Org. Synth. 2002, 78, 123
DOI: 10.15227/orgsyn.078.0123
(1'R)-(−)-2,4-O-ETHYLIDENE-D-ERYTHROSE
AND ETHYL (E)-(−)-4,6-O-ETHYLIDENE-(4S,5R,1'R)-4,5,6-TRIHYDROXY-2-HEXENOATE
[
1,3-Dioxane-(R)-4-carboxaldehyde, 5-hydroxy-2-methyl-, [2R-(2α,4α,5β)]-
and
D-erythro-Hex-2-enonic acid, 2,3-dideoxy-4,6-O-ethylidene-,
ethyl ester [2E,4(S)]-
]
Submitted by M. Fengler-Veith, O. Schwardt, U. Kautz, B. Krämer, and V. Jäger
1
.
Checked by Brian Haney, Brian Bucher, and Dennis P. Curran.
1. Procedure
A. (1'R)-(−)-4,6-O-Ethylidene-D-glucose
.
A 500-mL, round-bottomed flask is charged with
D-glucose
(81.8 g, 454 mmol, Note 1)
and
paraldehyde (68.0 g,
514 mmol, Note 2).
Concentrated sulfuric acid (0.5
mL) is added dropwise within 30 sec (Note 3)
with shaking. The mixture is mechanically shaken for 40 min (Note 4)
and then left for 3 days at room temperature.
Ethanol
(300 mL, Note 5)
is added to the adhesive, colorless mass, then the pH is adjusted to 6.5-7 (Note 6) by addition of a 1 N solution of potassium
hydroxide
in ethanol
(Note 7).
The residue is dissolved by careful heating. During this procedure the pH is maintained
constant by gradual addition of more 1 N ethanolic potassium
hydroxide
. Charcoal (5 g, Note 8)
is added to the yellow solution and the mixture is filtered through a sintered-glass
funnel containing a 2-cm pad of Celite. The filter cake is washed with
hot ethanol (50 mL).
The filtrate, on standing overnight in a freezer at −30°C,
deposits a colorless solid material that is recrystallized from
ethanol
(90 mL) at −30°C (Note 9) to
yield 39.4 g (42%) of
(−)-4,6-O-ethylidene-D-glucose
. The combined mother
liquors are concentrated by rotary evaporation (30°C, 30 mm), followed by removal
of solvent and excess
paraldehyde
at room temperature and 0.02 mm (oil vacuum). Recrystallization of the yellowish solid
residue from
ethanol
at −30°C
as described above gives another 22.5 g
(24%) of product. The combined
yield of
(1'R)-(−)-4,6-O-ethylidene-D-glucose
is 61.9 g (66%), mp 173-174°C
(Note 10).
B. (−)-2,4-O-Ethylidene-D-erythrose
.
A 1-L, three-necked, round-bottomed flask, equipped with a
thermometer and two 200-mL pressure-equalizing dropping
funnels, is charged with a suspension of
sodium
metaperiodate (59.2 g, 277 mmol, Note 11) in water (450 mL). The flask is cooled
to 0°C using an ice-water bath. A solution of
(−)-4,6-O-ethylidene-D-glucose
(29.2 g, 142 mmol, Note 12)
in water (120 mL) is added dropwise with stirring and under permanent control of the
pH (Note 6) and temperature. The temperature in the flask should
be kept below 10°C, and the pH is maintained at approximately 4 by dropwise addition
of 8 N aqueous sodium hydroxide
(Note 13). After stirring for 3 hr at = 10°C (Note 14),
the pH is adjusted to 6.5 by addition of more 8 N sodium
hydroxide
(Note 15) and stirring is continued
for another 2 hr at room temperature. The solution is evaporated under reduced pressure
(50°C, 30 mm) and the residue dried at room temperature and 0.02 mm (oil vacuum).
