Aug., 1948
2763
THEADDITION OF ACYLAMIDOMALONATES TO ACROLEIN [CONTRIBUTION PROM THE CHEMICAL LABORATORIES, GENEXAL MILLS,INC.]
1,4-Addition Reactions. I. The Addition of Acylamidomalonates to Acrolein'" BY OWEN A. MOBAND DONALD T. WARNER The 1,Caddition of ethyl acetamidomalonate to acrolein proceeded smoothly in an alcoholic solution in the presence of catalytic quantities of sodium ethoxide. Because of the exothermic character of the reaction, the acrolein was added a t a slow rate to a stirred suspension of ethyl acetamidomalonate. Concentration of the neutralized solution yielded y-acetamido-y,y-dicarbethoxybutyraldehyde I as a straw-colofed, viscous oil. The action of phenylhydrazine on either the original reaction mixture or the viscous oil yielded the crystalline phenylhydrazone of compound I in 65-85y0 yield. The 1,4-addition of ethyl acetamidomalonate to acrolein R' R' also proceeded smoothly in NaOEt R-C!!-COOEt CHFCHCHO R-C!!-COOEt the absence of alcohol when benzene was used as the solH I CHs vent and the phenylhydra\lCH&HzCH(OEt)n I CHFCHCN zone was obtained in 87y0 FHz HoH \ I yield directly from the reI R' CHO action mixture. I The reaction between R-C-COOEt I* CH'CoNH' R' = ethyl phthalimidomalonate I and acrolein yielded 7,y-diCH z = iR' = I carbethoxy- y -phthalimdoCH z butyraldehyde I1 which was 'I1' = CHaCoNHpR' = CN characterized as the phenylCN I hydrazone and the 2,4-diniSnClz trophenylhydrazone. Ethyl acetamidocyanoacetate R' IHCl R' yielded a crystalline adduct R-C!-COOEt (r-acetamido-y-carbethoxyI 7-cyanobutyraldehyde) CHI which was characterized as CHo I the crystalline 2,Cdinitrophenylhydrazone. I CHiOH The structure of the aldeIV, R=CHoCONH, R' = COPEt hydo compound I was VI, R CHaCONH, R' = COOEt proved by two d8erent spnNH, theses. The first method R' involved the alkylation of I I ethyl acetamidomalonate R-C-CONHr with 6-chloropropionaldeCHz I hyde diethylacetal. Hydrolysis of the product with I CHI dilute acid gave compound I I. In the second synthesis, CHiOH ethyl a-acetamido-a-carbCONHi V, R = CHsCONH. R' ethoxy - y - cyanobutyrate' This paper describes the successful 1,Caddition was reduced by the action of stannous chloride of three such compounds (ethyl acetamidomalo- and hydrogen chloride.2 The resulting crystalnate, ethyl phthalimidomalonate and ethyl aceta- line complex was readily hydrolyzed with warm midocyanoacetate) t o acrolein. The products, water to I. As a by-product there resulted a crysobtained in excellent yields, have structures I, I1 talline compound melting at 181-182'. The anand 111,respectively. (1) Albvtson and Archer, THIS JOURNAL, 47, 2043 (1946).
The 1,Caddition reactions between malonate systems and a,p-unsaturated aldehydes have not been reported. Instead, under the conditions employed, a Knoevenagel condensation occurs and the reaction involves a 1,a-addition. However, the latter reaction requires two a-hydrogen atoms for completion (addition followed by loss of water) whereas the former reaction requires only one ahydrogen atom. Since both reactions, 1,2-addition and 1,4-additionJ are reversible, it appeared that a 1,li-addition reaction of acrolein might be realized provided the addend possessed only one, but sufficientlyreactive, a-hydrogen atom.
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(1.) Paper No, Wl Journat Rerien, Riuarr$ kkrrntoria, Ccnerd MiUa, insR
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(2) (a) Stephen, J . Ckm. SOE.,lSYl 1974 (1886) I
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