close

Вход

Забыли?

вход по аккаунту

?

Flash Thermolysis of Organic Compounds.

код для вставкиСкачать
Flash Thermolysis of Organic Compounds
By Gunther Seybold["]
Flash thermolysis is a special form of gas-phase thermolysis that is particularly suitable
for the production and isolation of thermolabile reaction products. The theoretical basis and
the instrumental requirements of the method are first given, and the preparative importance
of flash thermolysis for the synthesis of thioketenes, allenes, arynes, highly strained ring systems,
quinodimethanes, and other reactive compounds is then demonstrated with the aid of examples.
1. Introduction
Thermolysis has long been of great preparative utility
in organic chemistry. A special form of thermolysis, i. e. flash
thermolysis, has recently found wide application in the synthesis of thermolabile compounds, in spectroscopic characterization of short-lived intermediates, and in the investigation
of thermolytic reactions[' -41. The principle of this technique
has long been applied in isolated cases, but it is only recently
that the great potential of the method has been recognized
and utilized in systematic fashion.
Since the generation of radicals has been described in detail
in earlier
the present article will deal mainly
with the application of flash thermolysis to the production
of nonradical compounds.
of the substance. z can be readily calculated. Thus, for a
cylindrical tube of length L and diameter D :
where k is a correction factor taking account of the ratio
L/DC6].Thermal excitation of the molecules occurs mainly
by molecule-wall collisions. This form of flash thermolysis
is also called flash vacuum thermolysis (often abbreviated
to FVT) or very low pressure pyrolysis (VLPP).
b) The compound to be pyrolyzed is carried into the reactor
in a stream of inert gas, pressures of lo-' to 10 torr generally
being used. The contact times can be calculated from Poiseuille's flow equation when the flow is nonturbulent[61. For
a cylindrical tube of length L and diameter D, with pressures
P I and P Z at the tube ends, we have
2. The Principles of Flash Thermolysis
Flash thermolysis is a special form of gas-phase thermolysis
characterized by three important features:
1) The substance to be pyrolyzed remains in the hot zone
for only a very short time. The mean residence or contact
times are between 1 x
and 1 s.
2) Flash thermolyses are carried out in such a way that
the steady-state concentration of the substance to be pyrolyzed,
and thus also the concentration of the products in the hot
zone, is very low.
3) Immediately after passage through the hot zone the thermolyzate is cooled to very low temperatures (- 196°C) and
thus protected from modification by subsequent reactions.
The short contact times and the low steady-state concentrations are achieved by arranging that the substance to be
pyrolyzed flows through a heated tube (the reactor) and is
condensed in a cold trap as soon as it leaves the hot zone.
The necessary flow can be produced in two ways.
a) A high vacuum is used, the substance being brought
into the reactor by molecular distillation. In this case molecular
beams are produced[5! According to Knudsen's work[5,61,
when the pressure is I
torr the contact time T depends
only on the molecular velocity V and the reactor geometry,
but it is independent of the pressure and of the rate of addition
[*] Dr. G. Seyhold
where '1 is the coefficient of friction of the inert gas. Thus,
in this form of flash thermolysis z depends on the geometry
of the reactor, the pressure drop in the reactor, and the viscosity
of the carrier gas. In contrast to the situation in vacuum
flash thermolysis, thermal excitation occurs here mainly by
molecule-molecule collisions.
If the pressures and the rate of substance injection E (mol/s)
are constant, a steady state is established within the reactor.
The steady-state concentration c depends on the contact time
z,the reactor volume R, and the injection rate E :
c = E r / R [mol/l]
In very fast thermolytic reactions (tl ,2 < T ) , c defines the product
concentration in the reactor. The steady-state concentration
in the reactor increases if the rate of injection E is increased
(high throughput); this has the consequence that the occurrence of undesirable reactions is greatly enhanced, such as
dimerization, polymerization, chain reactions, and generally
speaking subsequent reactions with a bimolecular initiation
step.
We shall now show, by an example, how the still just
tolerable steady-state concentration and thus the optimal injection rate E can be calculated.
Let A be a reactive thermolysis product that can dimerize
in the reactor in an undesirable side reaction:
Institut fur Organische Chemie der Universitat
Karlstrasse 23, D-8000 Miinchen 2 (Germany)
Present address: BASF AG, Farbenforschung, D-6700 Ludwigshafen
(Germany)
Angew. Chem. I n t . Ed. Engl. 16,365-373 ( 1 9 7 7 )
k2
2A+Az
365
(k2 =rate constant). We then have:
___=
k 2 . [A]'
dr
or. for small time intervals:
where A t = z , because the reaction takes place only in the
reactor.
If the proportion of A that undergoes the undesirable side
reaction is less than 1 %. we have
A [A]/[A]
SO.01
The steady-state concentration of A can then have, at the
most, the value:
[A] 10.01/(k2.r)
Forr=10-3sand k 2 = 1 0 4 to 1081mol-' s - l (order of magnitude for fast molecule-molecule reactions), a steady-state concentration of
to lo-' mol/l may not be exceeded. If
A has radical character, then k2 lies in the region 10" to
10" 1 mol-' s-' and the steady-state concentration must
be kept extremely low, which in turn requires a very slow
rate of injection and hence means low throughputs. Conversely,
with stable products (stable with respect to bimolecular subsequent reactions) correspondingly high rates of injection can
be used and high throughputs are achieved.
