Study of the reactivity of alkenylcyclopropanes by model reactions

2164

I . S . LISHANSKIIet al.

tion w i t h respect to m o n o m e r a n d catalyst, t h e reaction r a t e a n d t h e a c t i v a t i o n e n e r g y are s t r o n g l y d e p e n d e n t on t h e n i t r o m e t h a n e c o n c e n t r a t i o n a n d on the reaction temperature. (2) I t has been f o u n d t h a t the r a t e o f t e r m i n a t i o n of t h e growing p o l y m e r i c cation is r e d u c e d w i t h a rise in the dielectric c o n s t a n t of t h e m e d i u m , a n d t h e m o l e c u l a r weight of p o l y s t y r e n e is increased to p r a c t i c a l l y 43,000. This molecular w e i g h t has n o t p r e v i o u s l y been o b t a i n e d in t h e p o l y m e r i z a t i o n o f s t y r e n e b y a cationic m e c h a n i s m .

Translated by R. J. A. I-IENDRY REFERENCES 1. A. F. NIKOLAYEV, K. V. BELOGORODSKAYA and Ye. M. BABUSHKINA, Zh. Prild. Khim. 41: 1865, 1968 2. D. C. PEPPER, Trans. Faraday Soc. 45: 404, 1949 3. V. V. KORSHAK, Metody vysokomolekularnoi organicheskoi khimii (Methods of High Molecular Weight Organic Chemistry). Publ. by AN SSSR, p. 349, 1953 (In Russian) 4. P. VATSULIK, Monomer chemistry, Vol. 1, p. 684. Forgein Lit. Pub. House, 1960 5. P. I. VOSKRESENSKII, Tekhnika laboratornykh rabot (Laboratory Experiments and Methods). p. 459, 466, Moscow, 1962, 6. J. J. THROSSELL, S. P. SOOD, M. IZWARK and V. 8TANNETT, J. Amer. Chem. Soc. 78: 1122, 1956 7. C. P. BROWN and A. R. MATHIESON, J. Chem. Soc., 3612, 1957 8. D. C. PEPPER, and P. I. REILLY, Proc. Chem. Soc., 200, 1961; J. Polymer Sci. 58: 639, 1962; Proe. Roy. Soc. 291: No. 1424, 41, 196~ 9. A. R. GANTMAKHER and 8. 8. MEDVEDEV, Zh. fiz. khim. 25: 1328, 1951 10. J. GEORGE and H. WECHSLER, J. Polymer Sci. 6: 725, 1951

STUDY OF THE

REACTIVITY BY MODEL

OF ALKENYLCYCLOPROPANES REACTIONS*

I. S. LISHAI~SKII, A . G . ZAK, N . D . VINOGRADOVA, A . M . GULIY~V, O . S . FOMINA a n d A. S. KHACHATUROV High Molecular Weight Compounds Institute, U.S.S.R. Academy of Sciences

(Received 27 July 1967) I s A previous i n v e s t i g a t i o n we established t h e possibility of c a r r y i n g o u t the free-radical p o l y m e r i z a t i o n o f some a l k e n y l e y c l o p r o p a n e (ACP) d e r i v a t i v e s , * Vysokomol. soyed. AI0: No. 8, 1866-1877, 1968.

Study of reactivity of alkenylcyclopropanes

2 ! 65

and the structure of the resulting polymers showed that the process takes place through the opening of both double bond and ring. I t was suggested that in this case there is a two-stage process of isomerization, the first of these stages being the attack of a radical at the double bond to form a cyclopropylcarbinyl radical which in the second stage isomerizes with ring opening [1]. This suggestion was confirmed b y a study of the polymerization kinetics, and b y determining the structure of the polymer chain [2]. In view of the considerable interest attached to the new type of polymer formed in this type of process we studied the behaviour of a series of A 0 P in reactions of free-radical addition of thiophenol to determine the relationship between the structure of these compounds and the reactivity of the double bond, and also between their structure and isomerizabflity with ring opening. We investigated the folloiwng series of compounds synthesized mainly b y the addition of carbenes to conjugated dienes [3] (Table 1)* As has already been shown [4] the reaction under investigation proceeds through a two-stage isomerization mechanism, the first stage being the formation of a cyclopropylcarbinyl (CPCR) type adduct-radieal C6HsSH+RI -~ C,H~S.+RiH I k~da I . I CeHbS--C--C--C--C((CPCR) ~+

I

V

c

\

~+J.

