GB945319A - Derivatives of partially hydrogenated tetracenes and process for preparing them - Google Patents

Abstract

The invention comprises compounds of formula: <FORM:0945319/C2/1> wherein R1 represents a hydrogen or chlorine atom, R2 a hydrogen atom or an alkyl radical with 1-4 carbon atoms, R3 a hydrogen atom or a methyl group, and X a hydrogen atom or the group COOR4, R4 being an alkyl radical with 1 to 4 carbon atoms, a benzyl radical or a phenyl radical, and a process for the preparation thereof in which an aldehyde of formula: <FORM:0945319/C2/2> or <FORM:0945319/C2/3> wherein the grouping O-alkylene-O represents a radical of ethylene glycol or propandiol-1,3, is treated either (a) with a malonic acid ester <FORM:0945319/C2/4> in the presence of a basic condensing agent, and the product reacted with an alkali metal salt of an aceto-acetic ester CH3. CO-CH2-COOR4, or a mixture of an aceto-acetic acid ester and an alkali metal and an alkali metal alcoholate; or (b) with an aceto-acetic acid ester in the presence of the basic condensing agent, and the product reacted with an alkali metal salt of a malonic acid ester or a mixture of a malonic acid ester and an alkali metal alcoholate, and the reaction product treated with dilute acids followed by ring closure with a strongly basic condensing agent in the absence of oxygen. A list of starting materials is given and examples describe the preparation of desdimethylamino-6:12a-bisdesoxy-descarboxamido -4- carbethoxy-aureomycin -10- methyl ether and desdimethylamino -6:12abis desoxy - descarboxamido -4-aureomycin -10- methyl ether among others, and the products are used as intermediates in the preparation of pharmaceutically valuable compounds.