Synthesis of Isoflavones from 2′-Hydroxychalcones Using Poly[4-(diacetoxy)iodo]styrene or Related Hypervalent Iodine Reagent

Abstract

Isoflavones are synthesized in an one-pot reaction by treating the hypervalent iodine(III) reagent, [hydroxy(tosyloxy)iodo]benzene (HTIB, Koser’s reagent) with 2′-benzoyloxychalcones in MeOH. A combined use of (diacetoxyiodo)benzene (DIB)/p-toluenesulfonic acid (TsOH) is also effective for the same purpose. As an extension of these monomeric reagents, polymer-supported DIB {PSDIB, poly[4-(diacetoxy)iodo]styrene} with TsOH works also well. The merits of the latter are the ease of separation of iso­flavones from the reaction mixture, no liberation of PhI, and reuse of the reagent.

chalcones - isoflavones - protecting groups - hypervalent iodine - oxidative rearrangements

References

<A NAME="RF04202SS-1">1</A> Wong E. The Flavonoids   Harborne JB. Mabry TJ. Mabry H. Chapman and Hall; London: 1975.  p.184 

<A NAME="RF04202SS-2">2</A> McKillop A. Swarn BP. Taylor EC. Tetrahedron Lett.  1970,  5281 

<A NAME="RF04202SS-3">3</A> Jain AC. Lal P. Seshadri TR. Indian J. Chem.  1969,  7:  305 

<A NAME="RF04202SS-4">4</A> Hoshino Y. Miyaura N. Suzuki A. Bull. Chem. Soc. Jpn.  1988,  61:  3008 

<A NAME="RF04202SS-5A">5a</A> Tsukayama M. Oda A. Kawamura Y. Nishiuchi M. Yamashita K. Tetrahedron Lett.  2001,  42:  6163 

<A NAME="RF04202SS-5B">5b</A> Tsukayama M. Wada H. Kishida M. Nishiuchi M. Takahashi M. Kawamura Y. Chem. Lett.  2000,  1362 

<A NAME="RF04202SS-5C">5c</A> Tsukayama M. Li H. Tsurumoto K. Nishiuchi M. Kawamura Y. Bull. Chem. Soc. Jpn.  1998,  71:  2673 

<A NAME="RF04202SS-6A">6a</A> Horie T. Kawamura Y. Sakai C. Akita A. Sasagawa M. Yamada T. J. Chem. Soc., Perkin Trans 1  1996,  1987 

<A NAME="RF04202SS-6B">6b</A> Horie T. Kawamura Y. Sakai C. Akita A. Kuramoto M. J. Chem. Soc., Perkin Trans 1  1994,  753 

<A NAME="RF04202SS-6C">6c</A> Horie T. Yamada T. Kawamura Y. Tsukayama M. Kuramoto M. J. Org. Chem.  1992,  57:  1038 

<A NAME="RF04202SS-7A">7a</A> Moriarty RM. Khosrowshahi JS. Prakash O. Tetrahedron Lett.  1985,  26:  2961 

<A NAME="RF04202SS-7B">7b</A> Koser GF. Wettach RH. J. Org. Chem.  1976,  41:  3609 

<A NAME="RF04202SS-7C">7c</A> Prakash O. Aldrichimica Acta  1995,  28:  63 

<A NAME="RF04202SS-8A">8a</A> Miki Y. Kobayashi S. Hachiken H. Synlett  1994,  1001 

<A NAME="RF04202SS-8B">8b</A> Miki Y. Fujita R. Matsushita K. J. Chem Soc., Perkin Trans 1  1998,  2533 

<A NAME="RF04202SS-9">9</A> Koser GF. Wettach RH. J. Org. Chem.  1977,  42:  1476 

<A NAME="RF04202SS-10">10</A>

The amount of NaOH was calculated as follows: The amount (1.5 equiv) needed for the ring closure of acetal 2h-Bz plus the amount (3.0 equiv) of HOAc formed by decomposition of DIB and that of TsOH (2.0 equiv).

<A NAME="RF04202SS-11">11</A>

Yields of one-pot synthesis of 3 from the corresponding 1-Bz using DIB/TsOH in CH₂Cl₂-MeOH are as follows: Isoflavones 3i (70%), 3j (77%), 3k (70%), and 3l (67%). In addition, the one-pot reactions of 1k-Bz with DIB/TsOH and PSDIB/TsOH proceeded without difficulty even in a mmol scale (a few grams), indicating the applicability of the present method for synthesis of a larger quantity as well. [16]

<A NAME="RF04202SS-12A">12a</A> Togo H. Nogami G. Yokoyama M. Synlett  1998,  534 

<A NAME="RF04202SS-12B">12b</A> Togo H. Abe S. Nogami G. Yokoyama M. Bull. Chem. Soc. Jpn.  1999,  72:  2351 

<A NAME="RF04202SS-13A">13a</A> Abe S. Sakuratani K. Togo H. Synlett  2001,  22 

<A NAME="RF04202SS-13B">13b</A> Abe S. Sakuratani K. Togo H. J. Org. Chem.  2001,  66:  6174 

<A NAME="RF04202SS-14A">14a</A> Tohma H. Morioka H. Takizawa S. Arisawa M. Kita Y. Tetrahedron  2001,  57:  345 

<A NAME="RF04202SS-14B">14b</A> Kita Y. Tohma H. Hatanaka K. Takada T. Fujita S. Mitoh S. Sakurai H. Oka S. J. Am. Chem. Soc.  1994,  116:  3684 

<A NAME="RF04202SS-15">15</A> Ley SV. Thomas AW. Finch H. J. Chem. Soc., Perkin Trans 1  1999,  669 

<A NAME="RF04202SS-16">16</A>

The experiments were done as a part of our ongoing synthetic studies on isoflavonoids. Details will be submitted elsewhere.

<A NAME="RF04202SS-17">17</A> Khanna MS. Om VS. Chandra PG. Ram PK. J. Chem. Soc., Perkin Trans 1  1992,  2565 

<A NAME="RF04202SS-18">18</A> Bezuidenhoudt BCB. Vincent Brandt E. Ferreira D. J. Chem. Soc., Perkin Trans 1  1987,  1081 

<A NAME="RF04202SS-19">19</A> Sekizaki H. Yokosawa R. Chinen C. Adachi H. Yamane Y. Biol. Pharm. Bull.  1993,  16:  698