Synthesis of some novel α-cyanoketene-n, s-acetals derived from secondary aliphatic amines and their use in pyrazole synthesis
New α-cyanoketene-N,S-acetals 2(a–g) and β-dialkylamine-α-cyanoacrylates 3(g–i) were synthesized in good to excellent yields by the reaction of ethyl 2-cyano-3,3-bis(methylthio)acrylate 1 with secondary aliphatic amines (i.e., N-methylalkyl- and N-ethylalkylamines), and pyrrolidine, in the presence...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English English |
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Taylor & Francis
2013
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| Online Access: | http://psasir.upm.edu.my/id/eprint/30236/1/Synthesis%20of%20some%20novel%20%CE%B1.pdf |
| _version_ | 1796971700446822400 |
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| author | Al-Adiwish, Wedad M. Mohamed Tahir, Mohamed Ibrahim Wan Ahmad, Wan Yaakob |
| author_facet | Al-Adiwish, Wedad M. Mohamed Tahir, Mohamed Ibrahim Wan Ahmad, Wan Yaakob |
| author_sort | Al-Adiwish, Wedad M. |
| collection | UPM |
| description | New α-cyanoketene-N,S-acetals 2(a–g) and β-dialkylamine-α-cyanoacrylates 3(g–i) were synthesized in good to excellent yields by the reaction of ethyl 2-cyano-3,3-bis(methylthio)acrylate 1 with secondary aliphatic amines (i.e., N-methylalkyl- and N-ethylalkylamines), and pyrrolidine, in the presence of triethylamine, under reflux in ethanol, for 1–16 h, depending on the amine used. Five N-methylalkyl amines and pyrrolidine yielded exclusively mono-substituted N,S-acetals 2(a–f) in good yields. On the other hand, N-ethylbenzylamine gave a mixture of monosubstituted products including N,S-acetal 2g in 35% yield and the unexpected product ethyl 3-[benzyl(ethyl)amino]-2-cyanoacrylate 3g in 50% yield. N-Ethylcyclohexylamine and N-ethylbutylamine did not produce N,S-acetals and gave only the unexpected products ethyl 2-cyano-3-[cyclohexyl(ethyl)amino]acrylate 3h and ethyl 3-[butyl(ethyl)amino]-2-cyanoacrylate 3i in good yields. The α-cyanoketene-N,S-acetals 2(a–f), 2j, and 2k underwent cyclization with the binucleophile hydrazine in ethanol under reflux to afford substituted pyrazoles 4(a–f), 4j, and 4k in good yields. |
| first_indexed | 2024-03-06T08:16:54Z |
| format | Article |
| id | upm.eprints-30236 |
| institution | Universiti Putra Malaysia |
| language | English English |
| last_indexed | 2024-03-06T08:16:54Z |
| publishDate | 2013 |
| publisher | Taylor & Francis |
| record_format | dspace |
| spelling | upm.eprints-302362015-09-21T02:13:27Z http://psasir.upm.edu.my/id/eprint/30236/ Synthesis of some novel α-cyanoketene-n, s-acetals derived from secondary aliphatic amines and their use in pyrazole synthesis Al-Adiwish, Wedad M. Mohamed Tahir, Mohamed Ibrahim Wan Ahmad, Wan Yaakob New α-cyanoketene-N,S-acetals 2(a–g) and β-dialkylamine-α-cyanoacrylates 3(g–i) were synthesized in good to excellent yields by the reaction of ethyl 2-cyano-3,3-bis(methylthio)acrylate 1 with secondary aliphatic amines (i.e., N-methylalkyl- and N-ethylalkylamines), and pyrrolidine, in the presence of triethylamine, under reflux in ethanol, for 1–16 h, depending on the amine used. Five N-methylalkyl amines and pyrrolidine yielded exclusively mono-substituted N,S-acetals 2(a–f) in good yields. On the other hand, N-ethylbenzylamine gave a mixture of monosubstituted products including N,S-acetal 2g in 35% yield and the unexpected product ethyl 3-[benzyl(ethyl)amino]-2-cyanoacrylate 3g in 50% yield. N-Ethylcyclohexylamine and N-ethylbutylamine did not produce N,S-acetals and gave only the unexpected products ethyl 2-cyano-3-[cyclohexyl(ethyl)amino]acrylate 3h and ethyl 3-[butyl(ethyl)amino]-2-cyanoacrylate 3i in good yields. The α-cyanoketene-N,S-acetals 2(a–f), 2j, and 2k underwent cyclization with the binucleophile hydrazine in ethanol under reflux to afford substituted pyrazoles 4(a–f), 4j, and 4k in good yields. Taylor & Francis 2013 Article PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/30236/1/Synthesis%20of%20some%20novel%20%CE%B1.pdf Al-Adiwish, Wedad M. and Mohamed Tahir, Mohamed Ibrahim and Wan Ahmad, Wan Yaakob (2013) Synthesis of some novel α-cyanoketene-n, s-acetals derived from secondary aliphatic amines and their use in pyrazole synthesis. Synthetic Communications, 43 (23). pp. 3203-3216. ISSN 0039-7911; ESSN: 1532-2432 10.1080/00397911.2013.774019 English |
| spellingShingle | Al-Adiwish, Wedad M. Mohamed Tahir, Mohamed Ibrahim Wan Ahmad, Wan Yaakob Synthesis of some novel α-cyanoketene-n, s-acetals derived from secondary aliphatic amines and their use in pyrazole synthesis |
| title | Synthesis of some novel α-cyanoketene-n, s-acetals derived from secondary aliphatic amines and their use in pyrazole synthesis |
| title_full | Synthesis of some novel α-cyanoketene-n, s-acetals derived from secondary aliphatic amines and their use in pyrazole synthesis |
| title_fullStr | Synthesis of some novel α-cyanoketene-n, s-acetals derived from secondary aliphatic amines and their use in pyrazole synthesis |
| title_full_unstemmed | Synthesis of some novel α-cyanoketene-n, s-acetals derived from secondary aliphatic amines and their use in pyrazole synthesis |
| title_short | Synthesis of some novel α-cyanoketene-n, s-acetals derived from secondary aliphatic amines and their use in pyrazole synthesis |
| title_sort | synthesis of some novel α cyanoketene n s acetals derived from secondary aliphatic amines and their use in pyrazole synthesis |
| url | http://psasir.upm.edu.my/id/eprint/30236/1/Synthesis%20of%20some%20novel%20%CE%B1.pdf |
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