Synthesis of Spiropyrimidodiazepines and Spirodiazepinopurines by Tandem Nitroso‐ene/Diels–Alder Reactions |
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Authors: | Fang‐Li Zhang Andrea Vasella |
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Institution: | Laboratorium für Organische Chemie, Departement Chemie und Angewandte Biowissenschaften, ETH Zürich, HCI, CH‐8093 Zürich |
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Abstract: | New spirocyclic heterocycles 8, 16, 19/20, 25, 27 , and 30 derived from pyrimido4,5‐b]1,4]diazepin]‐8′(9′H)‐one were synthesised by a tandem nitroso‐ene/Diels–Alder reaction of 4‐(alkenoylamino)‐5‐nitrosopyrimides. The crystal structure of 16 was established by X‐ray analysis. It is characterised by four pairs of intermolecular H‐bonds linking every two molecules in the unit cell. Sequential imine reduction and intramolecular condensation of the C(4′)‐(acylamino)‐pyrimido4,5‐b]1,4]diazepines 27 and 30 led to the 1,4]diazepino1,2,3‐gh]purines 28 / 29 and 31 , respectively. |
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Keywords: | Ene reaction Pteridines Purines Diels– Alder reactions Cycloadditions Nitroso compounds Pyrimidodiazepines |
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