While subsequent reactions with a bimolecular primary
step can in all cases be excluded by an appropriate choice
of the experimental conditions, it is in principle impossible
to avoid fast monomolecular subsequent reactions.
jacket is outside the vacuum system (external heating). This
type of flash thermolysis apparatus is derived from the apparatus often used for conventional gas-phase thermolysis, e.g.
for the pyrolysis of esters['], and is characterized by simple
construction and easy cleaning; a simple type is illustrated
in Figure 1. Many variants of this type are described in the
l o 2 ]. Th e contact times can be extended as
desired by the introduction of quartz wool or other filling
material into the pyrolysis tube.
The disadvantage of this type of apparatus is the large
distance between the hot zone and the cooling traps, and
it is therefore unsuitable for the isolation of thermally very
unstable products. For the latter purpose those types of apparatus are preferable in which the pyrolysis tube is heated inside
the vacuum
15'.
This has the advantage that the
distance between the surface of the cold traps and the hot
zone can be kept very small, whereby even very short-lived
molecules such as radicals can be investigated. The disadvantage here is the high cost of construction and operation of
this type of apparatus, although this has been largely overcome
in the apparatus developed by
(Fig. 2). Our version
is characterized especially by the facts that the contact times
can be altered in a defined manner by changing the pyrolysis
tube and that the capacity of the cold traps has been much
increased by use of a rotatable cold finger. This apparatus
has recently become commercially
it is suitable
for preparative flash pyrolysis of amounts of up to log. A
modified injection system has been developed for substances
of very low volatility["].
II
rL
t7
3. Apparatus for Flash Thermolysis
In correspondence with the three basic steps in the thermolysis method, namely injection of the substance, thermolysis
in the hot zone, and quenching or condensation of the pyrolyzate, a flash pyrolysis apparatus must in principle consist
of three components: an injection unit for the sample, pyrolysis
tube, and lastly a cooling or condensation region. The apparatus requirements depend on the problem in question. If the
end products are all relatively stable, it is usually sufficient
to use one of the types of apparatus in which the heating
7
Fig. 1. Flash thermolysis apparatus with external heating. 1 , cooling trap:
2, to pump; 3, solvent supply vessel: 4, to manometer: 5, electrically heated
quartz tube: 6, substance supply vessel: 7, inert-gas inlet.
366
Fig. 2. Flash thermolysis apparatus with internal heating. 1, to pump; 2,
rotatable cold finger; 3, coolable tap; 4, receiver; 5, cooling water inlet:
6, solvent supply vessel: 7, to manometer; 8, electrically heated quartz tube;
9, sublimation tube; 10, connection for thermostat; 11, electric leads; 12,
inert-gas inlet; 13, storage vessel for volatile substances. The compounds
to be pyrolyzed can optionally be introduced at 9 or 13.
The type of cold trap shown in Figure 2 has proved particularly valuable in flash thermolysis, since the labile pyrolyzate
can be collected under very mild conditions as the trap thaws.
In flash pyrolyses an inert low-boiling solvent is usually added,
so that a solvent matrix is formed on the cold trap surface,
in which the pyrolyzate exists in finely divided form. When
the cold trap thaws out one then obtains a dilute solution
of the pyroly~ate['~~.
Moreover, a trapping agent may be
used in place of the solvent.
One prerequisite for successful flash thermolysis in a molecular beam or in a stream of inert gas is an efficient pumping
Angers. Chem. Int. Ed. Engl. 16.365-373 ( 1 9 7 7 )
system. High-vacuum pumps fitted with ionization gauges
are generally used for this purpose['5!
If the cold trap is fitted with quartz or NaCl windows,
the thermolyzate can be investigated directly by spectroscopic
methods['.2.'8-201. If the cold trap is replaced by the ion
source of a mass spectrometer, the pyrolysis products can
be investigated by mass spectro~copy['*~,
21,221. The cornbination of pyrolysis with mass spectroscopy not only provides
valuable information about short-lived molecules, e. 9. the
ionization potentials of radicals in the gas phase, but also
permits the optimal thermolysis temperatures for preparative
flash thermolysis to be determined.
4. Applications of Flash Thermolysis
N-N-TOS
Flash thermolysis of phenyldiazomethane has been studied
very thoroughly[28-321. The phenylcarbene ( 3 ) first formed
exists in equilibrium with cycloheptatrienylidene ( 4 ) , which
at high steady-state concentrations dimerizes to heptafulvene
(5)[*'1; at low steady-state concentrations ( 4 ) stabilizes itself
by ring contraction to give the products (6) and (7)["1.
If p-, m-, or o-tolyldiazornethane is used, dihydrocyclobutabenzene and styrene are formed as the end products in all
cases[3o,311. The mechanism of these reactions has been elucidated by investigations with isotopically labeled compound~1~~J.
In the following sections the preparative uses of flash thermolysis will be demonstrated by selected examples, though
the list of flash thermolyses given here is not claimed to
be comprehensive.
Because of the short contact times, appreciably higher temperature are required in flash thermolyses than in thermolyses
effected in solution or in the stationary gas phase. For example,
whereas 1,2,3-benzothiadiazole in solution is completely
cleaved at 200°C with evolution of N21231,in the gas phase @H=N-I&Tos
(3)
(41
with a contact time of 10-3s a temperature of 850°C is
required for quantitative fission["J. Bond fissions leading to
L (7)
CH2
the formation of nonstabilized radicals generally require temperatures in excess of 1ooO"C. In the fission of methyl iodide
into methyl and iodide radicals a conversion of 20% is achieved
only above l100°C[241.The temperatures are lower when
Phenylnitrene, formed as the primary product in the flash
molecules with an even number of electrons are formed by
thermolysis of phenyl azide, stabilizes itself in a manner analothe thermolysis, as is the case in retro-Diels-Alder reactions
gous to that observed with phenylcarbene: a cyclopentadieneor when small stable molecules such as Nz, CO, COz, SOz,
carbonitrile is found as the main product[33-36,441. Wentrup
or HX are expelled.
et al. also investigated the hetarylnitrenes formed in the flash
thermolysis of annelated tetrazole derivatives[37.looJ.
