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. 2023 Feb 2;15(2):498. doi: 10.3390/pharmaceutics15020498

Table 1.

Optimization of reaction conditions.

graphic file with name pharmaceutics-15-00498-i001.jpg

Entry a Solvent b Base T (°C) t (h) Yield (%) c 6a:7a e
1 [mPy](OTf)/H2O Et3N rt 2 50 90:10
2 [mPy](OTf)/H2O Et3N rt 24 51 80:20
3 [mPy](OTf)/H2O Et3N 50 2 67 96:4
4 [mPy](OTf)/H2O Et3N 85 2 32 95:5
5 [mPy](OTf)/H2O DBU 50 2 42 96:4
6 [mPy](OTf)/H2O DMAP 50 2 38 96:4
7 [mPy](OTf)/H2O NaOH 50 2 traces -
8 [mPy](OTf)/H2O K2CO3 rt 2 72 96:4
9 [mPy](OTf)/H2O K2CO3 50 2 85 96:4
10 d [mPy](OTf)/H2O K2CO3 50 2 90 97:3
11 d [Bmim]Cl/H2O K2CO3 50 2 75 95:5
12 d [Bmim][BF4]/H2O K2CO3 50 2 78 96:4
13 d DMF K2CO3 50 2 52 76:24
14 d DMSO K2CO3 50 2 64 82:18

a Reaction Conditions: enaminone 5a (1 eq), base (2.5 eq), hydrazonyl chloride 4a (1 eq) in 12 mL of solvent mixture. b IL/H2O 9:1 v:v; c isolated yield. d reaction conditions: enaminone 5a (1 eq), base (2.5 eq), hydrazonyl chloride 4a (1.3 eq) in 12 mL of solvent mixture. e regioisomeric ratio was determined by 1H NMR analysis of the crude reaction mixture (see Supplementary Materials).