To the pale-yellow, solid crude product,
ethyl
acetate (80 mL) is added and the flask is heated
for 2 min at 80°C with stirring. The suspension is filtered and the solid residue
is treated three times with
ethyl acetate
(80 mL each) as described above. The combined, filtered
extracts are dried over sodium sulfate for 1 hr with stirring and concentrated by
rotary evaporation (30°C, 30 mm), followed by slow (Note 16)
removal of solvent at 0.02 mm (oil vacuum) at room temperature to yield 20.1 g (97%)
of
(−)-2,4-O-ethylidene-D-erythrose
as a colorless, amorphous solid, mp 120-121°C
(Notes 17, 18).
C. Ethyl (E)-(−)-4,6-O-ethylidene-(4S,5R,1'R)-4,5,6-trihydroxy-2-hexenoate
.
A 1-L, two-necked, round-bottomed flask, fitted with a nitrogen
inlet
(Note 19) and a stopper,
is oven-dried (140°C) and flushed with nitrogen. The flask is
charged with a suspension of
sodium hydride
in paraffin (6.20 g), containing
60%
of sodium hydride
(Note 20).
The suspension is washed with
pentane
(3 × 30 mL, Note 21)
and the residue is freed from remaining
pentane
at 0.01 mm (oil vacuum) to give
3.72 g (ca.
155 mmol) of sodium hydride. Under nitrogen, a magnetic
stirring bar and
tetrahydrofuran
(200 mL, Note 22)
are added and the flask is sealed with a septum. The suspension
is cooled to 0°C and
triethyl phosphonoacetate
(39.2 g, 175 mmol, Note 23)
is added to the stirred
sodium hydride
/
tetrahydrofuran
suspension over a period
of 5 - 10 min by means of a 100-mL syringe. The mixture is
cooled to −78°C (2-propanol/dry ice) and a solution of
(−)-2,4-O-ethylidene-D-erythrose
(mainly as dimer, 14.6 g, 100 mmol) in
tetrahydrofuran (200 mL, Note
22) is added by means of a syringe
over 5-10 min. After the mixture is stirred for 15 min at −78°C, it is allowed
to warm to room temperature and stirred for another 45 min. The reaction is quenched
with saturated ammonium chloride solution
(250 mL) and transferred to a 2.5-L separatory
funnel with
1200 mL of ether.
The aqueous phase is separated and extracted with ether (4
× 100 mL). The combined organic layers are washed with a mixture
of saturated sodium bicarbonate/brine
(1:1) (2 × 200 mL), dried for 1 hr over
magnesium
sulfate
with stirring, filtered, and evaporated to dryness at
30°C/30 mm to leave 32.0 g of
a yellowish oil (Note 24). The crude product is purified by column
chromatography over silica
(Note 25) with
petroleum ether/ethyl acetate
3/2 as eluent (Note 26) to yield 19.2 g of a pale-yellow solid. Recrystallization of the product
from
n-hexane
(Notes 27, 28) affords
15.4 g (71%) of analytically
pure ethyl (E)-(−)-4,6-O-ethylidene-4,5,6-trihydroxy-2-hexenoate
;
colorless crystals, mp 62-63°C (Notes
29, 30).
2. Notes
1.
D-Glucose
(BioChemika, = 99.5%) was obtained from Fluka Feinchemikalien
GmbH, Neu-Ulm, Germany or Aldrich Chemical Company, Inc.
2.
Paraldehyde (=
97%) was obtained from Fluka Feinchemikalien GmbH, Neu-Ulm,
Germany or Acros Chemical Company
, and
was used without distillation.
3.
If the
sulfuric acid is added too fast, the
reaction mixture becomes brown, probably from charring of the
glucose.
4.
The submitters used a
shaking machine (IKA
Labortechnik KS 250 basic, ca. 500/min). The checkers used a shaking machine from
Lab Line Instruments (Model number 4600).
5.
The submitters distilled
ethanol
(technical grade) from
sodium
and diethyl phthalate
. The checkers used
absolute ethyl alcohol from Pharmco
.
6.
The pH was checked with Merck Universal-Indikatorpapier, range
1-14.
7.
Approximately
18 mL
of 1 N ethanolic potassium hydroxide
was needed.
8.
Charcoal (powdered) was obtained from E. Merck KGaA, Darmstadt,
Germany or J. T. Baker Chemical Company.
9.
