вход по аккаунту


Mechanism of Cyanation of Tertiary Amines.

код для вставкиСкачать
driven to completion by the use of an excess of base without
the concomitant formation of other products, the present
reaction required very careful control of the reagents and
experimental conditions in order to achieve optimum conversions. The isolation of (2a) was accomplished only after
fractional crystallization at low temperatures. The structure of (2a) is supported by spectral data [IR (CCl,):
v=1850cm-'; NMR (CDCI,, 60MHz, &-value in ppm
relative to TMS): 2.53 (H3/s),3.16 (1 H/broad s),ca. 2.4-1.4
(29 H/m); mass spectrum: m/e 325 (M')].
under the same conditions requires 3.5 h. The chemical
stability of (2a) is equally remarkable: its complete decomposition in boiling methanol at a concentration of
1.5 mmol/lO ml occurs only after 1.75 h. By comparison,
(26) requires 30 h for complete decomposition under
identical conditions, and ( 2 c ) is reported to decompose in
methanol at 5°C within 20 minutes''! Thus, the stability
of (2a) is superior to that of ( 2 ~ ) and
' ~ approaches
of (2d), the most stable class of a-lactams known so far.
Received: July 5,1971 [Z 471 IE]
German version: Angew. Chem. 83,848 (1971)
(a), R i = 1-adamantyl, R 2 = 2-adamantyl
fb), R i
fC), R'
( d ) , R'
R2 = 1-adamantyl
C,H5, R 2 = C(CH,),
R2 = tert-alkyl
The thermal stability of the novel a-lactam (2a) is illustrated by the observation that its complete decomposition in
boiling xylene (138°C) at a concentration of 0.4 mmol/6 ml
requires 1 h, whereas the complete decomposition of (2b)
[I] See E. R. Talaty and C. M . Utermoehfen,Tetrahedron Lctt. 1970,
3321, and references cited there; J . C. Sheehan and M . M . Nafssi-K
J. Org. Chem. 35, 4246 (1970); S. Sarei, B. A. Weissman, and Y: Stein,
Tetrahedron Lett. 1971,373.
[2] I. Lengyef and J . C . Sheehan, Angew. Chem. 80.27 (1968); Angew.
Chem. internat. Edit. 7, 25 (1968).
[ 3 ] P. E. Afdrich, E. C . Hermann, W E. Meier, M . Paulshock, W W.
Prichard, J . A. Snyder, and J . C. Watts, J. Med. Chem. 14, 535 (1971).
[4] E. R . Tafaty, A. E. Dupuy, Jr., and A. E. Cancienne, Jr., J. Heterocyclic Chem. 4, 657 (1967).
[5] H. E. Baumgarten, R . L. Zey, and U . Krolls, J. Amer. Chem. SOC.83,
4469 (1961).
[6] The published data on the thermal stability of (2c)-appreciable
decomposition at 105°C-do not allow an accurate comparison with
( 2 a ) and (2b); J . J . Fuerholzer, Ph. D. dissertation, University of
Nebraska, 1965.
Reactions of Adamantanes and Their Derivatives
in Sulfuric Acid
By J . Schiatmann'"]
Under suitabie conditions I-adamantanol can be converted
into adamantanone in concentrated sulfuric acid. The key
reaction is the reversible isomerization of 1- to 2-adamantanol; the equilibrium is much in favor of the I-isomer. It
has been proved that this isomerization occurs intermolecularly. The 2-adamantanol present in the reaction mixture
is transformed into adamantanone by a hydride shift, the
hydride acceptor being either the adamantanyl cation
(yielding adamantane as a by-product) or the sulfuric acid.
Adamantane is reconverted into I-adamantanol by sulfuric
acid; thus the synthesis of adamantanone can also be
carried out from adamantane (yield ca. 50%).