4.1. Flash Thermolysis with the Removal of Nitrogen
J
P+ WZCH
4.1 .I. Flash Thermolysis of Diazoalkanes and Azides
Because of their relatively long lives in the gas phase, the
carbenes formed as the primary products in the flash thermolysis of diazoalkanes stabilize themselves by rearrangement[lo01.For example, whereas the Wolff rearrangement does
not occur on thermolysis of diazomalonic ester (I ) in solution,
it is observed on flash thermolysi~[~~1.
H3COOC\
,C=N=N
H3COOC
-
Flash thermolysis of the sulfonyl azide (8) gave surprising
results: whereas at 300°C, as in thermolysis in solution, the
formation of the thiazine derivative ( 9 ) predominated, at
650°C a 65 % yield of the cyclopentapyridine derivative ( I 0)
was obtained[3s].Compound ( 9 ) is formed by an insertion
420 "C
(1)
These considerations have found application in the preparation of [7]paracyclophane (2)[261: the salt of the toluenesulfonylhydrazone affords first the diazo
which
then decomposes in the gas phase with loss of nitrogen.
Angew. Chem. Int. Ed. Engf. 16,365-373 (1977)
R
13%
reaction of the nitrene formed as an intermediate. For the
formation of (10) the authors assumed addition of the nitrene
to the benzene ring with subsequent release of SO, and rearrangement.
4.1.2. Flash Thermolysis of Triazoles and Thiadiazoles
Flash thermolysis of IH-1,2,3-triazole derivatives has been
thoroughly investigated by Rees et ul.[39-411. 2H-Azirines,
indole derivatives,ketene imines, and nitriles could be isolated,
depending on the nature of the substituent and the pyrolysis
conditions. According to the experimental data available, flash
thermolysis of 1,2,3-triazolevery probably involves the antiaromatic 1H-azirine as an intermediate. Thus, flash pyrolysis
of the isomeric triazoles ( 1 1 ) and (12) gives in each case
the same mixture of products (13) to (16) together with
benzor~itrile[~~].
thermolysis of the thiadiazoles is carried out in a high-boiling
solvent then only the secondary products derived from the
thioketenes can be isolated[s2].
Flash thermolyses of benzotriazole[' '1 and benzothiadiazole[I7]have also been investigated. In agreement with expectation, the ring-contraction products cyclopentadienecarbonitrile and fulvene-6-thione, respectively, are produced.
4.1.3. Flash Thermolysis of Pyridazine and Triazine Derivatives
The pyridazine derivative ( 1 7 ) loses nitrogen at 900°C
and the diazabiphenylene (18) is formed by ring contracti0n[~~1.
The diazanaphthoquinone (20) formed as an intermediate
in the flash thermolysis of (19) behaves in the same way1461,
the cyclobutabenzenedione (21 ) being isolated as the product
f
H5C61
H3C
"
1
~
L
n
R = N a
R-CH=CH,
+
0
(16)
CsHsCN
Similar results are obtained on using isotopically labeled
compounds[41].
On flash thermolysis phenyl-substituted 1,2,4-triazolesyield,
surprisingly, isoindoles, but the reaction becomes understandable if a primary 1,3-shift of the phenyl group is assumed[421.
P
N
900 "C
0.04 Torr
in 88 % yield. Compound (21) can also be prepared, but
in a lower yield, by flash thermolysis of the sulfoximide (22)r'I.
Nonannelated pyridazines such as (23) fragment into acetylene derivatives on flash thermoly~is[~~'];
since no symmetri-
Flash thermolysis of 1,2,3-thiadiazolesleads to good yields
of thioketenes, a class of compounds that with a few exceptions
was previously unknown['7' 431.Here the preparative advantage of flash thermolysis is particularly evident, since if the
~ & 9,&
\
0.04 Tarr
0
' '3;"
(191
60-70%
368
Anyew. Chem. I n t . Ed. Engl. 16,365-373 (1977)
cally substituted acetylene is formed, it is impossible that
the reaction should proceed through an intermediate cyclobutadiene or tetrahedrane['071.
4.2. Flash Thermolysis with Removal of COz, CO, SOz, or
HX
4.2.1. Flash Thermolysis of Lactones
680-725"C
0.01 Ton
Y
70-80%
The lactone (28) decomposes on flash thermolysis into
carbon dioxide and the allenic derivative (6); a certain amount
of the cyclopentadienylacetylene (7) is also produced as a
secondary product from (6)['03 "I. The reaction can be controlled in such a way that it serves as a preparative method
for the allene (6)[''1.
In contrast, on flash thermolysis of the triazine ( 2 4 ) an
azacyclobutadiene could be isolated for the first time, namely
tris(dimethy1amino)aete (25)r4'1, in which the amino groups
contribute in a special way to stabilization of the molecule[481.
