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Txhua Yam Koj Yuav Tsum Paub Txog Pyridines

Txhua Yam Koj Yuav Tsum Paub Txog Pyridines

Txhua Yam Koj Yuav Tsum Paub Txog Pyridines

Pyridine yog qhov yooj yim heterocyclic compound ntawm azine zoo. Pyridine yog muab los ntawm benzene los ntawm kev hloov ntawm CH pawg los ntawm N-atom. Cov Pyridine qauv zoo ib yam li cov qauv ntawm benzene, vim hais tias nws muaj feem xyuam los ntawm kev hloov cov CH pawg ntawm N. Cov kev sib txawv loj yog:

  1. Tawm los ntawm ib qho chaw zoo nro hexagonal geometry vim muaj qhov hetero atom, kom meej, luv luv nitrogen-carbon bonds,
  2. Hloov ntawm ib lub xaum dej hauv lub nplhaib lub dav hlau nrog lub khoob electronically tsis zoo, zoo li nyob hauv lub nplhaib lub dav hlau, nyob hauv sp2 hybrid orbital, thiab tsis koom rau hauv ib qho pauv hluav taws xob pauv hluav taws xob. Qhov no nitrogen leeg khub rau ib lub luag hauj lwm rau cov khoom yooj yim ntawm pyridines,
  3. Qhov ruaj khov ruaj khov dipole mus rau ib qho yooj yim dua electronegativity ntawm cov nitrogen atom piv nrog cov atom atom.

Pyridine nplhaib tshwm sim hauv ob peb qhov sib txuas lus tseem ceeb, nrog rau cov vitamins niacin, pyridoxine, thiab ntau yam tsawg.

Ib tug Scottish chemist, Thomas Anderson invented pyridine nyob rau hauv 1849 raws li ib qho ntawm cov compounds uas yog siv pob txha roj. Tom qab ob xyoos, Anderson tau muab cov pyridine ntshiab los ntawm feem ntau ntawm cov pob txha roj. Nws yog ib qho kub heev, tsis muaj xim, dej-soluble, weakly alkaline kua nrog ib tug tsis kaj siab, txawv ntses xws li tsw.

Pyridine yog ib txwm siv los ua cov tshuaj rau cov kws tshuaj thiab cov khoom agrochemicals thiab kuj yog ib qho tseem ceeb heev thiab muaj kuab heev. Pyridine yuav muab ntxiv rau ethanol yog tias koj xav ua kom tsis haum rau tib neeg noj. Nws yog tseem siv rau hauv cov tshuaj antihistaminic mepyramine thiab tripelennamine, hauv vitro synthesis ntawm DNA, nyob rau hauv cov khoom ntawm sulfapyridine (tshuaj rau kev kho kab mob kis kab mob thiab kab mob bacterial infections), thiab cov kab mob bactericides, herbicides, thiab cov tshuaj tua dej.

Feem ntau cov tshuaj tebchaw, txawm yog tsis ua los ntawm pyridine, muaj lub nplhaib qauv. Xws li cov tshuaj xws li B vitamins xws li pyridoxine thiab niacin, nicotine, nitrogen-muaj cov khoom cog, thiab cov tshuaj tiv thaiv tuberculosis hu ua isoniazid. Pyridine yog keeb kwm tsim ua ib byproduct ntawm cov roj gasification thiab cov thee thee. Txawm li cas los, skyrocketing demand rau pyridine coj mus rau kev tsim cov kev siv nyiaj txiag ntawm ammonia thiab acetaldehyde, thiab tshaj 20,000 tonnes yog tsim txhua xyoo thoob ntiaj teb.

Nomenclature ntawm pyridine

Lub npe ntawm pyridine lub npe, raws li lub npe hu ua Hantzsch-Widman uas yog IUPAC, yog tsawg. Tab sis systematic npe rau cov keeb kwm yooj yim siv tsis tshua muaj; es tsis txhob, nomenclature ntawm heterocycles raws li tsim tau ntau lub npe. IUPAC tsis txhawb kom siv tsawg thaum xa mus pyridine.

