V. Bertini et al. / Tetrahedron 63 (2007) 11672–11680
11679
dC (75.5 MHz, DMSO-d6) 41.7 (CH2N), 63.3 (C-6), 70.1
(C-3), 71.4 (C-4 or C-5), 72.4 (C-4 or C-5), 73.7 (C-2),
126.5, 127.0, 128.0, 139.4, 172.5 (C]O). Anal. Calcd for
C13H19NO6: C, 54.73; H, 6.71; N, 4.91. Found: C, 54.52;
H, 6.73; N, 4.93.
copolymer, dried at reduced pressure up to constant weight,
submitted to Schiff’s test and centrifuged at 3500 rpm
(15 min) showed fuchsia colour scaled from pale to deep
with reaction time.
Acknowledgements
4.9. Alkylation of 6 with 7 or 11
This work was financially supported by MIUR (Programmi
di Ricerca di Rilevante Interesse Nazionale 2006) and
University Funds.
4.9.1. General procedure. NaH (60% suspension in white
oil, 0.32 mmol, 0.9 equiv) was washed under N2 with dry
pentane (2ꢂ2 mL), dried, suspended in dry DMF (2 mL),
treated with a solution of 6 (0.35 mmol) in dry DMF
(2 mL) and magnetically stirred at rt until to get clear solu-
tion (30 min). The clear solution was treated with 7 or 11
(1 or 3 equiv) under stirring until no further modifications
of the composition of the mixture was evidenced by TLC
(CHCl3/MeOH¼4:1 as eluent). The mixture was then
treated with MeOH (2 mL) and evaporated at 60 ꢁC/
300 mmHg to give a syrup that was added with acetone to
precipitate unreacted 6, which was filtered and washed
with THF. Washings and filtrate were combined, concen-
trated and chromatographed by PLC using the same eluent
as above. Reaction conditions and product yields are col-
lected in Table 2.
Supplementary data
Supplementary data concerning the preparation of Olig4,
synthesis and characterization of 7, 8, 9, 10, 11, 12, 13 and
1
14, H and 13C NMR spectra of 6, 15 and 16 can be found
in the online version. Supplementary data associated with
this article can be found in the online version, at doi:10.1016/
References and notes
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Compound 15. Purity 97% by HPLC. IR (in CH2Cl2 0.1 mm,
n, cmꢀ1) 3413 (OH), 2686 and 1692 (aldehyde), 1660
(amide). dH (300 MHz, DMSO-d6) 3.38 (m, 2H+HOD),
3.57 (m, 2H), 3.94 (m, 2H), 4.08 (m, 2H), 4.33 (m, 4H),
4.55 (m, 2H), 4.67 (m, 2H), 5.98 (m, 2H), 7.30–7.13 (m,
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71.8 (C-4 or C-5), 82.9 (C-2), 115.3, 127.0, 127.4, 128.5,
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