700-750 "C
0. I Tarr
OC=CHz
@-CSCH
The pyridine nitrene ( 3 0 ) is similarly formed from the
oxadiazolone derivative (29) and, as expected, stabilizes itself
by the formation of mixed pyrrolecarbonitriles and by ring
opening155.1121
Similarly, benzotriazines afford benzazete, which can also be
isolated in
and whose structure had been proved
by a series of interesting trapping
Hedaya et al. studied the flash thermolysis of the lactone
(31)[s61. At 845 "C this smoothly extrudes COz with the formation of cyclobutadiene which on working-up dimerizes into
syn-tricyclooctadiene (32).
However, unlike benzotriazine, the pyridazinotriazine (26)
on flash thermolysis affords benzonitrile and a diacetylene
derivative. The authors postulate the formation of dehydropyridazine as an intermediate in this reactionf53!
Attempts to prepare cyclobutadiene by flash thermolysis
of the cyclobutadiene(tricarbony1)iron complex have so far
been unsuc~essful['~~
581. Ready and smooth loss of carbon
dioxide was observed on flash thermolysis of the peroxide
(33)[591.
- [o]-
*
&
3-5
Tort
0
Argon
2 1%
(33)
The readily accessible 1,2,4-triazines (27) also decompose
on flash thermolysis; they yield dehydrobenzene, nitrile, and
nitrogenLs '1.
Angew. Chrm. Int. Ed. Engl. 16,365-373 ( 1 9 7 7 )
4.2.2. Flash Thermolysis of Acid Anhydrides
Cyclic acid anhydrides, e. g. succinic or maleic anhydride,
split off carbon dioxide and carbon monoxide on flash thermolysis with the formation of olefins or acetylenes, respectively[loll. This reaction has been used especially for the preparation ofarynes and hetarynes (Table l), which are either trapped
or are isolated as their dimersf6'. 'I. Dehydropyridine
stabilizes itself by ring opening to an acetylene derivative[621.
The reaction does not, however, always proceed so smoothly.
In some cases only removal of carbon dioxide can be
achieved[67.681.
3 69
Table 1. Flash thermolysis of acid anhydrides.
Starting material
Ref.
Intermediate
Rg)$
occurs as an intermediate[70-721.However, direct proof is
still lacking. Indantnone (35) splits off CO in a smooth
reaction and gives biphenylene in a yield that amounts to
40 % after working u$733 * * '1.
[60, 61, 63, 1061
0
4.2.4. Flash Thermolysis of Carboxylic and SulfonicAcid Derivatives
11031
On flash thermolysis the methanesulfonic acid derivatives
(36) and (37) give a highly reactive compound to which
the structure of a sulfene could be assigned on the basis
7s1. Sulfenes
of trapping reactions and the IR
<
(36) Cl-SO2-CHt-COOH
0
rn
(37) H3C-S02-N
11031
0
4
c
0
have in fact been postulated as intermediates in previous
reactions, but so far their existence has not been demonstrated
directly.
Sulfinecould be obtained in the same way from methanesulfinyl chloride and other
a$
0
600 "C
H3C-SO-C1
&
+ HC1
HZC=SO
A method similar in principle to the above has long served
for making reactive ketenes on a preparative scale[771.
0
_ _-_
-
9 9
[a] Products isolated.
H3C
550°C
H3C-CH2-C-O-C-CH2-C
H3
0.01 Ton
Hedaya tried to prepare triafulvene (34) (unknown until
recently) by this reaction, but was able to isolate only a
mixture of acetylenes, whose composition could not be used
Lo
H,C=S02
[ ]
720°C
r-1~-3s
~
H2 C=C H-C
-+
>-c=o
H
90%
The fission of the ester (38) into isoindole, methanol, and
is a related reaction. A further interesting
carbon
CH
- 550°C a
HCECH
-
a
H
0.01 Tori
CH3-CE CH
(34)
OCH,
to establish with certainty the intermediate occurrence of
(34)[691.
(38)
reaction of a carboxylic acid derivative is the formation of
aromatic nitriles by flash thermolysis of t h i o f ~ r m a n i l i d e s ~ ~ ~ ~ .
4.2.3. Flash Thermolysis of Quinones
On flash thermolysis, quinones lose one or two molecules
of carbon monoxide[' 6].The cyclopentadienone arising from
the o-quinone at 550°C has been identified by Chapman by
means of IR spectros~opy['~!
S
H-t-NH-Ar
700°C
NC-Ar
65-100%
Trahanousky obtained the very unstable methylenecyclobutenone (39) by flash thermolysis of the furan derivative (40);
he assumed that propadienylketene occurred as an intermediate["].
0
At higher temperatures two molecules of CO were removed,
and it was concluded from the products that cyclobutadiene
@
0
(35)
370
[4-m
2EL
0.2 Ton
40%
Fulven-6-one was demonstrated as an intermediate in the
flash thermolysis of a salicylic ester[". 821.
Quinone methides could be prepared in a related reaction
and were then examined by IR spectroscopyr83!