Lub zauv ntawm lub nplhaib atoms hauv azine pib ntawm nitrogen. Kev faib cov haujlwm ntawm Greek cov tsiaj ntawv tsab ntawv (α-γ) thiab cov npe ntawm lub npe hloov npe rau homoaromatic systems (para ortho, lub hom phiaj,) siv qee zaus. Ntawm no α, β thiab γ xa mus rau ob, peb, thiab plaub haujlwm, feem.

Lub npe lub npe rau lub derivatives ntawm pyridine yog pyridinyl, qhov twg muaj pes tsawg tus precedes cov atomised positionis preceded los ntawm ib tug xov tooj. Tab sis lub npe keeb kwm pyridyl raug pom zoo los ntawm IUPAC thiab dav siv rau qhov chaw ntawm lub npe teeb tsa. Qhov ua tsim ua los ntawm kev sib ntxiv ntawm ib qho electrophile rau nitrogen atom yog hu ua pyridinium.

4-bromopyridine

2,2'-bipyridine

Dipicolinic acid (pyridine-2,6-dicarboxylic acid)

Qhov yooj yim daim ntawm pyridinium cation

Ntau lawm ntawm pyridine

Pyridine tau txais raws li kev byproduct ntawm cov roj gasification los yog muab rho tawm cov thee thee. Qhov no yog qhov ua tau zoo thiab siv zog: kev siv hluav taws xob muaj nyob ntawm 0.1 feem pua ​​cov pyridine, thiab yog li yuav tsum tau siv ntau cov dej purification, uas txo cov zis ntxiv. Niaj hnub no, feem ntau cov tshuaj pyridine yog tsim los siv ntau lub npe kev xav, thiab feem ntau cov sawv daws tau tham txog hauv qab no.

Pyridine Synthesis los ntawm Bohlmann-Rahtz

Pyridine Synthesis los ntawm Bohlmann-Rahtz pub cim kev hloov pyridines nyob rau hauv ob theem loj. Lub condensation ntawm enamines siv cov tshuaj ethinylketones ua rau aminodiene intermediate uas, tom qab thaum tshav kub kub isomerization, undergoes cyclodhydration los tsim 2,3,6-trisubstituted pyridines.

Pyridine Synthesis los ntawm Bohlmann-Rahtz mechanism

Lub mechanism yog muaj feem xyuam rau qhov nrov Hantzsch Dihydropyridine Synthesis nyob qhov twghauv situ-paw muaj zog thiab enone hom tsim dihydropyridines. Txawm hais tias Bohlmann-Rahtz Synthesis yog ntau ntau yam, qhov kev kho kom huv nruab nrab thiab qhov kawg siab heev yuav tsum tau rau lub cyclodhydration yog cov teeb meem uas tau txwv nws cov dej taws. Feem ntau ntawm cov teeb meem tau raug overcomed, ua Bohlmann-Rahtz Synthesis ntau tseem ceeb hauv lub pyridines tiam.

Txawm tias tsis muaj kev tshawb fawb los ntawm kev tshawb fawb, tej zaum yuav raug txwv los ntawm H-NMR. Qhov no qhia tau hais tias cov khoom loj ntawm thawj Michael ntxiv thiab cov nqi xa tuaj hauv proton tuaj yeem yog 2Z-4E-heptadien-6-ib qho uas muab rho tawm thiab lim los ntawm kem chromatography.

Cov kab no tsis muaj peev xwm ua kom yooj yim dua Z/E isomerizations uas yog ib qho yuav tsum ua ua ntej rau heteroannelation.

