SYNTHESIS BASED ON ETHYL CYANOACETATE Текст научной статьи по специальности «Химические науки»

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CHEMICAL PROBLEMS 2023 no. 4 (21) ISSN 2221-8688

323

UDC 547-316

SYNTHESIS BASED ON ETHYL CYANOACETATE

V.M. Ismailov, N.N. Yusubov, N.D. Sadykhova, R.A. Gasymov, I.A. Mamedov,

F.M. Muradova

Baku State University AZ-1148 Baku, Z. Khalilov St., 23 e-mail: yniftali@gmail.ru

Received 16.07.2023 Accepted 18.10.2023

Abstract: It has been shown that self-condensation ethyl cyanoacetate under conditions of excess potash in DMSO undergoes an intermolecular Claisen-type condensation involving three substrate molecules to form ethyl 2,4-dicyano-2-[2-cyanoacetyl-3-oxo]-butanoate. Self-condensation ethyl cyanoacetate takes place in the presence of triethyl phosphite and zinc acetate with the participation of three reagent molecules resulting in triethyl 3-cyano-2,4-diiminopentane-1,3,5-tricarboxylate. Alkylation ethyl cyanoacetate with 1,2-dichloroethane, cycloalkylation products were obtained: cyclopropane and cyclohexane derivatives, as well as a polymer product. The reaction of ethyl cyanoacetate with 1,2,3-trichloropropane occurs in a 2:3 ratio giving ethyl 7-chloro-2-(2-chloroallyl)-2,5-dicyano-3-methylenoate-7-enoate and 2,5-bis(2-chloroallyl)-3-methylenehexanedinitrile.

Keywords: self-condensation, ethylcyanoacetate, triethyl phosphite, dichloroethane, trichloropropane DOI: 10.32737/2221-8688-2023-4-323-330

Introduction

Systematic studies of the alkylation of compounds with an active methylene group with haloalkanes have shown wide possibilities for creating the most diverse organic compounds of practical importance on their basis [1,2].

One of the interesting objects of research is ethyl cyanoacetate, on the basis of which

O

II

3c2h50—c-ch2cn—

various classes and types of compounds are synthesized. Nitrogen- and sulfur-containing heterocycles are obtained by condensation of ethyl cyanoacetate with carbonyl compounds [3,4]. Cyclotrimerization of ethyl cyanoacetate, tricyanocyclopropane - 1,2,3-tricarboxylate was obtained [5]

In the presence of iridium hydride as a of the nitrile group with the formation of an catalyst, C-H addition occurs at the triple bond unsaturated amine [6]

O

C2H50—c—CH2CN

O NH, o IrH II I II -C2H50-C-CH2-C=C—c—OEt

CN

www.chemprob.org CHEMICAL PROBLEMS 2023 no. 4 (21)

Results and discussion

In contrast to the above scheme, we have type intermolecular condensation with the

found that ethyl cyanoacetate, under conditions participation of three molecules of ethyl

of excess potash in DMSO at elevated cyanoacetate to form compound 1. temperatures (90-1000C), undergoes Claisen-

o „ O II o œ2Et

„TT » __ K2C03 V || 2NC CH2—c—OEt II I

NC-CH2-C—OEt-► NC-CH—c—OEt---► NCCH2-C-C—C~CH7CN

DMSO z I II

CN O

It also revealed that ethyl cyanoacetate in the of ethyl cyanoacetate simultaneously presence of triethyl phosphite and zinc acetate participate. enters into self-condensation, where three moles

o II

EtO—C-CH2C=NH

° I

II P(OEt)3 |

3NC-CH2-C-OEt „ , » EtO—C-C-CN

2 Zn(OCOCH3)2 II ■

o

EtO—C-CH2C=NH

II

o

2

A distinctive feature of this reaction from the previous study [7] is that the active methylene group of one molecule joins two nitrile fragments of the second and third

molecules of ethyl cyanoacetate, forming diiminoderivative 2 according to the trend as follows:

The 1H NMR spectrum of compound 2 contains triplets at 1.15 (3H) and 1.25 (6H) ppm, as well as quartets at 4.05 (2H, CH2O) and 4.15 ppm. (4H, 2CH2O) which confirm the presence of three ethoxy groups. Integral intensities confirm the ratio of these groups (1:2). Singlet at 3.35 ppm characterizes

methylene units. Broadened signal in a weak field 6.25 ppm should be classified as imino groups (C= NH) .

