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Konke Okudingeka Ukwazi NgePyridines

Konke Okudingeka Ukwazi NgePyridines

Konke Okudingeka Ukwazi Nge Ama-Pyridines

I-Pyridine iyisisekelo i-heterocyclic uhlobo lwe-azine uhlobo. I-Pyridine itholakala ku-benzene ngokufaka esikhundleni seqembu le-CH nge-N-athomu. Isakhiwo sePyridine sifana nesakhiwo se-benzene, ngoba sihlobene nokushintshwa kweqembu le-CH ngu-N. Ukuhlukana okukhulu kuhlanganisa:

  1. Ukuhamba kusuka geometry evamile ephindwe kabili ngenxa yebukhoma be-hetero, ukucacisa, izibopho ezincane ze-nitrogen-carbon,
  2. Ukushintshwa kwe-athomu ye-hydrogen endizeni yendiza ne-unshared electron pair, njengendiza yezinyathelo, e-sp2 hybrid orbital, futhi engabandakanyeki kumxube we-p-elektron ephunga. Lo mbhangqwana owodwa we-nitrogen ophethe izinto eziyisisekelo ze-pyridines,
  3. I-dipole enamandla engapheliyo elandelana ne-electronegativity ephakeme ye-athomu ye-nitrogen eqhathaniswa ne-athomu ye-carbon.

Indandatho ye-pyridine ivela eziningana zamakhemikhali ezibalulekile, kuhlanganise amavithamini niacin, pyridoxine, kanye nama-azines.

Isazi samakhemikhali saseScotland, uThomas Anderson wasungula i-pyridine ku-1849 njengenye yamakhemikhali enza i-bone oil. Ngemva kweminyaka emibili, u-Anderson wathola i-pyridine ehlanzekile nge-fractional distillation yamafutha we-bone. Liyisimanzi esinamandla kakhulu, esingenakubala, esingenangqamuzana, esingenakunama-alkaline elinomsoco onokungafani okumnandi, okunjengenhlanzi.

I-pyridine isetshenziswa ngaso sonke isikhathi njengesandulela semithi kanye nama-agrochemicals futhi ibuye isetshenziswe kakhulu futhi ixazululwe. I-pyridine inganezelwa ku-ethanol uma ufuna ukuyenza ingafaneleki ukusetshenziswa komuntu. Isebenza futhi ekukhiqizeni izidakamizwa ze-antihistaminic i-mepyramine ne-tripelennamine, in vitro ukuhlanganiswa kwe-DNA, ekukhiqizeni i-sulfapyridine (imithi yokwelapha izifo ezibangelwa amagciwane kanye nokutheleleka kwama-bacterium), kanye nama-bactericides, ama-herbicides, namanzi aphikisayo.

Amakhemikhali amaningi amakhemikhali, nakuba ayengakhiqizwa kusuka ku-pyridine, aqukethe isakhiwo sesendandatho. Amakhemikhali anjalo afaka amavithamini B njenge pyridoxine ne-niacin, i-nicotine, imikhiqizo enezitshalo eziqukethe i-nitrogen, kanye nomuthi olwa nesifo sofuba obizwa ngokuthi i-isoniazid. I-Pyridine yayikhiqizwa ngokomlando njengendlela yokukhiqizwa kwe-charification gasification kanye ne-tar yamalahle. Kodwa-ke, ukufuna ukuphakama kwe-pyridine kuholele ekuthuthukiseni izindlela zokwenza imali ezivela ku-ammonia ne-acetaldehyde, futhi ngaphezu kwama-20,000 amathani akhiqizwa ngonyaka wonke emhlabeni.

Isiqephu segama i-pyridine

Igama elihlelekile le-pyridine, ngokusho kwe-Hantzsch-Widman nomenclature okuphakanyiswe yi-IUPAC, i-azine. Kodwa amagama ahlelekile amakhemikhali ayisisekelo ayasetshenziswa kaningi; esikhundleni salokho, ukuchazwa kwamagama ama-hterocycle kulandela amagama ajwayelekile ajwayelekile. IUPAC ayikhuthazi ukusetshenziswa i-azine lapho ubhekisela kuwo i-pyridine.