Muaj ntau txoj kev uas tso cai rau synthesis ntawm tetra thiab trisubstituted pyridines nyob rau hauv ib tus txheej txheem ib kauj ruam tau tsim nyuam qhuav. Tsis txhob siv cov butynone ua ib lub substrate, Bagley tau soj ntsuam ntau yam tshuaj los ntawm kev hloov qis dua thiab pheej yig 4 - (trimethylsilyl) tab sis-3-yn-2-ib. Nws tau pom hais tias tsuas yog DMSO thiab EtOH yog cov tshuaj zoo tagnrho. EtOH yog lub meej fav raws li ua ncov qaumteb qabteb thiab tivthaiv hnyav thiab DMSO ua rau hnyav ncov qaum ncov qaum. Hauv ob lub tshuaj ua kua, cov kev tiv thaiv tau siv qhov teeb meem tshwm sim. Bagley tau kuj tau qhia tias acid catalysis pub rau cov cyclodhydration mus txuas ntxiv ntawm qhov kub dua.

Acid catalysis thiab boosts ntxiv cov conjugate. Ntau hom kab mob enamines tau pom zoo nrog ethynyl ketones nyob rau hauv (5: 1) sib xyaw ntawm acetic acid thiab toluene mus nrhiav functionalized pyridines nyob rau hauv ib kauj ruam hauv zoo heev yields.

Tom qab ua tiav ntawm Brønstedt acid catalysis, chemist tshawb xyuas lub peev xwm ntawm Lewis acid catalysts. Cov mob uas zoo tshaj plaws Siv ob lub lis piam mol% ytterbium triflate los yog kaum tsib mol% zinc bromide hauv cov tshuaj toluene. Txawm tias cov kev tshawb fawb kev tshawb fawb tsis tiav, peb tuaj yeem xav hais tias kev sib koom tes los ntawm cov catalyst ceev txog cov cyclodhydration, Michael ntxiv, thiab isomerization cov kauj ruam.

Cov downside yog qhov sib txig sib luag nrog cov qaub ncaug acid-rhiab. Piv txwv, acid-catalyzed decomposition ntawm tus enamines yuav siv qhov chaw nrog cyano thiab tert-lutilester li electron tshem tawm pawg. Lwm qhov sib txawv me ntsis yog daim ntawv thov ntawm Amberlyst-15 ion exchanging reagent uas tolerates tert-tab sis.

Txij li thaum cov kabmob tsis tau npaj txhij, thiab txhim khu lub chaw ntawm txoj haujlwm, muaj 3-tivthaiv cov tshuaj tiv thaiv tau siv cov ammonium acetate los ua qhov chaw ntawm cov amino pawg. Hauv txoj kev ua haujlwm no, tsim kom muaj kabmob enamine hauv situ uas tau teb nrog alkynone tam sim no.

Nyob rau hauv thawj mus sib, ZnBr2 thiab AcOH tau siv los ua cov tshuaj ntxiv nrog tshuaj toluene ua qhov hnyav. Txawm li cas los xij, nws tau txij li tau qhia tias cov kua qaub ncaug acid-sensitive substances yeej hnov ​​mob hauv ib qho chaw me me nrog EtOH ua tus hnyav.

Chichibabin Synthesis

Cov Chichibabin pyridine synthesis thawj zaug tau tshaj tawm hauv 1924 thiab tseem yog ib daim ntawv thov kev lag luam loj hauv cov kev lag luam tshuaj. Nws yog ib qho kev sib txuas lus rau hauv lub suab sib txuas, uas yog qhov kev sib haum xeeb ntawm cov kab sib tw, cov ketones, α, β-unsaturated carbonyl compounds. Tsis tas li ntawd, tag nrho cov qauv ntawm cov tshuaj tiv thaiv no muaj xws li kev sib xyaw ntawm cov khoom saud hauv cov ntshiab ammonia los yog nws cov dej caw.

Tsim kom muaj Pyridine

Kev tsim tawm ntawm formaldehyde thiab acetaldehyde

Formaldehyde thiab acetaldehyde yog qhov tseem ceeb ntawm kev hloov tsis tau pyridine. Yam tsawg kawg, lawv pheej yig thiab yooj yim heev.