Angew. Chem. Int. Ed. Engl. 16,365-373 ( 1 9 7 7 )
Attempts to obtain oxirene by flash thermolysis of dibenzobarrelene oxide ( 4 5 ) ended in failure; the aldehyde ( 4 6 ) was
the main product formed at 550"C['04! However, pentatetraene and other sensitive olefins could be prepared smoothly
by this reaction" "I.
aoH
22-L
CHzOH
4.2.5. Flash Thermolysis of Diazabasketene
On conventional thermolysis in solution or in the gas phase,
diazabasketene (41), prepared as precursor of cubane in a
multistep reaction, gave only an indefinite product mixture
and not the expected cubane. Flash thermolysis of this compound (41) was investigated by he day^[^^]. At 560°C the
compound fragmented to hydrogen cyanide and a very labile
compound to which the structure of azocine ( 4 2 ) could be
assigned on the basis of spectroscopic findings and chemical
reactions; this product (42) is stable only below -50°C.
qN- Q+HcN
For the interesting reaction (41) -+(42) the course illustrated
has been proposed[84! Attempts to make (42) more easily
accessible by flash thermolysis of tropyl azide were unsuccess-
Unusual products are often obtained in the pyrolysis of
fluorinated organic corn pound^['^^^ 41.For example, in flash
thermolysis of the dimeric perfluorocyclopentadiene (47) the
retro-Diels-Alder reaction competes with cycloelimination of
difluorocarbenef"O, '''1.
(47)
Flash thermolysis of ally1 sulfides gives thiocarbonyl compounds in a reaction that is formally a retro-ene reaction[87.
In this way thiocarbonyl compounds that were previously
unobtainable, or obtainable only with difficulty, can be prepared by a relatively simple route: examples are thioacrolein,
monothiobiacetyl, and thiobenzaldehyde.
R&2
60W800"C
H
ful ; the azide decomposes under these conditions into hydrogen cyanide, benzene, and nitrogenL5'].
43. Retrodiene and -ene Reactions
The retro-Diels-Alder reaction is of preparative importance
in organic chemistry[' 051. If the conditions of flash thermolysis
are chosen for this reaction, then thermally very sensitive
products can be isolated. Thus, Vogel prepared cyclopropabenzene by flash thermolysis of the Diels-Alder adduct (43)Le51.
400°C
H3COOC
0.1 Torr
HsCOOC
4.4. Cleavage of "Dimeric" Molecules
An interesting example ofthis type of reaction is the synthesis
of the highly reactive methylpentalene ( 4 9 ) by flash thermolysis of the dimer (48), which in turn is obtainable by a
retro-Diels-Alder reaction of (50). The latter reaction proceeds
by way of methylpentalene (49). This pentalene derivative
(49) is stable essentially only below -140°C and at higher
temperature dimerizes instantaneously into (48). In spite of
its instability, it was found possible to measure the IR and
UV spectra of this compound, which is also of great theoretical
interestra91.
6
, -6
1
Another preparatively interesting reaction of this type is
the fission of the epoxide (44) into isobenzofuran and ethylene[861.
a
0.1 Ton
(44)
G
O + C,H4
100%
Angew. Chrm. int. Ed. Engl. 16,365-373 (1977)
+ H,C=CH-CH,
H
600°C
(43)
R\
H,C=s
(48)
>-140%
(49)
c
600°C
-
- C5Hb
\
(50)
The cleavage of diketenes into the monomers, which must
happen to thermally sensitive ketenes under the conditions
of flash thermolysis, is a further example of this type of reaction[gO].The thermally very unstable dimethylthioketene was
371
first obtained by flash thermolysis of the cyclobutanethione
(51 ) in 62 % yield[91].
Bismethylene-l,3-dithietanes,e. g. the bis benzhydrylidene
compound, which are also formally thioketene dimers, can
similarly be cleaved to monomers by flash thermolysid' ',1081.
In an interesting reaction, bicyclic trienes (60), e. g. cyclobutafuran, could be prepared from the three-membered ring
compounds (59)19', 991.
A reaction that is of interest both industrially and theoreti5. Final Remarks
cally is the fission of [2,2]paracyclophane into p-quinodimethane (52) whose IR and UV spectra were m e a ~ u r e d [ ~ * , ~ ~ ] .
Thermolabile thermolysis products cannot in principle be
The monomer (52) polymerizes at room temperature to a
isolated
by conventional pyrolysis techniques, but they can
polymer which has found industrial use.
be obtained, even on a preparative scale, with the aid of
flash thermolysis. This has led to the first isolation of many
compounds, some of which were also of theoretical interest.
Use of this technique is still relatively complicated, and
the amount of reacting substance is generally limited. Each
case should therefore be examined carefully to determine the
reaction conditions and the requirements essential for the
solution of the problem.
Apparatus for flash thermolysis is now available commerBy suitable experimental arrangements it proved possible
cially, removing an important obstacle to the use of this
to deposit (52) on the surface of an article, so that the latter
method, and it can thus be expected that chemists will in
became covered by a
future make increasing use of this technique for the preparation
and study of reactive compounds.
4.5. Rearrangements
Rearrangements have also been studied under the conditions
of flash thermolysis, although in this type of reaction conventional thermolytic techniques are sufficient in many cases.
~ ~ ]a$Isoxazoles ( 5 3 ) rearrange at 960°C to ~ x a z o l e s [and
epoxy-silanes ( 5 4 ) are converted into enol ethers[951.
(53)
(54)
The sulfone ( 5 5 ) reacts on flash thermolysis by ring expansion, yielding (56)[96*14].
By flash thermolysis at 550°C the cyclization product ( 5 8 )
is obtained from the tetracyclic starting material (57)19".
312
Received: October 26, 1976 [A 170 [El
German version: Angew. Chem 89,377 (1977)
Translated by Express Translation Service, London
E . H e d a y a , Acc. Chem. Res. 2, 367 (1969).
[2] P. de Mayo, Endeavour 31, 135 (1972).
[ 3 ] H . J . Hageman, E . M'iersum, Chem. Br. 9 , 206 (1973).