Ukubalwa kwamatomu ensimbi ku-azine kuqala ku-nitrogen. Ukunikezwa kwezikhundla ngencwadi yesi-Greek (α-γ) kanye nephethini lokufaka esikhundleni segama lomumo wesigameko olufanekisela izinhlelo ze-homoaromatic (i-para ortho, meta,) lisetshenziswe ngezinye izikhathi. Lapha i-α, i-β ne-γ ibhekisela ezikhundleni ezimbili, ezintathu, nezine, ngokulandelana.

Igama lesistimu ye-derivatives ye-pyridine pyridinyl, lapho inomboro ingaphambi kwe-athomu engena endaweni elandelwe inombolo. Kodwa igama lomlando pyridyl Kunconywa yi-IUPAC futhi isetshenziselwa kabanzi esikhundleni segama elihlelekile. I-derivative eyenziwe ngokufaka i-electrophile ku-athomu ye-nitrogen iyaziwa ngokuthi i-pyridinium.

I-4-bromopyridine

2,2'-bipyridine

I-dipicolinic acid (i-pyridine-2,6-dicarboxylic acid)

Indlela eyisisekelo ye-pyridinium cation

Ukukhiqizwa kwe-pyridine

I-Pyridine yatholwa njengenye ye-charification gasification noma ekhishwe ngamakhadi amalahle. Le ndlela yayingasebenzi kahle futhi isetshenziswa kakhulu: i-tar yamalahle ibe ne-0.1 iphesenti ye-pyridine, ngakho-ke kwakudingeka ukuhlanzwa kwezinga eliphezulu, okwenyusa okukhiphayo. Namuhla, i-pyridine eminingi ikhiqizwa ngokwenziwa ngokusebenzisa amagama amaningana, futhi okuvame ukuxoxwa lapha ngezansi.

I-Pyridine Synthesis ngeBohlmann-Rahtz

I-Pyridine Synthesis ngeBohlmann-Rahtz ivumela isizukulwane sama pyridines ashintshiwe ezinyathelweni ezimbili ezinkulu. Ukunciphisa ama-enamine usebenzisa i-ethynylketones kubangelwa ukuthi i-aminodiene intermediate, ngemuva kokuba isomerization eshisa ukushisa, ihamba nge-cyclodehydration ukukhiqiza i-pyridines ye-2,3,6-trisubstituted.

I-Pyridine Synthesis ngokusebenzisa indlela ye-Bohlmann-Rahtz

Le ndlela ihlobene neHantzsch Dihydropyridine Synthesis ethandwayo laphoin situ-I-enamine ehlanjululwayo kanye ne-enone eziphilayo zikhiqiza i-dihydropyridines. Nakuba i-Bohlmann-Rahtz Synthesis ihambisana kakhulu, ukuhlanzwa kwamazinga aphezulu okushisa okudingekayo ukuze i-cyclodehydration yizinselele eziye zinciphisa usizo. Eziningi zezinselele ziye zanqotshwa, okwenza iBohlmann-Rahtz Synthesis ibaluleke kakhulu kulo i-pyridines isizukulwane.

Ngisho noma kungekho ucwaningo lwezocwaningo olwenziwe, ama-intermediates angabonakala nge-H-NMR. Lokhu kubonisa ukuthi umkhiqizo omkhulu we-First Michael Addition kanye nokudluliswa kweproton elandelayo kungaba yi-2Z-4E-heptadien-6-eyodwa ekhishwe futhi ihlanzwe ngokusebenzisa ikholomu ye-chromatography.

Ngakho-ke amazinga okushisa ama-cyclodehydration aphezulu kakhulu adingekayo ukuze enze lula Z/E isomerizations okuyimfuneko yokuthola i-hetero.

