It is known that the combination of pharmacophoric fragments in a single molecule often leads to a strengthening and/or to a change in the pharmacological properties of the molecule. In this connection there is significant interest in studying compounds which contain indole and -aminobutyric acid (e.g. -butyrolactone) fragments in the molecule. A single compound of this type has been synthesized previously [1] but the method proposed by the authors is inconvenient and is not sufficiently general. Some time ago we carried a simple synthesis of the 2-alkyl-3-(indol-3-yl-and -2-yl)isoindol-2-ones 1 and 2 [2]. N O R 4 N R 1 R 2 N N O R 4 R 3 R 1 1 2We suggested that using this method can also prove useful for synthesizing the 1-alkyl-5-(indol-3-yl)-pyrrolidin-2-ones 3a-k. The 5-hydroxypyrrolidin-2-ones 4a-d needed for this were prepared from succinic anhydride and the corresponding amines 5a-d.The intermediate succinamic acids 6a-d were readily prepared by mixing succinic anhydride with the corresponding amine in stoichiometric quantities in chloroform. Their cyclization to the corresponding imides 7a-d occurs with prolonged refluxing in benzene in a DeanStark apparatus in the presence of equivalent

have been obtained in good yield on amidoalkylation of indoles with 2-alkyl-3-hydroxyphthalides in chloroform at room temperature in the presence of catalytic quantities of boron trifluoride etherate. When a substituent is present at position 3 of the indole, attack is directed to position 2 of the indole nucleus.

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In previous work [1], we reported the synthesis of new 1-alkyl-5-(1H-indolyl)pyrrolidin-2-ones 1 and 2, and found that these compounds do not undergo the Plancher rearrangement during their formation.However, in a continuation of this research, we found that the 1 H NMR signal at 6.88 ppm, which belongs to the indole system pyrrole ring proton in the product obtained from N-methylindole (3e) and 1-benzyl-5-hydroxypyrrolidin-2-one (4a), appears almost exactly in the middle between the signals for H-3 (6.45 ppm) and H-2 (7.26 ppm) in unsubstituted indole [2]. Thus, the spectrum does not permit us to establish the substitution pattern of the indole system, i.e., to clearly distinguish between the structures 1d and 2b (Table 1).In order to resolve this problem, we investigated the mass spectrometric behavior of compounds 1a-g and 2a.Compounds 1a-g and 2a were prepared from the indoles 3a-f and 1-alkyl-5-hydroxypyrrolidin-2-ones 4a and 4b according to our published procedure [1].The proposed schemes for electron impact fragmentation of indoles 1a-g and 2a are given in Figures 1-3. The numbering sequence of the fragment ions and the quantitative characteristics of this fragmentation are given in Tables 2 and 3.

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Synthesis and Spectral Features of New 1-Alkyl-5-(indol-2(3)-yl)pyrrolidin--2-ones. -(MYSOVA, N. E.; KOVROV, A. E.; SADOVOY*, A. V.; SVIRIDOVA, L. A.; GOLUBEVA, G. A.; VOROZHTSOV, N. I.; Chem. Heterocycl.

New activated indolylpyrrolidones—their methylthiopyrrolinium salts—in the reactions with several CH‐acids were studied. 2‐Nitromethylene‐ and 2‐dicyanomethyleneindolylpyrrolidines were obtained from 5‐indolyl‐2‐methylthiopyrrolinium salts with good yields. The reduction in these nitro compounds yields the respective aminomethylpyrolidines. The rigid structure of the starting compounds has significant stereoelectronic requirements of nucleophilic agents.