The solids are dissolved in hot
ethanol and
then kept overnight in the freezer at −30°C. The checkers found that standing
overnight at −5°C gave similar results.
10.
In
deuterium oxide (D
2O) the
product is a 34/66-mixture of α/β-anomers. The spectral properties of
(−)-4,6-O-ethylidene-D-glucose
are as follows:
1H
NMR (250 MHz, D
2O) δ: 1.22 (d, 3 H, J = 5.0, CHCH
3),
3.03-3.78 (m, 5 H, 2-H, 3-H, 4-H, 5-H, 6-H
a), 3.90-4.12
(m, 1 H, 6-H
b), 4.40-5.13 (m, 5 H, 1-H, 3 OH, CHCH
3)
;
2a
[α]D
20 −2.3°
(H2O, 2 d, c 19.7),
2a
[α]D
20 −2.37°
(H2O, equilibrium, c 19.7).
3
11.
Sodium periodate
(NaIO4) (98%) was obtained from Fluka Feinchemikalien
GmbH, Neu-Ulm, Germany or Aldrich Chemical Company, Inc.
12.
In several experiments it was found that the yield of
2,4-O-ethylidene-D-erythrose
generally is somewhat lower when the reaction is performed on a larger scale.
13.
Approximately
24 mL
of 8 N sodium hydroxide
was used.
14.
The pH was checked every 30 min and, if necessary, more aqueous
sodium hydroxide was added to keep the pH at 4.
15.
Approximately
16 mL
of 8 N sodium hydroxide
was needed.
16.
Caution: The evaporation of the solvent must be done
slowly and carefully because the product shows a strong tendency to foam.
17.
It is difficult to give exact spectral properties of
(−)-2,4-O-ethylidene-D-erythrose
because of rapid di- and/or oligomerization. The melting points given in the literature
differ from 65-80°C
4
to 150-151°C,
5 depending on the degree
of oligomerization of the product. With the present procedure, mainly the dimer is
obtained. In order to check the optical purity of the product, it is convenient to
compare the equilibrium value of specific rotation, as obtained after 2 days in aqueous
solution at room temperature:
[α]D
20
−39.5° (H2O, 2 d, c 1.00),
6
[α]D
20 −36.8° (H2O, equilibrium,
c 8.25),
3
[α]D
25 −36.2° (H2O, equilibrium,
c 8.2).
5 The analytical data of the
product were as follows:
2a Calcd for C
6H
10O
4
(146.14): C, 49.31; H, 6.90. Found: C, 49.18; H, 7.07;
1H NMR (200.1 MHz, D
2O) δ:
1.38 (d, 3 H, J = 5.0, CHCH
3), 3.39-3.99 (m,1 H, OCH),
4.06-4.31 (m, 2 H, OCH
2), 4.75-5.63 (m, 1 H, OH, CHCH
3)
;
13C NMR (50.3
MHz, D
2O/dioxane) δ: 20.1 (CHCH
3), 61.2
(CHOH), 67.1, 67.9, 68.4 (CH
2O),
70.3, 71.5, 76.0, 78.5, 80.8,
90.6, 91.6 (CHO), 95.6, 97.4,
100.3, 101.2 (O
2CHCH
3)
.
18.
According to ref.
5,
monomeric
(−)-2,4-O-ethylidene-D-erythrose may
be obtained by heating a solution of the dimer in
ethyl acetate
with a catalytic amount of
glacial acetic acid
or
100%
phosphoric acid
for 20 min at 90°C.
19.
Nitrogen was dried by means of a Sicapent
(r)
(E. Merck) drying tube. The checkers used dry
argon.
20.
Sodium hydride
(60%
sodium hydride in paraffin) was obtained
from Fluka Feinchemikalien GmbH, Neu-Ulm, Germany or Aldrich
Chemical Company, Inc.
21.
Pentane (technical
grade) was purified by distillation from
sodium
.
22.
Tetrahydrofuran
was purified by distillation under
nitrogen from a blue solution
of
sodium
and
benzophenone
.
23.
Triethyl phosphonoacetate
(Aldrich Chemical Company, Inc.) was purified by distillation
(bp 142°C, 10 mm).
24.
