Preparation and Reactions of Certain Racemic and Optically Active Cyanohydrins Derived from 2-Chlorobenzaldehyde, 4-Fluorobenzaldehyde, Benzo[d][1,3]-dioxole-5-carbaldehyde and 2,3-Dihydrobenzo[b][1,4]dioxine-6-carbaldehyde. Antimicrobial and in vitro Antitumor Evaluation of the Products
作者:Yosef, Hisham Abdallah A.、Elmasry、Ibrahim, Nabila M.、Ismael, Eman H. I.、Mahran
DOI:10.21608/ejchem.2017.3262
日期:2017.4.30
THE CHEMOENZYMATIC reaction of selected aldehydes, ……...namely 2-chlorobenzaldehyde (1a), 4-fluorobenzaldehyde (1b), benzo[d][1,3]dioxole-5-carbaldehyde (1c) and/or 2,3-dihydrobenzo [b] [1,4] dioxine-6-carbaldehyde (1d) with hydrogen cyanide in presence of (R)-oxynitrilase (R)-Pa HNL [EC 4.1.2.10] from almonds, as a chiral catalyst, gave the optically active cyanohydrin enantiomers (R)-2a-c, respectively. Acetone cyanohydrin (3), was also used, as a transcyanating agent, to give the same products. The racemic cyanohydrins (R,S)-2a-d have been synthesized, as well, by treating compounds 1a-d with aqueous potassium cyanide solution in presence of a saturated solution of sodium metabisulphite (Na2S2O5). The optical purity of cyanohydrins (R)-2a-c was determined through their derivatization with (S)-naproxen chloride (S)-5 to the respective diastereomers (R,2S)-6a-c which were obtained in diastereomeric excess (de) values up to 93 % (1H NMR). Heating compounds (R)-2a,b and / or their racemic analogues (R,S)-2a-c with concentrated hydrochloric acid gave the respective α-hydroxycarboxylic acids 7a-c. Moreover, reduction of cyanohydrins (R,S)-2b,c under different conditions resulted in a hydrodecyanation giving the respective primary alcohols 8a,b. Structures and configurations of the new compounds were confirmed with compatible elementary microanalyses and spectroscopic ( IR, 1H NMR, 13C NMR, MS and single crystal X-ray crystallography) measurements. The antimicrobial activity of derivatives 6a-d against four bacterial species (Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) and two fungi (Aspergillus flavus and Candida albicans) were undertaken. Moreover, compounds (R,2S)-6b, (R,2S)(S,2S)-6b and (R,2S)−6c were screened for their in virto antitumor activity against three human solid cancer cell lines (HCT 116, HepG2 and MCF-7). In general, the tested compounds were found inactive or showed weak activities in comparison with the standard drugs.
选定的醛类化合物,即2-氯苯甲醛(1a)、4-氟苯甲醛(1b)、苯并[d][1,3]二氧杂环戊烯-5-甲醛(1c)和/或2,3-二氢苯并[b][1,4]二氧杂环己烯-6-甲醛(1d),在氢氰酸与杏仁来源的(R)-氧腈酶((R)-Pa HNL [EC 4.1.2.10])作为手性催化剂的存在下,发生了化学酶促反应,分别得到了光学活性的氰醇对映体(R)-2a-c。此外,丙酮氰醇(3)也被用作氰基转移剂,得到了相同的产品。通过将化合物1a-d与含有饱和焦亚硫酸钠(Na2S2O5)溶液的氰化钾水溶液反应,也合成了外消旋的氰醇(R,S)-2a-d。通过与(S)-萘普生氯(S)-5的衍生化反应,确定了氰醇(R)-2a-c的光学纯度,得到了其在非对映体过量(de)值高达93%的非对映体(R,2S)-6a-c(1H NMR)。将化合物(R)-2a,b及其外消旋类似物(R,S)-2a-c与浓盐酸加热,得到了相应的α-羟基羧酸7a-c。此外,在不同条件下还原氰醇(R,S)-2b,c,得到了进行氢解反应的相应一级醇8a,b。通过配合元素微分析和光谱(IR、1H NMR、13C NMR、MS和单晶X射线晶体学)测量,确认了新化合物的结构和构型。对衍生物6a-d进行了抗微生物活性测试,针对四种细菌(枯草芽孢杆菌、金黄色葡萄球菌、大肠杆菌和铜绿假单胞菌)和两种真菌(黄曲霉和白色念珠菌)。此外,化合物(R,2S)-6b、(R,2S)(S,2S)-6b和(R,2S)-6c在体外进行了抗肿瘤活性筛选,针对三种人类实体癌细胞系(HCT 116、HepG2和MCF-7)。总的来说,与标准药物相比,测试的化合物被发现不活跃或显示出微弱的活性。