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Proton Activity of the 1 3-Dithiolium System.

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of hydrogen-deuterium exchange by measuring the N M R
spectra of ( I ) in 60 v/v CF3COOD/D20 at 34 5: 2°C we
have obtained the following results:
(1,3,4,6-Tetra-O-acetyl-~-D-glucos-2-yl)carbodiimides
By Dr. J. C. Jochims
lnstitut fur Chemie, Max-Planck-Institut
fur Medizinische Forschung, Heidelberg (Germany)
(1,3,4,6-Tetra-O-acetyl-~-~-glucos-2-yl)thioureas
[ l ] can be
desulfurized with yellow HgO t o give (1,3,4,6-tetra-Oacetyl-$-~-glucos-2-yl)carbodiimides,
which are very stable
compounds that exhibit no mutarotation. Five grams of the
thiourea were shaken with 2.5 molar equivalents of HgO
[DAB 6 quality, from E. Merck, Darmstadt (Germany)] in
50 ml of chloroform plus 25 ml of carbon disulfide at room
temperature until the suspension turned black (often only
after 20-30 h). The solution was filtered and the solvent
evaporated ; the residual syrup was crystallized from ether/
petroleum ether [( 1) from benzene/petroleum ether, (5)
from ethanol/petroleum ether]. The structures of the carbodiimides were inferred from their infrared spectra and for (2)
from hydrogenation t o the formamidine stage [2].
Concn. [mole/ll
It can be noticed that the half-life decreases with the magnetic
shielding of the 2-position. The rate of H / D exchange
decreases with increasing activity of the CF3COOD, parallel
with the acid-base equilibrium below.
(1,3,4,6-Tetra-0-acetyl-~-~-glucos-2-yl)carbodiimides,
R--N=C=N-R'
Yield [ %]
M.p. [ "Cl
1,3,4,6-Tetra-O-acetyl-[<-O-glUCOS-2-yl [3]
p-Tolyl
Cyclohexyl
Benzyl
9-Fluorenyl
(6)
from 72
25.4
89
62-64
78-79
72-73
171- 172
25.7
17.4
19.9
9.0
62
93
88
83
11.5
87
When the acids ( l a ) - ( l c ) are dissolved in acetonitrile and
treated at 20 "C with an excess of N-ethyldiisopropylamine,
the 1,4,5,8-tetrathiafulvalenes (4n)-(4c) [5] are immediately
formed in 30-40 "/, yields as mixtures of the geometrical
isomers.
(decamp.)
I Diphenylmethyl
95-97
[a] c = I in dimethylformamide.
Bis-(1,3,4,6-tetra-O-acetyl-~-~-glucos-2-yl)carbodiimide
(I)
[3] crystallizes only after standing for several weeks in a
refrigerator. It is recovered unchanged after boiling for 12 h
in benzene with a molar equivalent of 1,3,4,6-tetra-O-acetyI$-D-glucosamine; no trisubstituted guanidine derivative is
formed.
During the formation of (Z), N-( 1,3,4,6-tetra-O-acetyl+-~glucos-2-yl)-N'-(p-tolyl)urea is produced as a by-product.
Desulfuration of N-cyclohexyl-N-hydroxy-N'-(1,3,4,6-tetraO-acetyl-~-D-glucos-2-yl)-thiourea
[I] afforded a 90 "/, yield
of the carbodiimide (3) and elemental sulfur. Carbodiimide
N-oxide formed as a n intermediate appears t o oxidize unreacted starting material [4]. N-( 1,3,4,6-0-Tetraacetyl-p-~glucos-2-yl)-N"-phenylthiosemicarbazide cannot be desulfurated with HgO to an aminocarbodiimide.
tZ 939/765 IEI
Received: March 18th, 1965
German version: Angew. Chem. 77, 454 (1965)
[ I I J. C. Jochims and A. Seeliger, Tetrahedron 1965, in the press.
