Abstract: A method for producing adenine compound (1): wherein m and n are independently an integer of 2 to 5, R1 is C1-6 alkyl group, R2 and R3 are the same or different, and hydrogen atom, or C1-6 alkyl group, or R2 and R3 are combined with an adjacent nitrogen atom to form pyrrolidine, morpholine, piperidine, piperazine, etc., and R4 is C1-3 alkyl group, which comprises a step of reacting compound (2): and compound (3): in the presence of a boron-containing reducing agent.

Abstract: A method for preparing compound (4): wherein m and n are independently an integer of 2 to 5, R1 is C1-6 alkyl group, R2 and R3 are combined with an adjacent nitrogen atom to form pyrrolidine, morpholine, thiomorpholine, etc., and R4 is C1-3 alkyl group, or a pharmaceutically acceptable salt, which is useful as a medicament, which comprises step (a) for preparing compound (2): wherein m, n, R1, R2 and R3 are the same as defined above, or its salt which comprises subjecting compound (1): wherein k is an integer of 1 or 2, R is hydrogen atom, halogen atom, etc., or a salt thereof to debenzylation reaction, and then step (b) for preparing compound (4) or a pharmaceutically acceptable salt which comprises reacting compound (2) or its salt prepared in the above step (a) or salt thereof and compound (3): wherein R4 is C1-3 alkyl group, in the presence of a boron-containing reducing agent.

Abstract: A method for producing adenine compound (1): wherein m and n are independently an integer of 2 to 5, R1 is C1-6 alkyl group, R2 and R3 are the same or different, and hydrogen atom, or C1-6 alkyl group, or R2 and R3 are combined with an adjacent nitrogen atom to form pyrrolidine, morpholine, piperidine, piperazine, etc., and R4 is C1-3 alkyl group, which comprises a step of reacting compound (2): and compound (3): in the presence of a boron-containing reducing agent.