~r I

I

I

I

V

\

c

kisom

C6H6S--C---C~---C--C--C" I

I

I

I

I

I

I

I

I

CeH~SH ~ kpri 1

CaHsSH ~ kpri I

I

I

I

I

C6HsS--C---C=C--C---C--- + CeH~S" CoH~S--C--C---C---C~/ I

1

I

Adduct A

Adduct B

V

c

\

-bC6HsS"

The reaction of thiophenol addition was selected because it was necessary first of all to prevent any possibility of oligomer formation, and secondly to enable the structure of adducts to be investigated b y NMR. The reaction with thiols has a number of advantages over the alkyl radical addition reactions wchich are often used to determine the relative reactivity of monomers. At the same time there would then be the possibility of kinetic complications since the reaction of free-radical addition of thiols to unsaturated compounds is theoretically reversible in the first stage owing to possible dissociation of the a d d u c t radical. * Substances I, II and III were supplied by O. M. NEFEDOV,whom the authors wish to thank.

2166

I.S.

LISHANSKII et ed.

The relative reactivities (RR) of two comparable compounds m a y be determined using the I n g o l d - S m i t h formula

RR

=

log [~0/[M]~ log [M']o/[M']t'

(I)

where [l~I]0and [M']0 are the initial,and [IV[]tand [M']t are the final concentrations of the compounds reacting simultaneously with the c o m m o n reagent. W h e n the investigated reactions are irreversiblethe experimentally obtained TABLE 1. INITIALA¥.1r~IN-YLCYCLOPROPANESOF FORMULA R'"CH=C--CR"--CR'"'R'

I

R I

II

III

IV

R R'

H H

CHs

R'" R"' R ....

H H H

H H H

C6H5 I-] H H H

COOCaH~ H H H

H

\

CH

/

V

H

VI

H

H

CONHz H H H

C00C2H 6 CH, H H 'Continuation)

VII R

H

R'

CONH, CHs

R" R"'

R ....

VIII

IX

H

H

H

CH8

CHN

COOC~H5 CHs

I~

H

X

XI

XII

XIII

H

CHs

H

H

I~

CI CH8

H1

H

COOC2H5 COOC2H~

H

H

H

CH3 H

tt H

C1

value of R R is the constant of relative reactivity l~el=kadd/k'ad a, where kaaa a n d k'add are rate constants for addition to the pair of compounds under investigation. L e t us consider the differential equations applicable in the reaction under review:

d[M]

dt : k a d d [~]

[CeHsS]--/CdJs[CPCR]

(2)

d [CPCR] dt :]~add [M] [CeHsS]--kmB [CPCR]---ki,om [CPCR]--kpr i [CPCR] [CeHaStt ]

(3)

As an approximation to the s t a t i o n a r y state d[CPCR] dt

=0

and [ C P C R ] =

kadd [M] [CeHsS ]

kj~om+kms+kpri [CeHsSH]

(4)

P u t t i n g (4) into (2) we have _ d[M~]= [M] [C6H5S]" kadd (kisom-~-kpri[CsHsSH]) dt kisom-[- kdis ~- kprI [CeHsSH]

(5)

Study of reactivity of alkenylcyclopropanos

2167

The ratio of depletion rates for the pair of monomers under investigation m a y be expressed as: ~]

] [M'] -- lCadd/kadd (ki,om~-lc~,+k,ri [C~H,SH]) (kisom~-kpr i [C,H,SH]) (6)

B y integrating this equation we obtain an expression for I~R reflecting the complex dependence on the thiol concentration. In a special case when only the reaction with one of the compounds is reversible, i.e. k~, ~ 0 a n d / c ~ ¢ 0, we get the expression

RR=kaad/k'ad d k;'°m % k ~ Wlc'Pri [C6HsSH] =kadJb'acld" C ki',om% IC'pri[C6HsSH]

(7)

