A facile convergent total synthesis of the selective, potent, and orally active V 2 nonpeptide antagonist, SR-121463, was developed by modification of the discovery route. One of the late intermediates, the sulfonyl chloride 1, was synthesized from 3-hydroxybenzoic acid (19) by regioselective sulfonation, O-methylation and amidation in four steps. Another late intermediate, indolin-2-one 2, was prepared from p-phenetidine (8) through the indolin-2-one 16, where the cyclohexanone moiety of 27 was introduced into the active 3-methylene group of 16 by sequential transformation using methyl acrylate and KOtBu. After formation of the cyclic ketal moiety of 13, its ring-opening was achieved by using NaBH 4 in the presence of CCl 3 COOH. The morpholino group in 2 was introduced in accordance with the discovery approach, starting from the 2-hydroxyethoxy derivative 14 through the tosyloxy derivative 15 with morpholine in a one-pot reaction. In this way, the indolin-2-one 2 was synthesized from 8 in six steps. Finally, acylation of the indolin-2-one 2 was achieved with the sulfonyl chloride 1 in the presence of KOtBu in dimethyl sulfoxide (DMSO) at room temperature. This synthetic route proved to be applicable for the large-scale synthesis of SR-121463.

Spirocyclohexylindolinone is used as a moiety in drug substances. A number of synthetic methods have been suggested to introduce the cyclohexyl ring into the C(3) position of N‐protected indolinones, which complicates their preparation. A previously developed, consecutive, one‐pot, multicomponent method is studied from a mechanistic aspect. We set out to clarify the details of this mechanism and the role of the acryl ester as a reagent and a protecting group in the same flask, by using theoretical and analytical methods, in order to optimise the preparative conditions. A mechanistic energy profile of the reaction is computed at the DFT level of theory. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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