Izindlela eziningana ezivumela ukuhlanganiswa kwe-tetra kanye ne-pyridines esetshenzisiwe kuhlelo olulodwa olusetshenziswe kamuva nje. Esikhundleni sokusebenzisa i-butynone njenge-substrate, i-Bagley ihlolwe i-solvents ehlukahlukene yokuguqulwa kwe-4- (trimethylsilyl) engabizi kakhulu kodwa engabizi kakhulu kodwa-3-yn-2-eyodwa. Kwaboniswa ukuthi kuphela i-DMSO ne-EtOH yizixazululo ezinhle. I-EtOH iyathandwa ngokucacile njenge-solvents polar ne-protic vs. i-DMSO njenge-solder aprotic solvent. Kulezi zixazululo ezimbili, i-protodesilylation yenzeke ngokuzenzekelayo. I-Bagley ibuye yabonisa ukuthi i-acid catalysis ivumela ukuthi i-cyclodehydration iqhubeke nokushisa okuphansi.

I-Acid catalysis ibuye ikhulise ukuhlanganisa kokuhlanganiswa. Ama-enamine ahlukahlukene aphendulwa nge-ethynyl ketones ku-5: 1) ingxube ye-acetic acid ne-toluene ukukhokhela ama-pyridines esebenzayo ngesinyathelo esisodwa ekuvuneni okuhle kakhulu.

Ngemuva kokuphumelela kwe-Brønstedt acid catalysis, isazi samakhemikhali sasihlola ikhono lama-catalysts ase-Lewis acid. Izimo ezingcono kakhulu ezisetshenzisiwe ziyi-20% ye-mol% ytterbium triflate noma i-15% ye-mol% zinc bromide ku-toluene ye-refluxing. Ngisho noma ucwaningo lwamacebo alukwenziwanga, singacabanga ukuthi ukuxhaswa yi-catalyst kuhamba ngesivinini se-cyclodehydration, Michael Addition, nezinyathelo ze-isomerization.

Ukuphazamiseka ukuhambisana okulinganiselwe ne-substrates e-acid-sensitive. Ngokwesibonelo, ukubola kwe-acid-catalyzed of the enamines kwenzeka nge-cyano futhi tert-butylester njengeqembu le-electron elihoxisayo. Enye enye indlela emnene ukusetshenziswa kuka-Amberlyst-15 ion ukushintshanisa i-reagent okubekezelayo tert-butchersters.

Njengoba ama-enamine ayitholakali kalula, futhi ukukhulisa isikhungo senqubo, ukusabela kwe-3-yenziwa nge-acetate ye-ammonium njengomthombo weqembu lama-amino. Kule nqubo ephumelelayo, i-enamine ikhiqizwa in situ okuyinto ephendula ne-alkynone okwamanje.

Esivivinyo sokuqala, i-ZnBr2 futhi i-AcOH yayisetshenziswa njengezakhi ezengeziwe nge-toluene njenge-solvent. Kodwa-ke, sekuye kwaboniswa ukuthi ama-substrates ahlaselwe yi-acid ahlala esabela esimweni esibucayi ne-EtOH njengesixazululo.

Chichibabin Synthesis

I-Chichibabin pyridine synthesis yabikwa kuqala ku-1924 futhi isasebenza kakhulu embonini yamakhemikhali. Kuyinto yokusabela okwenza izindandatho, okubandakanya ukusabela kokunciphisa ama-aldehydes, amaketoni, ama-α, β-unsaturated compounds. Ngaphezu kwalokho, ifomu jikelele lokuphendula kungabandakanya noma yikuphi ukuhlanganiswa kwemikhiqizo engenhla ku-ammonia ehlanzekile noma izakhi zalo.

Ukwakhiwa I-Pyridine

Ukwakhiwa kwe-formaldehyde ne-acetaldehyde

I-formalmalhyde ne-acetaldehyde imithombo emikhulu ye-pyridine engabhalwanga. Okungenani, zingabizi futhi zifinyeleleke kalula.

