saturated aldehydes and cyclopropanaldehydes give only adducts of composition i:I under these conditions [i, 3]. A final solution of this problem can be achieved by quantum-chemical calculations for the acetal--vinyl ether-catalyst reaction complex, which supposedly will be carried out in the future. CONCLUSIONS i. The MINDO/2 method was used to carry out a quantum-chemical study of the addition of acetals to vinyl ethers in the presence of an acid catalyst, and it was shown that despite the previously proposed mechanism, the reaction does not proceed via a step of carbocation formation. 2. A reaction mechanism has been proposed with intermediate participation of an acetal-catalyst-vinyl ether reaction complex. LITERATURE CITED i. 2. 3.

L.A. Yanovskaya, S. S. Yufit, and V. F. Kucherov, Chemistry of Acetals [in Russian], Nauka (1975), K. Ya. Burshtein and Yu. I. Khurgin, Izv. Akad. Nauk SSSR, Ser. Khim., 1687 (1974), A. Kh. Khusid, G. V. Kryshtal I, V. F. Kucherov, and L. A. Yanovskaya, Izv. Akad. Nauk SSSR, Ser. Khim., 444 (1976).

REACTIONS OF CARBONYL COMPOUNDS IN THE PRESENCE OF PHASETRANSITION CATALYSTS. 4.

STUDY OF THE REACTION OF ACETOACETIC ESTER WITH I-CHLORO-

3-METHYL-2-BUTENE IN THE PRESENCE OF VARIOUS ALKALINE AGENTS I. A. Esikova and S. S. Yufitl

UDC 541.124;541.128:547.484.34:547.413

The alkylation of carbonyl compounds with alkyl halides proceeds through a step involving deprotonation. This reaction is usually carried out in anhydrous media in the presence of alkali metals or their hydrides or alkoxides [i]. Extractive alkylation [2] and alkylation in a two-phase catalytic system [3-5] are other methods, The latter method makes it possible to alkylate carhonyl compounds at high rates and does not require anhydrous solvents or large amounts of quaternary ammonium salts. In the present research we studied the reaction of acetoacetic ester (AAE) with l-chloro-3-methyl-2-butene [prenyl chloride (PC)] in the presence of various alkaline agents and triethylbenzylammonium (TEBA) chloride (QCI) under heterogeneous conditions. EXPERIMENTAL According to the results of gas--liquid chromatography (GLC), the PC contained 83,5% lchloro-3-methyl-2-butene and 16.5% 3-chloro-3-methyl-l-butene; it was obtained in 60% yield by the method in [6] by hydrochlorination of isoprene and had bp 59-60~ (ii0 mm), The AAE was distilled prior to the experiments and had bp 62-63~ (14 mm) and nn 25 1.4200, The benzene was purified thoroughly by the method in [7]~ the KOH was granulated analytical-grade material, the K2CO3 was analytical-grade material, and the water was distilled. The TEBA chloride was obtained in 75% yield from triethylamine and PhCH2CI [8] and had mp 188~ Monoprenyl- (I) and diprenyl-substituted (II) AAE were synthesized by the method in [9]. Compound I had bp 140~ (50 mm) and nD 2~ 1.4431. PMR spectrum (CC14, ~, ppm): 1.19 t (CHsCH2), 1.58 br s [(CH3)20=], 2.065 s [CH3C(0)], 2.38 br t (==CHCH2CH2), 3.23 t (=CH), 4.06 q--(CH2C in COOEt), ~nd 4.92 t (C-CH). --Compound II had bp 197 C (70 mm) and nn=~ PMR spectrum (CCI~, ~, ppm): 1.15 t (CH3CH2), 1.6 br d [(CH3)2C = ] , 1.955s [CH3C(0)],2.405 d (----CHCH2CH2),

N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow, Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 507-514, March, 1980. Original article submitted December 18, 1978.

