C11(S)
O
O11
C21(R)
N
H
2
N21
C31(R)
O
H
O31
C41(S)
O
H
O41
C51(R)
O
O51
C61
O
H
O61
C12(R)
N
H
2
N12
C22
C32(S)
N
H
2
N32
C42(R)
C52(R)
O
O52
C62(S)
O
H
O62
C13(S)
C23(R)
O
H
O23
C33(S)
O
O33
C43(R)
O
O43
C53
O
H
O53
C14(R)
C24(R)
N
H
2
N24
C34(R)
O
H
O34
C44(S)
O
H
O44
C54(S)
O
O54
C64
N
H
2
N64