  1. Thawj kauj ruam yog tsim cov acrolein los ntawm formaldehyde thiab acetaldehyde los ntawm Knoevenagel hws.
  2. Qhov kawg khoom yog ces condensed los ntawm acrolein nrog acetaldehyde thiab ammonia, sib sau dihydropyridine.
  3. Tus txheej txheem zaum kawg yog qhov tshuaj tiv thaiv oxidation nrog lub zog ntawm-state catalyst los ua pa pyridine.
  4. Cov tshuaj tiv thaiv saum toj no tau ua nyob rau hauv cov roj theem nrog rau qhov kub thiab txias ntawm 400-450 ° C. Cov compound tsim muaj pyridine, picoline los yog methylated pyridines yooj yooj yim, thiab lutidine. Txawm li cas los, qhov muaj pes tsawg leeg yuav raug rau cov khoom siv nyob rau hauv kev siv thiab qee qhov twg, nws txawv nrog qhov xav tau ntawm lub khw. Feem ntau, cov catalyst yog ib qho kev hloov hlau ntsev. Cov feem ntau yog manganese (II) fluoride los yog cadmium (II) fluoride, tab sis thallium thiab cobalt compounds yuav ua tau zoo.
  5. Cov pyridine yog zoo tu qab los ntawm cov khoom siv los ntawm cov txheej txheem multistage.Tus loj ntawm Chichibabin pyridine synthesis yog nws cov qaug tawm, txhais lus txog 20% ntawm cov khoom kawg. Vim li no, cov ntaub ntawv ntawm cov lus no tsis tshua zoo sib xws.

Bönnemann cyclization

Bönnemann cyclization yog tsim los ntawm ib qho khoom siv los ntawm ob qho ntawm acetylene molecule thiab ib feem ntawm cov nitrile. Ua tau, tus txheej txheem yog hloov kho ntawm Reppe synthesis.

Tus mechanism yog facilitated los ntawm tshav kub los ntawm kom kub thiab siab los yog los ntawm yees duab huas cycloaddition. Thaum tshuab txais los ntawm lub teeb, Bönnemann cyclization yuav tsum tau CoCp2 (cyclopentadienyl, 1,5-cyclooctadiene) ua ib qho kev ua kom zoo.

Txoj kev no tuaj yeem tsim cov saw hlau pyridine nyob ntawm seb cov khoom siv. Piv txwv li, acetonitrile yuav ua rau 2-methylpyridine, uas muaj peev xwm siv tau dealkylation los ua pyridine.

Lwm txoj kev

Lub Kröhnke pyridine synthesis

Hom no siv cov pyridine ua ib qho chaw, txawm tias nws yuav tsis muab tso rau hauv qhov kawg khoom. Contrary, qhov tshuaj tiv thaiv yuav tsim tau hloov pyridines.

Thaum reacted nrog α-bromoesters, pyridine yuav ua raws li Michael zoo li cov tshuaj tiv thaiv nrog cov unsaturated carbonyls rau cov pyridine substituted thiab pyridium bromide. Cov tshuaj tiv thaiv no kho nrog ammonia acetate hauv 20-100 ° C mob me.

Lub Ciam-Dennstedt rearrangement

Qhov no txhawb nqa lub nplhaib-nthuav cov pyrrole nrog dichlorocarbene tsim 3-chloropyridine.

Gattermann-Skita synthesis

Hauv cov tshuaj tiv thaiv no, malonate ester ntsev reacts nrog dichloromethylamine nyob rau hauv muaj ib puag.

Boger pyridine synthesis

Tshua ntawm pyridines

Cov kev tshwm sim hauv qab no tuaj yeem kwv yees rau pyridines los ntawm lawv cov qauv hauv tshuab hluav taws xob:

  1. Cov kab mob heteroatom ua rau pyridines tsis tshua muaj siab rau qhov kev hloov ntawm electrophilic aromatic tshua. Conversely, pyridines yog raug cov kab mob nucleophilic. Pyridines nyob rau hauv electrophilic hloov qhov kev tshua (SEAr) ntau reluctantly tab sis nucleophilic hloov chaw (SNAr) ntau dua li lub benzene.
  2. Electrophilic reagents tua dua li ntawm Natom thiab nyob rau hauv bC-atoms, thaum nucleophilic reagents nyiam qhov a- thiab cC-atoms.

