Ueber Tetra‐ und Hexahydrocarbazolverbindungen und eine neue Carbazolsynthese. (Mitbearbeitet von. A. Witte und W. Bothe.)

Synthesis of the Indole Nucleus

“…However, this explanation seems to be unlikely to account for the isolation, in 4% yield, of 2-phenylindole from the Synthesis of the lndole Nucleus 297 zinc chloride indolization of 4-chloroacetophenone 2,6-dichlorophenylh y d r a~o n e .~~~ b. REARRANGEMENTS OF ALKYL GROUPS. That indolization of ethyl pyruvate 2,6-dimethylphenylhydrazone (191) when heated with zinc chloride gave a very small yield of ethyl 4,7-dimethylindole-2-carboxylate (193),87 a product that could only have arisen from migration of a methyl group, was corroborated by the results obtained when acetophenone 2,6-dimethylphenylhydrazone was heated with zinc chloride in nitrobenzene". 241 (Eq.…”

Dramatic liquid-phase dehydrogenation rate enhancements using gas-phase hydrogen acceptors

“…These routes are based mainly around the liquid-phase dehydrogenation of 1,2,3,4-tetrahydrocarbazole (THCZ) (Fig. 1a) developed from Borsche carbazole synthesis [9]. A number of reducing agents [10] have been examined, including lead oxide as well as heterogeneous catalysts, such as Raney Ni [11] and supported Pd/C [12].…”

On 1,2‐benzisoxazole‐3‐acetic acid and 3‐methyl‐1,2‐benzisoxazole: a restatement

“…First, the starting material used in our synthesis, a liquid described as 3-methyl-1,2-benzisoxazole (I) (2), proved on further examination to be a rough mixture in which the isomeric 2-methyl-benzoxazole (ll), apparently formed by a Beckmann type rearrangement (3), was often predominant (4). Under the reaction conditions used in our former paper (I), the only reactive compound in the mixture was found to be 11, which underwent the Claisen condensation to give the already known series of products leading to benzoxazole-2-acetic acid (111) (5). For these reasons all the compounds described in our former paper as benzisoxazole derivatives are to be considered identical to the corresponding members of the isomeric benzoxazole series: a comparison of the physical constants confirms this restatement.…”