[4] D. M . Golden, G. N . Spokes. S. W Bensnn, Angew. Chem. 85, 602
(1973); Angew. Chem. Int. Ed. Engl. 12, 534 (1973).
[5] M . Knudsen, Ann. Phys. (Leipdg) 28, 75, 999 (1909).
[6] S. Dushmori, J . M . Lafferfyr Scientific Foundations of Vacuum Technique. 2nd Edit., Wiley, New York 1962.
171 C . H . De Puy, R . W King, Chem. Rev. 6 0 , 431 (1960); M . Hanack,
W Kraus in Houben-Weyl-Miiller: Methoden der Organischen Chemie. 4th Edit.. Thieme, Stuttgart 1972, Vol. 5/1b, p. 105.
[S] D. J . Andcrsoiz, D.C . Horwell. E . Stanton, T L. Gilrhrisi, C . W Rees.
J. Chem. SOC. Perkin 1 1 9 7 2 , 1317.
191 J . A . Oliver, P. A. Ongley, Chem. Ind. (London) 1965, 1024.
[lo] U . E. Wiersum, 7: Niewenhuis, Tetrahedron Lett. 1973, 2581.
[ I l l R . F . C. BrOM%, R. K . Solly, Aust. J. Chem. 19, 1045, 1052 (1966).
[I21 W S. Trahunotsk~,C . C . Ong, J . G. Pataky, F. L. Weitl, P . W Mullen,
J . C . Clnrdy, R . S . Hansrii, J . Org. Chem. 36, 3575 (1971).
1131 E . Heduya, D . McNeil, J . Am. Chem. SOC.89, 4213 (1967).
[I41 J . F. King, P. dr Mayo, C . L. Mclntosh, K . Piers. D. J . H . Smith,
Can. J. Chem. 48, 3704 (1970).
[IS] G. Seyhold. U . Jersak, Chem. Ber. 110. 1239 (1977).
[I61 Manufacturer: Otto Fritz GmbH (Normag?,
Feldstr. I ,
D-6238 Holheim.
1171 G. Seyhold, C . Hrihl, Chem. Ber. 110, 1225 (1977).
[I81 J . M . Pearson, H . A . Six, D . J . Willrams, M . Levy, J . Am. Chem.
SOC.93, 5034 (1971).
[I91 0. L. Chapman, C . L . M c l n f o s h , Chem. Commun. 1971. 770.
[20] J . S. Ogderi, J. J. Turner, Chem. Br. 7 , 186 (1971).
[21] H . F . Griirzmachrr, J . Lohmann, Justus Liebigs Ann. Chem. 705, 81
( I 967).
[I]
Aiigew. Chrm. lnr. Ed. Engl. 16, 365-373 ( 1 9 7 7 )
1221 F . P. Lossing in C . A . McDowell: Mass Spectrometry. McCraw-Hill,
New York 1963. p. 442.
[23] R . Huisgen, V Weberndiirfer, Experientia 17, 566 (1961).
[24] S. W. Benson. C. N . Spokes, J. Am. Chem. Soc. 89,2525 (1967).
1251 M. Jones, D. C. Richardson, M . E. Hendrick, J. Am. Chem. SOC.93,
3790 (1971).
1261 A. D. Wo/L V. V Kane, R . H . Leuin, M . Jones, J. Am. Chem. SOC.
95, I680 ( I 973).
[27] G. M . Kaufman, J . A . Smith, G. G. VanderStouw, H . Shechter, J. Am.
Chem. SOC.87,935 (1965).
[2X] R. C. Joines, A . B. Turner, W M. Jones, J. Am. Chem. Sac. 91, 7754
(1969): C. Wentrup, K. Wilcreck, Helv. Chim. Acta 53, 1459 (1970).
[29] P. 0. Schiasel. M. E. Kenr, D. J . M c A d o o , E. Hedaya, J. Am. Cheni.
SOC.92, 2147 (1970).
[30] W J . Baron, M. Jonec, P. P. Guspar, J. Am. Chem. SOC. 92, 4739
(1970).
[31] R . Gleiter, W Rettig, C. Wentrup, Helv. Chim. Acta 57, 2111 (1974).
[32] E. Hedapa, M. E . K e n t , J. Am. Chem. SOC.93, 3283 (1971).
[33] W D. Crow, C. Wentrup, Tetrahedron Lett. 1967, 4379.
1341 E. Hedaya, M. E. Kent, D. W McNeil, F. P. Lossing, 7: McAllisrer,
Tetrahedron Lett. 1968, 3415.
[35] W D. Crow, C. Wentrup, Chem. Commun. 1968, 1026.
[36] C. Thhaz, C. Wentrup, J. Am. Chem. SOC.98, 1258 (1976).
[37] R. Harder, C. Wenrrup, J. Am. Chem. SOC.98, 1259 (1976).
[38] R . A . Abrumuaitch, W D. Hulcomb, J. Am. Chem. SOC.97, 676 (1975).
[39] D. J . Anderson, T 1.Gilchrist, G . E . Cymrr. C. W Rees, Chem. Commun.
1971, 1518; 7: L. Gilchrist, G. E. Gymer, C. W Rees, ibid. 1971, 1519;
J . Chem. SOC. Perkin I 1973, 555.
[40] 7: L. Gilchrist, G. E. Gymer, C . W Rees, J. Chem. SOC. Perkin I
1975, 1.