Crude product contains
triethyl phosphonacetate;
the isomeric purity (E/Z) of
ethyl 4,6-O-ethylidene-(4S,5R,1'R)-4,5,6-trihydroxy-2-hexenoate
was > 95 : 5 according to
13C NMR.
25.
A 20 cm × 5 cm column packed with 200 g of Kieselgel 60, (E.
Merck, 0.040-0.063 mm, 250-400 mesh) was used. The checkers used a 40 cm × 10 cm column
packed with silica gel (Bowman Chemical Co., 60Å) and eluted with
1/1
hexane/ethyl acetate
with similar
results.
26.
Ethyl acetate and
petroleum ether (technical grade; boiling range 40-80°C)
were purified by distillation.
27.
Hexane (technical
grade) was distilled before use.
28.
Hexane was added
to the solid in 5-mL portions (ca. 35 mL were needed)
until a single phase was formed. On slowly cooling to room temperature, the liquid
again separates into two phases before crystallization starts.
29.
The analytical data (after chromatography) were as follows:
6 Calcd for C
10H
16O
5 (216.23):
C, 55.55; H, 7.46. Found: C, 55.40; H, 7.43. The E/Z ratio was found to be > 99:1
(determined by HPLC): t
E = 4.50 min; t
z =
3.40 min,
eluent
hexane/
ethyl acetate 60/40 [LiChrosorb
Si 60 column, E. Merck]. (The Z-diastereomer reference sample was prepared as described
in Ref.
7).
TLC: R
f = 0.38 (petroleum ether/
ethyl acetate 60/40).
[α]D
20 −41.3°
(CHCl3; E/Z > 99:1, c 0.500),
mp 62-63°C, ref.
7:
[α]D
25 −35.2°
(CHCl3, c 1.21),
mp
59-60°C.
13C
NMR (75.5 MHz, CDCl
3) δ: 14.2 (OCH
2CH
3),
20.4 (O
2CHCH
3), 60.8 (OCH
2CH
3),
65.1 (C-5), 70.7 (C-6), 79.9 (C-4), 98.8
(O
2CHCH
3), 122.2 (C-2), 143.7 (C-3),
166.7 (C-1)
;
1H
NMR (300 MHz, CDCl
3) δ: 1.30 (t, 3 H, J = 7.1, OCH
2CH
3),
1.36 (d, 3 H, J = 5.1, O
2CHCH
3), 2.85 (bs,
1 H, OH), 3.44 (t, 1 H, J = 9.5, 6-H
a), 3.52
(dt, 1 H, J = 4.4, J = 9.5, 5-H), 4.01 (ddd, 1 H,
4J = 1.7,
J = 4.5, J = 9.5, 4-H), 4.14 (dd, 1 H, J = 4.4, J = 9.9, 6-H
b),
4.20 (q, 2 H, J = 7.1, OCH
2CH
3), 4.74 (q,
1 H, J = 5.1, O
2CHCH
3), 6.16 (dd, 1 H,
4J
= 1.7, J = 15.8, 2-H), 7.09 (dd, 1 H, J = 4.5, J = 15.8, 3-H)
.
30.
In various runs,
20 to 100 mmol
of
D-erythrose acetal
were used, with yields
ranging from
65 to 73%.
Handling and Disposal of Hazardous Chemicals
The procedures in this article are intended for use only by persons with prior training in experimental organic chemistry. All hazardous materials should be handled using the standard procedures for work with chemicals described in references such as "Prudent Practices in the Laboratory" (The National Academies Press, Washington, D.C., 2011 www.nap.edu). All chemical waste should be disposed of in accordance with local regulations. For general guidelines for the management of chemical waste, see Chapter 8 of Prudent Practices.
These procedures must be conducted at one's own risk. Organic Syntheses, Inc., its Editors, and its Board of Directors do not warrant or guarantee the safety of individuals using these procedures and hereby disclaim any liability for any injuries or damages claimed to have resulted from or related in any way to the procedures herein.
