Calcium Carbonate → diethyl N-{p-[N-((6RS)-2-methyl-4-oxo-3-pivaloyloxymethyl-3,4,7,8-tetrahydro-6H-cyclopenta[g]quinazolin-6-yl)amino]benzoyl}-L-glutamate

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Reaktionsschritte

A mixture of 6-bromo-2-methyl-3-pivaloyloxymethyl-3,4,7,8-tetrahydro-6H-cyclopenta[g]quinazolin-4-one (21 g), prepared as described in section (6) of Example 1, diethyl p-aminobenzoyl-L-glutamate (52.5 g), prepared as described in the Journal of Medicinal Chemistry, 1985, 28, 1428, calcium carbonate (27.5 g) and DMA (200 ml) was stirred and heated to 110° C. for 30 minutes. The mixture was cooled to ambient temperature. The mixture was evaporated and the residue was partitioned between ethyl acetate and water. The organic phase was dried (MgSO4) and evaporated. The residue was purified by column chromatography using initially a 1:1 mixture of hexane and ethyl acetate as eluant and then a 1:3 mixture of hexane and ethyl acetate as eluant. There was thus obtained a gum which on trituration under diethyl ether gave diethyl N-{(p-[N-((6RS)-2-methyl-4-oxo-3-pivaloyloxymethyl-3,4,7,8-tetrahydro-6H-cyclopenta[g]quinazolin-6-yl)amino]-benzoyl}-L-glutamate (13.5 g), m.p. 156° C.;

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