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Dimethyl Sulfate Complexes of N-Monoalkylformamides.

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Tahle 4.
Reactants
+
(C6H5)2CO
CH,-CH=CH-CH==NR
Yield
M. p.
1 %I
r 'CI
')I
x1 83
22
156-157
+
(3)
60-61
55 % 8-Phenylcrotonaldehyde (b.p.
125- I30 T / 1 3 mm)
I- 22 % methyl styrene
80
46---47
42 % 8-lonylideneacetaldehyde (b.p.
115-l20T/
10-3 mm)
GHs-CHO
CH3 CH-NR
94
79-80
77 %. Cinnamaldehyde (b. p.
I17--120°C/12 m m )
Cyclohexanone -1
CH3-CH-NR
92
62-62.5
58
CsHs-CO -CH3
CH3-CH-N R
B-lonone 4
CH3-CH-N
R
+
yet bccn attained and no further addition of titrating solution
takes place. If equilibrium has been reached, the potentials
in the two condensers will be equal. The monitor then records
a point on the titration curvc and cnergizes a dosage pump to
add a measured quantity 0 1 titrating solution.
This control sequence ib pcriodically rcpedted until thc
entire titration is recorded. 'I'hc cquilibralion times for
the individual equilibrium potentials can be quite different
throughout the process. Since the sensitivity of the monitor
can also be altered, it is also possible to determine automatically the normal potentials of compounds with equilibrium
potentials which are established only very slowly. In this
way we have, for instance, round the normal redox potential
of 7-hydroxyactinomycin C'I [2], which is of interest in connection with the bonding of actinomycins onto DNA [3],
to be +204 mV.
A number of redox potenti;d determinations were replicated
in order to determine the reprodicibility of the results (cf.
Table 1).
Table I. Itedox potentials of some compounds.
% Cyclohexyl-
ideneacetaldehyde
(semicarbazone,
rn. p. 208-209 "C)
The reaction of (I) with halides (in a molar ratio of I : I ) gives
extended Schiff's bases (see Table 2).
E,, found pa]
[ I mV1
Compound
2,5-Dihydroxybenzoquinone 437
2-Hydroxynaphthoquinone
3.59
5-Hydroxynaphthoquinone
4SO
lin-Naphthindazole-4.9154
quinone
I
ED literature value
[t-mV1
438
360
45 I
155 [c]
I
433
356
452
154.1
435 [b]
357 [b]
452[b]
154.8 [d]
Table 2.
Halide
Schiff's base
CH~-CHZ-CH=NR
C~HS-CH~-CH=NR
H?C=CH-CHrCHz-CH=NR
98-100
GHZ-CH~-CH~--CH=NR [*I
I*] Gives dihydrocinnamaldehyde (b.p. 102--104"C/13 mm) in 5 1 %
yield on treatment with dilute HCI.
Received, March 27th, 1963
[Z 583/406 [I?]
Publication delayed until now a t the request of the authors.
German version: Angew. Chem. 75, 978 (1963)
[I] Cf. 0 . Buyer in Hoitben-Weyl: Methoden der organischen
Chemie. Thieme, Stuttgart 1954, Vol. VII, part 1, p. 76 et seq.
[2] G. Wittig, H.-J. Schmidt, and H . Renner, Chem. Ber. 95,2377
(1962).
A New Type of Automatic Redox Titrator
By Dr. P. Boldt and Dr. H. Lackner [I]
Organisch-Chemisches Institut der Universitlt GBttingen
(Germany)
Dedicated to Prof: Dr. Hans Brockmann on the occasion of his
60th hirthduy
Rrdox potentials of organic compounds are usually established only very slowly. They cannot be determined accurately
with conventional automatic titrators, since these usually add
the titrating solution relatively fast or in increments at preselected time intervals, which are frequently insufficient for the
establishment of equilibrium. Our automatic redox titrator
adds fresh titrating solution only after equilibrium has been
established. This is achieved by storing the measured potential
(after amplification) in a condenser located in the conlrol
mechanism. The potential is again measured after an adjustable, preselected time interval (checking time) and stored in a
second condenser. The stored potentials are then compared in
the monitor. If their values are different, equilibrium has not
684
The deviation from the mcim of single measurements was
within : 2 mV (evaluated from 10 titrations): the time for one
titration was between 6 and 8 hours.