As the thiol concentration increases the correction factor in (6) decreases, approaching unity when [CeHsSH] -> oo. Consequently the discovery of the dependence of the experimentally determinable value of R R on the thiol concentration shows that dissociation of the adduct-radical is an important factor. This relation, which was also linear, was found only in three pairs ( I - X I I , I I - X I I and X I - a - m e t h y l styrene) out of the total number of competing reactions for 10 pairs of monomers investigated b y us. I t m a y therefore be said that dissociation is substantial only for adduct-radicals formed from I, II and a-methyl styrene. In these cases b y extrapolating to 100% thiol concentration (~10mole/1.) we obtained R R values which m a y be taken as the relative constants, though of course they are slightly overestimated (Fig. 1). In all other cases the experimentally obtained values of R R are the direct values of kreI . These data are given in Table 2, showing the experimental error. To compare the reactivity of any pair of ACP there is no need to carry out competing reactions for all possible combinations; it is sufficient to get the data for a definite number of pairs in which all the compounds under investigation are each once represented, and then to carry out the appropriate conversions, e.g.:

kIX

bIV kXI ]gVI 0.315 × 3.37

bw

b xI

k w : k Ix

kv1 0.385 b Ix -- 0.315 × 3.37

0.385 -

-

'

0.365

These data also are given in Table 2. Note the quite permissible level of error and the satisfactory agreement between experiment and recalculation based on independent data. The relationships found between the reactivity of the double bond and the structure of the compounds under review m a y be explained on the basis of the well-known ideas about the increased reactivity of a double bond accompanying a higher degree of stabilization of the resulting radical. I t is known that a substi-

2168

I.S.

LISTrAZcS][II e* og.

tuent that is capable of stabilizing a free radical through conjugation or an induction effect also stabilizes the double bond as well, though always to a lesser extent [5]. For this reason the isopropenyl derivatives I I and X I are more reactive 2

RR

"-

3"0 z.o

~~3~

f.o~,"

,

a

0.2

0.3

-

f

o.#

[ RSH~fmole/L

FIO. l

Fig. 2

FIG. 1. Dependence of relative reactivity on thiol concentration: / - - p a i r X I I - I ;

2-- XII-II; 3-- IX-=-methyl styrene. FIG. 2. Chromatograms of mixtures of isomers of IV: /'--before experiment; 2--after reaction with thiophenol. than the vinyl derivatives I and IV (kII/kI----1.75; kxz/kzv=3.2), since the tertCPCR formed from II and X I through CeH'sS" radical addition is more stable than the fluoro-CPCR formed from I and IV. The lower reactivity of compounds with a methyl substituent in the ring, demonstrated with three pairs of compounds, m a y be attributed to difference in the effectiveness of hyperconjugation: H

CH,

C,H,S--C--C--C--C< H

R

C /~

H

C,HsS--C H

H

~--C--C( / ~/\

kvz/kIV=0.95

R

kzx/kxz----0.8 kXlII/kXII-~ 0.7

C /~

Here the effect is less considerable than that caused b y a methyl group at the double bond, and this is normal. According to a set of spectroscopic data [6] it is possible to have conjugation between a double bond and a three-membered ring, i.e. there is some analogy between the cyclopropane group and the olefin double bond. Conjugation is possible because the p-orbitals participating in the formation of two adjacent bent bonds in the ring overlap with the p-orbital of the nearest carbon atom of the unsaturated group. As for the capacity of a three-membered carbon ring to trans-

