Abstract
With 2,6-Cl2 C6 H3 COCl and 1-methylimidazole, the title condensation completed at room temperature within
12 hours, which is shorter time than that with the standard DCC/DMAP system. Use of
easily separable 1-methylimidazole from the crude product by chromatography is an
additional advantage of the present reagent system.
Key words
carboxylic acids - condensation - esterification - furans - lipids
References
<A NAME="RU15405ST-1">1 </A>
Eibl H.
Angew. Chem., Int. Ed. Engl.
1984,
23:
257
<A NAME="RU15405ST-2A">2a </A>
Berliner JA.
Subbanagounder G.
Leitinger N.
Watson AD.
Vora D.
Trends Cardiovasc. Med.
2001,
11:
142
<A NAME="RU15405ST-2B">2b </A>
Berliner JA.
Vasc. Pharmacol.
2002,
38:
187
<A NAME="RU15405ST-2C">2c </A>
Podrez EA.
Poliakov E.
Shen Z.
Zhang R.
Deng Y.
Sun M.
Finton PJ.
Shan L.
Gugiu B.
Fox PL.
Hoff HF.
Salomon RG.
Hazen SL.
J. Biol. Chem.
2002,
277:
38503
<A NAME="RU15405ST-2D">2d </A>
Jerlich A.
Schaur RJ.
Pitt AR.
Spickett CM.
Free Radical Res.
2003,
37:
645
<A NAME="RU15405ST-3">3 </A>
Ramirez F.
Marecek JF.
Synthesis
1985,
449
<A NAME="RU15405ST-4A">4a </A>
Baba N.
Yoneda K.
Tahara S.
Iwasa J.
Kaneko T.
Matsuo M.
J. Chem. Soc., Chem. Commun.
1990,
1281
<A NAME="RU15405ST-4B">4b </A>
Hébert N.
Beck A.
Lennox RB.
Just G.
J. Org. Chem.
1992,
57:
1777
<A NAME="RU15405ST-4C">4c </A>
Yoneda K.
Sasakura K.
Tahara S.
Iwasa J.
Baba N.
Kaneko T.
Matsuo M.
Angew. Chem., Int. Ed. Engl.
1992,
31:
1336
<A NAME="RU15405ST-4D">4d </A>
Menger F.
Wong Y.-L.
J. Org. Chem.
1996,
61:
7382
<A NAME="RU15405ST-4E">4e </A>
Deng Y.
Salomon RG.
J. Org. Chem.
1998,
63:
7789
<A NAME="RU15405ST-4F">4f </A>
Deng Y.
Salomon RG.
J. Org. Chem.
2000,
65:
6660
<A NAME="RU15405ST-4G">4g </A>
Sun M.
Deng Y.
Batyreva E.
Sha W.
Salomon RG.
J. Org. Chem.
2002,
67:
3575
<A NAME="RU15405ST-4H">4h </A>
Gu X.
Sun M.
Gugiu B.
Hazen S.
Crabb JW.
Salomon RG.
J. Org. Chem.
2003,
68:
3749
<A NAME="RU15405ST-4I">4i </A>
Gugiu B.
Salomon RG.
Org. Lett.
2003,
5:
2797
<A NAME="RU15405ST-5A">5a </A>
Boss WF.
Kelley CJ.
Landsberger FR.
Anal. Biochem.
1975,
64:
289
<A NAME="RU15405ST-5B">5b </A>
Warner TG.
Benson AA.
J. Lipid Res.
1977,
18:
548
<A NAME="RU15405ST-5C">5c </A>
Diyizou YL.
Genevois A.
Lazrak T.
Wolff G.
Nakatani Y.
Ourisson G.
Tetrahedron Lett.
1987,
28:
5743
<A NAME="RU15405ST-5D">5d </A>
Beck A.
Heissler D.
Duportail G.
J. Chem. Soc., Chem. Commun.
1990,
31
<A NAME="RU15405ST-6A">6a </A>
Robles EC.
Berg DVD.
Biochim. Biophys. Acta
1969,
187:
520
<A NAME="RU15405ST-6B">6b </A>
Gupta CM.
Radhakrishnan R.
Khorana HG.
Proc. Natl. Acad. Sci. U.S.A.
1977,
74:
4315
<A NAME="RU15405ST-6C">6c </A>
Mason JT.
Broccoli AV.
Huang C.-H.
Anal. Biochem.
1981,
113:
96
<A NAME="RU15405ST-6D">6d </A>
Xia J.
Hui Y.-Z.
Tetrahedron: Asymmetry
1997,
8:
451
<A NAME="RU15405ST-7A">7a </A>
Bruzic KS.
Salamónczyk G.
Stec WJ.
J. Org. Chem.
1986,
51:
2368
<A NAME="RU15405ST-7B">7b </A>
Burgos CE.
Ayer DE.
Johnson RA.
J. Org. Chem.
1987,
52:
4973
<A NAME="RU15405ST-7C">7c </A>
Lindh I.
Stawiński J.
J. Org. Chem.
1989,
54:
1338
<A NAME="RU15405ST-7D">7d </A>
Ali S.
Bittman R.
J. Org. Chem.
1988,
53:
5547
<A NAME="RU15405ST-7E">7e </A>
Hébert N.
Just G.
J. Chem. Soc., Chem. Commun.
1990,
1497
<A NAME="RU15405ST-7F">7f </A>
Ishihara M.
Sano A.
Chem. Pharm. Bull.
1996,
44:
1096
<A NAME="RU15405ST-7G">7g </A>
Roodsari FS.