328

0568-5230/80/2903- 0328507.50

9 1980 Plenum Publishing Corporation

\ 4.08 q (CH2C in COOEt), and 4.8 t ( / ~ H ~ o Compounds I and II were used to identify the peaks on the chromatograms of the reaction mixtures, The formation of I, II, and 2-methylhept-2-en-6-one (MH) was observed during the reaction of AAE with PC in the presence of alkaline condensing agents; HsC2OOCCH~CCHaq- (CHa)~C=CHCH2CI-~ HsC2OOCCIIC--CH3q- HsC2OOCCR2CCH3 q- RCH2COCH~ U

O

(R--el)

II]

11

n O (i)

O (H)

The reaction products were analyzed by GLC with a Khrom-4 chromatograph under conditions with temperature programming at 6 deg/min from 50 to 230~ with 2.4 m by 0.5 cm glass columns filled with Chromaton N-AW-DMCS (0.2-0.25 mm) (treated with hexamethyldisiloxane) and 15% Reoplex. The following components of the reaction mixture were separated: ether, acetone, 3-chloro-3-methyl-l-butene, C2HsOH, C~H6, PC, CI~H28, MH, AAE, I, and II, The internal-standard method was used for the quantitative calculation of the chromatograms. The calibration coefficients for the principal components of the reaction mixture were first determined; MH [molecular weight (mol. wt.) 126] 1.3, I (mol. wt. 198) 1.83, and II (mol. wt. 266) 1.31. Tridecane (Cx3H2s) served as the standard for GLC, The error in GLC analysis was • The effect of various condensing systems was studied: A) solid K2C03 and TEBA chloride; B) solid KOH; C) solid KOH and TEBA chloride; D) 50% aqueous K~CO3; E) 50% aqueous K2C03 and TEBA chloride; F) 50% aqueous KOH; G) 50% aqueous KOH and TEBA chloride. A 5-g sample of K2C03 or KOH and 0.23 g of TEBA chloride were used. The use of solid condensing systems (A, B, and C) leads to the formation of a heterogeneous two-phase solid--liquid system, while the use of aqueous alkaline phases leads to the formation of a heterogeneous two-phase liquid--liquid system, Potassium chloride, the potassium salt of prenylacetoacetic acid, and potassium derivatives of AAE and I, which precipitate to give a solid phase, are formed during the alkylation and deearboxylation reactions. The compositions of the organic and aqueous phases also change during the reaction due to the liberation of water and acetone, as well as I, II, and MH. Condensing system D is an aqueous solution of K2C03 and KOH, which is formed during hydrolysis of the salt, In conformity with KD 2~ = K H 2 0 / ~ C 0 3 - = 2,26.10 -~ [i0], the OH- concentration in 50% aqueous K2C03 solution is 0,035 g-ion/liter. The principal properties of system D are determined by the presence in it of C032- and OH- ions, Our thermodynamic calculation of reactions (I) and (If) shows that Keq(I) = 117,000, and Keq(II ) = 0~178; OH- + H A ~ H~O + A-

Keq(1)= K H _ ~ K H ~

CO~- + HA ~ HCO3- + A-

Ke~(II)=

K~-AIKHcO,-

(I) (II)

where HA is AAE, A- is the AAE anion, KH= 0 = 1.80o10 -16 is the dissociation constant of H20 [I0], ~ C 0 3 -

= 5'6"i0-i~ is the second dissociation constant of H2CO3 [10] 3 and KHA = 2,1o

I0 -:: is the dissociation constant of AAE [ii]. The differences in the catalytic properties of systems D and F are due to the low OH- concentration in system D and the enormous difference in the Keq(1) and Keq(ll) values in these systems, Condensing system E is system D with the addition of 0.23 g of TEBA chloride, Potassium carbonate dissolves and a new upper organic layer is formed when 5 g of solid K=C03 is added to a solution of 0.23 g of TEBA chloride in 5 ml of water: K~COs q- H~O ~ KHCO3 q- K O H K O H q- QCI ~ Q+OH- q- KCI In conformity with the general concepts of the possible pathways of conversion of K=C03, KOH~ and TEBA chloride, as well as the data i n [12], the upper layer is the TEBA base (Q+0H-), It has alkaline properties, a weak amine odor, and a yellowish color. The TEBA base is quite soluble in water, alcohol, and acetone but is insoluble in benzene, PC, and a mixture of AAEI with benzene. The organic base is also formed in the reaction of TEBA chloride with aqueous solutions of alkalies and is liberated from 25-30% aqueous solutions of KOH, 329

TABLE I. Accumulation of the Products in the Organic Phase Under the Influence of Various Alkaline Systems ([PC] = [AAE] = 1.75 moles/liter, benzene, 5 g of the solid system, i0 g of the aqueous system, 40~

Concn.,molcJ~t~ system

.