Besides adamantanone, adamantanediols are formed from
I-adamantanol in sulfuric acid, presumably also in hydride
shift reactions, with either the adamantanyl cation or the
sulfuric acid as hydride acceptor. Although these are
unimportant side products when the reactions are performed in concentrated sulfuric acid, conditions can be
p] Dr. J. Schlatmann
N. V. Philips-Duphar
Weesp (Holland)
found in which the diol formation will be enhanced and the
adamantanone formation suppressed because all these
reactions are influenced differently by the concentration
of the sulfuric acid. Thus in 20% fuming sulfuric acid the
formation of the 1,3-, 1,4- and 2,6-adamantanediols predominates. After oxidation with chromic acid the components of the reaction mixture can be separated and 5hydroxyadamantanone (yield ca. 50%) and 2,6-adamantanedione can be isolated in pure form.
Lecture at Aachen on May 25,1971 [VB 309 IE]
German version: Angew. Chem. 83, 732 (1971)
Mechanism of Cyanation of Tertiary Amines['*]
By Gabor Fodor and Shiow-yueh Abidi"]
We have been able to show that the von Braun cyanogen
bromide degradation of tertiary amines proceeds by two
successive steps :
Prof. Dr. G. Fodor and Dr. Sh. Abidi
West Virginia University
Department of Chemistry
Morgantown, West Virginia 26506 (USA)
[**I This work is being supported by National Science Foundation,
Grant GP-26558.
Angew. Chem. internat. Edit. / Vol. 10 (1971)
/ No. 10
1. Electrophilic addition of a cyano group to nitrogen,
giving an N-cyano ammonium salt in a reaction that is
immeasurably fast even at -60°C.
2. Attack by the bromide ion on a carbon atom attached
to nitrogen, giving a cyanamide and RBr in a reaction
whose rate is measurable between -30 and -9°C.
NMR measurements on l-cyano-trans-decahydro-l-methylquinolinium bromide show the second stage to be a
reaction of the first order; it occurs ten times faster in
CDC1, than in CD,CN. The activation energy of decomposition amounts to 18 kcal/mol. On replacement of the
bromide by a less nucleophilic (or non-nucleophilic) anion,
e. g., hexachloroantimonate, methanesulfonate, p-toluenesulfonate, or tetrafluoroborate, stable quaternary N-cyano
ammonium salts can be isolated for the first time, analyzed,
and subjected to examination of their chemical behavior.
Recently also we have been able to trap the adduct formed
from methyl chloroformate and trans-decahydro-l-methylquinoline at low temperature and to stabilize it as fluoroborate.
To determine the stereochemistry of the N-isomeric products obtained we have separated them as fluoroborates
and are presently studying (a) their nuclear Overhauser
effect at 250 MHz and at 100 MHz, (b) their l3C-NMR
spectra, and (c) the structure of the major product by X-ray
Lectures at Darmstadt on May 26, 1971, Miinchen on June 4, 1971,
and at Erlangen on June 7,1971 [VB 310 IE]
German version: Angew. Chem. 83,732 (1971)
Synthesis and Structure of Haloamines
By Jochen Jander, Klaus Knuth, Ro[fMinkwitz,and
Werner Renz"'
The lecture concerned, inter aha, the synthesis and solidstate FIR-spectroscopic study of the structure ofNI,. 3NH,
( I ) , the so-called NH,I.NH3 (2), the so-called NH,I (3)
[better formulated, in view of the results below, as NI,
. -5NH, (2) and NI,. -2NH, ( 3 ) , respectively] as well
as of the N-iodomethylamines CH,NI,. CH,NH, ( 4 ) ,
( 6 ) , CH,NI, (71,
CH,NIz. PY f 5 ) , CH,NI,.(CH,),N
and (CH,),NI (8). The NI, adducts were obtained by
treatment of IC1 or I, with NH, in aqueous solution or
with liquid NH,; (NI,.NH,), can be used as iodinating
agent, as well as ICl or I,, for preparation of the N-iodomethylamines[']. Because of their sensitivity, compounds
(1)-(4) and (7)-(8)
can be studied only at low temperatures; this was possible by use of a new low-temperature
measurement technique.