1411 7: L. Gilchrisr, C. W Rees, C. 7homas. J. Chem. SOC. Perkin I 1975,
8.
[42] 7: L. Gilchrisr, C. W Rees, C . Thomas, J. Chem. SOC.Perkin 1 1975,
12.
[43] G. Sephold, C. Heibl, Angew. Chem. 87, 171 (1975); Angew. Chem.
Int. Ed. Engl. 14, 248 (1975).
[44] W D. C r o w . M. N . P a d d e w R o w , Tetrahedron Lett. 1972. 2231.
[45] J . A . H . McBrrde, J. Chem. SOC.Chem. Commun. 1974, 359.
[46] D. L. Forsrer. 7: 1. Gilchrist. C. W Rees, E. Sranron, Chem. Commnn.
1971. 695.
1471 G. Sryhold, U . Jersak, R . Gonipper, Angew. Chem. 85, 918 (1973);
Angew. Cheni. Int. Ed. Engl. 12, 847 (1973).
[48] H . L’. Wagner, Angew. Chem. 85, 920 (1973); Angew. Chem. Int.
Ed. Engl. 12. 848 (1973).
[49] B. M. Adger, M. Keating, C. W Rees, R . C. Sturr, J. Chem. SOC.
Chem. Commun. 1973, 19; B . M. Adger, C. W Rees, R . C. Storr,
J. Chem. SOC.Perkin I 1975.45.
[50] C. W Rees, R . Somanutlmi, R . C . S t o w , A . D. Woolhouse. J. Chem.
SOC. Chem. Commun. 1975, 740; 1976, 125.
[5l] G . Sri-hold, unpublished results, Munchen 1973-1974.
[52] H . Staiidingrr, J . S i e g w r r , Ber. Dtsch. Chem. Ges. 49, 1918 (1916).
[53] 7: L. Gilchrisr, G. E. Gynier. C. W Rees, J. Chem. SOC.Chem. Commun.
1973. 819; J. Chem. SOC.Perkin 11975, 1747.
[54] C. W w r u p , P . Miiller. Tetrahedron Lett. 1973, 2915.
[55] R . F . C. Brown, R . J . Smith, Aust. J . Chem. 25, 607 (1972).
1561 E. H e d a r . ~R, . D . Miiller, D. W McNei1, P. F. D’Anqdu, P . 0. Schissel,
J . Am. Chem. SOC.91, 1875 (1969).
[57] P. H . Li, H . A. McGee, Chem. Commun. 1969, 592.
[ S S ] E. Herluw, 1. S. Krrrll. R . D. Miller, M. E. Kent, P. F. DAngelo,
P. Scbissel, J. Am. Chem. SOC.91, 6880 (1969).
[59] G. Witrig, H . F. E M , Justus Liebigs Ann. Chem. 650, 20 (1961).
[60] E. K. Fields, S . Mr),erson. Adv. Phys. Org. Chem. 6, I (1968).
[61] E. K . Fields. S . Meperson, Chem. Commun. 1965, 474.
1621 M. P. Cut's, M . J . Mirchell, D. C. DrJongh, R . Y. VunFossen, Tetrahedron
Lett. 1966, 2947.
[63] R . F. C. Brown, D. C: Cardner, J . F. W McOmie, R. K. Solly, Chem.
Commun. 1966, 407.
E. K . Fields, Chem. Commun. 1966, 275.
1641 S. MPJ~).SON.
[65] M . G. Reinecke, J . G. Newsom, J. Am. Chem. SOC. 98, 3021 (1976).
[66] R . J Spangler, J . H . Kim, Tetrahedron Lett. 1972, 1249.
. ~ ,Braoo. Tetrahedron Lett. 1970, 4631.
1671 M. P . C L I L L.
[68] 0. A . Mamer. F . P. Lossing, E. Hedayn, M. E. Kent, Can. J. Chem.
48, 3606 (1970).
[69] I . S. Krull, P. F . D’Angelo, D. R. Arnold, E. Hedaya, P. Schissel,
Tetrahedron Lett. 1971, 771.
[70] H. J . Hoqrman, U . E. Wiersutn, Tetrahedron Lett. 1971, 4329.
A I I ~ E MClier?i.
’.
lnt. Ed. EuqI. 16, 365-373 (1977)
[71] H . J . Hugeman, U . E. Wiersuni, Chem. Commun. 1971. 497; Angew.
Chem. 84, 314 (1972): Angew. Chem. Int. Ed. Engl. 11, 333 (1972).
1721 P. de Champlain, P. d<, Mayo, Can. 1. Chem. 50,270 (1972).
[73] R . F. C. Brcti~n,R . K . Solly. Aust. J. Chem. 19, 1045 (1966).
1741 J . F. King, P. de Mayo, D. L. Verdun, Can. J. Chem. 47. 4509 (1969);
J . F . King, R. A. Mart!,. P . de Muyo. D. L. Verduu. J. Am. Chem.
SOC.93, 6304 (1971).
1751 19:J . Mijs. J . B. Reesink, U . E. Wiersuin, J. Chem. SOC.Chem. Commun.
1972,412.
[76] E. Block, R . E. Penn, R . J . Olsen, P. F. Sherwin, J . Am. Chem. SOC.
98, 1264 (1976).
[77] A. D. Jenkins, J. Chem. SOC 1952, 2563.
[78] R . Bonnett, R . F. C. Brown. J . Chem. SOC. Chem. Commun. 1972,
393.
1791 R. F . C. Brown, J . M. Coddington. I . D. Rae, G. J . Wright. Aust.
.I_Chem. 29. 931 (1976).
