4-Nitrophenyl 2-O-alpha-D-galactopyranosyl-alpha-D-mannopyranoside 79580-50-0 NGAPM Para-nitrophenyl 2-O-alpha-D-galactopyranosyl-alpha-D-mannopyranoside alpha-D-Mannopyranoside, 4-nitrophenyl 2-O-alpha-D-galactopyranosyl-