  1. Isinyathelo sokuqala sihilela ukwakhiwa kwe-acrolein kusuka e-formaldehyde nase-acetaldehyde ngokusebenzisa ukukhishwa kwe-Knoevenagel.
  2. Umkhiqizo wokuphela ukhishwa ku-acrolein nge-acetaldehyde ne-ammonia, ekwakheni i-dihydropyridine.
  3. Inqubo yokugcina iyindlela yokusabela nge-oxidation ne-catalyst esebenzayo ukuze kutholakale i-pyridine.
  4. Ukusabela okungenhla kwenziwa esiteshini segesi ngezinga lokushisa lika-400-450 ° C. I-compound eyakhiwe iqukethe i-pyridine, i-picoline noma i-pyridine e-methylated elula, ne-lutidine. Noma kunjalo, ukwakheka kuncike ekutheni kusetshenziswe ukuthi kusetshenziswe futhi ngezinga elithile, kuhluka nezidingo zomenzi. Ngokuvamile, i-catalyst iyinsawoti yensimbi yenguquko. Okuvamile kakhulu yi-manganese (II) i-fluoride noma i-cadmium (II) i-fluoride, nakuba ama-thallium namakhemikhali e-cobalt kungaba ezinye izindlela.
  5. I-pyridine itholakele kumikhiqizo ngemikhiqizo eningi. Ukunciphisa okukhulu kwe-Chichibabin pyridine synthesis kuyinto isivuno sayo esincane, ukuhumusha cishe mayelana ne-20% yemikhiqizo yokuphela. Ngenxa yalesi sizathu, amafomu angaqinisekisiwe ale nkampani ajwayelekile kakhulu.

Bönnemann cyclization

I-Bönnemann cyclization yilapho kuhlanganiswa i-trimer kusukela ekuhlanganiseni izingxenye ezimbili ze-acetylene molecule kanye nengxenye ye-nitrile. Eqinisweni, le nqubo ukuguqulwa kwe-Reppe synthesis.

Le ndlela ihlinzekwa ngukushisa okuvela emazingeni okushisa aphezulu nokucindezelwa noma ngokusebenzisa i-cycloaddition ekhishwa izithombe. Uma kusetshenziswe ukukhanya, i-Bönnemann cyclization idinga iCoCp2 (i-cyclopentadienyl, i-1,5-cyclooctadiene) ukuze isebenze njenge-catalyst.

Le ndlela ingakhipha uketshezi lwe-pyridine okutholakala kuye ngokuthi izakhi ezisetshenziswayo. Ngokwesibonelo, i-acetonitrile izonikeza i-2-methylpyridine, engayithola i-dealkylation yokwakha i-pyridine.

Ezinye izindlela

I-Kröhnke pyridine synthesis

Le ndlela isebenzisa i-pyridine njenge-reagent, nakuba ingayihlanganiswa nomkhiqizo wokuphela. Ngokuphambene nalokho, ukusabela kuzokhipha ama-pyridines ashintshiwe.

Uma usabela nge-α-bromoesters, i-pyridine izobhekana nokuphendula okunjengoMichael ne-carbonyls engasetshenziswanga ukuze kwenziwe i-pyridine ne-pyridium bromide. Ukusabela kuthathwa nge-ammonia acetate ngaphakathi kwe-20-100 ° C izimo ezinomusa.

Ukuhlelwa kabusha kwe-Ciamician-Dennstedt

Lokhu kuhlanganisa ukunwetshwa kwe-pyrrole ne-dichlorocarbene ekwakheni i- 3-chloropyridine.

Isitatimende se-Gattermann-Skita

Kule mpendulo, i-malonate ester usaba ne-dichloromethylamine phambi kwesisekelo.

I-Boger pyridine synthesis

Ukuphendula kwe i-pyridines

Ukuphendula okulandelayo kungabikezelwa ukuthi i-pyridines kusuka kwesakhiwo sabo se-elektroniki:

  1. I-heteroatom yenza i-pyridines ingasebenzi kakhulu ekusebenzeni okujwayelekile kokungenwa kwe-electrophilic okumnandi. Ngakolunye uhlangothi, ama-pyridines ahlaselwe ukuhlaselwa kwe-nucleophilic. Ama-Pyridines asebenza ngendlela yokufaka esikhundleni se-electrophilic (SEAr) ngokufakaza okungafaniyo kodwa okuyisisekelo se-nucleophilic (SNAr) kalula kune-benzene.
  2. Ukuhlaselwa kwe-electrophilic reagents ikakhulukazi ku-Natom nakwe-athomu ye-bC, kuyilapho ama-reagents e-nucleophilic akhetha i-a-ne-cc-athomu.