[SO] W S. Puhanocsky, M. G. Park, J. Am. Chem. SOC. 95, 5412 (1973).
[ E l ] H. F . Grltzinncher, J . Hubtier. Justus Liebigs Ann. Chem. 748. 154
(1971).
[82] H . F . Griirzmucher, J . Hiihner, Justus Liebigs Ann. Chem. 1973, 793.
[83] C. L. Mclutosh. 0. L. Chopman, Chem. Commun. 1971, 771.
[84] D. W McNeil, M . E . Kent, E. Hedaya, P. F. D’Angelo. P. 0. Schissrl,
J. Am. Chem. SOC.93, 3817 (1971).
[85] E. Vbgel, W Grimme. S. Korte, Tetrahedron Lett. 1965,3625; S. E~rrnimoto.
R . Schajer, J . lppen, E. Voyel, Angew. Chem. 88, 643 (1976); Angew.
Chem. Int. Ed. Engl. 1 5 , 613 (1976).
[86] U . E. Wiersurn, W J . Mib, J . Chem. SOC. Chem. Commun. 1972,
347.
[87] H . C . Giles, R. A. Marry, P. de Mayo. J. Chem. SOC.Chem. Commun.
1974, 409.
[88] H . G. Gilts, R . A. Morry, P. de Mayo. Can. J. Chem. 54, 537 (1976).
[89] R . Bloch, R. A. Marrj. P. d c , Mayo, J. Am. Chem. SOC. 93, 3071
(1971); Bull. SOC.Chim. Fr. 1972, 2031.
[90] Honben-Weyl-Miiller: Methoden der Organischen Chemie. 4th Edit.
Thieme, Stuttgart 1968, Vol. 714. p. 80.
,1913 G. Seybold, Tetrahedron Lett. 1974, 555.
[92] W F . Gorhain. DBP 1085673 (1960), Union Carbide.
1931 W F. Goriiuin, J. Polym. SCI.A-I 4, 3207 (1966).
[94] G. L. Aldous, J . H . Box,ie. M . J . Thompson, J . Chem. Soc. Perkin
11976, 16.
[95] P. F. Hudrlik. C . N. Wan, G. P. Withers, Tetrahedron Lett. 1976,
1449.
[96] J . F . King, K . Piers, D. J . H . Smith. C. L. M c l n t o s h , P . d e Muyo,
Chem. Commun. 1969, 31.
[97] R . Bloch. M. Borrolussi, Tetrahedron Lett. 1976, 309.
[98] M . B. D A m o r e , R . G . Bergman, M . Kenr, E. Hedayu, J . Chem. SOC.
Chem. Comniun. 1972, 49; K . P. C. Vollkardt. R. G. Brrgmati. J.
Am. Chem. SOC.95, 7538 (1973).
[99] K. P. C. Vollhardt, Top. Curr. Chem. 59, 113 (1975).
[lM] C. Wenrrup, Top. Curr. Chem. 62, 173 (1976).
[ l o l l F. 0. Rice, M. 7: Murphy, J. Am. Chem. SOC.64, 896 (1942).
11021 F . 0. Rice, P . M. Ruoff, E. L. Rodowskas, J. Am. Chem. Soc. 60,
955 ( 1 938).
[I031 E. K . Fields, S . Meyerson, J. Org. Chem. 31, 3307 (1966).
11041 E . Lenurs, C. Morrison, J . F d f o r d , Chem. Ind. (London) 1976, 488.
[I051 H . Kwart, K . King. Chem. Rev. 68, 415 (1968).
[I061 D. V. Gardnw, J . F. W McOmie, P. Alhriktseii, R . K . Harris, J . Chem.
SOC.C 1969, 1994.
[I071 R . D. Chambers. M. Clark. J . A . H . McBride, W Kennerll, R. Musgruce.
K . C. Srirustaou. J . Chem. SOC.Perkin I 1974, 125.
[I081 M. S. Rausch, J. Org. Chem. 35, 3470 (1970).
[I091 K E. Plutanoc. G. G. Yukobson. Synthesis 1976,374.
[I101 R . E . Banks, A. C. Harrison. R . N. Hpsx4dine, J. Chem. SOC.Cl966,
2 102.
[ I l l ] C. Wentrup. W D. Crow, Tetrahedron 26, 3965 (1970).
[112] The flash thermolysis of 4-phenyloxydiazolones leads to indazoles.
W. Reichen, Helv. Chim. Acta 59, 1636 (1976).
11131 R . W Hoffmanri, Angew. Chem. 83, 595 (1971): Angew. Chem. Int.
Ed. Engl. 10, 529 (1971).
[I 141 R . N . Warrener, E. E. Nunn, M. N . Paddull-Row. Tetrahedron Lett.
1976, 2639.
[I151 J . L. Ripoll. J. Chem. SOC. Chem. Commun. 1976. 235; Bull. SOC.
Chim. Fr. 1974, 2567.
[ I 161 The flash thermolysis of some quinone-like compounds has recently
been reported: G. Schaden, Angew. Chem. 89, 50 (1977): Angew.
Chem. Chem. Int. Ed. Engl. 16, 50 (1977).
[117] A . Morrineau. D. DeJungh. Can. J. Chem. 55, 34 (1977).
313
Документ
Категория
Без категории
Просмотров
0
Размер файла
758 Кб
Теги
compounds, thermolysin, flash, organiz
1/--страниц
Пожаловаться на содержимое документа