Received, June 18th. 1963
[Z 572/402 IE]
German version: Angew. Chem. 75, 978 (1963)
[ I ] Dctaiied description: Chemic-lng.-Techn. 35, 707 (1963).
[2] H. Brockmanrr and H . Pri[.rssen-Borstel, unpublished work ;
H . Peterssen-Borstel, Diploma Thais, UniversitSit Gottingenl961;
the authors wish to thank Dr. Werner Miilfer for supplying the
material.
[ 3 ] W. Miiller, NaturwissenschaCten 49, 159 (1962).
Dimethyl Sulfate Complexes of
N-Monoalkylformamides
By Prof. Dr. H. Bredereck, Dr. F. Effenberger,
and DipLChem. Erika Henseleit
Institut fur Organische Chemie und Organisch-chemische
Technologie der Technischcn Hochschule Stuttgart
(Germany)
On treatment of N-alkylformamides with a n excess of dimethyl sulfate (ca. 2 moles) [ I ] , we obtained very good yields
of methyl N-alkylformiminate/methyl sulfate complexes
[ ( I ) , R = CH3: n z = 1.4513, 95 '%, yield; R = C2H5: n $ =
1.4525, 80 %]. An excess of' amidc gave N,N'-dialkylformamidinium methyl sulfates (2) by way of (I). Examples:
(2), R-CH3: nyy== L.4665, 05j%,; n1.p. of picrate 169OC [2];
R - C ~ H S :ny:= 1.4583, 96 ?<',,m.p. ofpicrate 123.5--124.5"C
[31.
Acyl chloride complexes o f N-alkylformamides yield isonitriles with bases and thus do not react with nucleophilic
partners [4]. I n contrast, no isoiiitrilc is formed with the
Aiigrw. Chem. intrriiol. Edit.
/
Vol. 2 (1963)
No. I I
0-alkyl methyl sulfate salts ( I ) which, therefore, can react
with nucleophilic partners.
NHR
HC?@
CH3S04'
\HR
(2)
N(C2H5)3 and NH3 form similar yellow adducts with S20;
these then react further to yield rcd secondary products.
SOCIz*N(CH3)3(2) was obtained analogously from its components by fractional condensation at 30°C. Compound (2)
forms colorless crystals, sublimes in v m w above 20 "C, and
hydrolyses quantitatively to HCI. S02, and trimethylamine
S20 forms very unstable adducts by electrophilic addition of
BF3. Condensation of the components at -160°C yielded
bordeaux-red SzOmBF3 (n = 2 or 3), which could be freed
from excess BF3 only by thermal decomposition in vacw a t
-140OC. SOyBF3 [3], on the other hand, w d S stable under
these conditions at - I50 "C.
On reaction of (I) with triethylamine we obtained methyl
N-alkylformimindtes [(3), R = CH3: n'$ = 1.3875, m.p.
4 7 ~ 4 9 ° C ;R = C2H5: n t = 1.3881, m.p. 61-63°C] for the
first time. Care is needed in dealing with these new substances. Compound (I) and primary amines interact to give the
(also previously unknown) unsymmetrical N,N'-dialkylformamidinium methyl sulfates [(4), R' = C2H5, R = CH3: n g
- 1,4556; m.p. of picrate 1 I I - 112°C; R' = n-CdH9, R =
CH3: n g = 1.4554; R' = Cf,HII, R = C Z H ~n: g = 1.48131.
The free amidines are obtained from these under mild conditions but rearrange at higher temperatures to the symmetrical amidines.
Received, July Sth, 1963
[Z 5401361. 1El
German version: Angew. Chem. 75,790 (1963)
[ I ] For reactions of formamide and N,N-disubstituted formamides with dialkyl sulfates, see H. Bredereclc et al., Chem. Ber.
Y2, 329 (1959); 96, 1351 (1963).
[2] G . Simchen, Ph.D. Thesis, Technische Hochschule Stuttgart,
1962; E. C. Taylor and W . A. Ehrhardt, J. org. Chemistry 28,
1108 (1963).
131 J. W. Cornforth: The Chemistry of Penicillin. Princeton University Press, 1949, p, 851.
141 J. Ugi and I?. Meyr, Chem. Ber. 93,239 (1960); J. Hagedorn
and H . Tonjes, Pharmazie 12, 570 (1957).