It established that ethyl cyanoacetate is alkylated with 1,2-dichloroethane in the presence of potash in DMSO with the formation of three products: C,C-dialkylation with the

formation of a cyclopropane derivative -gemnitrilethoxycarbonylcyclopropane (3); a product of intermolecular tetra-C-alkylation with the participation of two moles of substrate and two moles of reagent (dichloroethane) -

NC—CH2-C02Et

c1ch2ch2c1 -

dms0/k2c03 80 °c

diethyl 1 -cyano-4-(cyanocarbonyl)cyclohexane-1,4-dicarboxylate (4) and a product of a polymeric nature, the composition and structure of which requires a separate studying.

+

Et02C

Et02C CN

C-CN

C02Et

+ polymer

The formation of amide 4 should be considered tetralkylation of 4a at the nitrile group. as a product of hydrolysis of the primary

h,o

NC Et02C

?

c—NH2

C02Et

4a

The resulting polymer is practically insoluble in organic solvents, which makes easy to isolate it from the mixture.

The phosphorus analogue of ethyl cyanoacetate,diethoxyphosphorylcyanomethylp hosphonate, under identical conditions is alkylated with 1,2-dichloroethane, forming only

the C,C-cyclodialkylation product - gem-cyanodiethoxyphosphoryl-cyclopropane (5), the structure of which is confirmed by , 13C and 31P NMR . Previously, compound 5 was obtained using 1,2-dibromoethane using various catalysts [8-10].

O

II

(C2H50)2P-CH2CN

C1CH2CH2C1 DMS0/K2C03j 80 °C

Doublet in the region of 1.7 ppm corresponding to four protons with 3JHP 12 Hz characterizes the hydrogens of the cyclopropane nucleus. The chemical shift of phosphorus is 22 ppm, which confirms the phosphonate structure. It ought to be noted that the condensation of ethyl cyanoacetate with 1,2-dibromoethane also

produces 5.

When ethyl cyanoacetate is alkylated with 1,3-dichloroacetone under identical conditions in a 2:1 ratio, 1,3-

di(ethoxycarbonylcyanomethyl) acetone is formed

О О о

Il II II DMS0/K,C03 80 °С

Eto-C—СН2 + С1-СН2-С—СН2-С1 + Н2с—с—OEt -:—►

CN CN

о

î

ЕЮ—с—сн—сн,—С—СНо—сн-

о

-с-

-OEt

CN

CN

Alkylation of ethyl cyanoacetate with dehydrochlorination also occurs. Alkylation

1,2,3-trichloropropane under the above product A under the reaction conditions

conditions takes place with the participation of undergoes partial or complete hydrolysis of the

two moles of substrate and three moles of ester fragment with further decarboxylation to

reagent simultaneously. Along with alkylation, form the appropriate products 7 and 8.

2EtO-C—CH2CN + 3CH2C1CHC1CH2C1

A

NC—С—H

I

CH,

CI

CH,-C=CH2

HOH

C=CH2

I

NC—С—C02Et

H^c—Ç=CH2 Cl

-co,

о

s

сл

о

Ni

о о

о

»о

о

Cl

СНт—с—СН2

/

NC—С—COoEt

I

Н2с I

с=сн2 I

NC—С—C02Et

H2C-Ç=CH2

I

Cl A

HOH

-2C02

Cl

/сн2-с=сн2 NC—c—H

I

CH2

I

C=CH2

I

NC—c—H

H2C—C=CH2

2 ! 2

Cl

The structure of the obtained products 7 and 8 was confirmed by 1H and 13C NMR spectroscopy data. The NMR spectrum of compound 8 completely lacks resonance signals of ethoxy groups. Multiplets in the region of 2.6-2.8 and 3.3-3.4 ppm characterize the methylene and methine hydrogen atoms, respectively. Resonance signals in a weak field 5.35-5.5 ppm should be classified as vinyl protons.