Electrophilic Ntxiv ntawm Nitrogen

Hauv kev cuam tshuam uas muaj kev sib txuas ntawm daim ntawv cog lus siv lub khub nruab nrab ntawm electrons ntawm lub nplhaib nitrogen, xws li protonation thiab quaternization, pyridines coj xws li tertiary aliphatic los yog ntxhiab amines.

Thaum lub pyridine reacts li lub hauv paus los yog ib qho nucleophile, nws ua ib qho pyridinium cation uas muaj cov kab uas muaj suab thaj, thiab nitrogen tau txais kev pom zoo.

Protonation ntawm Nitrogen

Pyridines daim ntawv crystalline, nquag siv hygroscopic, ntsev nrog ntau cov tshuaj tiv thaiv acids.

Nitration ntawm Nitrogen

Qhov no tshwm sim los ntawm cov tshuaj tiv thaiv ntawm pyridines nrog nitronium ntsev, xws li nitronium tetrafluoroborate. Protic nitrating cov neeg ua hauj lawm xws li nitric acid, tau kawg, ua rau cov N-protonation tsuas yog.

Acylation ntawm nitrogen

Acid chlorides thiab arylsulfonic acids sai nrog cov pyridines generating 1-acyl- thiab 1-arylsulfonylpyridinium ntsev hauv kua.

Alkyl halides thiab sulfates react nrog pyridines muab quaternary pyridinium salts.

Nucleophilic Substitutions

Tsis zoo li benzene, ntau cov nucleophilic substitutions yuav zoo thiab kev nraaj yuav sustained los ntawm pyridine. Nws yog vim hais tias lub nplhaib muaj ib qho yooj yim electron censor ntawm carbon atoms. Cov kev xav no muaj xws li hloov kev tshem tawm ntawm ib qho kev rhuav tshem cov kua hluav taws xob thiab kev tshem tawm ntxiv kom tau ib qho kev sib xyaw aryne thiab feem ntau mus rau 2- lossis 4-txoj hauj lwm.

Pyridine ib leeg tuaj yeem tsis tshwm sim nyob rau hauv tsim ntawm ntau cov nucleophilic substitutions. Txawm li cas los xij, kev hloov pyridine nrog bromine, sulfonic acid tawg, chlorine, thiab fluorine tuaj yeem ua rau pawg neeg tawm hauv tsev. Lub cev ntawm cov khoom nruab nrog cev tuaj yeem kho tau los ntawm qhov zoo tshaj tawm hauv pab pawg ntawm cov tshuaj fluorine. Thaum siab muaj zog, nucleophilic tuaj yeem ua haujlwm nrog alkoxides, thiolates, amines, thiab ammonia compounds.

Tsawg heterocyclic kev tshwm sim tuaj yeem tshwm sim vim yog siv cov pluag tawm hauv pawg xws li hydride ion. Pyridine derivatives ntawm 2-txoj hauj lwm yuav muab tau los ntawm Chichibabin cov tshuaj tiv thaiv. 2-aminopyridine tuaj yeem kawm tau tiav thaum sodium amide yog siv cov nucleophile. Cov tshuaj hydrogen molecule yog tsim thaum cov protons ntawm cov amino pawg ua ke nrog hydride ion.

Zoo li benzene, pyridines Intermediates xws li heteroaryne tuaj yeem tau los ntawm kev hloov pauv nucleophilic rau pyridine. Kev siv cov alkalines uas muaj zog xws li sodium thiab potassium tert-butoxide yuav pab kom tshem tau cov tshuaj phiv tawm thaum siv txoj cai tawm hauv pawg. Tom qab qhia txog lub nucleophile rau daim ntawv cog lus ntawm triple, nws txo qhov selectivity thiab ua rau cov uas muaj qhov sib tov uas muaj ob lub txiaj ntsim ntxiv.

