INVESTIGATION OF A SYNTHESIS OF MESO-PORPHYRINS EMPLOYING HIGH-CONCENTRATION CONDITIONS AND AN ELECTRON-TRANSPORT CHAIN FOR AEROBIC OXIDATION
INVESTIGATION OF A SYNTHESIS OF MESO-PORPHYRINS EMPLOYING HIGH-CONCENTRATION CONDITIONS AND AN ELECTRON-TRANSPORT CHAIN FOR AEROBIC OXIDATION
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DOI：
10.1021/jo00082a014
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发表时间：
1994-02-11
影响因子：
3.6
通讯作者：
CHUANG, YY
中科院分区：
文献类型：
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作者：
LINDSEY, JS;MACCRUM, KA;CHUANG, YY
以四苯基卟啉（TPP）和四均三甲苯基卟啉（TMP）为模型，在醛和吡咯浓度大于或等于10.1M的条件下，研究了室温下meso卟啉的合成。在较高反应物浓度下发生的产率下降可以用较高的酸催化剂浓度部分抵消。0.1 M苯甲醛和吡咯的反应在三种酸（三氟乙酸、BF 3.OEt（2）或甲磺酸）的适当浓度下使用酸催化缩合然后醌氧化的两步法提供20-30%产率的TPP。研究了醛、吡咯、酸催化剂和氧化剂同时存在下卟啉的一步合成。在五种醌类化合物中，只有对氯醌（TCQ）能成功氧化。在0.1M的浓度下进行的一步合成以10-20%的产率提供TPP。由于氧化所需的TCQ量，高浓度下的一步和两步合成都涉及浆料。采用TCQ和铁（II）酞菁（FePc）在催化量和O-2作为末端电子受体的电子传输链已被改编为卟啉合成。FePc在室温下活化O-2并使还原的TCQ还原。这种电子传递链提供温和的有氧氧化。需氧氧化过程比用化学计量量的TCQ氧化更清洁，并且可以作为一步或两步卟啉合成的一部分来实施。0.1M苯甲醛和吡咯在5mol%TCQ和5mol%FePc存在下在温和通风下在酸催化下反应，以11%（一步）或24%（两步）产率得到TPP。均三甲苯醛在0.1 M浓度下与BF 3-乙醇共催化和有氧氧化反应后转化为四均三甲苯基卟啉。在温和的环境条件下进行有氧氧化的两步合成，从50-mL反应中得到类似于100 mg卟啉，并且应该证明通常可用于制备规模合成meso-卟啉。
The room-temperature synthesis of meso-porphyrins has been investigated at aldehyde and pyrrole concentrations greater than or equal to 10.1 M using tetraphenylporphyrin (TPP) and tetramesitylporphyrin (TMP) as models. The decline in yield that occurs at-higher reactant concentrations can be offset partially with higher acid catalyst concentrations. Reactions of 0.1 M benzaldehyde and pyrrole afford 20-30% yields of TPP at appropriate concentration of three acids, trifluoroacetic acid, BF3.OEt(2), or methanesulfonic acid, using the two-step process of acid-catalyzed condensation followed by quinone oxidation. A one-step synthesis of porphyrins has been investigated where aldehyde, pyrrole, acid catalyst, and oxidant are present simultaneously. Among five quinones examined only p-chloranil (TCQ) provides successful oxidation. The one-step synthesis performed at concentrations of 0.1 M affords TPP in 10-20% yields. Both the one- and two-step syntheses at high concentrations involve slurries due to the amount of TCQ required for oxidation. An electron transport chain employing TCQ and iron(II) phthalocyanine (FePc) in catalytic amounts and O-2 as the terminal electron acceptor has been adapted for the porphyrin synthesis. FePc activates O-2 and recycles reduced TCQ at room temperature. This electron transport chain provides mild aerobic oxidation. The aerobic oxidation process is cleaner than oxidation with stoichiometric amounts of TCQ and can be implemented as part of a one-step or two-step porphyrin synthesis. Reaction of 0.1 M benzaldehyde and pyrrole with acid catalysis in the presence of 5 mol% TCQ and 5 mol% FePc with gentle aeration affords TPP in 11% (one step) or 24% (two step) yield. Mesitaldehyde is converted to tetramesitylporphyrin upon reaction at a concentration of 0.1 M with BF3-ethanol cocatalysis and aerobic oxidation. The two-step synthesis with aerobic oxidation proceeds under mild ambient conditions, affords similar to 100 mg porphyrin from 50-mL reactions, and should prove generally useful for preparative scale syntheses meso-porphyrins.