Study of reactivity of alkenylcyclopropanes

2169

fer conjugation like a double bond, there are so far no convincing data supporting this [7]. I t is therefore of special interest to discover the strong influence exerted by the ester group as substituent in the ring: k I V / ~ 3-8 and kxI/~I~-6.7. In our view this shows t h a t a three-membered carbon ring is able to transfer conjugation between a carbonyl group and an unpaired electron, resulting in considerable stabilization of CPCR. A comparison of esters and dihalogeno-derivatives shows that the reactivity of the former is greater: kIV/kXII~.2 and kVI/kXm~3.16. The probable reason for this is the smaller interaction of the 2p-orbitals of the ring with the 3p-orbital of the unshared pair of the chlorine compared with the interaction with the ~-orbital of the carbonyl group. In the case of one of the compounds investigated by us, compound IV, it was possible to identify stereoisomers [3] by the gas-liquid chromatography method, so that we were able to study the competing reaction of thiophenol addition to the mixture of cis- and trans-isomers in IV. I t was found that the cis-isomer has 1.3 times higher reactivity than the trans-isomer (Fig. 2). The analogous but unexplained fact of the higher reactivity of the cis-isomer was noted in [8] in the reaction of (2-phenylcyclopropyl)phenylcarbinol with tertiary butyl peroxide which proceeds with abstraction of a hydrogen from the carbinol C-atom to form a cyclopropylcarbinyl-type radical. The higher reactivity of the cis-isomer of IV m a y presumably be explained by the fact that along with the existence of a conjugated chain (carbonyl-groupring-double bond) it is possible in the case of esters of alkenylcyclopropanecarboxylic acids to have another mechanism of transfer of electron effects. Owing to the special features of the conformational behaviour of cyclopropane derivatives it is possible to assume that with the cis-isomer of IV there is overlapping of the p-orbital occupied by the unpaired electron with the orbitals of the carbonyl group by means of the molecular u-orbital or the p-orbital of the oxygen atom), which has the effect of further stabilizing the cis-form of CPCR. It was certainly shown by the electron diffraction method [9, 10] that in cyclopropyl methyl ketone, cyclopropyl carboxaldehyde, and the acid chloride of cyclopropenecarboxylic acid an s-cis-configuration is thermodynamically preferable, i.e. the position of the carbonyl group over the ring plane. If this also holds good in the case of the ester, i.e. IV, we obtain by calculation an interring nonbonded distance of C...O 2.4A. At this distance the overlap integral has the still considerable value of ~ 0-1 ft. An alternative explanation is possible based on the greater geometrical similarity of the structure of the transition state of CPCR isomerization to a homoallyl radical with the structure of the cis-form of CPCR. This problem is currently being studied with a number of compounds, but it must be said that the proposed explanation based on the transfer of electron effects is not theoretically new, since the literature contains descriptions of the solvolysis of bicyclic compounds and also of allyl and benzyl homologous series, when the

2170

T.S. LISHA~SKIIe~a/.

anomalously high reaction rates are explainable only by stabilization of the carbonium through overlapping with the spatially remote ~-electron system. and it is the peculiar geometry of these molecules which makes this possible [11], It follows from the general scheme of the reaction (page 2165) that the yields of adducts A and B are determined by the ratio of the rates of two competing reactions: the isomerization of CPCR, and the abstraction of a hydrogen from the thio] by CPCR. It is essential that the relation between this ratio and the structure of ACP should be elucidated, in view of its important bearing upon features of the free-radical polymerization of ACP, and in particular with a view to determining the ccmditions under which polymers with a poly(pentenamer) chain structure are formed [2]. To determine the ratio of adducts A and B we used the high resolution NMR method. Adducts of type A show in the NMR spectrum as signals in the region of 3=4.0-4.8, corresponding to protons of the double bond, and in the region of 3=6.2-0.75, corresponding to methylene protons in the --S--CH2--C=C--

I

I

group. In the ease of VIII, IX and XI signals in the region of 3=8.3-8.7 are also characteristic, and are related to the protons of methyl groups at the double bond. The presence of adducts of type B is shown by broad multiples in the region of 3=8-10, characteristic of protons of cyclopropane groups [12] and signals in the region of ~-----6.9--7.3 characteristic of methylene protons in the

I

CeHsS--CH~--C--[13]. Products of thiophenol interaction with all the ACP

I are given in Table 1, and according to elementary analysis correspond to an adduct composition of 1 : 1. In the NMR spectra of adducts from I V - X I I I there were only signals corresponding to structures of adducts of type A (on conducting the reaction at 80°). The products obtained under these same conditions from I, II and III, and also from VIII at --10 ° give rise to signals in the NMR spectra characteristic of both types of adduct: the ratio of the latter was determined from the areas of peaks for the corresponding signals (Table 3). The first fact of interest is the considerable number of adducts of type B formed from I, II and III (59, 43 and 35% respectively), which shows that there is close similarity between the values of the isomerization constant and the chain transfer constant. This was confirmed for reaction I with thiophenol where the gas-liquid chromatography method was selected for quantitative determination of the ratio of adducts A and B. On comparing the chromatograms (Fig. 3) it will be seen that the proportion of the B adduct increases with increase in the thiol concentration. This once again confirms the existence of a cyclopropylcarbonyl radical. But the main consideration is that it makes it understandable why it was for I and I I in particular that the dependence of relative activity on thiol concentration was discovered. In the case of I although the resulting CPCR is slightly stabilized by conju-

