5,11-Dihydro-6H-pyrido(2,3-b)(1,4)benzodiazepin-6-one → 5,11-dihydro-11-[1-oxo-4-pentynyl]-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

22.4 ml of a 1.6 molar solution of n-butyl-lithium in n-hexane are added dropwise with stirring, at 0° C., to a suspension of 3.7 g (0.017 mol) of 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one in 150 ml of absolute tetrahydrofuran. After it has all been added, the mixture is stirred for a further 30 minutes and then mixed with a solution of 2.04 g (0.0175 mol) of 4-pentynoic acid chloride in 20 ml of tetrahydrofuran. The mixture is heated to 30° C. and stirred for a further hour. The reaction mixture is then poured into a saturated saline solution. The organic phase is diluted with ethyl acetate and, after being separated off, washed twice with saline solution, filtered over charcoal and evaporated to dryness in vacuo. The crude product is purified by column chromatography on silica gel using chloroform as eluant. 2.2 g (43% of theory) of colourless crystals were obtained, melting point 179°-180° C.

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