Qhov sib txawv tseem ceeb ntawm synthon thiab hluavtaws sib npaug yog tias synthon yog moiety ntawm cov tshuaj sib xyaw uas tuaj yeem tsim los ntawm cov txheej txheem hluavtaws paub, qhov sib npaug hluavtaws yog cov reagent uas ua haujlwm ntawm lub synthon.
Cov ntsiab lus synthon thiab hluavtaws sib npaug tuaj nyob rau hauv ceg ntawm kev tshuaj xyuas retrosynthetic. Nws yog cov txheej txheem uas muaj txiaj ntsig zoo rau kev daws cov teeb meem uas tshwm sim thaum lub sij hawm npaj cov txheej txheem organic synthesis. Hauv cov txheej txheem kev tshuaj xyuas no, peb yuav tsum hloov pauv lub hom phiaj molecule rau hauv cov qauv yooj yim yam tsis muaj kev cuam tshuam ntawm kev sib cuam tshuam ntawm cov reagent. Qee zaum, peb siv cov ntsiab lus synthon thiab hluavtaws sib npaug sib hloov, tab sis lawv yog ob yam sib txawv.
Synthon yog dab tsi?
Synthon yog moiety ntawm cov tshuaj lom neeg uas tuaj yeem tsim los ntawm cov txheej txheem hluavtaws paub. Nws yog ib chav tsev hypothetical nyob rau hauv lub hom phiaj tshuaj compound (organic compound). Ib tug synthon sawv cev rau lub peev xwm pib reagent rau retroactive synthesis ntawm lub hom phiaj molecule. Lub tswv yim ntawm synthon yog tsim los ntawm E. J. Corey nyob rau hauv 1967. Thaum lub sij hawm ntawd, nws siv lub sij hawm synthon los ua ib tug retrosynthetic fragmentation qauv, tab sis tam sim no peb feem ntau siv nws rau lub npe hluavtaws tsev blocks.
Daim duab 01: Synthons thiab Synthetic Equivalents
Synthons raug nqi tshuaj lom neeg. Tab sis, nyob rau hauv cov txheej txheem synthesis, peb tsuas yog siv cov ntaub ntawv nruab nrab vim hais tias cov tsiaj raug them tuaj yeem ua rau cov synthons tsis zoo. Yog tias peb xav txog ib qho piv txwv, rau kev sib txuas ntawm phenylacetic acid, peb tuaj yeem pom ob lub synthons thaum npaj cov txheej txheem synthesis no. Ob lub synthons tam sim no nyob rau hauv phenylacetic acid molecule yog carboxylic pawg los yog –COOH thiab electrophilic benzyl pawg los yog –PhCH2+ pawg.
Lub sijhawm npaj no, peb yuav tsum txheeb xyuas cov khoom sib npaug uas tsim nyog thiab. Rau qhov piv txwv no ntawm kev sib txuas ntawm phenylacetic acid, qhov tsim nyog hluavtaws sib npaug rau pawg carboxyl yog cyanide anion. Rau -PhCH2+ pawg, benzyl bromide yog cov synthon tsim nyog. Tom qab ntawd cov kauj ruam tshuaj tiv thaiv rau ob lub synthons yog raws li hauv qab no:
PhCH2Br + NaCN → PhCH2CN + NaBr
PhCH2CN + 2 H2O → PhCH2COOH + NH 3
Peb tuaj yeem faib cov synthons li carbanionic synthons thiab carbocationic synthons. Hauv cov txheej txheem retrosynthesis, peb feem ntau rhuav tshem cov ntawv cog lus heterolytically (tsis yog homolytically), uas tsim cov carbanions thiab carbocations. Ob daim ntawv no yog tom qab ntawd muaj rau tus kws tshuaj los tsim cov txheej txheem organic nyuaj.
Dab tsi yog Synthetic sib npaug?
Synthetic sib npaug yog ib qho reagent uas ua haujlwm ntawm lub synthon. Synthons yog reacted nrog cov hluavtaws sib npaug kom tau txais lub hom phiaj molecule. Piv txwv li, cov hluavtaws sib npaug rau pawg carboxylic acid nyob rau hauv cov synthesis ntawm phenylacetic acid yog cyanide anion.
Qhov txawv ntawm Synthon thiab Synthetic Equivalent yog dab tsi?
Cov ntsiab lus synthon thiab hluavtaws sib npaug tuaj nyob rau hauv ceg ntawm kev tshuaj xyuas retrosynthetic. Qhov sib txawv tseem ceeb ntawm synthon thiab hluavtaws sib npaug yog tias synthon yog moiety ntawm cov tshuaj sib xyaw uas tuaj yeem tsim los ntawm cov txheej txheem hluavtaws paub, qhov sib npaug hluavtaws yog ib qho reagent uas ua haujlwm ntawm lub synthon. Qhov ntawd txhais tau tias; synthon yog ib feem ntawm lub substrate molecule uas peb yuav hloov nws cov qauv nyob rau hauv thiaj li yuav tau txais cov qauv uas xav tau, thaum hluavtaws sib npaug yog cov molecule uas peb yuav tsum tau hnov mob nrog cov synthon thiaj li yuav tau txais cov khoom xav tau.
Hauv qab no yog cov ntsiab lus ntawm qhov sib txawv ntawm synthon thiab hluavtaws sib npaug.
Summary – Synthon vs Synthetic Equivalent
Cov ntsiab lus synthon thiab hluavtaws sib npaug tuaj nyob rau hauv ceg ntawm kev tshuaj xyuas retrosynthetic. Qhov sib txawv tseem ceeb ntawm synthon thiab hluavtaws sib npaug yog tias synthon yog moiety ntawm cov tshuaj sib xyaw uas tuaj yeem tsim los ntawm cov txheej txheem hluavtaws paub, qhov sib npaug hluavtaws yog cov reagent uas ua haujlwm ntawm cov synthon.