[2] J. C. Jochims, Chem. Ber. 97 (1965), in the press.
[31 Bis-(2,3,4,6-tetra-O-acetyl-~-D-glucos-l-yl)carbodiimide
has
recently been described: A. Messmer, J . Pinter, and F. Szego,
Angew. Chern. 76, 227 (1964); Angew. Chern. internat. Edit. 3,
228 (1964).
[41 E . Sclimidf and M . Seefelder, Liebigs Ann. Chern. 571, 83
(1950).
Proton Activity of the 1,3-Dithiolium System
By Doz. Dr. H. Prinzbach, Dip1.-Chem. H. Berger, and
Prof. Dr. A. Liittringhaus
Chemisches Laboratorium
der Universitit Freiburg/Breisgau (Germany)
Like their thiazolium [2], oxazolium 131, and imidazolium [4]
analogues, I ,3-dithiolium cations ( I ) [ I ] have a considerable
C-H acidity in the 2-position. On determining the half-lives
A r i , ~ c ~ nCliein.
l.
interntrt. Edit. / Vol. 4 (1965)
/
Nu. 5
( 4 a ) : yellow needles from ethanol, m.p. 96-1OO0C; Amax
in tetrahydrofuran: 453 m p (E = 180), 298 (7500); N M R i n
CS2: 4.28 T [2 H , S ] ; 7.97 T [6 H , Sl.
(46) : orange-yellow needles from benzene/ethanol, m. p.
254-256°C; Amax in tetrahydrofuran: 392 m y (E = 5100),
332 (12100); 270 (22700).
(4c) : orange-yellow needles from benzene, m. p. 202-206 ' C ;
A,,ax in tetrahydrofuran: 403 m p (E = 2700); 329 (9000);
259 (12100); N M R in CS2: 3.61 T [2 H , S]; 2.71 T [lo H, MI.
The mass spectrum of the dimethyl derivative (4n) [Hitachi
RMU-6A instrument, glass inlet system a t 120OC; 2000 V
accelerating voltage, 80 eV electron voltage] contains the
peak of the molecular ion (m/e = 232) and in comparable
abundance the peak of the dithiacarbene (2) (m/e = 116) [6].
To o u r knowledge, this is the first time that such a carbene
has been detected by mass spectrometry.
Received: March 19th, 1965
[ Z 918/775 1EI
German version: Angew. Chem. 77, 453 (1965)
[ I ] For the preparation of ( l o ) and ( l b ) . see A . Liictringhous,
H. Berger, and H . Prinzbach, Tetrahedron Letters 1965, in the
press; ( l c ) was made according to D . Leaver, W. A. H. Robertson, and D . M . McKinnon, J . chern. SOC. (London) 1962,
5101.
[2] R . Breslow, J. Arner. chern. Soc. 80, 3719 (1958); H . W . Wnnzlick and H . J . Kleiner, Angew. Chem. 75, 1204 (1963); Angew.
Chern. internat. Edit. 3, 65 (1964); H . Quast and S. Hiinig,
Angew. Chern. 76, 989 (1964); Angew. Chern. internat. Edit. 3.
800 (1964); H . Ball;, Angew. Chem. 76.995 (1964); Angew. Chem.
internat. Edit. 3 , 809 (1964).
131 P. Haake and W. B. Miller, J . Amer. chern. SOC.85, 4044
(1 963) ; H . A . Stnab, M . Th. Wu, A . Mannschreck, and G. Sch wnlbach, Tetrahedron Letters 1964, 845.
141 R. A. Olofson, W. R . Thonipson, and J . S. Michelnion, J. Arner.
chern. SOC.86, 1865 (1964).
[ 5 ] W. R. H . Hurtley and S. Smiles, J. chern. SOC.(London) 1926,
2263.
[61 The mass spectrum was kindly measured by Dr. J. Seibl, Eidgenossische Technische Hochschule, Zurich (Switzerland).
435
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