Study of reactivity of alkenylcyclopropanes

2171

gation with the ring, it is nevertheless the least stable in the investigated series, and so /cp~ for it must be highest. At the same time k~om must be the lowest, since isomerization causes loss of stabilization energy owing to transition from the secondary CPCR to the primary isomerized radical (not counting the loss of energy due to r~moval of ring stress). Consequently the position could be reached where the apparent total constant of CPCR consumption is reduced, and this is in fact the condition for the development of reversibility. CPCR formed from I I is more stabilized (tert.-radical) and this must lead to a lower value of/CprI compared with I. However, k~om also must be lower since isomerization involves transition from a tertiary to a primary radical. Since ~ 5 7 ~ of adduct A is formed, it must follow that kprI is reduced to a greater extent than ki~ m. Similar reasoning applies also to the reaction ofthiophenol with III: in this case CPCR is still more stabilized, and the constants of both competing reactions are reduced still further compared with I. The formation of ~ 6 5 ~ of adduct A also indicates that the stabilization of CPCR affects the value of kp~ more than k~om. I f we apply similar reasoning to reactions with the participation of ACP containing in the ring substituents capable of participating in conjugation we m a y predict preferential formation of the adduct of type A. Certainly the stabilization of CPCR reduces both kprI and klBom, although the considerable decrease in stabilization energy to 16 kcal/mole owing to the transition during isomerization from the hydrocarbon CPCR, for instance, to the acrylate CPCR, must lead to a great increase in kisom. Consequently the total apparent rate constant of CPCR consumption is high, and this precludes reversibility. In these cases the exclusive formation ofadducts of type A shows considerable predominance of' k~om over kpri. I t is interesting to note that during the U V irradiation of a solution of VI in thiophenol in the presence of benzoin at --10 ° a product containing a slight amount of adduct B was obtained, while at 80 ° only adduct A is formed in the presence of the dinitrile of azoisobutyric acid. I t follows that the activation energy for the isomerization of CPCR formed from VI is slightly higher than that for the abstraction of a hydrogen atom from the thiophenol b y the same CPCR. Therefore there is similarity between the capacity of a given substituent, whether at the double bond or in the ring, to increase the reactivity of the double bond in ACP, and its capacity to displace the reaction towards the formation of an isomerizcd product. The exclusive formation of A adducts in the reaction of I V - X I I I with thiophenol means that the free-radical polymerization of these compounds will result in substituted poly (pentenamers) of pure structure, since in these cases the reaction competing with the isomerization process will be the addition of CPCR to the monomer molecule, i.e. a process which we know has a lower rate constant than the reaction of chain transfer to thiophenol.

2172

I.S.

LIBHANSKII et (/J.

XTr C6H5Cl

~T B

2

1

2

~

FIG. 3

L

Fro. 4

FIG. 3. Chromatograms of mixtures of adducts of I with thiophenol. I : thiol ratio 1 : 1(1) and 1 : 10 (2); A - - a d d u c t A; B - - a d d u c t B. FIG. 4. Chromatograms for mixture of IVq-XII-l-chlorobenzene (internal stand a r d ) : / - - b e f o r e experiment; 2 - - a f t e r reaction with thiophenol.