The NMR spectrum of compound 7 contains a signal of the ethoxy group with a

chemical shift of 1.15 ppm. (triplet) and 4.0 ppm (quartet) (2H, CH2O). The difference in boiling points of products 7 and 8 allows them to be identified by vacuum distillation. Of interest was the use of a-halopropionate in the alkylation reaction of ethyl cyanoacetate, where the activity of the halogen is significantly higher than their activity in alkyl halides. When ethyl cyanoacetate is alkylated with ethyl a-bromopropionate, only the C,C-dialkylation product is formed.

0®r 0 CH3

|| CH3-CH-C02Et J' VN

NC—CH2—C—OEt -► btuc CH^C-C09Et

K2C03 flMCO EtOC-CH

' il I

o CH3 9

In this case, the monoalkylation product in [11], where the formation of C-mono and was not obtained, in contrast to the results given C,C-dialkylation products was noted.

Experimental part

1H and 13C NMR spectrum was recorded on a Bruker spectrometer AV-300 [300 (1H) and 75 (13C) MHz, respectively], internal standard -TMS. The melting point was determined on an SMP 30 Stuart instrument. Elemental analysis was carried out on a Carlo instrument Erba 1106. The purity of the obtained compounds was monitored by TLC on Silufol plates UV -254, eluent - acetone-hexane (1:1). General procedure for self-condensation of ethyl cyanoacetate in the presence of K2CO3 and DMSO. A mixture consisting of 0.12 mol of ethyl cyanoacetate, 0.25 mol of K2CO3 in 50 ml of DMSO was stirred for 12 hours at 800C. The mixture was stirred for 12 hours at 800C. Cooled, treated with water and extracted with ethyl ether. The extract was dried with MgSO4 , the solvent was distilled off, and the residue was distilled under vacuum.

Ethyl 2,4-dicyano-2-(2-cyanoacetyl)-3-

oxobutanoate (1). From 14 g of ethyl cyanoacetate we obtained 1. Yield 22.80 g (76%), bp 154-1570C (2 mm Hg), no20 1.4652. Found, %: C 53.87; H 4.32; N 17.65. C11H9N3O4 . Calculated, %: C 53.44; H 3.64; N 17.00. 1H NMR (DMSO-d6), 5 ppm: 1.15 t (3H, CH3) , 4.0-4.2 m (6H, 3OCH2) . 13C NMR (DMSO-d6), 5C ppm: 16.44 (CH3), 24.88 (CH 2 ), 60.65 (OCH2), 118.66 (C = N), 164.95, 165.86 (COO), (C=O), (-C- C -C-). Self-condensation of ethyl cyanoacetate in the presence of triethyl phosphite and zinc acetate. Under similar conditions, triethyl 3-cyano-2,4-diiminopentane-1,3,5-tricarboxylate (2) was obtained from 42 g of ethyl cyanoacetate, 20 g of P(OC2H5)b and 18 g of zinc acetate. Yield 28.86 g (64.65%), bp 121-1230C (2 mm Hg), no20 1.4573. 1H NMR (DMSO-6), 5 ppm: 1.15 t (3H, CH3) , 1.25 t (6H, 2CH3) , 4.05 k (2H, CH2o), 4.15 k (4H,

2CH2O), 3.35 s (4H, 2CH2), 6.25 br.s. (2H, C=NH). 13C NMR (DMSO-d6) 5C ppm: 14.24; 16.44 (CH3), 24.85 (CH2), 60.58, 60.65, 61.66 (OCH2), 115.36 (C=NH), 118.63 (C=N), 164.70, 165.95 (2 COO). Found,%: C 53.87; H 6.21; N 12.36. C15H20O6N3. Calculated, %: C 53.25; H 5.91; N 12.42.