Ukwengezwa kwe-Electrophilic ku-nitrogen

Ekuphenduleni okubandakanya ukubunjwa kwamabhontshi usebenzisa i-electron eyodwa kuphela e-nitrogen ye-ring, njenge-protonation ne-quaternization, ama-pyridines aziphatha njengama-aliphatic ephakeme noma ama-amine aphunga.

Uma i-pyridine ithatha njengesisekelo noma i-nucleophile, yenza i-pyridinium cation lapho kugcinwa khona i-sextet elimnandi, kanti i-nitrogen ithola icala elihle elihlelekile.

Ukukhonjiswa kwe-Nitrogen

I-pyridines ifomu i-crystalline, ngokuvamile i-hygroscopic, usawoti onama-protic acid amaningi.

I-nitration e-nitrogen

Lokhu kwenzeka kalula ngokusabela kwe-pyridines ne-nitronium usawoti, njenge-nitronium tetrafluoroborate. Ama-protic nitrating agents ezifana ne-nitric acid, eqinisweni, aholela kuphela ku-N-protonation.

Acylation at nitrogen

Ama-chloride yama-acidi nama-acry aullsulphonic asabela ngokushesha nge-pyridines eyenza i-1-acyl- ne-1- arylsulfonylpyridinium usawoti.

I-Alkyl halides ne-sulfates isabela ngokushesha ngama-pyridines enikeza ama-quaternary pyridinium usawoti.

Izikhungo zeNucleophilic

Ngokungafani ne-benzene, izakhi eziningi ze-nucleophilic zingasetshenziswa ngokuphumelelayo nangokuphumelelayo nge-pyridine. Kungenxa yokuthi indandatho ine-electron esincane kakhulu ye-athomu ye-carbon. Lezi zindlela eziphendulayo zifaka ukufaka esikhundleni sokususwa kwe-hydride ion kanye nezengezo zokuqeda ukuze uthole ukulungiswa okuphakathi kwe-aryne futhi kuvame ukuqhubeka ne-2- noma i-4-isikhundla.

I-Pyridine yedwa ayikwazi ukuholela ekwakheni izinsiza eziningana ze-nucleophilic. Noma kunjalo, ukuguqulwa kwe-pyridine ne-bromine, izingcezu ze-sulfonic acid, i-chlorine, ne-fluorine kungaholela eqenjini elishiya. Ukwakhiwa kwe-organolithium compounds kungatholakala kwiqembu elihle kakhulu lokushiya i-fluorine. Ecindezini eliphezulu, i-nucleophilic ingasabela ngama-alkoxides, thiolates, amines, nama-ammonia.

Bambalwa i-heterocyclic ukusabela kungenzeka ngenxa yokusebenzisa iqembu elimpofu elishiya njenge-hydride ion. Izidakamizwa ze-Pyridine endaweni ye-2 zingatholakala nge-Chichibabin ukusabela. I-2-aminopyridine ingaqhubeka iphumelele uma i-amide ye-sodium isetshenziswa njenge-nucleophile. I-molecule ye-hydrogen yakha lapho ama-protini weqembu lama-amino ehlanganisa i-hydride ion.

Efana ne-benzene, i-pyridines Izisetshenziswa ezifana ne-heteroaryne zingatholakala ngokusebenzisa izakhi ze-nucleophilic kuya ku-pyridine. Ukusetshenziswa kwamakhemikhali anamandla afana ne-sodium ne-potassium tert-butoxide kungasiza ukuqeda izidakamizwa ze-pyridine lapho usebenzisa ilungelo lokushiya iqembu. Ngemva kokusungulwa kwe-nucleophile esibophweni esithathu, sinciphisa ukhetho futhi kuholela ekusungulweni kwenhlanganisela enezikhangiso ezimbili.