The glittering green ( I ) , the pale red ( 2 ) , and the black
(3) contain the same polymeric structure as (NI,. NH,),
consisting of NI, tetrahedra joined by common iodine
differences were found as follows:
[*] Prof. Dr. J. Jander and Dr. K. Knuth
Anorganisch-Chemisches Institut der Universitat
69 Heidelberg, Im Neuenheimer Feld 7 (Germany)
Dr. R. Minkwitz
Institut fur Anorganische Chemie der Freien Universitat
IBerlin 33, Fabeckstrasse 34-36 (Germany)
Dr. W. Renz
Farbwerke Hoechst AG.,
8261 Gendorf/Obb. (Germany)
Angew. Chem. internat. Edit.
Vol. 10 (1971) / No. 10
( I ) and (2) bind more NH, than (NI,.NH,), and, because
the contact sites are occupied by NH,, they contain no
1-1 contacts between the tetrahedron chains as (NI,.NH,)does; (2) and (3)15' are amorphous to X-rays and thus
contain only ill-developed and possibly shorter tetrahedron chains than (NI,.NH,),.
The reddish-yellow ( 4 ) , the brick-red ( 5 ) , the orange ( 6 ) ,
and the reddish-brown (7) are also polymeric and consist
of NI,C tetrahedron chains which either, as in (7),use the
iodine atoms that are not part of the chain for binding by
1-1 contacts or, as in (4)-(6), for binding the nitrogen
base. This result has been confirmed for (5) by X-ray
The yellow ( 8 ) is probably monomeric; two very longwave FIR bands < 100 cm- ' can be interpreted either as
lattice vibrations or as very weak intermolecular N-I
contacts, i. e. as a precursor of a stable tetrahedron chain.
Lecture at Aachen on June 8, 1971 [VB 311 IE]
German version: Angew. Chem 83,767 (1971)
[l] 3. Jander, U . Engelkardt, and G . Weber,Angew. Chem. 74,75 (1962);
Angew. Chem. internat. Edit. I , 46 (1962).
[2] J . Jander, L. Bayersdorfer, and K . Hiihne, 2. Anorg. Allg. Chem.
357, 215 (1968).
[3] H . Hartl, H . Biirnighausen, and 3. Jander, Z. Anorg. Allg. Chem.
357, 225 (1968).
[4] K . Knuth, 3. Jander, and U . Engelhardt, Z. Naturforsch. 246, 1476
[5] J . Jander and U . Engelhardt, Z. Anorg. Allg. Chem. 339,225 (1965).
Molten Salts at High Pressures and High
By Klaus Todheide'*]
The macroscopic properties of molten salts cannot yet be
calculated from the properties of the ions and molecules
by means of statistical mechanics. Thus models for molten
salts have been developed in order to enable interpretations of experimental results as well as predictions, where
experimental information is missing. For the purpose of
testing the capability of these models to describe the density
dependence of macroscopic properties of molten salts
correctly, experiments at high pressures are necessary. It
is only in recent years that the first investigations of this
type have been performed.
The specific conductivity of the molten alkali metal nitrates
has been measured up to 60 kbar. In the region of low and
medium pressures (for NaNO, up to about 20kbar)
straight lines were obtained for the logarithm of the specific
conductivity as a function of pressure and as a function of
the reciprocal absolute temperature. From the slopes of
these lines, and from experimentally determined PVT data,
the activation volumes and activation energies for the
equivalent conductivity have been calculated. The activation volume increases from 0.7 cm3/mol for LiNO, to
8.0 cm3/mol for CsNO,, while the isochoric activation
energy decreases from 3.5 to 1.4 kcal/mol. The ratio of the
isochoric to the isobaric activation energy decreases from
0.97 for LiNO, to 0.36 for CsNO,. This result indicates
[*] Dr. K. Todheide
Institut fur Physikalische Chemie und Elektrochemie
der Universitat
75 Karlsruhe, Postfach 6380 (Germany)
Без категории
Размер файла
221 Кб
mechanism, cyanation, amines, tertiary
Пожаловаться на содержимое документа