3om~

A

I 60.min

0,7

0,6 0,58

C G

O,O4 0,04 0,125

C F

G

0,45

B

J

0,97 0,92 0,21 0,18

[

~to rain

0,475

0,8,5

0,19 0,2t

0,23 0,17

0,42

0,83

0,51

0,47

0,t25 0,t4

'~

0,26

o,~

Methylheptenone (MI-I) 0,02 0,05 0,1 0,11

0,06

0,t7

0,82

Diprenylacetoacetic este= (ID 0,09 [ 0,i05 0,tl 0,09 [ 0,14 0,14 0,22 0,27 0,28

0,01 0,02 0,05

C F G

0,78

0,82 0,8 0,19 0,2

F

B

t80 mia

Monoprcnylaeetoacetie ester (I) 0,085 0,I1 0,13

o~

E B

i20 min

[

0,045 0,010 0,19 0,225

I

0,28

0,09 0,23 0,26 0,33

%57 %32 0,4i

TABLE 2. Effect of Various Condensing Systems on the Initial Rates of Formation of I, II, and MH ([PC] = [AAE] = 1.75 moles/liter, benzene, 5 g of the solid system, i0 g of the aqueous system, 40~

Condensing system A B C D E F

G

Intttal rate, (mole, llte,r a . iw~e-a).10s

wi

wn

WMH

5,5 110 110 0 55 20 44

0 2,5 2,7 0 0 11,t 52,5

0 0 0 3 3,75

W~

5,5

112,5 112,7 0 55 34,1 100,2

Thus the E and G condensing systems are two-phase liquid systems in which a 50% aqueous solution of KOH or K2C03 is not miscible with the TEBA base, and the addition of a benzene solution of AAE and PC leads to the formation of a third layer. The solid products that precipitate during the reaction (see above) and are only slightly soluble in both the aqueous and organic layers form a fourth (solid) phase, The reaction was carried out for 4 h with vigorous stirring at 40~ A 25-mi sample of a benzene solution of equimolar amounts of AAE and PC (1.75 moles/liter) was poured into a round-bottomed flask located in a thermostat and equipped with a stirrer, thermometer, and reflux condenser, and 1 g of C~sHas and the condensing agent were added. Samples were selected from the organic phase and were analyzed by GLC, The samples were analyzed without prior treatment, since it was demonstrated by PMR spectroscopy that Q+OH- does not pass into the organic phase, The changes in the concentrations of the principal products of the reaction of AAE with PC in the presence of the listed alkaline systems with time are given in Table l, The kinetic curves of the accumulation of the reaction products were analyzed with determination of the initial reaction rates by graphical differentiation; the degree of conversion did not exceed 5-30%, The average error in the determination of the rate was • due to the low accuracy of the graphical method. The initial rates of formation of I, II, and MH are presented in Table 2, Experiments were carried out as described above to study the effect of the amounts of 50% aqueous KOH solution on the rate of accumulation of II and MH; the amount of 50% aqueous alkali was varied from i0 to 40 g (Table 3), The reactions in the pres330

TABLE 3. Effect of the Amount of 50% Aqueous KOH on the Initial Rates of Formation of II and MH ([PC] = [AAE] = 1.75 moles/liter, benzene, 40~ Amount of 50% aqtmom KOH. g

IInitial rate, (mole.~ter -x 9sec -l)7l-0S

t0 20 40

WII

wMH

52,5 10,3 2,3

3,75 5,1 2,4

TABLE 4. Accumulation of I, II, and MH as a Function of the KOH Concentration in the Aqueous Phase ([PC] = [AAE] = 1.75 moles/ liter, organic phase volume 25 ml, i0 g of the aqueous phase,

40~ Conen~ mole/~lm

eoner~ ~

8orain

so .min

i2o rain

t8o rain

2~0 rain

0,088 I 0,i07 0,i9t t 0,226 0,48 0,54 0,91 0,84 0,21 0,t8 Diprenylacetoacetic ester (II)