3. Discussion
Optically active C
4-building blocks of type
1 are versatile starting
compounds in organic synthesis. Important members of this class, among numerous others,
are derivatives of
threose
8,9 and
erythrose, respectively, such
as
2,4-O-ethylidene-D-erythrose
2, the corresponding "Horner enoate"
3, or the
erythritol
4.
As described here,
2 can be prepared in two steps from commercially available
D-glucose in up to
65%
overall yield. Procedures to obtain the ethylidene glucose
10,11,12 and the ensuing oxidative degradation
3,5,12,13,14,15,16 are based on earlier
literature reports. The
D-erythrose acetal
2 has also been prepared
from
D-mannitol
in three steps, with an overall yield of
7%.
17 The erythritol
4 can be synthesized
from
2 by reduction with
sodium borohydride
.
3 A mixture of Z/E-
3 (ca. 2 : 1) is known to result from
a Witting reaction of
2 with
ethoxycarbonylmethylenetriphenylphosphorane
.
2a,6,7
Erythrose derivatives such as
2-
4, with a free hydroxy function,
offer many possibilities for regioselective conversions; in addition, the free hydroxy
group in
2 or
3 does or may influence the regio- and stereoselectivity
of additions to the carbonyl group.
2,4-O-Ethylideneerythrose
,
because of its di- or oligomeric form, is configurationally stable at room temperature
and can be stored for several months at room temperature.
9,10,11,12,13,14,15,16,17,18
Both enantiomers of
2,4-O-ethylideneerythose have been used
as intermediates in the preparation of free
D- and
L-erythrose.
12,13,15,16,17 In some reactions
it proved advantageous to promote monomer formation of
2 from the dimer/oligomers
by addition of 2-pyridone.
2,19
The N-benzylimine
20 and some hydrazones
20,21
of
2 have been described earlier in the literature. Imines, nitrones, oximes,
and nitrile oxides derived from
2 were recently employed in a variety of additions
and cycloadditions.
2,22,23
Aldehyde
2 has been transformed in various other Wittig reactions
24,25,26
and in an Abramov reaction with dimethyl phosphite.
27
Formation of the diethyldithioacetal,
28 the dimethyl phosphonate,
29 or the condensation with
nitromethane
4,12,30
represent other uses of
2. 2,3-Epoxyamides were prepared by treating
2
with stabilized sulfur ylides generated in situ.
31
(−)-2,4-O-Ethylidene-D-erythrose
2 has been used for the preparation of
2-deoxy-D-ribose
via addition of stabilized ylides and subsequent hydrolysis in the presence of mercuric
ion.
5 Further, diastereoselective propargyl addition
to the aldehyde
2 was recently performed with
propargyl bromide
and
zinc.
32
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
(1'R)-(−)-2,4-O-Ethylidene-D-erythrose:
1,3-Dioxane-4-carboxaldehyde, 5-hydroxy-2-methyl-, [2R-(2α,4α,5β)]-
(10); (70377-89-8)
Ethyl (E)-(−)-4,6-O-ethylidene-(4S,5R,1'R)-4,5,6-trihydroxy-2-hexenoate:
D-erythro-Hex-2-enonic acid, 2,3-dideoxy-4,6-O-ethylidene-, ethyl
ester, Ref. 7: [2E,4(R)]-
(12); (125567-87-5)
Ref. 7: [2Z,4(S)]- (12); (125567-86-4)
This prep: [2E,4(S)]- (1'R)-(−)-4,6-O-Ethylidene-D-glucose:
Glucopyranose, 4,6-O-ethylidene- (8);
D-Glucopyranose,
4,6-O-ethylidene- (9); (18465-50-4)
D-Glucose:
α-D-Glucopyranose
(8,9); (492-62-6)
Paraldehyde:
s-Trioxane, 2,4,6-trimethyl-
(8);
1,3,5-Trioxane, 2,4,6-trimethyl- (9); (123-53-7)
Sodium periodate:
Periodic acid, sodium salt
(8,9); (7790-28-5)
Sodium hydride (8,9); (7646-69-7)
Triethyl phosphonoacetate:
Acetic acid, phosphono-,
triethyl ester (8);
Acetic acid, (diethoxyphosphinyl)-, ethyl
ester (9); (867-13-0)
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