Adducts of Disulfur Monoxide
By Prof. Dr. P. W. Schenk and cand. chem. R. Steudel
Anorganisch-Chemisches tnstitut der Technischen Universitlt
Berlin and Institut fur Anorganische Chemie der Freien
Universitat Berlin (Germany)
Disulfur monoxide is strongly unsaturated owing to its S=S
double bond [l] and polymerizes readily to polysulfur oxides
with partial decomposition to SO2 [2]. Stabilization of monomeric S20 can be achieved by nucleophilic addition of amines
with sharing of the 3d-orbitals of the sulfur. Trimethylamine
reacts with S 2 0 to yield intense lemon-yellow, crystalline
S20.N(CH3)3 (I), which separates out at - 30°C/2 mm totdl
pressure. At 1-20O C , (I) decomposes slowly into trimethylamine, SO;?,and sulfur.
The yellow color of (I) indicates its partial double bond
character.
Received, July Eth, 1963
[Z 545/374 IEI
German version: Angew. Chern. 75,793 (1963)
[ I ] P . A . Giguere, J. physic. Chem. 64, 190 (1960).
[2] P. W.Schenk, Z . anorg. allg. Chem. 233, 385 (1937).
[3] H. S. Booth and D. R. Martin, J. Amcr. chem. SOC.64, 2198
(1942).
Amides and Imides of Tetravalent Titanium and
Zirconium
By Prof. Dr. 0. Schmitz-DuMont, G. Mietens, and B. Ross
Anorganisch-Chemisches Institut der Universitat
Bonn (Germany)
The amides of trivalent titanium, chromium, and cobalt
were previously obtained as amorphous precipitates from
solutions of K3ri(SCN)6] [l], [Cr(NH3)6](NO&, and
[Co(NH3)6](N03)3[2] in liquid amonia by precipitation
with the equivalent quantity of KNH;?. Analogous preparations of the amides of tetravalent titanium and zirconium
were attempted.
Ti(N03)4 (I), obtained according to Schmeiswr [3] by treating
Tic14 with N205, dissolves in liquid ammonia with partial
ammonolysis to give a yellow solution. Small ammounts of
orange-yellow material Ti(NH2)2.83(NH3)x(N03)1.17(x =
1.08-1.15) precipitate. The reaction of ( I ) with KNH;?
(1 :4) leads to a brown product corresponding almost exactly
to the formula Ti(NH2)4. On passing nitrogen even at -78 OC
over this compound, the color deepens and NH3 is split off
leading to the formation of the imide, which could not be
analyzed owing to its explosive nature.
Crystalline Zr(N03)42HN03, which still contains H N 0 3 and
which is prepared from zirconium hydroxide and nitric acid,
is not suitable for the preparation of Zr(NH2)4 since in liquid
NH3 it forms a heterogeneous precipitate containing Zr,
N, and 0. By treating ZrCI4 with KSCN in acetonitrile,
K2[Zr(SCN),j]*CH3CN (2) was obtained; this loses all of its
CH3CN on heating Lo 90 "C in vucuo. The acteonitrile-free
complex salt dissolves in liquid NH3 to give a pale yellow
solution; o n evaporating the NH3, K;?[Zr(SCN)6].4 NH3 is
left as residue.
On addition of KNH2 to a solution of acetonitrile-free (2)
(4: I), a pale yellow precipitate results, which, after standing
in a current of nitrogen at 22°C has the composition
Zr(NH);?. This imidc is amorphous and, in contrast to the
titanium compound, is not explosive.
[Z 552/378 IEl
Received, July 10th. 1963
German version: Angew. Chem. 75, 792 (1963)
Compound (I) sublimes in VLICIIO above -10°C. Free SzO can
be detected in the vapor by means of its ultraviolet spectrum.
In this way, reversible vaporization of condensed S20 has
hcen attained for the first time.
[I J 0 . Schmitz-DuMont and G. Brojn, Z. anorg. allg. Chem. 258,
307 (1949).
[2] 0. Schmitz-DuMont, J . Pilzecker, and H . F. Piepenhrink, Z .
anorg. allg. Chem. 248, 175 (1941).
131 M . Sclimeisser, Angew. Chem. 67. 4'93 (1955).
68.5
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