A Catalytic Route to Ampakines and Their Derivatives

Hydroformylation of pyrolysis oils to aldehydes and alcohols from polyolefin waste

Waste plastics are an abundant feedstock for the production of renewable chemicals. Pyrolysis of waste plastics produces pyrolysis oils with high concentrations of olefins (>50 weight %). The traditional petrochemical industry uses several energy-intensive steps to produce olefins from fossil feedstocks such as naphtha, natural gas, and crude oil. In this work, we demonstrate that pyrolysis oil can be used to produce aldehydes through hydroformylation, taking advantage of the olefin functionality. These aldehydes can then be reduced to mono- and dialcohols, oxidized to mono- and dicarboxylic acids, or aminated to mono- and diamines by using homogeneous and heterogeneous catalysis. This route produces high-value oxygenated chemicals from low-value postconsumer recycled polyethylene. We project that the chemicals produced by this route could lower greenhouse gas emissions ~60% compared with their production through petroleum feedstocks.

Access to Chiral Tetrahydroquinazolines/1,3-Benzoxazines via Iridium-Catalyzed Asymmetric [4 + 2] Cycloaddition

An iridium-catalyzed asymmetric [4 + 2] cycloaddition of 1,3,5-triazinanes with 2-(1-hydroxyallyl)anilines/2-(1-hydroxyallyl)phenols has been developed, providing a straightforward and efficient approach to a wide range of tetrahydroquinazolines in good yields and excellent enantioselectivities (up to >99% ee). Typically, chiral 1,3-benzoxazines, which are challenging substrates in asymmetric [4 + 2] cycloaddition, could be obtained in excellent enantioselectivities via this protocol.

Gold(I)-Catalyzed Heteroannulation of Salicylic Amides with Alkynes: Synthesis of 1,3-Benzoxazin-4-one Derivatives

Gold(I)-catalyzed heteroannulation affords the efficient and straightforward construction of heterocyclic compounds. Herein, we developed a gold(I)-catalyzed heteroannulation of salicylic amides with alkynes producing a broad range of 1,3-benzoxazin-4-ones. The utility of this protocol was highlighted by synthesizing variously substituted benzoxazinones containing quaternary carbon centers, showing a high functional group tolerance and excellent atom economy of the thus introduced reaction course.

ZnCl2-promoted domino reaction of 2-hydroxybenzonitriles with ketones for synthesis of 1,3-benzoxazin-4-ones

A ZnCl2-promoted synthesis of 1,3-benzoxazin-4-one from 2-hydroxybenzonitriles and ketones was developed. This method displays facile access to a diverse range of substituted 1,3-benzoxazin-4-ones in good yields. This synthetic protocol has advantages: (i) easy availability of starting material; (ii) strong corrosive acid-free condition; (iii) high yield.

Copper-catalyzed tandem aryl–halogen hydroxylation and CH2Cl2-based N,O-acetalization toward the synthesis of 2,3-dihydrobenzoxazinones

Copper-catalyzed tandem reactions consisting of Ar–halogen hydroxylation andN,O-acetalization are designed for the concise synthesis of 2,3-dihydrobenzoxazinones.

I2-Catalyzed cross dehydrogenative coupling: rapid access to benzoxazinones and quinazolinones

An efficient and applicable I₂-catalyzed intramolecular dehydrogenative C–O/C–N coupling reaction has been developed for the first time to provide both benzoxazinones and quinazolinones.

Crystal structure of 3-bromo-2-hy-droxy-benzo-nitrile

The crystal structure of the title compound, C7H4BrNO, has been determined, revealing a partial mol-ecular packing disorder such that a 180° rotation of the mol-ecule about the phenol C-O bond results in disorder of the bromine and nitrile groups. The disorder has been parameterized as a disorder of only the bromine and nitrile substituents on a unique phenol ring. An intra-molecular O-H⋯Br contact occurs. In the crystal, O-H⋯Br/O-H⋯Nnitrile hydrogen bonding is present between the disordered bromine and nitrile substituents and the phenol group, forming a spiral chain about a twofold screw axis extending parallel to the b-axis direction. Within this spiral chain, the mol-ecules also inter-act, forming offset face-to-face π-stacking inter-actions with plane-to-centroid distance of 3.487 (1) Å.

Facile cleavage of C-C bond: conversion of pyrane derivative to 1,3-oxazin derivative

A cascade reaction that involves a unique C-C bond cleavage has been discovered. This protocol affords an unusual and facile method for the synthesis of 1,3-oxazin derivatives under mild conditions.