6
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1.2. Background of 2-Substituted Benzothiazoles
Zopolrestat
Antitumor agent
Fatty acid amide hydrolase inhibitor
7
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1.2.1. Main Synthetic Methods of 2-Substituted Benzothiazoles
entry 1 2 3 4
substrate
product
yield (%) 82 63c 75c 50c
5
80
6
69
7
55
8
75
9
81
23
b: isolated yield, c: reaction temperature was 120 °C
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4. Summary
1) transition-metal-free 2) tolerate many functional groups 3) staring material readily available
80d 82c 86c 79c
6
79
6
80
24
. 88
6
.91
6
86
24
60
III. Transition-Metal-Free Cyclization For the Preparation of 2-Substituted Benzothiazoles
20
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Table 1. Optimization of Reaction Conditions
