Ketone Tosylhydrazones Research Articles

Steric effects in the reactions of αβ-unsaturated ketonep-tolylsulphonylhydrazones: a route to 1,2-benzodiazepines via 1,7-ring closure of 1,1-diaryl-3-diazoalkenes

The influence of steric effects and substituents on the reactions of the sodium salts of αβ-unsaturated ketone tosylhydrazones has been studied. The tosylhydrazone salts of acyclic αβ-unsaturated ketones and those of 2-methylenecyclohexanones underwent ready thermal 1,5-ring closure to give pyrazoles but the reactions of some 2-methylenecyclopentanone tosylhydrazones were atypical. Although 2-methylenecyclopentanone tosylhydrazone salts having a β-hydrogen atom cyclised to give 1H-pyrazoles in high yield, the ββ-dialkyl and the ββ-diaryl analogues both failed to give 3H-pyrazoles; the former decomposed by a carbenic route to give dienes and the latter underwent 1,7-ring closure to give 3H-1,2-benzodiazepines. The effect of solvent proticity on some of these reactions has been investigated, and the mechanisms of pyrazole and benzodiazepine formation are discussed. The 13C n.m.r. spectra of 3H-pyrazoles, 3H-1,2-benzodiazepines, and 1H-2,3-benzodiazepines show that ring size strongly affects the chemical shift of the saturated carbon atom attached to the azo-group.

Reactions of Tosylhydrazide Derivatives Having Olefinic Groups

Abstract When α,β-unsaturated ketone tosylhydrazones (5) were heated in 85% aqueous acetic acid, a smooth decomposition was induced and β-tosylketones (4) were obtained in fair yields. Tosylhydrazones, devoid of an olefinic group in the specified position, failed to undergo the present reaction. When allyl halides (17) were reacted with the anion of tosylhydrazide in DMSO, substitution occurred on the N-1 of tosylhydrazide, unlike as in the case of the reaction of chlorides with tosylhydrazide in pyridine, which effected the substitution on N-2. On warming in acetic acid, these 1-allyltosylhydrazides (18) afforded olefins (19) in fair yields, with a complete allylic rearrangement. A concerted cyclic mechanism was proposed for the 5→4 and 18→19 reactions.

Synthesis of 1<I>H</I>-Pyrrolo [1, 2-a] indole Derivatives. II. Synthesis of 7-Nitro-2, 3, 9, 9a-tetrahydro-1<I>H</I>-pyrrolo [1, 2-a] indoles

In connection with synthesis of the ring system of mitomycins, 1H-pyrrolo [1, 2-a] indoles (HI to VI) were synthesized. Indole (XVIII) was synthesized by the reaction of aminodiester (XVII) and 2-chloro-5-nitrobenzaldehyde in one step. Dieckmann reaction of XVIII afforded pyrroloindole (III). By the carbene cyclization reaction, tosylhydrazone (XX) of aldehyde (XIX) gave the compound IV in poor yield, and tosylhydrazones (XXV and XXX) of ketones (XXIV and XXVIII) afforded the desired pyrroloindoles (V and VI) in good yield, respectively.