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gabriel colman rearrangement wikipedia jump to content main menu main menu move to sidebar hide navigation main page contents current events random article about wikipedia contact us contribute help learn to edit community portal recent changes upload file special pages search search appearance donate create account log in personal tools donate create account log in contents move to sidebar hide top 1 mechanism 2 applications 3 see also 4 references toggle the table of contents gabriel colman rearrangement 7 languages العربية deutsch español فارسی 日本語 nederlands 中文 edit links article talk english read edit view history tools tools move to sidebar hide actions read edit view history general what links here related changes upload file permanent link page information cite this page get shortened url switch to legacy parser print export download as pdf printable version in other projects wikimedia commons wikidata item appearance move to sidebar hide from wikipedia the free encyclopedia chemical reaction the gabriel colman rearrangement 1 is the chemical reaction of a saccharin or phthalimido ester with a strong base such as an alkoxide to form substituted isoquinolines 2 first described in 1900 by chemists siegmund gabriel and james colman this rearrangement a ring expansion is seen to be general if there is an enolizable hydrogen on the group attached to the nitrogen 3 since it is necessary for the nitrogen to abstract a hydrogen to form the carbanion that will close the ring 4 as shown in the case of the general example below x is either co or so 2 gabriel colman rearrangement overall reaction mechanism edit gabriel colman rearrangement mechanism the reaction mechanism 5 6 starts with an attack on the carbonyl group by a strong base such as methoxide ion the ring is then opened forming an imide anion this is then followed by a rapid isomerization of the imide anion to the carbanion this is facilitated by the electron withdrawing effect of the substituent which allows for greater stabilization of the adjacent carbanion with respect to the imide anion the reaction is then completed when the methoxide is displaced by the ring closing which results in a ring expansion the rate determining step of this reaction is the attack of the carbanion on the carbomethoxy group the displacement of the methoxide is analogous to the displacement seen in the dieckman condensation as it is also a result of a ring closure gabriel colman rearrangement tautomerism furthermore tautomerization can occur on both of the carbonyl groups on the ring with interconversion of the keto form to the enol form and the amide form to the imidic acid form applications edit the major application of the gabriel colman rearrangement is in the formation of isoquinolines due to the relatively high yield of the desired products therefore studies in which either the product or an intermediate is an isoquinoline the gabriel colman rearrangement can be utilized this reaction has been utilized in the production of intermediates for the synthesis of potential anti inflammatory agents 7 it has also been used in the study of phthalimide and saccharin derivatives as mechanism based inhibitors for three enzymes the human leukocyte elastase cathepsin g and proteinase 3 8 phthalimide derivatives were seen to be inactive while saccharin derivatives were seen to be fair inhibitors of these enzymes a first example of the gabriel colman rearrangement in a study 9 of the derivatives of 3 oxo 1 2 benzoisothiazoline 2 acetic acid 1 1 dioxide the gabriel colman rearrangement was employed in the conversion of isopropyl 1 1 dioxido 3 oxo 1 2 benzothiazol 2 3h yl acetate to isopropyl 4 hydroxy 2h 1 2 benzothiazine 3 carboxylate 1 1 dioxide as shown above this reaction has shown a percent yield of 85 another example of the gabriel colman rearrangement in another study 10 n phthalimidoglycine ethyl ester was used to synthesize 4 hydroxyisoquinoline through use of a gabriel colman rearrangement as shown above this reaction has shown a percent yield of 91 the formation of this product was an important step in the study of the synthesis of 4 4 functionalized 1 1 biisoquinolines see also edit dieckmann reaction claisen condensation chan rearrangement references edit gabriel s colman j 1900 ueber eine umlagerung der phtalimidoketone berichte der deutschen chemischen gesellschaft 33 2 2630 2634 doi 10 1002 cber 190003302209 koelsch c f lindquist r m 1956 some attempts to prepare derivatives of benz f isoquinoline and a synthesis of benz h isoquinoline the journal of organic chemistry 21 6 657 659 doi 10 1021 jo01112a018 allen c f h 1950 the naphthyridines chemical reviews 47 2 275 305 doi 10 1021 cr60147a004 pmid 24538878 hauser charles r kantor simon w 1951 rearrangement of benzyl ethers to carbinols by potassium amide mechanism of isomerization of carbanions involving 1 2 shifts journal of the american chemical society 73 4 1437 1441 bibcode 1951jachs 73 1437h doi 10 1021 ja01148a011 hill john h m 1965 mechanism of the gabriel colman rearrangement the journal of organic chemistry 30 2 620 622 doi 10 1021 jo01013a078 li jie jack 2009 gabriel colman rearrangement name reactions p 250 doi 10 1007 978 3 642 01053 8_107 isbn 978 3 642 01052 1 lombardino joseph g wiseman edward h mclamore w m 1971 synthesis and antiinflammatory activity of some 3 carboxamides of 2 alkyl 4 hydroxy 2h 1 2 benzothiazine 1 1 dioxide journal of medicinal chemistry 14 12 1171 1175 doi 10 1021 jm00294a008 pmid 5116229 groutas william c chong lee s venkataraman radhika epp jeffrey b kuang rongze houser archield nadene hoidal john r 1995 the gabriel colman rearrangement in biological systems design synthesis and biological evaluation of phthalimide and saccharin derivatives as potential mechanism based inhibitors of human leukocyte elastase cathepsin g and proteinase 3 bioorganic medicinal chemistry 3 2 187 193 doi 10 1016 0968 0896 95 00013 7 pmid 7796053 schapira celia b perillo isabel a lamdan samuel 1980 3 oxo 1 2 benzoisothiazoline 2 acetic acid 1 1 dioxide derivatives i reaction of esters with alkoxides journal of heterocyclic chemistry 17 6 1281 1288 doi 10 1002 jhet 5570170627 laschat sabine kapatsina elisabeth lordon marie baro angelika 2008 convergent synthesis of 1 1 biisoquinolines tethered to calamitic subunits synthesis 2008 16 2551 2560 doi 10 1055 s 2008 1067184 retrieved from https en wikipedia org w index php title gabriel colman_rearrangement oldid 1297306984 categories carbon carbon bond forming reactions heterocycle forming reactions rearrangement reactions name reactions hidden categories articles with short description short description matches wikidata this page was last edited on 25 june 2025 at 10 43 utc page was rendered with parsoid text is available under the creative commons attribution sharealike 4 0 license additional terms may apply by using this site you agree to the terms of use and privacy policy wikipedia is a registered trademark of the wikimedia foundation inc a non profit organization privacy policy about wikipedia disclaimers contact wikipedia legal safety contacts code of conduct developers statistics cookie statement mobile view search search toggle the table of contents gabriel colman rearrangement 7 languages add topic