Abstract
A convenient synthetic route for preparation of val uable synthetic intermediates - 1-(1- ethoxyethyl)-3-iodo-1H-pyrazole derivatives has been developed. During th is work protection reaction of N-H bond in substituted 3-iodo-1 H-pyrazole derivatives with ethyl vinyl ether and migration of ethoxyethyl protecting group was inves tigated. Synthetic possibilities of Sonogashira cross-coupling reactions of substituted 1-(1-ethoxy ethyl)-3-iodo-1H-pyrazole derivatives with phenylacetylene were studied and evaluated.
Highlights
Pyrazole scaffolds can be found in a number of small molecules possessing biological activity.[1,2]. It is used in design of new OLED materials.[3]
Substituted pyrazole derivatives may be used as ligands for transition metal-catalyzed reactions.[4]
One of the most common ways for the synthesis of 3-substituted pyrazole derivatives is based on the formation of pyrazole ring via condensation of functionalized 1,3-dicarbonyl compounds with hydrazines.[8]
Summary
Pyrazole scaffolds can be found in a number of small molecules possessing biological activity.[1,2] it is used in design of new OLED materials.[3]. Purification by column chromatography (ethyl acetate in n-hexane) gave the titled compound as slightly yellow oil, yield 74.9%, 5 g. Purification by column chromatography (ethyl acetate in n-hexane (1:4)) gave product 18 (Rf = 0.4) as slightly yellow oil, yield 55%, 1.65 g.1H NMR (400 MHz, DMSO-d6) δ: 1.06 (t, J 7.0 Hz, 3H, CH2CH3), 1.60 (d, J 6.0 Hz, 3H, CHCH3), 3.25 (dq, J 9.6, 7.0 Hz, 1H, CHHCH3), 3.47 (dq, J 9.6, 7.0 Hz, 1H, CHHCH3), 5.64 (q, J 6.0 Hz, 1H, NCH), 8.60 (s, 1H, Ar-H), 9.69 (s, 1H, CHO).13C NMR (100 MHz, DMSO-d6) δ: 15.1, 21.5, 64.1, 87.9, 100.4, 124.6, 135.4, 185.5.
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