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Cleavage of Aryl-substituted Tertiary Amines by Acyl Halides.

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The quantity b is normally a constant of the system, whereas
a and c depend on the experimental conditions (e.g., c is
related to the rate of uptake of sulfur). The coordinates of
the S, maxima, [SPlma, and tmax, calculated from eq. (t),
are in excellent agreement with experiment.
If the formation and degradation of S,-sulfur are first-order
processes, a kinetic expression can be developed, integration
of which leads to:
Phenylogous S,N-acetals of type (7) react with carbonyl
chlorides and with chloroformic esters at low temperatures
(about -60 "C), yielding addition products, e.g. (S), that
decompose a t room temperature to p(methy1thio)benzyl
chloride (9) and N,N-dimethylurethane (R = C2Hs) (10).
Other benzylamines behave similarly: the stability of the
addition compounds increases as the para-substituent is
changed in the order (CH3)2N, CH3O, CH3S, H , CH3SO2.
kl and kZ are the rate constants for decrease in [s,] and of
[S,,], respectively, and [&lo is the initial sulfur concentration.
The factor E is the quotient of the experimental IS,] maxima
and those calculated on the assumption that all the sulfur
2 atoms) reacts further,
contained in a cross-link ( p
+
The rate constant kz is obnamely, [S,],a,/[S,
tained by use off,,,,
as in eq. (3):
+
klt,,,
=
In o ( m l ) - l , where Q
=
kz/kl
(3)
The total rate of formation of all the subsequent products,
C [PI, is given by
d C [PJ/dt =
(4)
/<2[Ep]
Inserting the expression for [S,] from eq. (2) and integrating
gives
/
On the other hand, inserting the expression for [S,] from
eq. (4) into eq. (1) gives:
C [PI
=
(kzo!c?) [l-e-ct-ce-ct]
(6)
The kinetics thus developed were tested o n vulcanization of
natural rubber in the presence of ZnO, zinc benzothiazoyl
sulfide, and zinc myristate or stearate in three series of experiments, in which the temperature, the inital concentration
of sulfur, or the content of accelerator were varied.
For determination of the S,-sulfur the vulcanizate was
degraded with lithium tetrahydridoaluminate; p sulfur atoms
were split off as H2S from the alkenyl alkyl polysulfide bridge
bonds each containing ( p + 2) sulfur atoms, while in each
case two sulfur atoms remain on the polymer chain as thiol
groups; it should be noted that that the ZnS formed in the
vulcanization must be separately determined and taken into
account.
The relation between S p content of the vulcanizate and
reaction time calculated from eq. (2) is in excellent agreement
with experiment; calculation of the final concentration
(t = m) of the subsequent products by means of eqs. ( 5 ) and
(6) gave values also in good agreement with experimental
results. These facts can be considered as confirmation of the
kinetics developed, since no assumptions were made in
deriving eq. (l), on which eq. (6) is based.
[Lecture at Hannover, May 26th, 19661
[VB 10 IE]
German version: Angew. Chem. 78, 828 (1966)
Reaction of a-halogenated amines (2) and 2,4,6-trichloro- or
2,4,6-trimethyl-N-methylanilines(12) makes accessible the
unsymmetrical aminals (13), which on distillation (80 "C,'
10-2 mm) symmetrize t o compounds (17) and (14) and on
cleavage with a carbonyl chloride give N,N-dialkylchloromethylamine(2a) together with a substituted benzanilide(1 I).
0,N-Acetals (15) were similarly prepared from chloromethyl
methyl ether and the aniline ( I 2 ) , and they also symmetrize
Ar-N-CO-C6H5
CH3 (11)
+
RzN-CHzCI
(2a)
/+ C6H5COC1
Ar-NH-CH3
+ R2N-CH2Hel (2)
(12)
Ar-N-CHz-NR2
6H3 (13)
I
1 1 1 2 :?CHI
+ CICH2-O-CH,
Ar-y-CHz-0-CH3
- 1/2 (CH,O),CH,
CH3 (15)
(16)*
112
Ar,
Ar
N-CH~-N:
H3C' (17) CH3
1.
CH,-COCI
Cleavage of Aryl-substituted Tertiary Amines by
Acyl Halides
Ar-N-CHzC1
,
6 H s (I8)
+
CH3COzCH3
(19)
H . Bohme, Marburg (Germany)
The reaction of S,N-acetals (1) with carbonyl halides in
indifferent solvents leads to a-halogenated amines (2),
together with thiocarboxylic esters (3). By the analogous
fission of phenylogous S,N-acetals of type (4) we have
isolated the first of the rather unstable, phenylogous ahalogenated amines (5), which were characterized by reaction
with secondary amines to the previously described phenylogous aminals.
