Arabinofuranose 1,2,5ꢀorthobenzoate
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 2, February, 2009
483
through cotton, and the solvent was evaporated. The residue was
dried and recrystallized from benzene—light petroleum to
obtain compound 1 as white crystals (2.42 g, 78%), Rf 0.56
(Me2CO—C6H6, 4 : 6 v/v), [α]D24 –28.2 (c 1.0, CHCl3) (Ref. 5:
[α]D –28 (c 0.94, CHCl3)), m.p. 147—150 °C (Ref. 4:
m.p. 147—149 °C).
incorrect assignment of one of the signals for the arabinoꢀ
furanose ring protons: the signal at δC 77.2 has been
assigned5 to chloroform. Our assignment is based on
the qualitative similarities of the spectra of ortho ester 1
obtained for solutions in CDCl3 and in DMSOꢀd6 (see
Experimental).
In conclusion, a new and practically convenient
procedure for the transformation of βꢀDꢀarabinofuranose
1,2ꢀ(methyl)orthobenzoate (2) into βꢀDꢀarabinofuranose
1,2,5ꢀorthobenzoate (1) in good yield has been suggested,
which can be used for the synthesis of 1 on the scale of
several grams.
25
1H NMR (DMSOꢀd6), δ: 3.89 (dd, 1 H, H(5a), J5a,5b = 12.8 Hz,
J5a,4 = 1.5 Hz); 4.03 (dd, 1 H, H(5b), J5b,4 = 2.9 Hz); 4.24 (d, 1 H,
3ꢀOH, J3,OH = 3.9 Hz); 4.34—4.38 (m, 1 H, H(4)); 4.62 (dd,
1 H, H(3), J3,OH = 3.9 Hz, J3,4 = 1.3 Hz); 5.53 (d, 1 H, H(2),
J1,2 = 4.0 Hz); 6.14 (d, 1 H, H(1), J1,2 = 4.0 Hz); 7.33—7.42 (m,
3 H, Ph); 7.49—7.58 (m, 2 H, Ph).
13C NMR (DMSOꢀd6), δ: 68.5 (C(5)); 76.0, 83.16, 83.24
(C(2), C(3), C(4)); 103.5 (C(1)); 120.0 (PhC); 125.8, 127.8,
129.2, 136.6 (Ph).
1H NMR (CDCl3), δ: 2.10 (d, 1 H, 3ꢀOH, J3,OH = 7.2 Hz);
4.06 (dd, 1 H, H(5a), J5a,5b = 13.0 Hz, J5a,4 = 3.0 Hz); 4.14 (dd,
1 H, H(5b), J5b,4 = 1.1 Hz); 4.39—4.43 (m, 1 H, H(4)); 4.50 (d,
1 H, H(3), J3,OH = 7.2 Hz); 4.71 (dd, 1 H, H(2), J1,2 = 3.8 Hz,
J2,3 = 1.5 Hz); 6.13 (d, 1 H, H(1), J1,2 = 3.8 Hz); 7.37—7.42 (m,
3 H, Ph); 7.61—7.68 (m, 2 H, Ph).
13C NMR (CDCl3), δ: 68.3 (C(5)); 77.2, 83.7, 83.8 (C(2),
C(3), C(4)); 103.7 (C(1)); 121.1 (PhC); 125.9, 128.1, 129.5,
135.9 (Ph).
Experimental
Reactions were carried out using commercially available
reagents (Aldrich, Fluka). Anhydrous solvents were prepared
following standard procedures. Solvents distilled and purified by
standard procedures were used for chromatography and extracꢀ
tion. Thinꢀlayer chromatography was performed on DCꢀAlufolien
Kieselgel 60 F254 plates (Merck). Visualization of compounds
was made by heating of the plate on a heating plate (150 °C),
dipping in a mixture 85% aq. H3PO4—96% aq. EtOH (1 : 10 v/v),
and repeated heating.
1H and 13C NMR spectra were recorded on a Bruker AM 300
instrument (300.13 and 75.47 MHz, respectively). 1H NMR
chemicals shifts are given relative to the residual signal for CHCl3
(δH 7.27) and DMSOꢀd5 (δH 2.50), 13C{1H} NMR shifts, relative
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 07ꢀ03ꢀ00830).
References
to the signal for CDCl3 (δ 77.0) for solutions in CDCl3 or
C
1. M. Joe, Y. Bai, R. C. Nacario, T. L. Lowary, J. Am. Chem.
Soc., 2007, 129, 9885 and references cited therein.
2. T. Bamhaoud, S. Sanchez, J. Prandi, Chem. Commun., 2000,
659.
3. (a) N. K. Kochetkov, A. Ya. Khorlin, A. F. Bochkov, I. G.
Yazlovetskii, Izv. Akad. Nauk SSSR, Ser. Khim., 1966, 2030
[Bull. Acad. Sci. USSR, Div. Chem. Sci. (Engl. Transl.), 1966,
15, 1996]; (b) I. G. Yazlovetskii, PhD Thesis, N. D. Zelinsky
Institute of Organic Chemistry of the Russian Academy of
Sciences, 1968, 120.
4. A. F. Bochkov, Ya. V. Voznyi, V. N. Chernetskii, V. M.
Dashunin, A. V. Rodionov, Izv. Akad. Nauk SSSR, Ser. Khim.,
1975, 420 [Bull. Acad. Sci. USSR, Div. Chem. Sci. (Engl.
Transl.), 1975, 24, 348].
5. S. Sanchez, T. Bamhaoud, J. Prandi, Eur. J. Org. Chem.,
2002, 3864.
relative to the signal for DMSOꢀd6 (δ 39.50) for solutions in
DMSOꢀd6. The assignment of signals iCn 13C{1H} NMR spectra
was made using the APT (JMODXH) experiment. Optical
rotation was measured on a PUꢀ07 polarimeter (Russia) at 24 °C.
βꢀDꢀArabinofuranose 1,2,5ꢀorthobenzoate (1). 1,2ꢀDibromoꢀ
ethane (2.76 mL, 32.0 mmol) was added dropwise to a suspenꢀ
sion of magnesium chips (845 mg, 35.2 mmol) in THF (35 mL)
with intensive stirring at such a rate as to keep gentle boiling of
the mixture. After the addition was over, the reaction mixture
was cooled, that led to crystallization of magnesium bromide.
This mixture was heated again to 55 °C and a solution of ortho
ester 2 (3.52 g, 13.1 mmol) (see Ref. 5) in THF (27 mL) was
added under Ar. Preliminarily, ortho ester 2 was dissolved in
toluene, the solvent was repeatedly added to and evaporated
(1×20 + 2×10 mL), and the residue was dried in vacuo. The
solution obtained was stirred at 55 °C for 2 h. The reaction
mixture was cooled to ~25 °C, diluted with ethyl acetate
(~50 mL), washed with saturated aqueous NaHCO3 (~100 mL,
accompanied by precipitation of MgCO3), the aqueous layer
was extracted with AcOEt (3×30 mL). The combined organic
layer (~120 mL) was washed with brine (~150 mL), filtered
Received October 31, 2008;
in revised form January 29, 2009