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s русский 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 leimgruber batcho indole synthesis is a series of organic reactions that produce indoles from o nitro toluenes 1 the first step is the formation of an enamine 2 using n n dimethylformamide dimethyl acetal and pyrrolidine the desired indole 3 is then formed in a second step by reductive cyclisation the leimgruber batcho indole synthesis in the above scheme the reductive cyclisation is affected by raney nickel and hydrazine palladium on carbon and hydrogen stannous chloride sodium hydrosulfite or iron in acetic acid are also effective reducing agents reaction mechanism edit in the initial enamine formation dimethylamine a gas is displaced by pyrrolidine from the dimethylformamide dimethylacetal producing a more reactive reagent the mildly acidic hydrogens of the methyl group in the nitrotoluene can be deprotonated under the basic conditions and the resultant carbanion attacks to produce the enamine shown with loss of methanol the sequence can also be performed without pyrrolidine via the n n dimethyl enamine though reaction times may be much longer in some cases in the second step the nitro group is reduced to nh 2 using hydrogen and a raney nickel catalyst followed by cyclisation then elimination of the pyrrolidine the hydrogen is often generated in situ by the spontaneous decomposition of hydrazine hydrate to h 2 and n 2 in the presence of the nickel the reaction is a good example of a reaction that was widely used in industry before any procedures were published in the mainstream scientific literature many indoles are pharmacologically active so a good indole synthesis is important for the pharmaceutical industry the process has become a popular alternative to the fischer indole synthesis because many starting ortho nitrotoluenes are commercially available or easily made in addition the reactions proceed in high chemical yield under mild conditions the intermediate enamines are electronically related to push pull olefins having an electron withdrawing nitro group conjugated to an electron donating group the extended conjugation means that these compounds are usually an intense red color variations edit dinitrostyrene reductive cyclization edit the reductive cyclization of dinitrostyrenes 2 has proven itself effective when other more common methods have failed an example of a dinitrostyrene reductive cyclization most of the standard reduction methods listed above are successful with this reaction see also edit bartoli indole synthesis fischer indole synthesis reissert indole synthesis references edit batcho a d leimgruber w u s patent 3 732 245 u s patent 3 976 639 batcho a d leimgruber w organic syntheses 1985 63 214 220 article clark r d repke d b heterocycles 1984 22 195 221 review maehr h smallheer j m j org chem 1981 46 1753 doi 10 1021 jo00321a053 garcia e e fryer r i j heterocycl chem 1974 11 219 ponticello g s baldwin j j j org chem 1979 44 4003 doi 10 1021 jo01336a065 chen b c hynes jr j randit c r zhao r skoumbourdis a p wu h sundeen j e leftheris k heterocycles 2001 55 951 960 v t e topics in organic reactions addition reaction elimination reaction polymerization reagents rearrangement reaction redox reaction regioselectivity stereoselectivity stereospecificity substitution reaction a value alpha effect annulene anomeric effect antiaromaticity aromatic ring current aromaticity baird s rule baker nathan effect baldwin s rules bema hapothle beta silicon effect bicycloaromaticity bredt s rule bürgi dunitz angle catalytic resonance theory charge remote fragmentation charge transfer complex clar s rule conformational isomerism conjugated system conrotatory and disrotatory curtin hammett principle dynamic binding chemistry edwards equation effective molarity electromeric effect electron rich electron withdrawing group electronic effect electrophile evelyn effect flippin lodge angle free energy relationship grunwald winstein equation hammett acidity function hammett equation george s hammond hammond s postulate homoaromaticity hückel s rule hyperconjugation inductive effect kinetic isotope effect lfer solvent coefficients data page marcus theory markovnikov s rule möbius aromaticity möbius hückel concept more o ferrall jencks plot negative hyperconjugation neighbouring group participation 2 norbornyl cation nucleophile kennedy j p orton passive binding phosphaethynolate polar effect polyfluorene ring strain σ aromaticity spherical aromaticity spiroaromaticity steric effects superaromaticity swain lupton equation taft equation thorpe ingold effect vinylogy walsh diagram woodward hoffmann rules woodward s rules y aromaticity yukawa tsuno equation zaitsev s rule σ bishomoaromaticity list of organic reactions carbon carbon bond forming reactions acetoacetic ester synthesis acyloin