| Autor: |
Jacquot-Rousseau, Sandrine, Schmitt, Gérard, Khatyr, Abderrahim, Knorr, Michael, Kubicki, Marek M., Vigier, Estelle, Blacque, Olivier |
| Zdroj: |
European Journal of Organic Chemistry; March 2006, Vol. 2006 Issue: 6 p1555-1562, 8p |
| Abstrakt: |
Treatment of 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene [Cl2C=C(H)-N=CPh2] (1) with excess sodium isopropylthiolate or sodium thiophenolate in DMF yielded the 2-azabutadiene derivatives (RS)2C=C(H)–N=CPh2 (2) (2a R = iPr; 2b R = Ph). Nucleophilic attack of the sodium salt of ethyl thioglycolate on 1 afforded as the sole product the six-membered heterocyclic compound ethyl 2-ethoxycarbonylmethylthio-5,5-diphenyl-5,6-dihydro-4H-1,4-thiazine-6-carboxylate (5). The reaction is initiated by substitution of the two vinyl-bound chloro substituents to give {EtO(O=)CCH2S}2C=C(H)–N=CPh2 (2c) as intermediate. A mechanism that accounts for the subsequent cyclisation reaction is proposed. The 2-azabutadiene derivative (PhO)2C=C(H)–N=CPh2 (7) was obtained by the reaction of 1 with sodium phenolate. The regioselectivity of the incoming nucleophile is roughly correlated with its hardness/softness in accord with Pearson’s HSAB principle. The molecular structures of 2a,b, 5 and 7 were determined by single-crystal X-ray diffraction. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) |
| Databáze: |
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