0,t13 0,22 0,57 0,8 0,21

O,tl 0,23 0,6 0,83 0,t7

0,08 0,08 0,48 [ 0,45 I ' Methylheptenone (MH) I 0,147 0,t2 0,23 [ 0,11 I

0,073 0,46

I

0,48 0~067

0,t7 0,29

I

0,42 0,173

Monoprenylacetoacetic eater (D 0,t04 0,23 0,79 0,25

9,i

16,5 27,8 44,4 50 44,4 50

I

0,457 0,067

[

44,4 50

I

0,04 0,064

I

TABLE 5. Effect of the Concentration of Aqueous KOH on the Initial Rates of Formation of Esters I and II and MH and on Monoalkylation W Z = W I + WII + WMH ([PC] = [AAE] = 1.75 moles/liter, i0 ml of benzene, organic phase volume 25 ml, i0 g of the aqueous phase, 40~ Rates, Cmole" litcr-~,see-x).i0s

KOH conch. % t mole/ liter 9,t 16,5 27,8 44,4 50

] 1,37 I 3,38 J 6,47 ] tt,62 J t3,69

tg aOH [11] all, O [tl]

0,08 0,63 1,3i2 2,352 2,627

0,93 0,845 0,63 0,25 0,t5

WI

5,8 t4,4 27,8 lit,0 44,0

WII

W ~ -I

~0

~0

0 4,1 52,5

0 3,4 3,75

WE 5,8

t4,4 27,8 1t8,5 t00,2

lg WE +5 aH20

0,797 1,232 1,643 2,677 2,826

ence of 9.1, 16.5, 27.8, 44.4, and 50% aqueous KOH solutions were carried out in benzene at starting AAE and PC concentrations of 1.75 moles/liter in the presence of 0.23 g of TEBA chloride (Table 4), The dependence of the initial rates of accumulation of I, II, and MH on the hydroxide activity is presented in Table 5, The rates of monoalkylation of AAE with PC in the presence of 44.4 and 50% aqueous KOH were estimated from the overall curve of the formation of the monoalkylation product with allowance for the dia!kylation and decarboxy!ation processes: O z = O I + Oil + O M H

WE = WI ~- WII-~- WMH

331

DISCUSSION OF RESULTS In the course of a study of the effect of various alkaline agents (see Table i) on the principles involved in the alkylation of AAE with prenyl chloride it was established that the principal reaction products are I, II, and MH. In conformity with the generally accepted concepts these substances are formed as a result of parallel and consecutive reactions;

xee~!

HsC2OOCC~CHs + KOH < ~ H~C2OOCCH-.-=~CCHs+ H~O ... .o RC!

I

KOH

(I) ~HsC2OOCCR=-~CH 3 RCl> (II) H20

J,

K@

H,O, --C,HsOH

! K00CCHRCCHs ~ HOOCCHRCCH3 ~ MH fj KOH II -co, 0 0

Diisopentenylacetone, which might have been formed as a result of analogous decarboxylation of II, was not detected. The decarboxylation of AAE evidently proceeds at an insignificant rate, by virtue of which ethanol is detected only when MH is present in amounts that correspond to the hydrolysis of I, while virtually no acetone is formed, It might be assumed that the potassium salt of acetoacetic acid does not accumulate in the reaction system and that the observed discrepancy between the consumption of AAE and PC is due to the accumulation in the system of only the potassium derivative of AAE, The solid potassium derivative of AAE was isolated in the reaction of 50% aqueous KOH solution with a 10% excess of AAE with respect to the stoichiometric amount of KOH. The precipitated light-yellow product was removed by filtration, washed with ether, and dried; the yield was quantitative, When alkaline system D was used, the formation of a solid precipitate, I, II, and MH was not observed, Compound II and MH were formed only under the influence of systems B, C, F, and G, The initial rate of monoalkylation was determined for a comparative estimate of the alkaline systems under the assumption that II and MH are formed only from I, A comparison of the initial rates of monoalkylation shows that alkylation under the influence of KOH proceeds more rapidly than alkylation under the influence of K2COs, The differences in the condensing activities of KOH and K=CO3 are evidently due to their different basicities~ which determine the thermodynamic constants of their reaction with AAE (see the Experimental section). This assumption is reflected in the data on the effect of the KOH concentration on the rate of monoalkylationo The activity of water decreases and the activity of OH- (aOH-) increases on passing from dilute KOH solutions to more concentrated solutions [13], The OH- activity may serve as a measure of the basicity in concentrated alkali solutions, The presence in the system of TEBA chloride should change the basicity of the system somewhat [14]; however, the error in the estimate of the basicity due to the presence of TEBA chloride will be systematic and is probably insignificant in view of the low TEBA chloride concentration. The analysis of the kinetics of alkylation (see Table 5) indicates a linear relationship between log WZ/aH20 and log aOH_. Thus it may be assumed that the OH- ions formed during dissociation are responsible for deprotonation of AAE; the deprotonation step determines the kinetic parameters of monoalkylation. We established that II is formed only when 44.4-50% KOH solutions are used, in which case the rate of dialkylation depends markedly on aOH-, These facts can be explained by the difference in the pK& values of AAE and alkyl-substituted AAE, It is known that the pKa of AAE is 10.68, as compared with 12.7 for ethyl-substituted AAE [15]. Since the introduction of an alkyl substituent decreases the acidic properties of AAE, the use of a stronger base is necessary for the deprotonation of I,

