R 30 Reaction of N-substituted 2-oxochromen-3-carboxamides with bromoderivatives of zinc enolates prepared from alkyl 2,2-dialkyl-4,4-dibromo-3-oxoalkanoates and zinc [Electronic resource] / V. V. Shchepin, P. S. Silaichev, N. Yu. Russkikh, M. I. Vahrin, M. I. Kodess // Russian Journal of Organic Chemistry (Translation of Zhurnal Organicheskoi Khimii). - 2006. - Vol. 42, № 8. - P1157-1163 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ZINC ENOLATES -- CARBOXAMIDES -- E-POSITION Аннотация: Zinc enolates obtained from ethyl 2,2-dialkyl-4,4-dibromo-3-oxobutanoates and zinc react with N-substituted 2-oxochromen-3-carboxamides forming ethyl 3-(1a-(R3-carbamoyl)-2-oxo-1a,7b-dihydrocyclopropa[c]chromen-1-yl)-2,2-dialkyl-3-oxopropanoate isomer with a Z-position of methine hydrogens. Zinc enolates prepared from alkyl 2,2-dialkyl-4,4-dibromo-3-oxopentanoates and-hexanoates and zinc react with N-substituted 2-oxochromen-3-carboxamides to give rise to esters of 3-(1-alkyl-1a-(R3-carbamoyl)-2-oxo-1a,7b-dihydrocyclopropa-[c]chromen-1-yl)-2,2-dialkyl-3-oxopropanoic acid as isomers with the E-position of the methine proton and the alkyl substituent. The reaction carried out in the presence of small quantities of THF and HMPA leads to the formation of 9c-alkyl-2-R3-9b,9c-dihydro-5-oxa-2-azacyclopenta[2,3]-cyclopropa[1,2-a]naphthalene-1,3,4-triones. Zinc enolates from alkyl 2,2-dialkyl-4,4-dibromo-3-oxopentanoates and-hexanoates and zinc with the secondary amides of 2-oxochromen-3-carboxylic acid form alkyl 3-(2-oxo-1a-(piperidinocarbonyl)-and 3-(6-R1-1a-(morpholinocarbonyl)-2-oxo-1a,7b-dihydrocyclopropa[c]chromen-1-yl)-2,2-R2,R2-3-oxopropanoates as single geometrical isomers \\\\Expert2\\nbo\\Russian Journal of Organic Chemistry\\2006, 42 (8), 1157.pdf |