S Y N T H E S I S OF FURAN A L D E H Y D E S C O N T A I N I N G

A T H R E E - M E M B E R E D RING

(UDC 547.72+547.38)

V. G. G l u k h o v t s e v , S. V. Z a k h a r o v a , a n d G. K. V a s i l e v s k a y a

N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences, USSR Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya No. 7, pp. 1830-1333, July, 1964 Original article submitted December 28, 1968

Alkylfuran compounds, possessing a labile hydrogen atol-n in the a-position of the nucleus, reacts with cg,3-un- saturated aldehydes and ketones according to the Michael reaction [1]. When a double or triple bond is present in the side chain of the furan compound, the yield of the reaction product is sharply reduced [2]. Three-membered rings in a number of cases behave similarly to the double bond. When the three-membered ring is conjugated with unsaturated groups, the electrons of the three-membered ring are similar to the rr-electrons of the double bond [3,4]. In view of this, we might expect that the cyclopropyl ring, conjugated with the furan ring, would also reduce the yield of products in this reaction. It was found that the cyclopropyl ring behaves like an alkyl radical, and not like an alkenyl radical in this reaction [5]. In contrast to the cyclopropyl ring, carbonyl, carboxyl, carbalkoxyl, alkoxyl, and hydroxyl groups [6-8], conjugated with the furan ring, reduce the mobility of the hydrogen in the furan ring. At the same time, electronegative groups not conjugated with the furan ring have practically no influence on the mobility of the hydrogen. "

The hypothesis was advanced earlier that a three-membered ring can transmit the effect of conjugation be- tween unsaturated groups similarly to a double bond [4]. Consequently, if a three-membered ring transmits the in- fluence of etectronegative groups to the furan ring like a double bond, then the mobility of hydrogen in the furan ring should be sharply reduced.

We found that if the cyclopropyl ring in 1-cyclopropyl-2-a-furylcyclopropane is replaced by an electronega- rive methylfuryl ring, then the mobility of the hydrogen in the unsubstituted furan ring is appreciably reduced. The yield of the reaction product of 1-(5-methylfury1-2)-2-(furyl-2)-cyclopropane with acrolein under the usual condi- tions is only 21~

H~ 0 C IE

Ig---]l / \ J f I t + CH~----CHCH CHs--~..oJ--CH--CH / \0 /

CH~COOH

H~ C O

When the furan ring is conjugated with the electronegative carbethoxy group through a three-membered epoxide ring, the mobility of the hydrogen in the ring is reduced still more.

0 0 0

If Ir /\ II II c ~ . c o o H ~-.oJ--CH--CH--COC2H.~ + CH~=CHCH __--> no reaction

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I f the furan ring is not conjugated with an e lec t ronegat ive group through a th ree -membered ring, then the react ion proceeds in satisfactory yield

O O ( ) "Hx.~ ~ II II CH,C00tt

O CH2CH~C HCOC~H5 ~- RCH=CHCH - - or H2SO~

O

O O II Ii i~ I1

- ~ HCCH2ICH~.x0JCH~CH~CH--CHC0 C~H5 \ /

tt 0 tt ~ H, CHa

E X P E R I M E N T A L

1 -( 5 -Methylfury1-2) -3 4 fury1-2) -propene -2 -one -1

O

oH:_ll!. 0 ~

I

To a mixture of 87 g acetosylvan [9], 1 g potassium hydroxide, and 10 ml of ethanol we added 68 g of furfuraL

After mixing for 6 h, the react ion mixture was diluted with water, extracted with ether, and the ether dist i l led off. We obtained 92 g (57.-5%) (I) with b.p. 142 ~ (8 ram); m.p. 76.5-77.5 ~ Found: C 71.44, 71.73; It 8.11, 5.12%.

Ci2H100 a. Calculated: C 71.27; H 4.98%.

1 -( 5 -Methylfury1-2) -2 -(fury1-2) -cyclopropane

CH2

To 71 g 1-( 8 -methylfuryl -2) -3 -( fu ry l -2 ) -p ropene-2-one-1 in 50 ml of ethanol we added 20 g of hydrazine hydrate. After mixing for 7 h at 85 ~ the ethanol , hydrazine hydrate , and water were dist i l led off, and the residue was redist i l led twice over 4 g of potassium hydroxide. Yield 58 g (80%) of (II) with b.p. 124 ~ (11 ram); n~ 1.f802;

d42~ 1.084-1. Found: C 76.48, 75.91; H 6.44, 6.48%; MR 88.83. C12H120 2. Calcula ted: C 76.57; H 6.42%; MR 58.90.

1 -(5 -Methylfuryl-2) -2-48' -oxopropylfuryl-2)-cyclopropane

CH~ O

II II II I l l / \ I', C H 3 - - ~ o J - - C H - - C H - - ~ . , . 0 J - - C H ~ C H 2 ( ] H (III) A mixture of 19 g 1 - (5 -methy l fu ry l -2 ) -2 - ( fu ry l -2 ) -cyc lopropane ,

10 g acrolein, 0.1 g hydroquinone, and 10 ml acet ic acid was mixed for 4 h. The react ion mixture was diluted with

water and extracted with ether. The ether extracts were neutral ized with sodium bicarbonate and the ether dis t i l led off. We isolated 2 g of the ini t ia l cyclopropane and 5 g (21%) of (Ill) with b.p. 139" (2.6 ram); n~ 1.5340, d~ ~ 1.1188. Found: C 72.85, 72.78; H 6.71, 6.64%; MR 67.88. C15HlgO a. Calcula ted: C 73.75; H 6.59%; MR 67.81.

