The reversible inhibitor scaffold that was optimal in terms of potency and selectivity was retained from the previous series , with only the n-butyl substituent on the central amine replaced by a methyl group, to balance the lipophilicity (Scheme 2). We have already established that positions 6 and 7 on the indole ring are suitable for the introduction of the carbamate warhead, and therefore only 6-and 7-substituted indolyl carbamates were designed and compared (Tables