condensation aldol condensation aldol reaction alkane metathesis alkyne metathesis alkyne trimerisation alkynylation allan robinson reaction arndt eistert reaction auwers synthesis aza baylis hillman reaction barbier reaction barton kellogg reaction baylis hillman reaction benary reaction bergman cyclization biginelli reaction bingel reaction blaise ketone synthesis blaise reaction blanc chloromethylation bodroux chichibabin aldehyde synthesis bouveault aldehyde synthesis bucherer bergs reaction buchner ring expansion cadiot chodkiewicz coupling carbonyl allylation carbonyl olefin metathesis castro stephens coupling chan rearrangement chan lam coupling claisen condensation claisen rearrangement claisen schmidt condensation combes quinoline synthesis corey fuchs reaction corey house synthesis coupling reaction cross coupling reaction cross dehydrogenative coupling cross coupling partner dakin west reaction darzens reaction diels alder reaction doebner reaction wulff dötz reaction ene reaction enyne metathesis ethenolysis favorskii reaction ferrier carbocyclization friedel crafts reaction fujimoto belleau reaction fujiwara moritani reaction fukuyama coupling gabriel colman rearrangement gattermann reaction glaser coupling grignard reaction grignard reagent hammick reaction heck reaction henry reaction heterogeneous metal catalyzed cross coupling high dilution principle hiyama coupling homologation reaction horner wadsworth emmons reaction hydrocyanation hydrovinylation hydroxymethylation ivanov reaction johnson corey chaykovsky reaction julia olefination julia kocienski olefination kauffmann olefination knoevenagel condensation knorr pyrrole synthesis kolbe schmitt reaction kowalski ester homologation kulinkovich reaction kumada coupling liebeskind srogl coupling malonic ester synthesis mannich reaction mcmurry reaction meerwein arylation methylenation michael reaction minisci reaction mizoroki heck vs reductive heck nef isocyanide reaction nef synthesis negishi coupling nierenstein reaction nitro mannich reaction nozaki hiyama kishi reaction olefin conversion technology olefin metathesis palladium nhc complex passerini reaction peterson olefination pfitzinger reaction piancatelli rearrangement pinacol coupling reaction prins reaction quelet reaction ramberg bäcklund reaction rauhut currier reaction reformatsky reaction reimer tiemann reaction rieche formylation ring closing metathesis robinson annulation sakurai reaction seyferth gilbert homologation shapiro reaction sonogashira coupling stetter reaction stille reaction stollé synthesis stork enamine alkylation suzuki reaction takai olefination thermal rearrangement of aromatic hydrocarbons thorpe reaction ugi reaction ullmann reaction wagner jauregg reaction weinreb ketone synthesis wittig reaction wurtz reaction wurtz fittig reaction zincke suhl reaction homologation reactions arndt eistert reaction hooker reaction kiliani fischer synthesis kowalski ester homologation methoxymethylenetriphenylphosphorane seyferth gilbert homologation wittig reaction olefination reactions bamford stevens reaction barton kellogg reaction boord olefin synthesis chugaev elimination cope reaction corey winter olefin synthesis dehydrohalogenation elimination reaction grieco elimination hofmann elimination horner wadsworth emmons reaction hydrazone iodination julia olefination julia kocienski olefination kauffmann olefination mcmurry reaction peterson olefination ramberg bäcklund reaction shapiro reaction takai olefination wittig reaction carbon heteroatom bond forming reactions azo coupling bartoli indole synthesis boudouard reaction cadogan sundberg indole synthesis diazonium compound esterification grignard reagent haloform reaction hegedus indole synthesis hurd mori 1 2 3 thiadiazole synthesis kharasch sosnovsky reaction knorr pyrrole synthesis leimgruber batcho indole synthesis mukaiyama hydration nenitzescu indole synthesis oxymercuration reaction reed reaction schotten baumann reaction ullmann condensation williamson ether synthesis yamaguchi esterification degradation reactions barbier wieland degradation bergmann degradation edman degradation emde degradation gallagher hollander degradation hofmann rearrangement hooker reaction isosaccharinic acid marker degradation ruff degradation strecker degradation von braun amide degradation weerman degradation wohl degradation organic redox reactions acyloin condensation adkins peterson reaction akabori amino acid reaction alcohol oxidation algar flynn oyamada reaction amide reduction andrussow process angeli rimini reaction aromatization autoxidation baeyer villiger oxidation barton mccombie deoxygenation bechamp reduction benkeser reaction bergmann degradation birch reduction bohn schmidt reaction bosch reaction bouveault blanc reduction boyland sims oxidation cannizzaro reaction carbonyl reduction clemmensen reduction