EXPERIMENTAL* Pre~rc~ion and study of the structure o / A C P c~d~ct~ with thiophenol. The i n t e r a c t i o n of ACP with thiophenol (TP), molar ratio 1 : 2, was conducted in sealed ampoules in the absence of oxygen at 80 ° for 3 hr; initiator--0.5 wt.°/o of the dinitrile of azoisobutyric acid (I)AA). At the end of the reaction the excess T P was removed by washing with an Na2COs solution. I n all cases elementary analysis corresponded to a 1 : 1 adduct composition. The NMR spectra were recorded in CC14, at 20°; internal s t a n d a r d - - h e x a m e t h y l disiloxane, frequency, 60 mc/s (Varian A-60 N MR spectrometer). The ratio of adducts from I was also determined by gas-liquid chromatography; Tsvet-1 chromatograph, stationary phase, 8~o polyethylene glycol succinate on chromosorb W, temperature 120% Determination of relative reactivity of A C P in reactions o] ,free-radical addition, of thiophenol. The initial mixture containing the competing reagents and an internal standard (IS) were subjected to chromatographic analysis. Then using the injection method part of the mixture was placed in a counterflow of argon in a prepared ampoule, thiophenol was added, 0.025-0.05 mole ~o DAA, the mixture was cooled to --78 °, sealed and thermostarted, temperature 60q-0.1 °. I n studying the dependence of the relative reactivity on the concentration of T P either benzene (experiments 2,4 and 8) or chlorobenzene (exper. iment 6) were used as diluents. The time of the experiments was selected so t h a t the conversion of each of the compounds under review did not exceed 80~/o. The reaction was stopped by cooling to --78 °, the ampoule was opened, the contents diluted with benzene, the excess thiophenol was bound with lead carbonate, the mixture was centrifuged, and the translucent solution was subjected to chromatography. The procedure and the results of experiments are given in Table 4, and a sample chromatogram, in Fig. 4. Chromatography conditions: stationary phases 10% of dioctylsebacate on INZ-600 (ex* L. T. K u p r i y a n o v a took part in the experimental section.

I

.

.

.

.

.

X

xI

XII

XlIk

.

.

.

.

.

--

-.

0.45

0.26

IV

. . .

2. R E L A T I V E

.

. . .

--

. .

1.064-0.08

0-48

0-27

VI

REACTIVITY

. . . .

0-365

.

0"3854-0.015

0.18

0"10

IX

VALUES FOR

* Obtained b y extrapolating to [C~HsSH]=10 mole/1. (Fig. 1). 1" Obtained b y independent recalculation.

--

VI

IX

-

--

-

0-57

IV

II

II

TABLE

. .

3.80

1.38

.

1"444-0.06

0.66

0-38

X

.

0.216

0,82

0.297

.

0.3154-0.05

0.15

0"08

XI

7"0

1.57

5.72

2-08

2-24-0.06

1-04-0.1"

0"57±0"I*

XlI

1.464-0.09(1.52)t

10'65

2-3

8-7

3.16

3"354-0'1

1"52

0"85

XlII

ACP I N R E A C T I O N S OF F R E E - R A D I C A L T H I O P H E N O L A D D I T I O N

0-082

0.125

0.88

0.19

0.72+0.05*

0.41

0"43

0.13

0.072

a-Methyl styrene

tO

,~

~

~

~

o

2-78

~2.80

II R----CH3

III R = C,H 5

6.51; 6.57 d (99) 6.04; 6-24 d (162)

(155)

6.55; 6-64 d

-S-CHs-C=

8.3--8.8 q

8.8-9.15 tr

2.8

8.33 4 . 0 8 - 7 . 9 3 - 8 - 3 9 . 0 7 - 9 . 3 1 2.78 s 4.96 q tr (110) ~ 2 . 8 i 4 . 0 1 - 7-77-8.6 8.93-9.20 ~ 2 . 8 4"57 q tr d

4.53-4.82 (128)

-C=

7.63; 6-73 d (90)

6.96; 7.2 d

for - - S - - C H s - C - - group in adduct B: 127'2 ( 1 - z ) ~ 9 0 , l - - x =

l l R

I

(205)

6-92; 7-29 d

- S - C H ~ - C -I

~2.8

8.95 d

8.3-8.8 m

--4-

9.5-9.8 m

~9.6 m

9.4-9.9 m

-CH-CH

A,

of

44; 42;36 a v e r a g e - 41

adduct

Amount

1019 (n ~ 8)

63; 65 average-64

822 49; 66 (n~-- 11) a v e r a g e - 57

1588 (n=9)

into account)

protons

(n-number of

St°tal*

SPECTRA

90 =0"35, x=0-65 (x is the molar ratio of adduct A in the mixture). 127.~

7.7-8.6 m

6.8-7.1 m

8.3-8-8 m

--CH--

Structural elements of adduct B

162 for - - S - - C H s - - C = group in adduct A: 127-2x~162, x=1~-~.2=0.63

* Without protons of phenyl group. Abbreviation~: d--doublet; q--quartet; m - m u l t i p l e t ; s--singlet; tr -- triplet. E~am~/e of ¢ ~ / a t / o ~ : for c a ~ of III: 1 proton--101918~127;