Izikhungo ze-Electrophilic

Izakhiwo eziningana ze-pyridine electrophilic zingase ziqhubekele phambili noma zingaqhubeki ngokuphelele. Ngakolunye uhlangothi, isici se-heteroaromatic singakhuthazwa ngokusebenzisa ukusebenza kwe-electron-donation. I-Friedel-Crafts alkylation (acylation) yisibonelo sama-alkylations nama-acylations. Lesi sici siphumelele ekuqhubeni i-pyridine ngoba kubangelwa ukungezwa kwe-athomu ye-nitrogen. Izingxenye ezithatha indawo ngokuyinhloko zenzeka endaweni yesithathu enye ye-athomu ye-carbon eline-electron elinezintambo ezenza kube lula ukufaka i-electrophilic.

Isakhiwo se-Pyridine N-Oxide

Ukufakelwa kwe-electrophilic kungaholela ekuguqulweni kwesimo se-pyridine esikhwameni se-2- noma se-4 ngenxa yempendulo ehlukumezayo ye-σ. Noma kunjalo, izindlela zokuhlola zingasetshenziswa ngenkathi kwenziwa ukufakelwa kwe-electrophilic ku-pyridine N-oxide. Kamuva kulandelwa i-nitrogen atom deoxygenation. Ngakho-ke, ukwethulwa kwe-oksijeni kuyaziwa ngokunciphisa inani le-nitrogen futhi kuthuthukiswe ukufakwa endaweni ye-2-isikhundla kanye ne-4-isikhundla samakhemikhali.

Amakhemikhali e-divalent sulfur noma i-phosphorus e-trivalent ayaziwa ukuthi i-oxidized etholakala kalula kakhulu isetshenziselwa ukususa i-athomu ye-oksijeni. I-Triphenylphosphine oxide iyisakhi esakhiwa emva kokushukela kwe-Triphenylphosphine reagent. Yenye enye into engasetshenziselwa ukuqeda i-athomu ye-oxygen evela kwenye into. Ulwazi olungezansi luchaza ukuthi ukufakelwa okuvamile kwe-electrophilic kuthinta kanjani ne-pyridine.

Ukuqondisa i-pyridine nitration kudinga izimo ezithile ezinzima, futhi ngokuvamile kunomkhiqizo omncane. Ukusabela kwe-dinitrogen pentoxide ne-pyridine phambi kwe-sodium kungaholela ekusungulweni kwe-3-nitropyridine. I-derivatives ye-pyridine ingatholakala nge-nitration ye-nitronium tetrafluoroborate (NO2BF4) ngokukhetha i-athomu ye-nitrogen ngokweqile nangokomakhalekhukhwini. Ukwenziwa kwamakhemikhali amabili e-6-dibromo pyridine kungaholela ekwakheni i-3-nitropyridine ngemva kokususwa kwe-athomu ye-bromine.

I-nitration eqondile ibhekwa njengokunethezeka kakhulu kune-sulfonation eqondile ye-pyridine. Ukubilisa kwe-pyridine ku-320 ° C kungabangela i-pyridine-3-sulfonic acid ngokushesha kunokubilisa i-sulfuric acid emazingeni afanayo afanayo. Ukwengezwa kwesakhi se-sulfur kuya kwe-athomu ye-nitrogen kungatholakala ngokuphendula iqembu le-SO3 phambi kwe-mercury (II) i-sulfate esebenza njenge-catalyst.

Ukuchithwa okuqondile nokubhanjiswa kungaqhubeka kahle ngokungafani ne-nitration kanye ne-sulfonation. I-3-bromopyridine ingatholakala ngokuphendula kwe-bromine yamangqamuzana ku-sulfuric acid ku-130 ° C nge-pyridine. Phezu kokukhenyuka, umphumela we-3-chloropyridine ungahle ube khona phambi kwe-aluminium chloride esebenza njenge-catalyst ku-100 ° C. Ukusabela okuqondile kwe-halogen ne-palladium (II) kungabangela kokubili i-2-bromopyridine ne-2-chloropyridine.

