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Isoindole derivatives R 0140 Sulfur Ylides. Part 13. Synthesis and Intramolecular Cyclization of Keto-Stabilized Sulfur Ylides. -Novel keto-stabilized sulfonium mono-and bisylides (VII), (XVII) and (XIII) are synthesized and their behavior under conditions of intramolecular cyclization is studied. Only α-ylide (XVII) undergoes an intramolecular cyclization furnishing pyrrolizidinedione derivative (XVIII). -(GALIN, F. Z.; SAKHAUTDINOV, I. M.; LAKEEV, S. N.; EGOROV, V. A.; FATYKHOV, A. A.; MAIDANOVA*, I. O.; Russ.

Regiospecific synthesis of conjugates containing a diterpenoid fragment and a pyrazole-ring pharmacophore by 1,3-dipolar cycloaddition of diazomethane to allenoates in the presence of Et 3 N was demonstrated.Pyrazoles are very important heteroaromatic compounds due to their broad distribution in natural products and pharmacologically active compounds [1-3]. Many pyrazole-containing compounds such as Celebrex [4], rimonabant [5], and Viagra [6] were successfully commercialized as drugs. Methyl maleopimarate (MEMPA) was obtained by the known method from levopimaric acid and maleic anhydride [7,8] and is a convenient and available reagent for synthesizing compounds with anti-inflammatory, antiulcer, fungicidal, and other activities [9][10][11][12]. In continuation of research on potential biologically active compounds, we synthesized conjugates with a diterpene fragment and pyrazole-ring pharmacophore. The key reaction was 1,3-dipolar cycloaddition of diazomethane to allenoates.Allenes 4a-c were synthesized from N-substituted amino acids 2a-c, which were obtained via condensation of MEMPA (1) with glycine, E-alanine, and J-aminobutyric acid in refluxing DMF. The reaction of N-substituted amino-acid chlorides 2a-c with Et 3 N passed through ketenes 3a-c, which reacted with methyl(triphenylphosphoranylidene)acetate to give allenoates 4a-c in yields of 63, 67, and 70%, respectively [13] (Scheme 1). The structures of the synthesized allenes were proved by physicochemical analytical methods. Thus, 13 C NMR spectra were characterized by resonances for two terminal allene C atoms C-2c and C-4c at G 96.13 and 91.17 ppm for 4a; 90.16 and 89.7 ppm, 4b; 91.86 and 88.56, 4c; and also central C atom C-2c at G 210.37 ppm for 4a; 212.89, 4b; and 212.44, 4c.

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