Electrophilic Substitutions

Qee cov pyridine electrophilic substitutions tau nce mus txog qee qhov taw qhia lossis tsis tas txuas ntxiv. Ntawm qhov tod tes, lub caij heteroaromatic yuav tau tsa los ntawm kev ua haujlwm ntawm kev siv hluav taws xob. Friedel-Crafts Alcoholation (acylation) yog ib qho piv txwv ntawm cov ntawv sau txog alkylations thiab acylations. Lub nam tsis tshua muaj pyridine txij li nws tau nyob rau hauv Ntxiv ntawm nitrogen atom. Cov hloov pauv tsuas yog tshwm sim nyob rau ntawm peb qho chaw uas yog ib qho ntawm cov hluav taws xob cov hluav taws xob nplua nuj carbon nyob rau hauv lub nplhaib uas nws nquag ntxiv rau cov khoom siv hluav taws xob ntxiv.

Tus qauv ntawm Pyridine N-Oxide

Electrophilic substitutions tuaj yeem ua rau hloov pyridine ntawm 2- los yog 4-txoj hauj lwm vim yog qhov tsis zoo rau σ txoj hauv kev tsis haum. Txawm li cas los xij, txoj kev sim yuav siv tau thaum siv lub electrophilic hloov pyridine N-oxide. Nws yog tom qab los ntawm nitrogen atom deoxygenation. Yog li, qhov qhia txog cov pa oxygen paub kom txo tau cov kab mob hauv nitrogen thiab kev hloov ntawm 2-position thiab 4-position carbons.

Cov qoob loo ntawm cov kws phais plaub hau los sis cov phomphorus trivalent yog paub tias yooj yim oxidized li feem ntau yog siv los tshem tawm cov pa atom. Triphenylphosphine oxide yog ib qho compound uas tau tsim tom qab oxidation ntawm Triphenylphosphine reagent. Nws yog lwm lub reagent uas siv tau los rhuav tshem ntawm cov pa taws los ntawm lwm lub caij. Cov ntaub ntawv hauv qab no piav qhia txog seb qhov kev hloov hluav taws xob zoo li cas hloov nrog pyridine.

Direct pyridine nitration xav tau qee qhov mob hnyav, thiab feem ntau nws muaj me ntsis yields. Cov tshuaj tiv thaiv ntawm dinitrogen pentoxide nrog pyridine nyob rau hauv muaj sodium muaj peev xwm ua rau tsim ntawm 3-nitropyridine. Cov derivatives ntawm pyridine tuaj yeem tau los ntawm nitration ntawm nitronium tetrafluoroborate (NO2BF4) los ntawm kev xaiv nitrogen atom sterically thiab electronically. Synthesis ntawm ob lub tebchaw ntawm 6-dibromo pyridine tuaj yeem raug tshwm sim ntawm 3-nitropyridine tom qab tshem tawm cov tshuaj atom brom.

Direct nitration suav hais tias yuav zoo tshaj qhov ncaj qha sulfonation ntawm pyridine. Kev kub cev ntawm pyridine ntawm 320 ° C tuaj yeem ua rau pyridine-3-sulfonic acid sai dua li cov dej qab ntsev sulfuric acid rau tib qhov sov. Ntxiv ntawm cov mis nyuj keeb mus rau nitrogen atom tuaj yeem tau los ntawm reacting SO3 pab pawg neeg nyob hauv lub xub ntiag muaj mercury (II) sulfate uas ua raws li cov catalyst.

Cov tshuaj ncaj qha chlorination thiab bromination tuaj yeem tsis zoo ib yam li nitration thiab sulfonation. 3-bromopyridine yuav muab tau los ntawm cov tshuaj tiv thaiv ntawm molecular bromine nyob rau hauv sulfuric acid ntawm 130 ° C nrog pyridine. Raws li chlorination, qhov tshwm sim ntawm 3-chloropyridine yuav ua tau qis qis nyob rau hauv muaj aluminium chloride uas ua raws li cov catalyst ntawm 100 ° C. Kev ncaj qha ras ntawm halogen thiab palladium (II) tuaj yeem ua rau 2-bromopyridine thiab 2-chloropyridine.