332

Assuming that the mechanisms of the reactions under the influence of systems E and G are identical and using the kinetic method to estimate the basicities of the systems [16], one can show that the kinetic basicity of system E corresponds to the basicity of a 33% aqueous KOH solution. Since alkylation does not occur in the presence of D, the high condensing activity of E is evidently due to the presence of the resulting TEBA base in the system, The role of the TEBA base reduces to the following, i. As an organic base, the TEBA base splits out a proton from AAE to give the Q+A- organic ion pair, which reacts with PC. If there were no aqueous or solid phase, the alkylation reaction would stop at this point, since it procesds stoichiometrically and irreversibly, When KOH is present in the system, the organic base (Q OH-) is regenerated, and the catalytic cycle is completed. 2. Cation exchange, which also leads to the formation of an organic ion pair that may pass into the organic phase and react with PC~ is possible in the reaction of the TEBA base with the potassium derivative of AAE or I. The cation-exchange reaction should be shifted markedly to favor the formation of K+A -, since this will be promoted by the enormous difference in the concentrations of KOH and the TEBA base and the heterogeneous character of the process. 3. Since the deprotonation of AAE and cationic exchange are interphase processes~ the role of the TEBA base as a phase-transition catalyst reduces to transport of the A carbanion from the phase interface to the organic layer, owing to which homogeneous alkylation becomes possible. In the case of high solubility of the TEBA base in the organic layer homogeneous deprotonation of AAE, i.e., OH transport into the organic phase, is possible, 4. The rate of monoalkylation is determined by the rate constants and the concentrations of PC and the ion pairs; the difference in k~ and k2 may be due to both the difference in the phase state of the ion pairs and the difference in their reactivities

W = kI[Q+A-][ PC ] + k,[K+A-][ PC ] /~AH] [A-I ~ ([Q+A-] +[K+A-]) = a~ ~H=O where [K+A-] is the concentration of the potassium derivative of AAE. Thus the initial rate of monoalkylation in the presence of a 50% aqueous KaCO3 solution (system E) is determined exclusively by the catalyticaction ofthe TEBAbase (W = kI[Q+A-][PC] = 55.10 -2 mole-liter-Z-sec-1). 5. A pathway that includes the heterogeneous reaction ofKOH with AAE and heterogeneous alkylation of the potassium derivative of AAE is realized under the influence of condensing system B (W = k2[K A-][PC] = 34.1.10 -5 mole~iter-1osec-1)o 6.

