscisco: W H Freeman & Co) p. 37Google Scholar
  26. Yeagle P L 1985Biochim. Biophys. Acta 822 267Google Scholar

Copyright information

© Indian Academy of Sciences 1994

Authors and Affiliations

  • Anil K. Lala
    • 1
  • A. P. Gokhale
    • 1
  1. 1.Biomembrane Lab, Department of ChemistryIndian Institute of TechnologyPowai, BombayIndia

Personalised recommendations