Izicelo ze-Pyridine

Enye yezinto ezisetshenzisiwe ezibaluleke kakhulu emafini amakhemikhali yi-pyridine. Ku-1989, ukukhiqizwa okuphelele kwe-pyridine emhlabeni wonke kwakungamathani ayi-26K. Njengakwa-1999, i-11 ezivela kumasayithi okukhiqiza we-25 amakhulu kakhulu e-pyridine ayeseYurophu. Abakhiqizi abakhulu be-pyridine bafaka iKoei Chemical, i-Imperial Chemical Industries, ne-Evonik Industries.

Ekuqaleni kwe-2000, ukukhiqizwa kwe-pyridine kwandiswe ngezinga eliphezulu. Isibonelo, izwe lase-China elilodwa lithinta umthamo waminyaka yonke wokukhiqiza wama-30,000 amathani. Namuhla, ukuhlanganisana okuhlangene phakathi kwe-US kanye ne-China kubangelwa ukukhiqizwa okuphezulu kwe-pyridine emhlabeni.

izibulala-zinambuzane

I-Pyridine isetshenziselwa ikakhulukazi njenge-precurse kuya kokubili kokubulala i-diquat ne-paraquat. Lapho kusetshenzwa ama-fungicide ase-pyrithione-based, i-pyridine isetshenziswa njengengxenye eyisiyisisekelo.

Ukusabela phakathi kweZincke kanye ne-pyridine imiphumela ekukhiqizeni ama-compounds amabili - laurylpyridinium ne-cetylpyridinium. Ngenxa yokwakhiwa kwazo, lezi zinhlanganisela ezimbili zengezwa kwimikhiqizo yokunakekelwa kwamazinyo nemlomo.

Ukuhlaselwa kwe-agent e-alkylating kuya ku-pyridine imiphumela ku-N-alkylpyridinium usawoti, i-cetylpyridinium chloride njengesinye isibonelo.

I-Paraquat Synthesis

Solvent

Enye isicelo lapho i-pyridine isetshenziselwa ukukhwehlela kwe-Knoevenagel, lapho isetshenziselwa khona njengesisombululo esincane esisebenzayo, se-polar, nesisekelo. I-Pyridine ingcono kakhulu ku-dehalogenation, lapho isebenza njengesisekelo sokusabela kokuqeda ngenkathi kuhlanganiswa i-hydrogen halide edala ukufaka usawoti we-pyridinium.

Ngama-acylations kanye nokucaciswa, i-Pyridine isebenza ama-anhydride noma i-carboxylic acid halides. Okusebenza nakakhulu kulezi zindlela yi-4- (1-pyrrolidinyl) pyridine ne-4-dimethylaminopyridine (i-DMAP), okuyizidakamizwa ze-pyridine. Ekuphenduleni kwemvelo, i-Pyridine isetshenziswe njengesisekelo.

Ukwenziwa kwe-pyridinium ngokusebenzisa ukusabela kokuqedwa nge-pyridine

I-Pyridine iyigugu elibalulekile embonini yezembatho. Ngaphandle kokusetshenziswa njenge-solvent ekukhiqizeni i-raber kanye nodayi, isetshenziselwa ukuthuthukisa ikhono lenethiwekhi yekotoni.

I-US Yokudla Nezidakamizwa Zezidakamizwa ivumela ukwengezwa kwe-pyridine ngamanani amancane ekudleni ukuze kubanikeze ukunambitheka okubabayo.

Ezisombululo, ukutholakala kwesibindi se-pyridine kuwu-1-3 mmol·LL-1 (79-237 mg · L-1). Ukuba isisekelo, i-pyridine ingase isetshenziswe njenge-Karag Fischer reagent. Kodwa-ke, i-imidazole ivame ukusetshenziswa njengengxenye esikhundleni se-pyridine njengoba i-imidazole inomlilo othakazelisayo.