Cov kev siv ntawm Pyridine

Ib qho ntawm cov raw cov ntaub ntawv uas tseem ceeb heev rau cov chemical factories yog pyridine. Hauv 1989, tag nrho cov khoom ntawm pyridine thoob ntiaj teb yog 26K tonnes. Raws li ntawm 1999, 11 tawm ntawm 25 loj pyridine ntau qhov chaw tau nyob hauv Europe. Cov pyridine producers muaj cov Koei Chemical, Imperial Chemical Industries, thiab Evonik Industries.

Nyob rau thaum ntxov 2000s, cov khoom ntawm pyridine ntau zog los ntawm cov paj zoo. Piv txwv, lub teb chaws suav teb chaws suav ua ib qho muaj peev xwm tshaj plaws ntawm 30,000 tonnes. Niaj hnub no, txoj kev sib koom ua ke ntawm Teb Chaws Asmeskas thiab Suav tau tshwm sim nyob rau hauv lub ntiaj teb lub siab tshaj plaws pyridine ntau lawm.

Tshuaj tua kab

Pyridine yog siv los ua ib qho ua ntej rau ob hom tshuaj herbicides diquat thiab paraquat. Hauv kev npaj ntawm pyrithione-based fungicides, pyridine yog siv los ua lub hauv paus compound.

Cov tshuaj tiv thaiv ntawm Zincke thiab pyridine tau tshwm sim hauv cov khoom ntawm ob lub tebchaw - laurylpyridinium thiab cetylpyridinium. Nws rov qab mus rau cov khoom siv antiseptic, ob lub tebchaw ntxiv rau cov khoom kho hniav thiab lub qhov ncauj.

Kev tua los ntawm ib tug neeg haus dej caw mus rau pyridine tau cov N-Alphpyridinium ntsev, cetylpyridinium chloride yog ib qho piv txwv.

Paraquat Synthesis

Hnyav

Lwm daim ntawv thov uas siv pyridine yog nyob rau hauv Knoevenagel condensations, uas nws siv los ua qis-reactive, ncov qaumteb, thiab qhov hnyav. Pyridine yog qhov tshwj xeeb tshaj yog rau cov dehalogenation, qhov chaw nws ua hauj lwm raws li lub hauv paus ntawm tshem tawm cov tshuaj tiv thaiv thaum sib cog cov tshuaj hydrogen halide tsim daim pyridinium ntsev.

Hauv acylations thiab esterifications, Pyridine activates lub anhydrides los yog carboxylic acid halides. Txawm hais tias muaj kev kub ntxhov ntau hauv cov kev sib txuam no yog 4 - (1-pyrrolidinyl) pyridine thiab 4-dimethylaminopyridine (DMAP), uas yog phyrathine derivatives. Hauv kev sib haumxeeb, Pyridine feem ntau yog ua raws li lub hauv paus.

Tsim cov pyridinium los ntawm kev tshem tawm cov tshuaj tiv thaiv nrog pyridine

Pyridine kuj yog ib yam khoom tseem ceeb hauv cov kev lag luam textile. Dhau li yog siv los ua ib qho hnyav nyob rau hauv cov roj hmab thiab dyes zus, nws tseem siv tau los txhim kho paj rwb lub peev xwm network.

Tsoomfwv Meskas Cov Khoom Noj thiab Tshuaj Yeeb Tshuaj pom zoo ntxiv cov pyridine hauv cov khoom noj me me kom ua rau lawv muaj qhov hnyav tsw.

Hauv kev daws teebmeem, qhov kev ntsuas pib ntawm pyridine yog nyob ib puag ncig 1-3 mmol·L-1 (79-237 mg • L-1). Yog lub hauv paus, pyridine kuj yuav siv los ua tus Karl Fischer reagent. Txawm li cas los xij, imidazole feem ntau yog siv los ua pyridine li nws (imidazole) muaj ib tus ntxhiab tsw qab.