The formation of I via several pathways is possible in the presence of system G:

HA~

Q+A- ~ (I) t (~> t

I

This also leads to an increase in the alkylation rate W = i00.2.10 -5 mole'liter-1"sec -a, At the same time, the rate of formation of I calculated as the sum of the rates of the reactions that take place under the influence of KOH and the TEBA base is 89.1.10 -5 mole'liter-~'sec-~, The value obtained by the calculation is in good agreement with the experimentally determined initial rate (the error is ~10%). Thus, the scheme of the process can be represented by the system of equations

HA + KOH HA + Q+OHHA + Q+OH Q+A- + KOH

~ K+A~ Q+A~ Q+A~__ K+A-

+ + + +

H~O H~O(hete~ogeaeottsly) H,O(homogeneomly Q+OH-

(1) (2) (3) (4)

333

Q+AT + R X -+ R A + Q+XK+A - + R X - ~ H A +

KX

Q+X- + KOH ~ Q+OH- + KX

(5) (6) (7)

All of the reactions except (3) proceed heterogeneously (either liquid--liquid or solid phase--liquid systems). Reaction.(5) may take place both heterogeneously and homogeneously~ depending on the solubility of QTA-. The contribution of the homogeneous pathway (OH- transport_to the organic phase) will be determined to a substantial degree by the solubility of Q OH in the organic phase. Since the solubility of the TEBA base in AAE and in a mixture of AAE and benzene is low under the investigated conditions, the contribution of the homogeneous pathway (3)--(5) is insignificant, In addition to this, a comparison of the rates of monoalkylation in the presence of systems E, B,~nd G makes it possible to assume that under the influence of system G the process takes place primarily through K+A - and Q+A-~ which were formed as a result of heterogeneous reactions of AAE with KOH and the TEBA base, respectively. All of the information presented above relative to the participation ofthe TEBA base in alkylation evidently also applies to the formation of II from I, In highly concentrated KOH solutions MH is formed in addition to I and II. The MH concentration increases monotonically at virtually a constant rate during the experiment. This is in agreement with the fact that the steady-state concentration of I is established very rapidly under such conditions (see Table i). The ketonic decomposition of I, which leads to MH, is accelerated slightly under the influence of TEBA. Since the ketonic decomposition ineludes a step involving the hydrolysis of the ester group of I [17, 18]~ the rate of formation of MH depends on the activity of the water in the reaction system. When the process is carried out under the influence of solid KOH, only the reaction water that is formed in the first step of the monoalkylation is present in the system, In fact, the reaction takes place with an induction period; the induction time of 135 min does not change when TEBA chloride is introduced in the system, and this indicates the independence of the rate of formation of I and, correspondingly, the rate of formation of water on TEBA chloride. The reaction involved in the formation of MH is characterized by two values, viz., the initial rate of formation (WoMH) and the rate after 180 min (W,8oMH), when the induction period is complete. The calculated values (in moles per liter per second) are as follows: alkaline agent KOH, WoMH.105 = 0.8, WIsoMH,105 = 3.6; alkaline agent KOH, TEBA chloride, WoMH,105 = An analysis of these data and Table 1 shows that the formation of MH with PC presupposes the formation of I, its alkaline hydrolysis, and acid. The latter process is accelerated under the influence of TEBA

2.4, WIsoMH.105 = 12.7, in the reaction of AAE decomposition of the chloride,

The data on the effect of a 50% aqueous alkali solution on the initial rates of formation of I, II, and MH are of particular interest. Thus, for example, the quasi-steady-state concentration of I is 0.2 mole/liter when i0 g of the solution is used, whereas only traces of I are formed when 20 and 40 g of the solution are used. The initial rate of formation of II decreases as the amount of alkali is increased (see Table 3)~ whereas the rate of formation of MH passes through a maximum. The facts presented above indicate that acidic cleavage of I, which leads to the formation of potassium salts of the acids that are not determinable by GLC, occurs under these conditions in addition to alkylation and the formation of M H. In addition, some of the I may exist in the reaction system in the form of the potassium derivative of I or in the form of the potassium salt of acetoacetic acid. The processes enumerated above evidently begin to dominate in the case of a large molar excess of KOH with respect to PC and AAE, and this is also responsible for the observed principles, Conditions under which one can selectively carry out the reaction and Obtain I, II, or MII in rather high yields can be pointed out. Thus the only product of the reaction of AAE with PC in the presence of system E is I (in 50% yield after 4 h with a selectivity of i00%), It is expedient to carry out dialkylation in system G, particularly in the case of a twofold to threefold excess of PC. Under these conditions, II is formed in quantitative yield with a selectivity of 100%. At the same time, MH is formed in preponderant amounts in the presence of system C (in 30% yield after 4 h with a selectivity of 60%). The direction of the reaction changes in the presence of aqueous solutions of KOH as a function of the alkali concentration. Thus, the principal product in the presence of 16.6% KOH is MH (in 30% yiel@ with a selectivity of 75%), whereas the principal product in the presence of 44.4% KOH is I

