Cyclisierungsreaktionen von Diazoalkenyl-phosphonsäureestern Synthese von Pyrazolyl- und 2,3-Benzodiazepinylphosphonsäureestern

Tosylhydrazones3 and4 of dialkyl 3-oxo-1-alkenylphosphonates1 and 1-oxo-2-alkenylphosphonates2, respectively, react with aqueous sodium carbonate to give the pyrazoles7 in excellent yields. Under analogous conditions the tosylhydrazone9 of diethylo-vinylbenzoyl phosphonate (8) affords diethyl 2-hydroxy-1-indanyl phosphonate (10). Upon thermolysis of the sodium salt12 generated from9 in anhydrousD M E, one obtains, depending on the reaction conditions, either the 1-H-benzodiazepinyl derivative14 or its 5H-isomer15. At room temperature the diazo compound13 cyclizes slowly to give14, which can be isomerized to15 by action of base.