Highly Convergent One‐Pot Four‐Component Regioselective Synthesis of Spiro‐pyranopyrazoles and Oxa‐aza‐[3.3.3]propellanes |
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| Authors: | Abdolali Alizadeh Fahimeh Bayat |
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| Affiliation: | 1. Department of Chemistry, Tarbiat Modares University, P.O. Box 14115‐175, Tehran, Iran, (phone: +98‐21‐88006631;2. fax: +98‐21‐88006544) |
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| Abstract: | A concise and efficient route for the synthesis of spiro‐pyranopyrazoles and oxa‐aza‐3.3.3]propellanes by simple regioselective multicomponent reaction of ninhydrin, malononitrile, hydrazine derivatives, and β‐keto esters or dimethyl acetylenedicarboxylate was developed. This protocol provides an alternative method for combinatorial and parallel syntheses in drug discovery. The value of this method lies in its simplicity, regioselectivity, and good yields. The structures of 3 and 4 were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS). A plausible mechanism for this type of reaction is proposed (Schemes 2 and 3). |
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| Keywords: | [3 3 3]Propellanes Spiro‐pyranopyrazoles Ninhydrin Hydrazine derivatives Malononitrile |
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