Systematic study on acylation of methyl 3-aminocrotonate with acid chlorides of aliphatic, aromatic and α, β-unsaturated acids: A comparative evaluation of the preference for regio- and stereoselectivity vis-à-vis 3-aminocrotononitrile
IR@NISCAIR: CSIR-NISCAIR, New Delhi - ONLINE PERIODICALS REPOSITORY (NOPR)
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| Title |
Systematic study on acylation of methyl 3-aminocrotonate with acid chlorides of aliphatic, aromatic and α, β-unsaturated acids: A comparative evaluation of the preference for regio- and stereoselectivity vis-à-vis 3-aminocrotononitrile
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| Creator |
Mukherjee, Attreyee
Mahalanabis, Kumar K |
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| Subject |
Methyl 3-aminocrotonate
Acylation Enaminones Enamides Regioselective Stereoselective |
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| Description |
291-302
Acylation of methyl 3-aminocrotonate <strong>1a</strong> in benzene with a variety of aliphatic and aromatic acid chlorides including α, β-unsaturated acid chloride in the presence of an added organic base, (either pyridine or triethylamine) is reported. The preferred N, C-site selectivity in these reactions has been compared with the terminal selectivity of the products obtained previously on acylation of methyl 3-aminocrotononitrile <strong>1b</strong>. A strong preference either for N- or C- selectivity in N, C-acylation has been observed for both <strong>1a</strong> and <strong>1b</strong> based on the choice of acid chlorides and added organic base. Interestingly, irrespective of the enamine <strong>1a</strong> or <strong>1b</strong>, acylation with α, β-unsaturated acid chlorides in the presence of triethylamine afforded 3,4-dihydropyridin-(2<em>H</em>)-one <em>via</em> [3.3] sigmatropic rearrangement of the corresponding intermediary N(E)-enamide. Accrued results show methyl 3-aminocrotonate to be a better precursor for preparation of enamides (N-acylated products) whereas 3-aminocrotononitrile is found to be a preferred choice for preparation of enaminones (C-acylated products). An attempt is made to offer a preliminary theoretical interpretation for observed site selectivity. |
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| Date |
2021-02-11T10:16:58Z
2021-02-11T10:16:58Z 2021-02 |
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| Type |
Article
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| Identifier |
0975-0983(Online); 0376-4699(Print)
http://nopr.niscair.res.in/handle/123456789/56209 |
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| Language |
en_US
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| Rights |
<img src='http://nopr.niscair.res.in/image/cc-license-sml.png'> <a href='http://creativecommons.org/licenses/by-nc-nd/2.5/in' target='_blank'>CC Attribution-Noncommercial-No Derivative Works 2.5 India</a>
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| Publisher |
NISCAIR-CSIR, India
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| Source |
IJC-B Vol.60B(02) [February 2021]
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