collins oxidation corey itsuno reduction corey kim oxidation corey winter olefin synthesis criegee oxidation dakin oxidation davis oxidation deoxygenation dess martin oxidation dna oxidation elbs persulfate oxidation emde degradation eschweiler clarke reaction étard reaction fischer tropsch process fleming tamao oxidation fukuyama reduction ganem oxidation glycol cleavage griesbaum coozonolysis grundmann aldehyde synthesis haloform reaction hydrogenation hydrogenolysis hydroxylation jones oxidation kiliani fischer synthesis kolbe electrolysis kornblum oxidation kornblum delamare rearrangement leuckart reaction ley oxidation lindgren oxidation lipid peroxidation lombardo methylenation luche reduction markó lam deoxygenation mcfadyen stevens reaction meerwein ponndorf verley reduction methionine sulfoxide miyaura borylation mozingo reduction noyori asymmetric hydrogenation omega oxidation oppenauer oxidation oxygen rebound mechanism ozonolysis parikh doering oxidation pinnick oxidation prévost reaction reduction of nitro compounds reductive amination riley oxidation rosenmund reduction rubottom oxidation sabatier reaction sarett oxidation selenoxide elimination shapiro reaction sharpless asymmetric dihydroxylation epoxidation of allylic alcohols sharpless epoxidation sharpless oxyamination stahl oxidation staudinger reaction stephen aldehyde synthesis swern oxidation transfer hydrogenation wacker process wharton reaction whiting reaction wohl aue reaction wolff kishner reduction wolffenstein böters reaction zinin reaction rearrangement reactions 1 2 rearrangement 1 2 wittig rearrangement 2 3 sigmatropic rearrangement 2 3 wittig rearrangement achmatowicz reaction alkyne zipper reaction allen millar trippett rearrangement allylic rearrangement alpha ketol rearrangement amadori rearrangement arndt eistert reaction aza cope rearrangement baker venkataraman rearrangement bamberger rearrangement banert cascade beckmann rearrangement benzilic acid rearrangement bergman cyclization bergmann degradation boekelheide reaction brook rearrangement buchner ring expansion carroll rearrangement chan rearrangement claisen rearrangement cope rearrangement corey fuchs reaction cornforth rearrangement criegee rearrangement curtius rearrangement demjanov rearrangement di π methane rearrangement dimroth rearrangement divinylcyclopropane cycloheptadiene rearrangement dowd beckwith ring expansion reaction electrocyclic reaction ene reaction enyne metathesis favorskii reaction favorskii rearrangement ferrier carbocyclization ferrier rearrangement fischer hepp rearrangement fries rearrangement fritsch buttenberg wiechell rearrangement gabriel colman rearrangement group transfer reaction halogen dance rearrangement hayashi rearrangement hofmann rearrangement hofmann martius rearrangement ireland claisen rearrangement jacobsen rearrangement kornblum delamare rearrangement kowalski ester homologation lobry de bruyn van ekenstein transformation lossen rearrangement mcfadyen stevens reaction mclafferty rearrangement meyer schuster rearrangement mislow evans rearrangement mumm rearrangement myers allene synthesis nazarov cyclization reaction neber rearrangement newman kwart rearrangement overman rearrangement oxy cope rearrangement pericyclic reaction piancatelli rearrangement pinacol rearrangement pummerer rearrangement ramberg bäcklund reaction ring expansion and contraction ring closing metathesis rupe reaction schmidt reaction semipinacol rearrangement seyferth gilbert homologation sigmatropic reaction skattebøl rearrangement smiles rearrangement sommelet hauser rearrangement stevens rearrangement stieglitz rearrangement thermal rearrangement of aromatic hydrocarbons tiffeneau demjanov rearrangement vinylcyclopropane rearrangement wagner meerwein rearrangement wallach rearrangement weerman degradation westphalen lettré rearrangement willgerodt rearrangement wolff rearrangement ring forming reactions 1 3 dipolar cycloaddition annulation azide alkyne huisgen cycloaddition baeyer emmerling indole synthesis bartoli indole synthesis bergman cyclization biginelli reaction bischler möhlau indole synthesis bischler napieralski reaction blum ittah aziridine synthesis bobbitt reaction bohlmann rahtz pyridine synthesis borsche drechsel cyclization bucherer carbazole synthesis bucherer bergs reaction cadogan sundberg indole synthesis camps quinoline synthesis chichibabin pyridine synthesis cook heilbron thiazole synthesis cycloaddition darzens reaction davis beirut reaction de kimpe aziridine synthesis debus radziszewski imidazole synthesis dieckmann condensation diels alder reaction feist benary synthesis ferrario ackermann reaction fiesselmann thiophene synthesis fischer indole synthesis fischer oxazole synthesis friedländer synthesis gewald reaction graham reaction hantzsch pyridine synthesis hegedus indole synthesis hemetsberg...