【摘要】：二苯甲酮類化合物是一類重要的精細(xì)化學(xué)品和有機(jī)合成中間體。傳統(tǒng)的二苯甲酮類化合物主要由親電�；磻�(yīng)和過渡金屬催化偶聯(lián)反應(yīng)合成,反應(yīng)底物受到一定的限制,且需要使用大量的路易斯酸或者過渡金屬配合物作為催化劑,對環(huán)境污染嚴(yán)重。N-雜環(huán)卡賓作為一種有機(jī)小分子催化劑,能夠催化芳香醛與芳香鹵代物的親核�；磻�(yīng),為合成二苯甲酮類化合物提供了一條新的途徑。合成了兩種類型的N-雜環(huán)卡賓前體:咪唑類卡賓前體和噻唑類卡賓前體。其中,咪唑類卡賓前體根據(jù)所含陰離子不同分為四氟硼酸鹽類和六氟磷酸鹽類兩種類型。利用紅外光譜、核磁共振氫譜等技術(shù)對合成的N-雜環(huán)卡賓前體進(jìn)行結(jié)構(gòu)確定。將合成的N-雜環(huán)卡賓用于催化單取代芳香醛與對氟硝基苯的親核�；磻�(yīng)。使用對氟苯甲醛與對氟硝基苯作為模型反應(yīng)底物,對卡賓前體種類、時(shí)間、溫度、催化劑用量等因素進(jìn)行優(yōu)化,確定了反應(yīng)的最佳條件:以1-丁基-3-甲基咪唑四氟硼酸鹽為卡賓前體,反應(yīng)時(shí)間為1 h,反應(yīng)溫度為0℃,DMF為溶劑,催化劑用量為反應(yīng)物用量的20 mmol%。考察了反應(yīng)物上不同取代基團(tuán)對反應(yīng)的影響;同時(shí),考察了咪唑類卡賓前體的循環(huán)使用情況。將合成的N-雜環(huán)卡賓用于催化單或雙鹵代芳香醛與3,4-二氟硝基苯的親核�；磻�(yīng)。使用2-氟苯甲醛與3,4-二氟硝基苯作為模型反應(yīng)底物,對卡賓前體種類、時(shí)間、溫度、催化劑用量等條件進(jìn)行優(yōu)化,確定了反應(yīng)的最佳條件:以1-丁基-3-甲基咪唑四氟硼酸鹽為卡賓前體,反應(yīng)時(shí)間為1 h,反應(yīng)溫度為0℃,DMF為溶劑,催化劑用量為反應(yīng)物用量的20 mmol%。在最佳條件下,催化2-氟苯甲醛、2,4-二氟苯甲醛、2,5-二氟苯甲醛、2,6-二氟苯甲醛分別與3,4-二氟硝基苯反應(yīng),反應(yīng)產(chǎn)率分別為76%、42%、42%和32%。氧雜蒽酮是一類重要的具有生物活性的天然產(chǎn)物。本文提供了一條合成氧雜蒽酮的新思路:首先N-雜環(huán)卡賓催化鄰甲氧基苯甲醛與3,4-二氟硝基苯的親核�；磻�(yīng),生成鄰位含有甲氧基的二苯甲酮;然后含甲氧基的二苯甲酮發(fā)生去甲基化反應(yīng),將二苯甲酮的甲氧基轉(zhuǎn)化為羥基;最后發(fā)生分子內(nèi)環(huán)化反應(yīng)生成氧雜蒽酮。使用1,3-二甲基咪唑碘鹽作為卡賓前體,分別催化2-甲氧基苯甲醛、2,4-二甲氧基苯甲醛、2,6-二甲氧基苯甲醛和2-甲氧基-5-溴苯甲醛與3,4-二氟硝基苯的反應(yīng),反應(yīng)產(chǎn)率分別為63%、75%、42%和65%。對4-硝基-2'-甲氧基-2-氟二苯甲酮、4-硝基-2',4'-甲氧基-2-氟二苯甲酮和4-硝基-2'-甲氧基-2-氟-5'-溴二苯甲酮進(jìn)行脫甲基化處理,反應(yīng)產(chǎn)率分別為52%、85%和60%。在碳酸銫的作用下,脫甲基化的產(chǎn)物4-硝基-2'-羥基-2-氟-二苯甲酮、4-硝基-2'-羥基-2-氟二苯甲酮、4'-硝基-2-羥基'-2-氟-5-溴二苯甲酮發(fā)生成環(huán)反應(yīng),得到相應(yīng)的氧雜蒽酮,反應(yīng)產(chǎn)率均在92%左右。
[Abstract]:Benzophenone compounds are an important class of fine chemicals and organic synthesis intermediates. The traditional benzophenone compounds are mainly synthesized by electrophilic acylation reaction and transition metal catalyzed coupling reaction. The reaction substrate is limited and a large number of Lewis acid or transition metal complexes are used as catalysts. N-heterocyclic carbene, as a small organic catalyst, can catalyze the nucleophilic acylation of aromatic aldehydes with aromatic halides, which provides a new way for the synthesis of benzophenone compounds. Two types of N- heterocyclic carbene precursors were synthesized: imidazole carbene precursors and thiazole carbenes precursors. Among them, imidazole carbene precursors are divided into tetrafluoroborate salt and hexafluorophosphate salt according to the anions contained. The structure of the synthesized N- heterocyclic carbene precursor was determined by infrared spectroscopy and nuclear magnetic resonance spectroscopy. The synthesized N-heterocyclic carbene was used to catalyze the nucleophilic acylation of monosubstituted aromatic aldehydes with p-fluoronitrobenzene. Using p-fluorobenzaldehyde and p-fluoronitrobenzene as the model substrate, the kinds of carbene precursors, time, temperature, amount of catalyst and other factors were optimized. The optimum reaction conditions were determined as follows: 1 Ding Ji 3 methyl imidazolium tetrafluoroborate was used as carbene precursor, the reaction time was 1 h, the reaction temperature was 0 鈩，

本文編號(hào)：2217570