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Preparation of 1 6-Dithio-D-glucose.

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Preparation of 1,6-Dithio-D-glucose
By Dr. J . Kocourek, Dipl.-Chcm. Marie Ticha, and
Dr. V. Jiratek
via the acid chloride to the dimethylamide, reduction of the
latter to N-dimethyl-l,4-dihydrobenzylamine,and methylation of the amine to give the quaternary salt (3); the latter is
heated with powdered KOH and the resultant vapors arc
passed into cooled ether.
Biochemistry Department, Faculty of Science,
University of Prague (Czechoslovakia)
We have found that the sequence of reactions given in
Scheme 1 is especially favorable for the preparation of 1,6dithio-D-glucose [l].
?
,
;6: ~6;::~
H 6 H ;
H
/
H
H
(1)
*co{g
//
c
-----c
(3)
f2)
HZ
1-31
HZ
An ether solution is obtained which has an ultraviolet absorption maximum at 242 inp with a shoulder at 247 mp,
log E = 4.4 (concentration determined by rearrangement to
toluene); toluene is also produced. Traces of mineral acid
destroy the absorption at 242 m v and increase the yield
of toluene. Sufficient (2) was obtained by preparative gas
chromatography to enable its N M R spectrum to be determined. The required proton ratio of 4:2:2 is observed.
The four vinyl protons attached t o the ring give signals
between 3.7 and 4.5 7 ; the exo-methylene-group protons
resonate at 5.35 T and the protons on the saturated carbon atom at 7.06 T. Confusion with ( I ) is not possible as
the latter exhibits an absorption maximum at 303 mp.
Received, October Zlst, 1963
[Z 607/440 IE]
German version: Angew. Cheni. 75, 1177 (1963)
[ I ] E. C. Homing, Chem. Reviews 33, 89 (1943).
[2] W. J. Bailey and R . A . Baylouny, J. org. Chemistry 27, 3416
(1962).
1,2-Isopropylidene-3,5-di-O-acetyl-6-deoxy-6-iodo-~-~-glucofuranose ( I ) [2] was subjected to acidic hydrolysis in acetone
plus aqueous HzSO4 and subsequent acetylation with sodium
N,N-Dimethylformamide Dineopentylacetal:
acetate and acetic anhydride to give a mixture of the tc- and
for Esterifying Carboxylic Acids with
a
Reagent
9-anomers of 1,2,3,4-tetra-O-acetyl-6-deoxy-6-iodo-~-glucopyranose (2) [3] in 56 yield. Acetobromination of the latter
Benzyl Alcohols
yielded 84 of compound (3) [4]. This derivative, which can
also be obtained in lower yields by direct acetobromination
By H. Biichi, Katharina Steen, and Prof. Dr. A . Eschenmoser
of the hydrolysate obtained from ( I ) after removal of the
Organisch-chemisches Laboratorium der Eidgenossischen
water, is readily converted with potassium thiobenzoate [5]
Technischen Hochschule Zurich (Switzerland)
in dimethylformamide at room temperature into ( 4 ) , m.p.
= -9.0" (c: 4 in CHCI-J, in 65
yield.
130-131 "C, [.*I:;
The results of stereochemical [ I ] and kinetic [2] invesCompound ( 4 ) can easily be converted into the free sugar
tigations support the view that the rate-determining step of
(61 %) by the usual methods.
the esterification [ l , 31 of carboxylic acids with Meerwein's
Received, October 17th, 1963 [Z 616/444 IEI
acetals of dimethylformamide [4] is the alkylation of the
German version: Angew. Cheni. 7 6 , 50 (1964)
carboxylate anion with an alkoxyimmonium ion of type ( I )
[5]; both of these ions and the alcohol R20H are in eqili[ I ] M . Akagi, S. Tejinza, and M . Hngo, Chem. pharmac. Bull. / I ,
briuni with the reagents.
58 (1963).
[2] G. R. Parker and R . W. Goodrich, S . chem. SOC.(London)
1949, Suppl. Issue No. I , p. 233.
[3] M . Karlovd-Tichd, Diploma Thesis, University of Prague,
1961; B. Helferich and H . Collatz, Ber. dtsch. chem. Ges. 61,
1640 (1928).
[4] P . C. Scheurer and F. Smith, S . Amer. chem. SOC.76, 3224
This reaction scheme predicts that, because of the low
( 1 950).
reactivity of the immonium ion [ ( I ) , R2 = neopentyl] in the
[5] J . Kocoirrek, Collect. czechoslov. chem. Commun., in the
s N 2 alkylation step, dimethylformamide dineopentylacetal
press.
(2) will mediate esterification according to Scheme 1 of
carboxylic acids with alcohols the alkoxyimmonium ions (Z)
of which are highly reactive. We have tested this hypothesis
l-Methylene-2,5-cyclohexadiene
with a number of amino-acid derivatives using p-dodecylbenzyl alcohol ( 3 ) and p-methoxybenzyl alcohol ( 4 ) ; the
By Prof. Dr. H. Plieninger and Dip1.-Chem. W. Maier-Borst
results are given in Table 1.
Organisch-Chemisches Institut
der Universitat Heidelberg (Germany)
7H3
R'-COOH
The existence of the two toluene isomers ( I ) and (2) has
long seemed to be unlikely [I]. Recently, however, 5-methylene - 1,3 - cyclohexadiene ( I ) was identified by Bailey and
Buylouny [2] as a chemical entity which is quite stable at
low temperature in dilute solution.
We have now managed to prepare I-methylene-2,5-cyclohexadiene (2) from 1,4-dihydrobenzoic acid by conversion
62
+
R20H
+ (CH3),N-CH(O-CH2-C-CH3)2
1
R'-COORZ
-t (CH3)zN-CHO
(2)
cH3
FH3
+ 2 HOCH2-C-CH3
I
CH3
Scheme 1
Angew. Chem. internat. Edit. Vol. 3 (1964)
1 No.I
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