93-58-3Relevant articles and documents
Synthesis and pyrolysis of two novel pyrrole ester flavor precursors
Cheng, Biao,Chu, Wenjuan,Fan, Wenpeng,Feng, Yingjie,Gao, Ziting,Ji, Xiaoming,Lai, Miao,Tian, Haiying,Zhang, Zhan
, (2022/03/31)
In order to develop the high-temperature-released pyrrole aroma, two novel flavors precursors of methyl 2-methyl-5-(((2-methylbutanoyl)oxy)methyl)-1-propyl-1H-pyrrole-3-carboxylate and methyl 2-methyl-5-(((2-methylbutanoyl)oxy)methyl)-1-propyl-1H-pyrrole-3-carboxylate were synthesized using glucosamine hydrochloride and methyl acetoacetate as raw materials through cyclization, oxidation, alkylation, reduction, and esterification. The target compounds were characterized by nuclear magnetic resonance (1H NMR, 13C NMR), infrared spectroscopy (IR) and high-resolution mass spectrometry (HRMS). Thermogravimetry (TG), differential scanning calorimeter (DSC) and the pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) methods were used to analyze the heating-stability of the target compounds, and the pyrolysis mechanism was inferred. Py-GC/MS results indicated that some fragrance compounds were formed during?thermal degradation such as 2-methylbutyric acid, 2-methylbutyrate, alkylpyrroles, and benzoic acid, which were important aroma components or flavor additives. This provided a theoretical reference for the application of pyrrole ester in cigarette and heat-processed food flavoring.
Using Data Science To Guide Aryl Bromide Substrate Scope Analysis in a Ni/Photoredox-Catalyzed Cross-Coupling with Acetals as Alcohol-Derived Radical Sources
Doyle, Abigail G.,Gandhi, Shivaani S.,Jiang, Shutian,Kariofillis, Stavros K.,Martinez Alvarado, Jesus I.,?urański, Andrzej M.
supporting information, p. 1045 - 1055 (2022/01/19)
Ni/photoredox catalysis has emerged as a powerful platform for C(sp2)–C(sp3) bond formation. While many of these methods typically employ aryl bromides as the C(sp2) coupling partner, a variety of aliphatic radical sources have been investigated. In principle, these reactions enable access to the same product scaffolds, but it can be hard to discern which method to employ because nonstandardized sets of aryl bromides are used in scope evaluation. Herein, we report a Ni/photoredox-catalyzed (deutero)methylation and alkylation of aryl halides where benzaldehyde di(alkyl) acetals serve as alcohol-derived radical sources. Reaction development, mechanistic studies, and late-stage derivatization of a biologically relevant aryl chloride, fenofibrate, are presented. Then, we describe the integration of data science techniques, including DFT featurization, dimensionality reduction, and hierarchical clustering, to delineate a diverse and succinct collection of aryl bromides that is representative of the chemical space of the substrate class. By superimposing scope examples from published Ni/photoredox methods on this same chemical space, we identify areas of sparse coverage and high versus low average yields, enabling comparisons between prior art and this new method. Additionally, we demonstrate that the systematically selected scope of aryl bromides can be used to quantify population-wide reactivity trends and reveal sources of possible functional group incompatibility with supervised machine learning.
Nickel-Catalyzed Photodehalogenation of Aryl Bromides
Higginson, Bradley,Sanjosé-Orduna, Jesus,Gu, Yiting,Martin, Ruben
supporting information, p. 1633 - 1636 (2021/04/23)
Herein, we describe a Ni-catalyzed photodehalogenation of aryl bromides under visible-light irradiation that utilizes tetrahydrofuran as hydrogen source. The protocol obviates the need for exogeneous amine reductants or photocatalysts and is characterized by its simplicity and broad scope, including challenging substrate combinations.
