The present invention concerns novel pharmaceutically active triterpene amine derivatives, pharmaceutical compositions containing the same, their use as medicaments, and the use of the compounds for the manufacture of specific medicaments. The present invention also concerns a method of treatment involving administration of the triterpene amine compounds. Specifically, the compounds are derivatives of betulinic acid having substitutions at one or more of the C-3, C-28 and C-19 positions as further described herein. The novel compounds are useful as antiretroviral agents. In particular, the novel compounds are useful for the treatment of Human Immunodeficiency Virus-1 (HIV-1).
An efficient method for the formation of macrocyclic dilactones via cyclization of (omega-carboxyalkyl)diphenylsulfonium salts 3 containing an ester linkage under mild conditions is described. These sulfonium salts 3 were cyclized in the presence of cesium carbonate under high-dilution conditions to give 11- to 16-membered dilactones 4 in good yields. The cyclization of sulfonium salt 22 was successfully carried out for the synthesis of 11-membered dilactonic pyrrolizidine alkaloid, 13,13-dimethyl-1,2-didehydrocrotalanine 23.