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Spectrophotometric comparison of 4-Nitrophenyl carbonates & carbamates as base-labile protecting groups

Kocalar et al. | Dec 12, 2022

Spectrophotometric comparison of 4-Nitrophenyl carbonates & carbamates as base-labile protecting groups

In organic synthesis, protecting groups are derivatives of reactive functionalities that play a key role in ensuring chemoselectivity of chemical transformations. To protect alcohols and amines, acid-labile tert-butyloxycarbonyl protecting groups are often employed but are avoided when the substrate is acid-sensitive. Thus, orthogonal base-labile protecting groups have been in demand to enable selective deprotection and to preserve the reactivity of acid-sensitive substrates. To meet this demand, we present 4-nitrophenyl carbonates and carbamates as orthogonal base-labile protecting group strategies.

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Singlet oxygen production analysis of reduced berberine analogs via NMR spectroscopy

Su et al. | Feb 10, 2023

Singlet oxygen production analysis of reduced berberine analogs via NMR spectroscopy

Berberine is a natural product isoquinoline alkaloid derived from plants of the genus Berberis. When exposed to photoirradiation, it produces singlet oxygen through photosensitization of triplet oxygen. Through qNMR analysis of 1H NMR spectra gathered through kinetic experiments, we were able to track the generation of a product between singlet oxygen and alpha terpinene, allowing us to quantitatively measure the photosensitizing properties of our scaffolds.

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Redesigning an Experiment to Determine the Coefficient of Friction

Hu et al. | Jun 27, 2016

Redesigning an Experiment to Determine the Coefficient of Friction

In a common high school experiment to measure friction coefficients, a weighted mass attached to a spring scale is dragged across a surface at a constant velocity. While the constant velocity is necessary for an accurate measurement, it can be difficult to maintain and this can lead to large errors. Here, the authors designed a new experiment to measure friction coefficients in the classroom using only static force and show that their method has a lower standard deviation than the traditional experiment.

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The Effect of Bead Shape and Texture on the Energy Loss Characteristics in a Rotating Capsule

Misra et al. | Jan 25, 2019

The Effect of Bead Shape and Texture on the Energy Loss Characteristics in a Rotating Capsule

Industrial process are designed to optimize speed, energy use and quality. Some steps involve the translation of product-filled barrels, how far and fast this happens depends on the properties of the product within. This article investigates such properties on a mini-scale, where the roll of bead size, texture and material on the distance travelled by a cylindrical capsule is investigated.

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