2.80

I R=H

R

Structural elements of adduct A

C h e m i c a l s h i f t s (v) o f g r o u p s o f p r o t o n s a n d c o r r e s p o n d i n g a r e a s o f p e a k s

T A B L E 3. STRUCTURE OF ADDUCTS OF TItIOPHENOL W I T H ~, ~ I , AND I I I ACCORDING TO THE RESULTS OF ~ M I ~

"~

~

t~

1-4 0.55 0-55

XII

2-23 2.23

1.02

I I (b)

XII

6

1.2 1.2

(a)

I V (a) X (b)

5

(b)

1.4

IV(a)

4

1.4 1.4 1.4

X I I (a) X I I I (b)

3

1.6 1.6 1.6 0-62 0.75

I V (a) X I I I (b)

1.1

I V (b)

2

1-1

I X (a)

1

a

Reagents

Exp. No.

mixture,

0.352

0.77 0-77

1.30 1.30

1.25 0-49 0.49

1 25

1.40 1.40 1.40

1.10 1.10 1.10 0.43 0-53

1.20

1.20

b(exp.l-8); b~c(exp.9,10)

Initial

8.0

5-7 5.7

5.7 5.7

5"7 3.3 3.3

5.7

5.7 5.7 5-7

5-7 5-7 5.7 3.3 8.0

5-7

5.7

TP

mole/1.

Octane

Chlorobenzene

benzene

Chloro-

Decane

Toluene

benzene

Chloro-

IS

30

35 40

27 31

30 70 30

25

40 50 60

28 35 45 53 24

40

30

rain

tion time,

Reac-

3.5

2.28

1.68

2-39

3.18

1-75

a/IS

initial

Ratio

1.01

2.98

1.295

2.5

2-30

1.91

b/IS

--

--

--

--

--

--

c/IS

mixture

peaks

0.784

1.39 1.19 0.88

1.7 1.58 1.0 1.96 1.75

1.3

1.6

2.29

2.5 2.18

0.86 0.81

0.70

0-79 0-70

1.58 1.38

--

---

---

----

--

----

------

--

b/IS c/IS

0.33 0.60 0.0838 0-356 0.68 0.88

0.55

0.963 0.819 0.566

1.2 0.83 0.212 1.86 1.26

0.67

1.09

a/IS

final mixture

of areas of chromatogram

T A B L E 4. C O N D I T I O N S FOR CARRYING OUT COMPETING REACTIONS

average

average

average

average

1.14

1.4 1-32

1.46 1.42 1-44

2.12 2-28 2.2 2.20

2-2

1.55 1.38 1.45 1.46

3.3 3.5 3.25 3.33 3.30 3-35

2.5 average 2.6

2-67

RR(a/b)

RR

--

---

---

----

--

----

------

--

--

(a/c)

t~

~,

3"

10

9

8

X I I (a)

7

0.9 0-9

1.90 1.90

1"86 1.86 1.86 1.86 1.86

1.52 1.52 0.59 0.59 0.71

1-22 1-22 0.476 0.476 0.570 0-89 0.89 0.89 0.89 0.89

1.03 0.34 0.59

0.352 0.208

1.91 0.63 1.1

1.02 0.6

a

5.7 5.7

5"7 5.7 5.7 5.7 5-7

5.7 5.7 3.3 3.3 8.0

5.7 2-1 7.5

8.0 3.3

b ( e x p . 1-8); bq-c (exp. TP 9, 10)

• Obtained b y extrapolating to C6HsSH= 10 mole/l. (Fig. 1).

X I I (a) I V - t r a n s (b) I V - c / s (c)

I V (a) X I (b) V I (c)

~ - M e t h y l s t y r e n e (b)

I (b) I X (a)

I I (b)

Reagents

6

Exp. N0.

Chlorobenzene

Chlorobenzene

Chlorobenzene

Toluene

IS

Initial mixture, mole/1.

