| 词条 | Hammick reaction |
| 释义 |
| Name = Hammick reaction | Type = Coupling reaction | NamedAfter = Dalziel Hammick }} The Hammick reaction, named after Dalziel Hammick, is a chemical reaction in which the thermal decarboxylation of α-picolinic (or related) acids in the presence of carbonyl compounds forms 2-pyridyl-carbinols.[1][2][3] Using p-cymene as solvent has been shown to increase yields.[4] Reaction mechanismUpon heating α-picolinic acid will spontaneously decarboxylate forming the so-called 'Hammick Intermediate' (2), which can be viewed as an aromatic ylide.[5] In the presence of a strong electrophile, such as an aldehyde or ketone, this species will undergo nucleophilic attack faster than protonation. After nucleophilic attack intramolecular proton transfer yields the desired carbinol (4). The scope of the reaction is effectively limited to decarboxylating acids where the carboxyl group is α to the nitrogen, (reactivity has been reported when the acids are located elsewhere on the molecule but with low yields)[6][7] thus suitable substrates are limited to the derivatives of α-picolinic acid[3][8] including the α-carboxylic acids of quinoline and isoquinoline. See also
References1. ^{{cite journal |author1=Dyson, P. |author2=Hammick, D. L. | journal = J. Chem. Soc. | year = 1937 | pages = 1724 | doi = 10.1039/jr9370001724 | title = 362. Experiments on the mechanism of decarboxylation. Part I. Decomposition of quinaldinic and isoquinaldinic acids in the presence of compounds containing carbonyl groups}} 2. ^{{cite journal |author1=Hammick, D. L. |author2=Dyson, P. | journal = J. Chem. Soc. | year = 1939 | pages = 809 | doi = 10.1039/jr9390000809 | title = 172. The mechanism of decarboxylation. Part II. The production of cyanide-like ions from α-picolinic, quinaldinic, and isoquinaldinic acids}} 3. ^1 {{cite journal |author1=Brown, E. V. |author2=Shambhu, M. B. | title = Hammick reaction of methoxypyridine-2-carboxylic acids with benzaldehyde. Preparation of methoxy-2-pyridyl phenyl ketones | journal = J. Org. Chem. | year = 1971 | volume = 36 | pages = 2002 | doi = 10.1021/jo00813a034 | issue = 14 }} 4. ^{{cite journal |author1=Sperber, N. |author2=Papa, D. |author3=Schwenk, E. |author4=Sherlock, M. | journal = J. Am. Chem. Soc. | year = 1949 | volume = 71 | pages = 887–90 | doi = 10.1021/ja01171a034 | title = Pyridyl-Substituted Alkamine Ethers as Antihistaminic Agents | pmid=18113525 | issue = 3}} 5. ^{{cite journal|last1=Hollóczki|first1=Oldamur|last2=Nyulászi|first2=László|title=Stabilizing the Hammick Intermediate|journal=The Journal of Organic Chemistry|date=July 2008|volume=73|issue=13|pages=4794–4799|doi=10.1021/jo8000035|pmid=18543975}} 6. ^{{cite journal|authorlink1=Kurt Mislow|last1=Mislow|first1=Kurt|title=An Extension of the Scope of the Hammick Reaction|journal=Journal of the American Chemical Society|date=October 1947|volume=69|issue=10|pages=2559–2559|doi=10.1021/ja01202a508}} 7. ^{{cite journal|last1=Betts|first1=M. J.|last2=Brown|first2=B. R.|title=Extension of the Hammick reaction to 2-pyridylacetic acid|journal=Journal of the Chemical Society C: Organic|date=1967|pages=1730|doi=10.1039/J39670001730}} 8. ^{{cite journal|last1=Cantwell|first1=Nelson H.|last2=Brown|first2=Ellis V.|title=An Investigation of the Hammick Reaction|journal=Journal of the American Chemical Society|date=March 1953|volume=75|issue=6|pages=1489–1490|doi=10.1021/ja01102a515}} 3 : Addition reactions|Carbon-carbon bond forming reactions|Name reactions |
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