... (1949), p. 1440. 11. C. Avendaño, T. Ramos, E. Gómez-Molinero. J. Heterocyclic Chem., 22 (1985), p. 537. 12. ... Heterocyclic synthesis using ethyl carboethoxyformimidate. 1982, Tetrahedron Letters more. Alexander McKillop, Alan Henderson, Partha S. Ray, Carmen Avendano,