Table 1. Biological Activities of the Synthesized 5-Aminothiazolesⁱ.

compound	R2	R4	R5	IC50 (nM)a (95% CI)		αSyn dimerization at 10 μM (%)b	autophagy at 10 μM (%)c	ROS at 10 μM (%)d
KYP-2047e				<1f		87 ± 1	89 ± 3	88 ± 3
HUP-28g				130	(71–230)	75 ± 5	71 ± 6	95 ± 7
HUP-55e				5.0	(3.2–7.6)	85 ± 2	87 ± 3	85 ± 3
HUP-46	Ph(CH2)3–	Me	(S)-2-cyanopyrrolidin-1-yl	8000	(4900–13,000)	74 ± 2	77 ± 3	85 ± 11
7	Ph(CH2)3–	Me	pyrrolidin-1-yl	4800	(2100–11,000)	74 ± 2	87 ± 4	75 ± 9
8	Ph(CH2)3–	Me	piperidin-1-yl	210,000	(74,000–590,000)	82 ± 11	106 ± 10	73 ± 26
9	Ph(CH2)3–	Me	(R)-3-fluoropyrrolidin-1-yl	97,000	(25,000–380,000)	95 ± 1	95 ± 2	n.d.
10	Ph(CH2)3–	Me	(S)-2-hydroxymethylpyrrolidin-1-yl	95,000	(35,000–260,000)	99 ± 19	96 ± 3	n.d.
11h	Ph(CH2)3–	Me	(S)-2-carbamoylpyrrolidin-1-yl	80,000	(15,000–420,000)	94 ± 8	84 ± 3	86 ± 4
12	Ph(CH2)2–	Me	pyrrolidin-1-yl	47,000	(18,000–120,000)	107 ± 15	89 ± 2	59 ± 18
13	Ph(CH2)3–	Me	2-tetrazolylpyrrolidin-1-yl	n.d.	n.d.	111 ± 10	98 ± 5	86 ± 11
16a	3,4-dimethoxyphenyl–(CH2)3–	Me	pyrrolidin-1-yl	12,000	(4100–33,000)	92 ± 5	83 ± 6	48 ± 3
16b	4-cyanophenyl–(CH2)3–	Me	pyrrolidin-1-yl	340	(68–1700)	113 ± 9	96 ± 1	53 ± 4
16c	4-iodophenyl–(CH2)3–	Me	pyrrolidin-1-yl	9800	(2600–38,000)	n.d.	97 ± 3	n.d.
16d	2-pyridyl–(CH2)3–	Me	pyrrolidin-1-yl	7300	(4800–11,000)	96 ± 7	104 ± 4	57 ± 2
16e	3-pyridyl–(CH2)3–	Me	pyrrolidin-1-yl	7900	(5700–11,000)	105 ± 3	102 ± 5	60 ± 3
16f	3-pyridyl–(CH2)2–	Me	pyrrolidin-1-yl	3300	(2000–5300)	96 ± 8	108 ± 3	62 ± 5
16g	3-indolyl–(CH2)2–	Me	pyrrolidin-1-yl	5700	(3700–8600)	105 ± 3	83 ± 5	55 ± 3
16h	1-benzimidazolyl–(CH2)2–	Me	pyrrolidin-1-yl	62,400	(37,680–103,200)	86 ± 8	78 ± 5	n.d.
16i	2-benzimidazolyl–(CH2)2–	Me	pyrrolidin-1-yl	2100	(730–6300)	93 ± 2	101 ± 6	59 ± 3
16j	Ph(CH2)3–	isopropyl	pyrrolidin-1-yl	4000	(2600–6100)	90 ± 6	97 ± 3	85 ± 5
16k	3-indolyl–(CH2)2–	isopropyl	pyrrolidin-1-yl	5800	(12,000–79,000)	105 ± 8	100 ± 6	83 ± 4
16l	Ph(CH2)3–	H	pyrrolidin-1-yl	126,000	(49,350–340,500)	125 ± 21	87 ± 4	n.d.
17	N-methyl-3-indolyl–(CH2)2–	Me	pyrrolidin-1-yl	3900	(1900–7700)	89 ± 8	103 ± 3	n.d.

^aAssessed using recombinant porcine PREP with Suc-Gly-Pro-AMC as the substrate.

^bLuminescence signal percentage of DMSO control with SEM, assessed with a split Gaussia luciferase-based method using Neuro2A cells.

^cGFP signal percentage of DMSO control with SEM, assessed using HEK-293 cells stably expressing GFP-LC3B.

^dFluorescence signal percentage of DMSO control with SEM, assessed using a fluorogenic ROS assay.

^eResults reported by Kilpeläinen et al.¹⁸

^fThe assay is limited by the enzyme concentration of 2 nM for IC₅₀ values under this concentration; KYP-2047 is a slow, tight-binding inhibitor with a K_i-value of 0.02 nM.^25,26

^gResults except ROS assay reported by Kilpeläinen et al.¹⁶ or Pätsi et al.¹⁹

^hSynthesis intermediate.

ⁱn.d.: not determined.