0000000000433224
AUTHOR
Isabella D'asdia
Polycondensed nitrogen heterocycles. XXII. A new synthesis of 5,6-dihydro-7H-pyrazolo[1,5-d][1,4]benzodiazepin-6-ones
A new synthesis of 2-methyl-9-R'-10-R-5,6-dihydro-7H-pyrazolo[1,5-d][1,4]benzodiazepin-6-ones (4a-c) is deserved. Reaction of ethyl hydrazinoacetate hydrochloride with 1,3-diketones 1a-c gave both 3-methyl-5-(4R'-5-R-2-nitrophenyl)pyrazol-1-yl-acetate acids (2a-c) and the corresponding ethyl esters 3a-c. Reduction with the appropiate reducing agent of compounds 2a-c and 3a-c directly gave the title compounds. Compound 4a showed insecticidal properties against the house fly.
Polycondensed nitrogen heterocycles. Part19. Pyrrolo[1,2-f]phenanthridines by pschorr-type cyclization brought about by hypophosphorous acid
Pyrrolo[1,2-f]phenanthridines were prepared in good yields by the diazotization in acetic acid of the amines la,b and subsequent treatment with hypophosphorous acid. The necessity for hypophosphorous acid in the reaction was demonstrated.
Polycondensed nitrogen heterocycles. X. 5,6,7,8-Tetrahydropyrrolo[1,2-e][1,5]benzodiazocin-7-ones. A new ring system
The synthesis of a new heterocyclic ring system is described. Condensation of 1,4-diketones 1a,b with β-alanine gave the substituted propionic acids 2a,b which upon reduction with palladium on charcoal afforded compounds 3a,b. Title compounds 4a,b were obtained by refluxing 3a,b in toluene with p-toluenesulphonic acid as catalyst.
Preparation of monohalopyrroles
Monobromo-, monochloro- and monoiodopyrroles are obtained in excellent yields by using N-halosuccinimides in dimethylformamide as halogenating agents.