418
J.M. Landeros et al. / Journal of Molecular Structure 1037 (2013) 412–419
poured into a glass flask without degassed, after which 0.54 mL
of trifluoroacetic acid (TFA, 7.0 mmol) were added. The solution
was stirred at room temperature for 1 h, after which it was dis-
solved and washed several times in a mixture of hexane and
dichloromethane, until the compound 6 was TFA free, the absence
of signal from tert-butyl indicating complete hydrolysis was
verified by 1H NMR and also no signal of TFA at 164 ppm by 13C
NMR indicate complete deprotection and high purities obtained
in good yield 94% (399 mg) of 6 as white solid, mp. 94–96 °C.
1H NMR (D2O, 400 MHz) d 2.52 (t, J = 5.9, 8 H), 3.28 (s, 8 H), 3.61
(t, J = 6.0, 8 H), 13C NMR (D2O, 400 MHz) d 176.4, 69.0, 66.8, 44.9,
34.4. IR (neat) v: 2870 (broad), 1726, 1252, 1068, 1100. GC–MS
(EI): m/z calcd for C17H28O12 424, found 424 [M + 1]+.
3-(2-Carboxy-ethoxy)-propionic acid, 7. Desprotection of
5
(400 mg, 1.45 mmol) as above in 0.5 mL of TFA afforded 211 mg
(90%) of
7 as a
white solid, mp 56–58 °C. 1H NMR (D2O,
400 MHz) d 2.6 (t, J = 5.9, 4 H), 3.7 (t, J = 5.8, 4 H), 13C NMR (D2O,
400 MHz) d 176.0, 65.8, 34.1. IR (neat) v: 2870 (broad), 1726,
1252, 1068, 1100. GC–MS (EI): m/z calcd for C6H10O5 162, found
162 [M + 1]+.
Fig. 8. 1H NMR spectra of compounds 9, 10, 11 (CDCl3, 300 MHz).
H), 2.47 (t, J = 6.2, 2 H), 3.67 (t, J = 6.2, 2 H) ppm. 13C NMR (CDCl3,
300 MHz) d: 28.38, 36.63, 66.88, 80.69, 170.9 ppm. IR cmÀ1: 2977,
2932, 2872, 1726, 1254, 1059, 1110 cmÀ1. GC–MS (EI): m/z calcd
for C14H26O5 274, found 274 [M + 1]+.
3-[3-(2-Carboxy-ethoxy)-2-(2-carboxy-ethoxymethyl)-2-methyl-
propoxy]-propionic acid, 12. Desprotection of 9 (504 mg, 1 mmol)
was carried out as above in 0.5 mL of TFA afforded 302 mg (92%)
of 9 as pale yellow viscous oil. 1H NMR (D2O, 300 MHz) d 0.86
(s, 3 H), 2.63 (t, J = 5.9, 6 H), 3.34 (s, 6 H) 3.74 (t, J = 5.9, 6 H). 13C
4.4. Synthesis of poly-O-alkylation of TME
NMR (D2O, 300 MHz)
d 176.4, 73.1, 67.0 40.5, 34.5, 27.5,
16.8 ppm. IR
v .
2872 (broad), 1698, 1254, 1102, 1068 cmÀ1
GC–MS (EI): m/z calcd for C14H24O9 336, found 336 [M + 1]+.
3-[3-(2-tert-Butoxycarbonyl-ethoxy)-2-(2-tert-butoxycarbonyl-
ethoxymethyl)-2-methyl-propoxy]-propionic acid tert-butyl ester, 9.
The compound 9 has been prepared by following the procedure de-
scribed above, TME (8, 120.15 mg, 1.0 mmol), NaOH solution
(0.8 mL, 40.0% w). The mixture was vigorously stirred at room tem-
perature for 1 h. Then, benzyltriethylammonium chloride (TEBAC)
(0.5 mmol, 0.5 eq. in 2 mL distilled water) was added via syringe.
The mixing was poured into an ice bath and tert-butyl acrylate
(3.1 mmol, 3.0 eq. 0.45 mL) was dropwise. After work up, product
9 was obtained in 79% (353 mg) as yelow oil. 1H NMR (CDCl3,
300 MHz) d 0.89 (s, 3 H), 1.45 (s, 27 H), 2.44 (t, J = 6.4, 6 H), 3.24
(s, 6 H) 3.60 (t, J = 6.4, 6 H). 13C NMR (CDCl3, 300 MHz) d: 17.16,
28.07, 36.39, 40.81, 67.07, 73.51, 80.23, 171.01 ppm. IR (neat) v:
2978, 2930, 2870, 1726, 1252, 1068, 1100 cmÀ1. GC–MS (EI): m/z
calcd for C26H48O9 504, found 504 [M + 1]+.
Acknowledgements
We are greateful to the CONACyT (81924), PAPIIT (IN101109-3)
for financial support. J.M. Landeros appreciates the support
Granted by CONACyT. The authors wish to thanks A. Peña-Huerta
and G. Cedillo-Valverde for NMR study, C. Damián Zea, and
S. Lopez-Morales for GC–MS study (Institute of Chemistry and
Institute of Materials Research; Universidad Nacional Autónoma
de México).
Supplementary material
Supplementary data containing FT-IR, RMN 1H and 13C spectra,
and computational details can be found, in the online version, at
3-[2-(2-tert-Butoxycarbonyl-ethoxymethyl)-3-hydroxy-2-methyl-
propoxy]-propionic acid tert-butyl ester, 10. Di-ester was obtained as
byproduct in the O-alkylation of TME with tert-butyl acrylate and it
was isolated (52 mg, 8%) as yelow oil by silica gel chromatography
with hexane–ethyl acetate gradient. 1H NMR (CDCl3, 300 MHz) d
0.81 (s, 3 H), 1.42 (s, 18 H), 2.43 (t, J = 6.1, 4 H), 3.38 (dd, J = 11.3,
J = 11.3, 4 H), 3.5 (s, 2 H) 3.64 (t, J = 6.1, 4 H) ppm. 13C NMR (CDCl3,
300 MHz) d: 17.37, 28.02, 36.20, 40.57, 67.15, 68.58, 75.2, 80.58,
171.01 ppm. IR (neat): 3320, 2976, 2929, 2870, 1726, 1252, 1110,
1068 cmÀ1. GC–MS (EI): m/z calcd for C19H36O7 376, found 376
[M + 1]+.
3-(3-Hydroxy-2-hydroxymethyl-2-methyl-propoxy)-propionic
acid tert-butyl ester, 11. 1H NMR (CDCl3, 300 MHz) d 0.77 (s, 3 H),
1.44 (s, 9 H), 2.48 (t, J = 5.8, 2 H), 3.47 (s, 2 H), 3.57 (dd, J = 15.0,
J = 6.1, 4 H), 3.66 (t, J = 5.8, 2 H). 13C NMR (CDCl3, 300 MHz) d:
17.19, 28.0, 35.98, 40.76, 67.1, 67.89, 75.77, 81.07, 171.46 ppm.
IR (neat) v: 3399, 2974, 2923, 2873, 1724, 1254, 1108,
1068 cmÀ1. GC–MS (EI): m/z calcd for C12H24O5 248, found 248
[M + 1]+.
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