334

(in 50% yield with a selectivity of 81%), and the principal product in the presence of 50% KOH is II (in 57% yield with a selectivity of 63%), The kinetic description of the process in the presence of system G will be given in our next communication. CONCLUSIONS i. The conditions for the selective formation of prenylacetoacetic ester (I) in the presence of a 50% aqueous K2CO3 solution and triethylbenzylammonium chloride (TEBA chloride) and of diprenylacetoacetic ester (II) in the presence of a 50% aqueous KOH solution and TEBA chloride were found. The effect of the concentration of aqueous alkali on the direction of the reaction was studied. 2. The difference in the condensing activities of KOH and K2COs is due to the large difference in the acid--base equilibrium constants of their reactions with acetoacetic ester (AAE). The effect of the concentrations of aqueous solutions of KOH in the presence of TEBA chloride on the rate of monoalkylation was studied, 3. The kinetic basicity of a 50% aqueous solution of K2C03 in the presence of a phasetransition catalyst was estimated, and it was assumed that the condensing activity of this system is determined exclusively by the catalytic action of TEBA hydroxide, 4. A scheme for the monoalkylation of AAE that presupposes several pathways is discussed. In the presence of a 50% aqueous solution of KOH and TEBA chloride the reaction proceeds through the potassium or triethylbenzylammonium derivative of AAE with KOH and the TEBA base, respectively. 5. Dialkylation proceeds only in the presence of concentrated aqueous solutions or solid KOH; this is associated with the difference in the acidities of AAE and ester I, 6. An induction period that does not depend on the presence of TEBA in the system and is due to the formation of water as a result of the reaction is observed during the formation of 2-methylhept-2-en-6-one in the presence of solid KOH, LITERATURE CITED i. 2. 3. 4. 5. 6. 7. 8. 9. i0. ii. 12. 13o 14. 15, 16. 17. 18.

H. Dupont Durst and L. Liebeskind, J. Org. Chem., 39, 3271 (1974), A. BrEndstrom and U. Junggern, Acta Chim. Scand., 2_~3, 2204 (1969), A. Jonczyk, M. Ludwikow, and M~ Makocza, Rocz. Chem., 47, 89 (1973), A. T. Babayan and M. Indzhikyan, Zh. Obshch, Khim., 2~4, 1887 (1954), A. T, Babayan and M. Indzhikyan, Zh. Obshch. Khim., 27, 1201 (1957). British Patent No. 851658 (1960); Chem. Abstr., 55, 9283 (1961). A. Weissberger, A. Proskauer, G. Riddick, and A. Toops, Organic Solvents [Russian translation], Inostr. Lit. (1958). M. Finkelstein, R. C. Pedersen, and S. D. Ross, J. Am. Chem. Soc.,. 81, 2361 (1969) o H. Gilman (editor), Organic Syntheses, Vol. i, J. Wiley and Sons, New York (1946), p. 248. P. Nadeinskii, Theoretical Foundations and Calculation in Analytical Chemistry [in Russian], Vysshaya Shkola (1959). A. J. Gordon and R. A, Ford, Chemist's Companion: A Handbook of Practical Data, Techniques, and References, Wiley-lnterscience (1973), I. Gyenes, Titrations in Nonaqueous Media, Van Nostrand-~Reinhold (1968), G. I. Mikulin (editor), in: Problems in the Physical Chemistry of Solutions of Electrolytes [in Russian], Khimiya (1968). R. Stewart and J, P. O'Donnell, Can. J. Chem., 42, 1681 (1964), R, G. Pearson and R. L, Dillon, J. Am. Chem. Soc,, 7_~5, 2439 (1953), Yu. V, Moiseev and M. I. Vinnik, Dokl. Akad. Nauk SSSR, 150 , 845 (1963). H.Gilman (editor), Organic Syntheses, Vol, i, J. Wiley and Sons, New York (1946), po 351. C. G. Swain, R. Fo W. Bader, R. M. Esteve, Jr., and R. N. Griffin, J. Am. Chem. Soc., 83, 1951 (1961).

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