- Pyrazolopyrimidines: Synthesis, effect on histamine release from rat peritoneal mast cells and cytotoxic activity
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A series of 1H-pyrazolo[3,4-d]pyrimidines (3-6) substituted at positions 1 (R1 = Ph, H, tert-butyl and ribosetribenzoate), 4 (R2 = chlorine, nitrogen and oxygen nucleophiles), and 6 (dimethylamino) have been synthesized and their effect on the release of histamine from rat peritoneal mast cells measured. After chemical stimulation, (polymer 48/80), several compounds (i.e. 3b, 4a, 4b, 4d, 4g, 5a), produce inhibition two to three times higher (40-60%) than DSCG but this action is lower after preincubation. 4b (R1 = Ph, R2 = NHCH2Ph; 50-70% inhibition) and 5a (R1 = H, R2 = OMe; 50-55% inhibition) are the most active ones in both experiments. With ovoalbumin as stimulus, several pyrazolopyrimidines show inhibition similar to DSCG, the most active compounds being 6a-d (IC50 = 12-16 μM; R1 = ribosetribenzoate, R2 = methoxy and amino). Compounds 4e (R1 = t-butyl, R2 = OMe) and 4g (R1 = t-butyl, R2 = piperidino) are inducers of the release of histamine (60 and 150% increase). Compounds 4b and 4c showed cytotoxic activity (IC50 = 1 μg/mL) to HT-29 human colon cancer cells.
- Quintela, Jose M,Peinador, Carlos,Moreira, Maria J,Alfonso, Amparo,Botana, Luis M,Riguera, Ricardo
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