Wu D.
Pum GS.
Hajdu J.
J. Org. Chem.
1999,
64:
7727
<A NAME="RU15405ST-7H">7h </A>
Xia J.
Hui Y.-Z.
Chem. Pharm. Bull.
1999,
47:
1659
<A NAME="RU15405ST-7I">7i </A>
Ohlsson J.
Magnusson G.
Tetrahedron
2000,
56:
9975
<A NAME="RU15405ST-8A">8a </A>
Nicholas AW.
Khouri LG.
Ellington JC.
Porter NA.
Lipids
1983,
18:
434
<A NAME="RU15405ST-8B">8b </A>
Bibak N.
Hajdu J.
Tetrahedron Lett.
2003,
44:
5875
<A NAME="RU15405ST-9">9 </A>
Lindberg J.
Ekeroth J.
Konradsson P.
J. Org. Chem.
2002,
67:
194
<A NAME="RU15405ST-10A">10a </A>
Delfino JM.
Stankovic CJ.
Schreiber SL.
Richards FM.
Tetrahedron Lett.
1987,
28:
2323
<A NAME="RU15405ST-10B">10b </A>
Delfino JM.
Schreiber SL.
Richards FM.
Tetrahedron Lett.
1987,
28:
2327
<A NAME="RU15405ST-11">11 </A>
Inanaga J.
Hirata K.
Saeki H.
Katsuki T.
Yamaguchi M.
Bull. Chem. Soc. Jpn.
1979,
52:
1989
<A NAME="RU15405ST-12">12 </A>
The racemic lyso-PC 1 was conveniently prepared from racemic glycidol in two steps according to the literature
procedure:
[9 ]
(i) POCl3 then [HO(CH2 )2 NMe3 ]+ ·TsO- ; (ii) C15 H31 CO2 Cs.
<A NAME="RU15405ST-13">13 </A>
Makino K.
Nakajima N.
Hashimoto S.
Yonemitsu O.
Tetrahedron Lett.
1996,
37:
9077
<A NAME="RU15405ST-14">14 </A>
Due to the low solubility of lyso-PC 1 , THF was omitted in the preliminary study using 4 .
<A NAME="RU15405ST-15">15 </A>
Reaction was carried out until 1 was consumed completely by 1 H NMR spectroscopy since separation of product 3a and remaining 1 by chromatography on silica gel by using a CH2 Cl2 -MeOH mixture as an eluent was quite difficult. TLC analysis was useless for monitoring
the progress of reaction.
<A NAME="RU15405ST-16">16 </A>
The R
f
values of compounds (Merck Silica gel 60 F254 , MeOH): 1 , 0.1-0.2; 2a -e , >0.8; 3a , 0.1-0.2; 3b , 0.1-0.2; 3c , 0.1-0.2; 3d , 0.2; 3e , 0.2; 3f , 0.2; DMAP, 0.1-0.15; 1-methylimidazole, 0.5; 1-butylimidazole, 0.6; and 1-benzylimidazole, 0.6.
<A NAME="RU15405ST-17">17 </A>
Chromatography of a reaction mixture on silica gel was conducted with CH2 Cl2 -MeOH (CH2 Cl2 only, then 5:1, finally 1:3). Excess 2a eluted very early, then DMAP, followed rapidly by product 3a, though DMAP was slightly more polar than 3a on TLC. Other by-product(s) derived from the acid chloride (or simply the hydrolyzed
acid) did not interfere with the purification of 3a . In addition, CH2 Cl2 -MeOH is a convenient solvent system for chromatography in comparison with conventional
CHCl3 -MeOH-H2 O because of fast elution during chromatography, easy evaporation of the eluent, and
no contamination of silica gel impurity that is frequently encountered with the latter
solvent system.
<A NAME="RU15405ST-18">18 </A>
Confer condensation of acyl imidazolide and lysophophorylcholines, see ref. 5.
<A NAME="RU15405ST-19">19 </A>
Waanders PP.
Thijs L.
Zwanenburg B.
Tetrahedron Lett.
1987,
28:
2409
<A NAME="RU15405ST-21A">21a </A>
Brown JM.
Christodoulou C.
Reese CB.
Sindona G.
J. Chem. Soc., Perkin Trans. 1
1984,
1785
<A NAME="RU15405ST-21B">21b </A>
Gaffney PRJ.
Reese CB.
J. Chem. Soc., Perkin Trans. 1
2001,
192
<A NAME="RU15405ST-22A">22a </A>
Bonar-Law RP.
Sanders JKM.
Tetrahedron Lett.
1992,
33:
2071
<A NAME="RU15405ST-22B">22b </A>
Gao H.
Dias JR.
Eur. J. Org. Chem.
1998,
719
<A NAME="RU15405ST-23A">23a </A>
Straus DS.
Glass CK.
Med. Res. Rev.
2001,
21:
185
<A NAME="RU15405ST-23B">23b </A>
Vila L.
Med. Res. Rev.
2004,
24:
399
<A NAME="RU15405ST-24A">24a </A>
Kobayashi Y.
Nakano M.
Kumar GB.
Kishihara K.
J. Org. Chem.
1998,
63:
7505
<A NAME="RU15405ST-24B">24b </A>
Kobayashi Y.
Kumar GB.
Kurachi T.
Acharya HP.
Yamazaki T.
Kitazume T.
J. Org. Chem.
2001,
66:
2011
<A NAME="RU15405ST-24C">24c </A>
Kobayashi Y.
Recent Res. Devel. Org. Chem.
2000,
4:
169