Precursor rau Piperidine

Pyridine hydrogenation nrog ruthenium-, cobalt-, los yog nickel-based catalyst ntawm kev kub muaj peev xwm nyob rau hauv cov khoom ntawm piperidine. Qhov no yog ib qho tseem ceeb ntawm nitrogen heterocycle uas yog lub tsev tsim hluav taws xob.

Cov tshuaj reagents tawm ntawm Pyridine

Hauv 1975, William Suggs thiab James Corey tau tsim cov tshuaj chlorochromate pyridinium. Nws ua ntawv thov kom oxidize secondary alcohols rau ketones thiab thawj cawv rau aldehydes. Pyridinium chlorochromate yog tau txais thaum cov pyridine ntxiv rau cov tshuaj kua txig ntawm hydrochloric thiab chromic acid.

C5H5N + HCl + CrO3 → [C5H5NH] [CrO3Cl]

Nrog chromyl chloride (CrO2Cl2) yog carcinogenic, lwm txoj kev yuav tsum tau nrhiav. Ib ntawm lawv yog siv cov pyridinium chloride los kho chromium (VI) oxide.

[C5H5NH+] Cl- + CrO3 → [C5H5NH] [CrO3Cl]

Lub Sarrom reagent (complex of chromium (VI) oxide nrog pyridine heterocycle hauv pyridine), pyridinium chlorochromate (PCC), lub pob kws tshuaj reagent (pyridinium dichromate, PDC), thiab Collins reagent (lub complex ntawm chromium (VI) oxide nrog pyridine heterocycle nyob rau hauv dichloromethane) yog sib piv chromium-pyridine compounds. Lawv kuj tau thov rau oxidation, xws li kev hloov cov theem nrab thiab thawj cov cawv rau ketones.

Cov Sarret thiab Collins reagents tsis yog qhov yooj yim los npaj, tab sis lawv kuj muaj kev puas tsuaj. Lawv hygroscopic thiab yog cov raug rau cov hluav taws thaum lub sij hawm npaj txheej txheem. Thiaj li, kev siv PDC thiab PCC raug pom zoo. Thaum ob lub reagents tau hnyav heev hauv cov 70s thiab 80s, lawv tsis tshua siv presently vim lawv toxicity thiab paub tseeb tias carcinogenicity.

Tus qauv ntawm Crabtree tus catalyst

Hauv kev sib koom tes chemistry, pyridine yog siv ntau heev li ligand. Nws yog derivative, raws li yog nws derivative 2,2'-bipyridine, muaj xws li 2 pyridine molecules txuas los ntawm kev sib txuas ib zaug, thiab terpyridine, ib lub cev ntawm 3 pyridine rings txuas nrog ua ke.

Lub zog Lewis puag yog siv los ua ib daim pyridine ligand uas yog ib feem ntawm cov hlau. Qhov cwj pwm no yog siv nyob rau hauv catalysis ntawm polymerization thiab hydrogenation tshua, siv, piv txwv li, Carabtree's catalyst. Lub pyridine Lingard uas tau hloov thaum lub sij hawm qhov tshuaj tiv thaiv yog rov tuaj tom qab nws tiav.

References

Nomenclature ntawm Organic Chemistry: IUPAC Cov Lus Qhia thiab Cov Lus Xaiv 2013 (Phau Ntawv Xiav). Cambridge: Lub Koom Haum Noob Noob ntawm Chemistry. 2014. p. 141.

Anderson, T. (1851). "Ueber tuag los ntawm cov khoom noj khoom haus kub nyhiab Destillation thierischer Materien" [rau cov khoom ntawm qhuav distillation ntawm tsiaj teeb meem]. Annalen der Chemie thiab Pharmacie. 80: 44.

Sherman, AR (2004). "Pyridine". Hauv Paquette, L. Encyclopedia ntawm Reagents rau Organic Synthesis. e-EROS (Encyclopedia ntawm Reagents rau Organic Synthesis). New York: J. Wiley & Tub.

Behr, A. (2008). Angewandte homogene Katalyse. Weinheim: Wiley-VCH. p. 722.