Phindela ku-Piperidine

I-Pyridine hydrogenation ene-ruthenium-, cobalt-, noma i-nickel-based catalyst emazingeni aphezulu okushisa kubangela ukukhiqizwa kwe-piperidine. Lena i-nitrogen heterocycle ebalulekile eyakhiwe ebalulekile yokwakha.

Ama-reagents akhethekile asekelwe ku-Pyridine

Ku-1975, u-William Suggs noJacob Corey bathuthukisa i-pyridinium chlorochromate. It isetshenziswa oxidize utshwala secondary kuya ketone kanye utshwala primary kuya aldehydes. I-pyridinium chlorochromate itholakala uma i-pyridine ingezwa kwisixazululo se-hydrochloric ne-chromic acid.

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

I-chromyl chloride (i-CrO2Cl2) ngokuba yi-carcinogenic, enye indlela kwakufanele ifunwe. Omunye wabo kumele asebenzise i-pyridinium chloride ukuphatha i-chromium (VI) oxide.

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

I-reagent ye-Sarret (eyinkimbinkimbi ye-chromium (VI) oxide ene-pyridine heterocycle e-pyridine), i-pyridinium chlorochromate (i-PCC), i-reagent ye-Cornforth (i-pyridinium dichromate, i-PDC), kanye ne-Collins reagent (eyinkimbinkimbi ye-chromium (VI) oxide ne-pyridine i-heterocycle ku-dichloromethane) zifana nama-chromium-pyridine. Zibuye zisetshenziselwe i-oxidation, njengokuguqulwa kweziphuzo zamanzi neziyisisekelo kuya kwamaketoni.

Ama-reagents ama-Sarret ne-Collins awagcini nje ukulungisa, kodwa nawo ayingozi. Ziyi-hygroscopic futhi ziyakwazi ukushisa ngesikhathi sokulungiselela. Ngenxa yalokho, kunconywa ukusetshenziswa kwe-PDC ne-PCC. Nakuba ama-reagents amabili asetshenziswe kakhulu kuma-70 naku-80s, ajwayelekile ukuthi asetshenziswe njengamanje ngenxa yobuthi bawo kanye nokuqinisekiswa kwe-carcinogenicity.

Isakhiwo se-Crabtree's catalyst

Ekusebenzisaneni kwamakhemikhali, i-pyridine isetshenziswa kakhulu njenge-ligand. Iphuma, njengoba iphuma yi-2,2'-bipyridine, equkethe ama-molecule e-2 pyridine ahlanganiswe nesibopho esisodwa, ne-terpyridine, i-molecule ye-3 pyridine amasongo axhunyiwe ndawonye.

I-base base-Lewis enamandla ingasetshenziswa njengendlela yokufaka i-ligridine ligand engxenyeni yinkimbinkimbi yensimbi. Lesi sici sisetshenziswa ekuhloliseni kwe-polymerization kanye nokuphendula kwe-hydrogenation, ngokusebenzisa, isibonelo, i-catalyst ye-Carabtree. I-pyridine Lingard eshintshiwe ngenkathi impendulo ibuyiselwa ngemuva kokuqedwa kwayo.

Okubhekwayo

Isikhundla se-Organic Chemistry: Izincomo ze-IUPAC namagama athandwayo 2013 (iBlue Book). I-Cambridge: I-Royal Society ye-Chemistry. I-2014. p. I-141.

U-Anderson, T. (1851). "Ueber die Producte der trocknen Destillation thierischer Materien" [Emikhiqizo ye-distillation eyomile yendaba yesilwane]. Annalen der Chemie und Pharmacie. 80: 44.

U-Sherman, AR (2004). "Pyridine". Ku-Paquette, L. I-Encyclopedia of Reagents ye-Organic Synthesis. i-e-EROS (i-Encyclopedia of Reagents ye-Organic Synthesis). I-New York: J. Wiley & Son.

I-Behr, A. (2008). Angewandte homogene uKatalyse. I-Weinheim: iWiley-VCH. p. I-722.