tala fou

I le faaopoopo atu i tekinolosi, o le tuufaatasiga o glycosides e masani lava ona fiafia i le faasaienisi, aua o se tali masani i le natura.O pepa talu ai nei a Schmidt ma Toshima ma Tatsuta, faʻapea foʻi ma le tele o faʻamatalaga o loʻo taʻua i totonu, na faʻaalia ai le tele o mea e mafai ona gaosia.
I le tuufaatasia o glycosides, o se vaega tele-suka e tuʻufaʻatasia ma se nucleophiles, e pei o ava malosi, carbohydrates, poʻo polotini, pe a fai o se tali filifilia ma se tasi o vaega hydroxyl o le carbohydrate e manaʻomia, o isi galuega uma e tatau ona puipuia i le laasaga muamua.I le mataupu faavae, enzymatic po o microbial faagasologa, ona o lo latou filifilia, e mafai ona suitulaga lavelave puipuiga kemisi ma deprotection laasaga e filifili mai glycosides i itulagi.Ae ui i lea, ona o le umi o talaʻaga o alkyl glycosides, o le faʻaaogaina o enzymes i le faʻaogaina o glycosides e leʻi suʻesuʻeina lautele ma faʻaaogaina.
Ona o le gafatia o faiga enzyme talafeagai ma le maualuga o tau o gaosiga, e leʻo sauni le faʻaogaina o le alkyl polyglycosides e faʻaleleia i le tulaga tau alamanuia, ma e sili atu le vailaʻau.
I le 1870, na lipotia ai e MAcolley le faʻasologa o le "acetochlorhydrose" (1, ata 2) e ala i le tali atu o le dextrose (glucose) ma le acetyl chloride, lea na iu ai ina taʻitaʻia le talaʻaga o auala faʻapipiʻi glycoside.
Ata 2. Fa'asologa o aryl glucosides e tusa ai ma Michael
Tetra-0-acetyl-glucopyranosyl halides(acetohaloglucoses) na maua mulimuli ane e avea ma mea faʻaoga faʻaoga mo le faʻaogaina o le stereoselective o le alkyl glucosides mama.I le 1879, na manuia ai Arthur Mikaele i le sauniaina maoti, faʻamaʻi faʻasaʻo aryl glycosides mai Colley's intermediates ma phenolates.(Aro-, Ata 2).
I le 1901, na fa'apipi'iina e Mikaele i le tele o ga'o ga'o ma aglycons hydroxylic, ina ua fa'ailoa mai e W.Koenigs ma E.Knorr a latou fa'agasologa o le glycosidation stereoselective (Ata 3).O le tali e aofia ai le suitulaga o le SN2 i le anomeric carbon ma fa'asolosolo fa'asolosolo fa'atasi ma le feliuliua'i o le fa'atulagaga, e fai mo se fa'ata'ita'iga le α-glucoside 4 mai le β-anomer o le aceobromoglucose intermediate 3. O le fa'asologa o Koenigs-Knorr e faia i luma o le siliva po'o le. fa'ameamea o le mercury.
Ata 3. Stereoselective synthesis of glycosides e tusa ai ma Koenigs ma Knorr
I le 1893, na tuʻuina atu ai e Emil Fischer se auala e matua ese ai le tuʻufaʻatasia o alkyl glucosides.O lenei faiga ua lauiloa nei o le "Fischer glycosidation" ma e aofia ai se tali faʻafefeteina o glycoses ma ava malosi.So'o se tala fa'asolopito e tatau lava ona aofia ai le taumafaiga muamua a A.Gautier na lipotia i le 1874, e fa'aliliu le dextrose i le ethanol anhydrous i le i ai o le hydrochloric acid.Ona o se suʻesuʻega faʻasesē elemene, na talitonu Gautier na ia mauaina se "diglucose".Na fa'aalia mulimuli ane e Fischer o le "diglucose" a Gautier o le mea moni lava o le ethyl glucoside (Ata 4).
Ata 4. Fa'asologa o glycosides e tusa ai ma Fischer
Na fa'amatala sa'o e Fischer le fa'atulagaina o le ethyl glucoside, e pei ona mafai ona va'aia mai le fa'asologa fa'asolopito o le furanosidic na fa'atu mai.O le mea moni, o oloa glycosidation Fischer e lavelave, o le tele o paluga paleni o α / β-anomers ma pyranoside / furanoside isomers lea e aofia ai foʻi oligomers glycoside soʻotaga.