Method for alkylation of ethyl cyanoacetate with mono- and polyhaloalkanes. To a

mixture of 14 g of ethyl cyanoacetate and 0.25 mol of K2CO3 in 50 ml of DMSO, 0.12 mol of 1,2-dichloroethane was added dropwise with stirring. The mixture was stirred for 12 hours at 800C, cooled, treated with water and extracted with ethyl ether. The extract was dried with MgSO4, the solvent was distilled off, and a residue was formed in the form of a viscous mass. The residue was treated with toluene and kept for 36 hours. The crystals that formed were ethyl 1-cyanocyclopropane-1-carboxylate (3). Exit 18.68 g (33.57%), mt 1720C. Found, %: C 60.76, H 6.12, N 10.54. C7H9 NO2 . Calculated,%: C 60.43; H 6.47; N 10.07. 1H NMR (CDCls), 5 ppm: 1.15 t (6H, 2CH3), 1.742.00 m (4H, CH2-CH2), 4.25 m (4H, 2OCH2). 13C NMR (CDCls), 5C ppm: 17.28, 32.21, 48.00, 62.00, 118.12, 166.02. Diethyl 1-cyano-4-

(cyanocarbonyl)cyclohexane-1,4-dicarboxylate (4). The residue not dissolved in toluene was treated with hot ethanol. After cooling, crystals 4 fell out .Yield 14.85 g (27%), mp 1270C. Found, %: C 56.21; H 7.13; N 10.23. C14H20N2O5 . Calculated, %: C 56.75; H 6.75; N 9.45 . 1H NMR (CDCl3), 5 ppm: 1.15 t (6H , 2CH3) , 1.85-2.36 m (8H , 4CH2) , 4.02 m (4H, 2OCH2) , 6.8-7.0 us.s. (2H, NH2). 13C NMR (DMSO-d6), 5 C ppm: 14, 27, 28, 37, 59.95, 94.20, 118.20, 157.40, 164.12, 166.30. Diethyl (1-cyanocyclopropyl)phosphonate (5).

Under similar conditions, from 22 g of diethylcyanomethylphosphonate and 12 g of dichloroethane, a residue was formed, distilled under vacuum to obtain 5. Yield 18.32 g (66%), bp 70-730C ( 2 mm Hg ) , nD 20 1.4464. Found, %: C 47. 64; H 7.21; N 6.45; P 15.87. C8H14NPO3 . Calculated, %: C 47.29; H 6.89; N 6.89;P 15.27. 1H NMR (CDCI3), 5 ppm: 1.08 t (6 H , 2CH3 , 3Jhh 7.2 Hz), 1.34 d (4H, CH2CH2), 3.95 m (4H, 2OCH2 ). 13C NMR (CDCI3 ) 5C ppm: 13.5, 15.6, 62, 119.2. Diethyl 2,6-dicyano-4-oxoheptanedioate (6). Under similar conditions, a thick mass in the form of syrup 6 was formed from 4.6 g of ethyl cyanoacetate and 2.4 g of 1,3-dichloropropan-2-one . Yield 7.3 g (72%). Found,%: C 53.44; H 5.45; N 9.43. C13H16N2O5. Calculated, %: C 55.71; H 5.71; 10.00. 1H NMR (CDQ3), 5 ppm: 1.1-1.3 t (6H, 2CH3), 2.3 d (4H, 2CH2 =O), 3.3 t (2H, CH-CH2), 4.15-4.30 m (4H, 2CH2O). 1H NMR (CDCls), 5C ppm: 15.59, 22.58, 31.61, 40.22, 60.22, 61.54, 63.40, 115.87, 118.26, 123.79, 147.81, 160.84, 163.43, 165.01, 200.56. Method of alkylation of ethyl cyanoacetate with trichloropropane in the presence of K2CO3 and DMSO. A mixture of 26 g of ethyl cyanoacetate, 50 g of potash in 70 ml of DMSO was added with stirring to 32 g of 1,2,3-triclopropane. The mixture was stirred for 8-10 hours at 110-1200C. Cooled, treated with water and extracted with ethyl ether. The extract was dried with MgSO4 , the solvent was distilled off, and the residue was distilled under vacuum. Ethyl 7-chloro-2-(2-chloroallyl)-2,5-dicyano-3-methyleneoct-7-enoate (7). Yield 14 g (54%), bp 90-93 0 C (2 mm Hg) . Found, %: C 56.21; H 5.88; N 8.65; Cl 21.23. C16H18N2O2Cl2. Calculated , %: C 56.30; H 5.27; N 8.21; Cl 20.82. 1H NMR (CDCI3), 5

