Table 1.

Structural and analytical properties of the α-MSH analogs and bioconjugates.

	Compound	m/z Calc. for [M+2H]2+	m/z Meas. 1 for [M+2H]2+	Deviation (ppm)	Rt (min) 2
1	H-NleEHFRWGK-NH2	536.2960	536.2954	1.1	6.0
2	Dau = Aoa-NleEHFRWGK-NH2	827.3884	827.3876	1.0	8.4
3	H-NleEHFRWGK(Dau = Aoa)-NH2	827.3884	827.3875	1.1	8.1
4	H-SYSNleEHFRWGKPV-NH2	802.9202	802.9192	1.2	7.2
5	Dau = Aoa-SYSNleEHFRWGKPV-NH2	1094.0127	1094.0114	1.2	8.6
6	H-SYSNleEHFRWGK(Dau = Aoa)PV-NH2	1094.0127	1094.0115	1.1	8.6

¹ ESI-MS data measured on a Thermo Scientific Q Exactive Focus mass spectrometer. ² Analytical UHPLC was performed using a Waters Acquity UPLC BEH C18 1.7 μm column (2.1 × 50 mm), at 40 °C; eluent A: water + 0.1% formic acid, eluent B: 80% acetonitrile + 0.1% formic acid. The following gradient was used: 0 min 2% B, 1 min 2% B, 17 min 100% B, 17.5 min 100% B, 18 min 2% B, 21 min 2% B. The flow rate was 300 μL min⁻¹. Dau stands for daunomycin, Aoa stands for aminooxyacetic acid, Nle stands for norleucine.