O O

I1 II / \ N 2- ( l ' , 2 ' -Epoxy-2 ' - ca rboe thoxye thy l ) - fu ran ~ o J - - C H - - C H C O C = H 5 (IV). To 38.5 g sodium ethyla te in

100 ml of ether we added a mixture of 67 g of the ethyl ester of monochloroacet ic ac id , 57 g furfural, and 100 ml of ether. The react ion mixture was heated to boil ing, diluted with water, extracted with ether, and the ether dist i l led off. We isolated 41 g (42%) of (IV) with b.p. 88.8" (2 ram); n~ 1.4892; d42~ 1.1817. Found: C 59.27, 59.12; H 8.66,

6.60%. CgHi004. Calcula ted: C 89.22; H 5.52%.

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0 O

}--CH~CH~C~t~CHCIOC,H5 (V). From 91.5 g of 243 ' -oxo- 2-(3',4'-Epoxy-4' -carbethoxybutyl)-furan O

propyl)-furan, 90.5 g of the ethyl ester of monochloroacetic acid, and 50 g C2HsONa, as described above, we ob- tained 62 g (40%) of (V) with b.p. 121 ~ (3 ram); n~ 1.4780; d~ ~ 1.1201. Found: C 62.94, 62.92; H 6.75%, 6.73%; MR 53.12. C11H1404. Calculated: C 62.84; H 6.71%; MR 52.59.

2 -( 1" -Methyl -3' -oxopropyl) -5 -( 3' ,4' -epoxy -4' -carbethoxybutyl) -furan

0 O O ll II ti / - , H HCCH~Ctl--~.O/9--CH~CIIeCH--CHCOC2Hs(~ I). To a mixture of 18 g 243',4'-epoxy-4'-carbethoxybutyl)-furan,

Cit3

13 g crotonaldehyde, and 0.2 g hydroquinone, we added 0.35 ml of 50% sulfuric acid. After mixing for 1 h and the usual treatment, we obtained 3 g of the initial furan and 10.5 g (44%) of (VI) with b.p. n~ 1.4890; d~ ~ 1,1204. Found: C 64.44, 64.50; H 7.38, 7.28%; MR 72.21. C15HmO 5. Calculated: C 64.25; H 7.19%; MR 72.01.

2-(3'-Oxopropyl)-5-(3' ~epoxy-4' -carbethoxybutyl)-furan

0 O O

HCCIIeCII~lt O --CIte CH2CtI--CHCOC2Hs(VII). From 19 g 2-(8',4'-epoxy-4'-carbethoxybutyl)-furan, 17 g of

acrolein, 0.2 g hydroquinone, and 20 ml of CHsCOOH, as described above, we obtained 6 g of the initial furan and 10 g (41.6%) of (VII) with b.p. 152~ ram); n~ 1.4910; d~ 1.1454. Found: C62.95,62.80,H6.75~ 6.78%; MR67.33. C14H180 ~. Calculated: C 63.14; H 6.81%; MR 67.35.

C O N C L U S I O N S

1. Three-membered rings-cyclopropane and epoxide-transmit the influence of electronegative groups to the furan ring, like a double bond.

2. 1 -( 5 - Methylfury1-2) - 2 4 fury1-2) -cyclopropane and 2 4 3' ,4' -epoxy -4' -carbethoxybutyl) -furan add ~,B-un - saturated aldehydes in acid medium, forming the corresponding furan aldehydes with a three-membered ring.

1.

2. 8. 4. 5.

6.

7. 8.

9.

LITERATURE CITED

YU. K. Yur'ev, N. S. Zefirov, and A. A. Shteinman, Zh. Obshch. Khimii, 38, 1150 (1963),

Yu. K. Yur'ev, N. S. Zefirov, and V. M. Ourevich, Zh. Obshch. Khimii, 31, 3831 (1961).

O, A. Nesmeyanov, M, Yu. Lukina, and B. A. Kazanskii, Dokl. AN SSSR, 153,357 (1963).

R. H. Eastman and S. K. Freeman, ] Amer. Chem. Soc. 77,6642 (1955).

V. O. Glukhovtsev, S. V. Zakharova, and A. D. Petrov, Izv. AN SSSR. Otd, Khim. N., 906 (1963);

USSR Patent No. 154538 (1962). V. G. Gtukhovtsev, S. V. Zakharova, and A. D. Petrov, Dokl. AN SSSR, 151,570 (1963). A. D. Petrov, V. G. Glukhovtsev, and S. V. Zakharova, Dokt. AN SSSR, 153, 1122 {1963). V. G. Gtukhovtsev and S. V. Zakharova, Izv. AN SSSR. Otd. Khim. N., 1874 (1963). N I Shuikin, I. F. Bel'skii, and G. K. Vasilevskaya, Izv. AN 8SSR, Otd. Khim., N., 363 (1961).

Al l a b b r e v i a t i o n s of p e r i o d i c a l s in the a b o v e b ib l iography are l e t t er -b y - l e t t er t r a n s l i t e r -

a t i o n s o f the a b b r e v i a t i o n s as g iven in the o r ig in a l R u s s i a n journal . Some or all of th is per i -

od ica l l i t e ra ture may wel l be a v a i l a b l e in E n g l i s h t ransla t ion. A c o m p l e t e l i s t o f the c o v e r - t o -

c o v e r E n g l i s h t r a n s l a t i o n s appears at the back o f th i s i s s u e .

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