30 35

45 30 20 15 20

20 30 24 20 9

70 75 55

35 40

min

tion time,

Reac-

1.32

3.97

3.19

2.03

2.26

3.40

3.72

1.31

1.75 0-88 0-62 0.392 1.38

0.96 0.49 0.82 2.27 1.37 1.60 1-27 1.38

0.94 0.81 0.745

2.53 0.76 1.655 0.696

2.32 0.66 0-514 0.338 0.564 0.396 0.224

1-08 2.00 2.35 3.02 3"07

------

----

---

b/IS c/IS

final mixture

a/IS

5.27 i 0 - 8 3 5 1.22 1-71 2.35 0.47 2.14 0.483

--

--

a/IS b/IS c/IS

initial mixture

Ratio of areas of ehromatogram peaks

1.14 1.94

(a/b)

a v e r a g e 0-48

0.47 0.49

a v e r a g e 0.31~

0"314 0.31~

average 0.72 *

a v e r a g e 1.0 * 1-89 2-28 1.67 average 1.75" 1.22 1.29 1.95 1.94 0-85

R-R

------

----

--

(a/c)

average 0.36

0.36 0.36

average 1.06

1-0 1.18 1.04 1.06 1.02

RR

(Table 4 cont.)

t~

"

..1

Study of reactivity of alkenylcyclopropanes

2177

periments 1-6, Table 4), 10°/o of tricyanoethoxypropane on INZ-606 (experimeut 9), 11 ~o of polyethylenesuccinate on celite-545 (experiment 7). The relative reactivity was calculated using formula (1) in which instead of (Mi]0 and [Mi]t we put the ratios of the areas of the chromatogram peaks, corresponding to M~ and IS, i.e.

The a u t h o r s t h a n k B. A. Dolgoplosk for his c o n s t a n t interest in these e x p e r i m e n t s a n d for valuable observations d u r i n g t h e discussion.

CONCLUSIONS (1) A s t u d y has been m a d e of c o m p e t i n g reactions of free-radical a d d i t i o n of thiophenol to a n u m b e r o f a l k e n y l c y c l o p r o p a n e derivatives a n d the s t r u c t u r e of the resulting additives has been determined. (2) I t has been s h o w n t h a t there is similarity (of slope) b e t w e e n the capaci t y o f the s u b s t i t u e n t a t the double b o n d or in the ring a t the second C a t o m to a c t i v a t e the molecule in thiol radical addition, a n d the c a p a c i t y of the resulting c y e l o p r o p y l e a r b i n y l radical to isomerize. Translated by R. J. A. HENDRY

REFERENCES 1. I. S. LISHANSKII, A. G. ZAK, Ye. F. FEDOROVA and A. S. KHACHATUROV Vysokomol, soyed. 7: 966, 1965 (Translated in Polymer Sci. U.S.S.R. A7: 6, 1066, 1965) 2. I. S. LISHANSKII, A. G. ZAK, Ye. I. ZHEREBETSKAYA and A. S. KHACHATUROV, Vysokomol. soyed. A9: 1895, 1967 (Translated in Polymer Sci. U.S.S.R. A9: 9, 2138, 1967) 3. I. S. LISHANSKII, A. G. ZAK, I. A. DYAKONOV and T. G. ALIEVA, Zh. organich. khimii 1: 1189, 1965; I. S. LISHANSKII and A. B. ZVYAGINA, Zh. organich, khimii 4: 184, 1968 4. I. S. LISHANSKII, A. M. GULIEV, A. G. ZAK, O. S. FOMINA and A. S. KHACHATUROV, Dokl. AN SSSR 170:1084, 1966 5. Kh. S. BAGDASARYAN, Theory of Radical Polymerization, publ. by "Nauka", ch. 7, 1966 6. M. Yu. LUKINA, Uspekhi khimii 31: 901, 1962 7. R. FUCHS and J. J. BLOOMFIELD,J. Organ. Chem. 28: 910, 1963; E. TRACHTENBERG and G. ODIAN, J. Amer. Chem. Soc. 80: 4018, 1958 8. D. C. NECKERS, A. P. SCHAAP and J. HARDY, J. Amer. Chem. Soc. 88: 1265, 1966 9. L. S. BARTELL and J. P. GUILLORY, J. Chem. Phys. 43: 647, 1965 10. L. S. BARTEL, J. P. GUILLORY and A. T. PARKS, J. Phys. Chem. 69: 3043, 1965 11. J. MATHE and A. ALLE, Principles of Organic Synthesis, Foreign Lit. Pub. House, p. 73-74, 1962 12. H. WEITKAMP and F. KORTE, Tetrahedron 20: 2125, 1964 13. D. N. HALL, A. A. OSWALD and K. GRIESBAUM, J. Organ. Chem. 30: 3829, 1965