Angew. Chem. internat. Edit. 1 Vol. 5 (1966)
/ No. 9
849
at about 80°C, yielding compounds (17) and (16); on
cleavage with acetyl chloride the acetals (15) yield N-(chloromethy1)aniline derivatives (18) and carboxylic esters (19) ;
the compounds (18) with hydrogen cyanide afford cyanides
(20), with dimethylaniline afford diamines (21), and with
monosubstituted indanediones afford compounds of type
(22).
[VB 13 IE]
[Lecture at Marl o n June 15th, 19661
German version: Angew. Chem. 78, 828 (1966)
Racemization of atropisomeric model compounds is first
order, but the polymer racemizes appreciably more slowly
and not according to first-order kinetics.
Polymers of type (3), with atropisomeric groups in the main
chain, have been obtained by interfacial polycondensation of
(+)-l,l’-binaphthyL2,2’-diamine with terephthaloyl dichloride.
[Lecture at Mainz (Germany),
June 23rd, 19661
WB 16 IE]
German version: Angew. Chem. 78, 909 (1966)
Methods and Problems in the Study of Optically
Active Polymers
Chemistry of o-Quinol Acetates
F. Wessely, Vienna (Austria)
R . C. Schrrlz, Mainz (Germany)
For the preparation of optically active polymers asymmetric
monomers were polymerized with radical or ionic initiators
[e.g., menthol and borneol acrylate and methacrylate,
menthol N-vinylurethane, N-substituted N-(a-methylbenzy1)acrylamides, N-vinylureas derived from a-amino acids], and
asymmetric substituents were introduced into optically inactive polymers in polymer-analogous conversions.
High-molecular crystalline polyesters ( I ) with softening
points of about 170 “ C were obtained by ring-opening polymerization of L-dilactide:
Whereas, in all cases studied so far, reaction of o-quinot
acetates with K C N leads to m-hydroxybenzonitriles, reaction
of compound ( I ) with KCN depends on the solvent. It gives
a m-hydroxy nitrile ( l a ) only in dimethylformamide, formation of this product being explained by 1,6-addition to the
conjugated system of ( I ) . However, in methanol compound
(Ib) is formed, a result for which a complicated rearrangement must be responsible. Both reactions proceed rapidly at
room temperaturt.
OH
(lo), 60%
0
6HO
KCN
C HO
( I b ) , 70%
(1)
In this reaction the configurations of all the asymmetric C
atoms are retained and are the same, so that a completely
isotactic polymer results. The optical rotatory dispersion and
circular dichroism were measured in several solvents. The
Cotton effect, which is observed only for poly-r-lactide,
indicates a secondary structure. The rotatory dispersion can
be described equally well by the modified two-term Drude
equation and by the Moffit-Yang equation; the constants
are similar to those for helical proteins and poly-L-aminoacids, but the signs are reversed.
I
C02CH3
O n treatment of compound (2) with KCN the product is
practically independent of the solvent. The reaction leads to
conversion of the aldehyde group into a carboxyl group,
which can be esterified by the alcohol used as solvent.
0
*CH3
All optically active polymers described previously contain
asymmetric C atoms. However, treatment of (+)-2’-methyl6’-nitrobiphenyl-2-carbonylchloride with polyvinyl alcohol
yields the first polymer (2) whose optical activity is due to
atropisomerism.
This polymer gives the same Cotton effects as monomeric
model compounds.
The specific rotation of the polymer corresponds precisely to
the analytically determined content of atropisomeric substituents. From the rotatory dispersion and the circular dichroism it can be concluded that there is n o mutual optical
interaction between the side groups of this polymer, that
the polymer structure has no influence on the specific rotation, and that in solution the macromolecules are randomly
coiled.
850
H3C OzC
85%
For the mechanism of the reaction leading from ( I ) to (Ib)
it is important that the quinol acetate (3) and KCN in
methanol give a 55 % yield of compound (Su), whereas only
a very small yield of (3a) is obtained from the quinol acetate
(4) under the same conditions. The structure of compound
(3.) has resemblances to that of compound (lb).
Reaction of ( I ) and (2) with trimethylsilyl azide in methanol,
or with the azide ion, leads to compounds ( I c ) and (2a).
Quinol acetates carrying alkyl groups on C-4 or C-5 do not
give such products. Thus the azide ion adds to an o-quinol
acetate only if the latter is activated by a formyl group. The
Angew. Chem. internat. Edit. 1 Vol. 5 (1966) 1 No. 9
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cleavage, halide, substituted, amines, aryl, acyl, tertiary
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