Abstract
Twelve new 5-[(5-trifluoromethyl-5-hydroxy-4,5-dihydro-1H-pyrazol-1-yl)-1-propan-1-one-3-yl]-2-methyl-7-trifluoromethylpyrazolo[1,5-a]pyrimidines were prepared by cyclocondensation between 2-methyl-7-trifluoromethylpyrazolo[1,5-a]pyrimidine-5-propanoyl hydrazide derived from 2-methyl-5-(methylpropanoate-3-yl)-7-trifluoromethylpyrazolo[1,5-a]pyrimidine and a series of versatile 1,1,1-trifluoro-4-alkoxy-3-alken-2-ones [F3CC(O)C(R2)=C(R1)OMe where R1 = H, Me, (CH2)2CHCMe2, (CH2)2Ph, (CH2)2CO2Me, Ph, 4-MeC6H4, 4-MeOC6H4, EtO and R2 = H; R1, R2 = -(CH2)4-, -(CH2)5-; R1 = Ph and R2 = Me]. The structures of new propionyl-spaced biheterocycles were derived from 1H, 13C, and 19F nuclear magnetic resonance (NMR) spectroscopy and mass spectrometric (MS) data.
Highlights
There has been increasing interest in the chemistry of organic trifluoromethyl compounds, largely due to the fact that they show enhanced biological activity and can be used as medicinal or agricultural chemicals, in addition to their role in the development of new potential technological materials
The reaction between 3e and 3-amino-5-methyl-1H-pyrazole was performed under conditions described previously[22] and there was exclusive formation of 2-methyl-5-(methylpropanoate-3-yl)-7trifluoromethylpyrazolo[1,5-a]pyrimidine 1 (Scheme 1).[22]
We present a novel method for synthesizing biheterocyclic products, demonstrating the versatility of precursors methyl 7,7,7-trifluoro-4-methoxy-oxohept6-enoate in cyclocondensations [3 + 3] and [3 + 2]
Summary
There has been increasing interest in the chemistry of organic trifluoromethyl compounds, largely due to the fact that they show enhanced biological activity and can be used as medicinal or agricultural chemicals, in addition to their role in the development of new potential technological materials.
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