a) Compounds 1-3 are three of the most potent fragments from a recent screening study. For each compound, state the number of hydrogen bond donors and hydrogen bond acceptors. (3 marks)

b) Based on your donor/acceptor counts, briefly comment on the reliability of rules such as the “Rule of Three”. (1 mark)

c) What molecular property is LogP a measure of? (1 mark)

d) Compounds 1 and 3 both bind to the same pocket of the same target protein. Compare the features of the two structures, and use this to explain the term bioisosteres? (3 marks)

NH2 1 3