反应详情

A key reagent in the preparation of many of the compounds according to the invention is 8-Br-cAMP. Up until now, reports in the literature only refer to small scale preparations (e.g. <100 mg) of this material using dilute (0.1M) solutions of cAMP in an acetic acid/acetate medium. Attempts to use similar dilute conditions in larger scale work resulted in problems due to the large volumes of solvent required. We have now found that the procedure may be scaled up using concentrated solutions of cAMP with a concentrated buffer to scavenge the HBr that is produced during the reaction of cAMP with bromine. By using concentrated cAMP solutions, a two-fold benefit is also achieved—the proportion of the 8-Br-cAMP product that is precipitated out as if forms is optimised (thus making product collection easier) and the cAMP(H) starting material contributes to the buffer system. Thus for example 0.2M cAMP(H) and 0.4M sodium acetate creates a buffer system equivalent to 0.2M NaOAc/AcOH with a pH which remains stable during the bromination at about 4.7.

1. customA key reagent in the preparation of many of the compounds
2. additionto use similar dilute conditions in larger scale work
3. customresulted in problems due to the large volumes of solvent