O le mea lea, e le faigofie ona tu'u'ese'ese ituaiga mole mole ta'itasi mai fefiloi fa'afefiloi Fischer, lea sa avea ma fa'afitauli tuga i aso ua mavae.Ina ua maeʻa le faʻaleleia atili o lenei metotia faʻapipiʻi, na mulimuli ane faʻaaogaina e Fischer le faʻasologa o Koenigs-Knorr mo ana suʻesuʻega.I le fa'aogaina o lenei faiga, o E.Fischer ma B.Helferich o le lipoti muamua lea o le tu'ufa'atasiga o se alkyl glucoside filifili umi o lo'o fa'aalia ai mea fa'aola i le 1911.
I le amataga o le 1893, na matauina sa'o e Fischer mea taua o alkyl glycosides, e pei o lo latou mautu maualuga agai i le oxidation ma le hydrolysis, aemaise lava i faʻasalalauga malosi.O uiga uma e lua e taua mo alkyl polyglycosides i faʻaoga faʻafefe.
O suʻesuʻega e fesoʻotaʻi ma le glycosidation tali o loʻo faʻaauau pea ma le tele o auala manaia i glycosides ua atiaʻe i le taimi ua tuanaʻi.O nisi o taualumaga mo le tuufaatasia o glycosides o loʻo aoteleina i le Ata 5.
I se tulaga lautele, e mafai ona vaevaeina faiga glycosidation kemikolo i faiga e tau atu i le oligomer equilibria lavelave i acid-catalysed glycosyl exchange.
Ata 5. Aotelega o metotia mo le tuufaatasia o glycosides
Tali i luga o mea'ai ga'o ga'o fa'agaoioi talafeagai (Fischer glycosidic reactions and hydrogen fluoride(HF) reactions with unprotected carbohydrate molecules) and kinetics controlled, irreversiable, and mainly stereotaxic substitution reactions.Ole ituaiga lona lua ole faiga e mafai ona o'o atu ai ile fa'atupuina o ituaiga ta'itasi nai lo le fa'afefiloiga lavelave o tali, aemaise pe a tu'ufa'atasia ma faiga fa'asao vaega.E mafai ona tu'u vaega i luga o le kaponi ectopic, e pei o halogen atoms, sulfonyl, po'o trichloroacetimidate vaega, pe fa'agaoioi e fa'avae a'o le'i liua i esters triflate.
I le tulaga faapitoa o le glycosidations i le hydrogen fluoride poʻo le faʻafefiloi o le hydrogen fluoride ma le pyridine (pyridinium poly [hydrogen fluoride]), o le glycosyl fluoride e fausia i totonu ma e sologa lelei ona liua i glycosides, mo se faʻataʻitaʻiga ma ava malosi.Na fa'aalia le fluoride o le hydrogen e malosi le fa'agaoioia, e le fa'aleagaina;equilibrium auto condensation(oligomerization) o loʻo matauina e tutusa ma le faiga o le Fischer, e ui lava atonu e ese le faiga faʻaalia.
Alkyl glycosides mama mama e na'o le talafeagai mo fa'aoga fa'apitoa.Mo se faʻataʻitaʻiga, o alkyl glycosides ua faʻaaogaina ma le manuia i suʻesuʻega faʻaola mo le faʻamalamalamaina o palatini membrane, e pei o le tolu vaega tioata o le porin ma le bacteriorhodopsin i le i ai o le octyl β-D-glucopyranoside (o isi suʻesuʻega e faʻatatau i lenei galuega e taʻitaʻia ai le Nobel. faailoga i le kemisi mo Deisenhofer, Huber ma Michel i le 1988).
I le gasologa o le atinaʻeina o alkyl polyglycosides, na faʻaaogaina auala stereoselective i luga o le fua suʻesuʻe e faʻapipiʻi ai le tele o vailaʻau faʻataʻitaʻiga ma suʻesuʻeina a latou mea faʻaletino, ona o lo latou lavelave, le mautu o vaeluagalemu ma le aofaʻi ma le taua tele o le faagasologa. fa'aleaga, fa'asologa o le ituaiga Koenigs-Knorr ma isi faiga fa'apolopolo o le a fa'atupuina fa'afitauli fa'apitoa fa'apitoa ma le tamaoaiga.Fischer-ituaiga faiga e faʻatusatusa le lavelave ma faigofie ona faʻatinoina i luga o se fua faʻapisinisi ma e tusa ai, o le auala sili lea mo le gaosiga o alkyl polyglycosides i luga o se fua tele.


Taimi fa'asalalau: Sep-12-2020