ppm: 1.25 t (3H, CH3), 2.65-2.80 m (4H, 2CH2), 3.05 s (2H, -CH2-), 3.35 m (1H , CH), 4.24 m (2H, OCH2), 5.45 d.d. (4H, 2CH=C). 13 C NMR (cDCl3 ) , SC ppm: 12, 19.18, 43.50, 48.7, 62.4, 117, 119, 137. 2,5-bis(2-chloroallyl)-3-methylenehexanedinitrile (8). Yield 9.8 g (38%), bp. 115-117 0 C (2 mm Hg). Found, %: C 60.24; H 5.87; N 10.12; Cl 26.97. C13H14N2Cl2 . Calculated, %: C 57.99; H 5.20; N 10.40; Cl 26.97.1H NMR (CDCl3), S ppm: 2.62-2.84 m (4H, 2CH2), 3.45 m (1H, CH), 5.35 d.d. (4H, 2CH2 =C). 13C NMR (CDO3), SC ppm: 12, 19.18, 43.50, 48.7, 62.4, 117, 119, 137.

Method for alkylation of ethyl cyanoacetate with ethyl 2-bromopropionate. A mixture of 5.1 g of ethyl cyanoacetate, 12 g of potash in 50 ml of DMSO was stirred for 1-2 hours at room temperature and 8.3 g of ethyl 2-bromopropionate was added dropwise. The temperature was gradually brought to 80 0 C and stirred for 8-10 hours. Cooled, treated with water and extracted with ethyl ether. The extract was dried with MgSO4 , the solvent was distilled off, and the residue was distilled under vacuum. The resulting product is tri-3-cyanopentane-2,3,4-tricarboxylate (9). Yield 4.6 g (58%), bp1 72-1750C (2 mm Hg), nD201.4580. Found, %: C 57.13; H 7.86; N 4. 97. C15H23NO6 Calculated, %: C 57.50; H 7.34; N 4.47. 1H NMR (CDQ3), S ppm: 1.15-1.23 m (9H, 3CH3), 1.37 d.d. (3H, CH3), 3.15 k, 3.20 k and 3.35 k (4H, 4CH), 3.95-4.25 m (6H, 3OCH2). 13CNMR (CDCl3), SC ppm: 13.45, 13.87, 14.20, 39.28, 40.21, 42.63, 43.64, 53.19, 53.94, 61.35, 61.48, 62.39, 77.24, 77.78, 166.10, 166.16, 171.08, 171.25,172.09.

Conclusion

It was established that self-condensation ethyl cyanoacetate under conditions of excess potash in DMSO undergoes an intermolecular Claisen-type condensation involving three substrate molecules to form ethyl 2,4-dicyano-2-[2-cyanoacetyl -3 -oxo] -butanoate. Self

condensation ethyl cyanoacetate in the presence of triethyl phosphite and zinc acetate also takes place with the participation of three reagent

molecules giving triethyl 3-cyano-2,4-diiminopentane-1,3,5-tricarboxylate. Alkylation ethyl cyanoacetate with 1,2-dichloroethane, cycloalkylation products were obtained: cyclopropane and cyclohexane derivatives, as well as a polymer product. The reaction of ethyl cyanoacetate with 1,2,3-trichloropropane occurs in a 2:3 ratio giving ethyl 7-chloro-2-(2-chloroallyl)-2,5-dicyano-3-methylenoate-7-

enoate and 2,5-bis(2-chloroallyl)-3- methylenehexanedinitrile.

References

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10. Kazakov P.V., Odinets I.L., Laretina A.P. et al. Cycloalkylation of compounds in the series of phosphorus-substituted derivatives of acetic acid. Russ Chem Bull, 1990, vol. 39, pp. 1702-1708.

11. Schmidt D., Chandi C. Malakar, and Beifuss U. 2,3-Dihalo-1-propenes as Building Blocks in Cu(I)-Catalyzed Domino Reactions: Efficient and Selective Synthesis of Furans. Organic Letters, 2014, vol. 16(18), pp. 4862-4865.

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1. Alexander V. Kel'in. Recent Advances in the Synthesis of 1,3-Diketones. Current Organic Chemistry, 2003, 7(16), pp. 1961-1711.

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3. Zhong Chen et al. Pyrrolopyridazine MEK

inhibitors. Bioorqanic Medicikal Chemistry Letters. 2006, vol. 16(3), pp. 628-632.

4. Guarin, Serqio Andres Perez. Photophysical Crystallographic, and Electrochemical Characterization of Symmetric and Unsymmetric Self-Assembled Conjugated Thiopheno Azomethines. J. Org. Chem. 2007, vol. 72, no. 7, pp. 2631-2643.

5. Michail N. Elinson et al. Electrochemical Cyclotrimerization of Cyanoacetic Ester into trans-1,2,3-Tricyanocyclopropane-1,2,3-Tricarboxylate. Mendeleev Communications. 1993, no. 5, pp. 192-193.

6. Takaya Nikaru et al. Iridium Hydride Complex Catalyzed Addition of Nitriles to Carbon-Nitrogen Triple Bonds of Nitriles. J. Am. Chem. Soc. 1998, vol. 120, no. 17, pp.

ETlL SlANOASETAT 3SASINDA SlNTEZ

V.M. Ismayilov, N.N. Yusubov N.D. Sadixova,, R.A. Qasimov, I.A. Mammadov, F.M. Muradova

Baki Dövldt Universiteti AZ 1148 Baki, Z. Khalilov küg., 23 e-mail: yniftali@gmail.ru

Xülasa: Etil siyanoasetat DMSO-da artiq kalium §araitinda ü? substrat molekulunun i§tiraki ila öz-özüna kondensla§arak molekullararasi Claisen tipli kondensasiyaya maruz qalir va etil 2,4-disiyano-2-[2-siyanoasetil-3-okso]butanoat amala gatiri. Trietilfosfit va sink asetatin i§tiraki ila etil siyanoasetatin öz-özünün kondensla§masi da ü? reagent molekulunun i§tiraki ila trietil 3-siano-2,4-diiminopentan-1,3,5-trikarboksilat verir. Etil siyanoasetatin 1,2 -dixloretan ila alkilla§masi naticasinda tsikloalkilla§ma mahsullari alda edilmi§dir: tsiklopropan va tsikloheksan töramalari, ham?inin polimer xarakterli birla§malar alinmi§dir. Etil siyanoasetatin 1,2,3-trixloropropan ila reaksiyasi 2:3 nisbatinda ba§ verir va etil 7-xloo-2-(2-xloroalil)-2,5-disiyano-3-metilenoat-7-enoat va 2,5-bis(2-xloroalil)-3-metilenheksan dinitril alinir. A^ar sözlar: öz-özüna kondensla§ma, trietilfosfit, dixloretan, trixlorpropan

СИНТЕЗ НА ОСНОВЕ ЭТИЛЦИАНОАЦЕТАТА

В.М. Исмаилов, Н.Н. Юсубов, Н.Д. Садыхова, Р.А. Гасымов, И.А. Мамедов, Ф.М. Мурадова

Бакинский государственный университет AZ1148 Баку, ул. З.Халилова, 23 e-mail: yniftali@gmail. ru

Аннотация: Показано, что самоконденсация этилцианоацетата в условиях избытка поташа в ДМСО подвергается межмолекулярной конденсации типа Кляйзена с участием трех молекул субстрата с образованием этил 2,4-дициано-2-[2-цианоацетил-3-оксо]бутаноата. Соконконденсация этилцианоацета в присутствии триэтилфосфита и ацетата цинка протекает также с участием трех молекул реагента, давая триэтил-3-циано-2,4-дииминопентан-1,3,5-трикарбоксилат. Алкилированием этилцианоацетата с 1,2-дихлорэтаном получены продукты циклоалкилирования: циклопропановые и циклогексановые производные, а также продукт полимерного характера. Реакция этилцианоацетата с 1,2,3-трихлорпропаном протекает в соотношении 2:3, давая этил 7 -хлор-2-(2-хлораллил)-2,5-дициано-3-метиленоат-7-еноат и 2,5-бис(2-хлораллил)-3-метиленгександинитрил. Ключевые слова: самоконденсация, триэтилфосфит, дихлорэтан, трихлорпропан