1,4,2-Dioxazol-5-ones as Isocyanate Equivalents: An Efficient Synthesis of 2-Quinolinones via β-Keto Amides

Synlett ◽  
2021 ◽  
Author(s):  
Ramakrishna Guduru ◽  
Anand Vala ◽  
Nirali Parmar ◽  
Jigar Y Soni ◽  
Sharadsrikar Kotturi
Keyword(s):  
Thermal Conditions ◽  
Efficient Synthesis ◽  
Carbon Nucleophiles

AbstractUnder thermal conditions, 1,4,2-dioxazol-5-ones are known to undergo decarboxylation followed by Lossen’s rearrangement to yield isocyanates. Described herein is the in situ trapping of the resulting isocyanates with carbon nucleophiles to synthesize β-keto amides. Furthermore, a general and mild method for the conversion of the resulting β-keto amides into quinolin-2-ones is reported.

Nickel-Catalyzed Regioselective Hydroalkylation of 1,3-Dienes with Hydrazones

2019 ◽  
Author(s):  
Leiyang Lv ◽  
Dianhu Zhu ◽  
Zihang Qiu ◽  
Jianbin Li ◽  
Chao-Jun Li
Keyword(s):  
Catalytic Method ◽  
Unsaturated Hydrocarbons ◽  
Carbon Nucleophiles ◽  
Aryl Aldehydes ◽  
Aldehydes And Ketones ◽  
Sterically Hindered

Hydroalkylation of unsaturated hydrocarbons with unstablized carbon nucleophiles is difficult and remains a major challenge. The disclosed examples so far mainly focused on the involvement of heteroatom and/or stabilized carbon nucleophiles as efficient reaction partners. Reported here is an unprecedented regioselective nickel-catalyzed hydroalkylation of 1,3-dienes with hydrazones, generated in situ from abundant aryl aldehydes and ketones and acted as both the sources of unstabilized carbanions and hydride. With this strategy, both terminal and sterically hindered internal dienes are hydroalkylated efficiently in a highly selective manner, thus providing a novel and reliable catalytic method to construct challenging C(sp3)-C(sp3) bonds.

scholarly journals Development of a Field Deployable Firebrand Flux and Condition Measurement System

2020 ◽  
Author(s):  
Simone Zen ◽  
Jan C. Thomas ◽  
Eric V. Mueller ◽  
Bhisham Dhurandher ◽  
Michael Gallagher ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Time History ◽  
Infrared Camera ◽  
Thermal Conditions ◽  
Particle Characterization ◽  
Fire Dynamics ◽  
Rate Of Spread ◽  
New Instrument ◽  
History Of

AbstractA new instrument to quantify firebrand dynamics during fires with particular focus on those associated with the Wildland-Urban Interface (WUI) has been developed. During WUI fires, firebrands can ignite spot fires, which can rapidly increase the rate of spread (ROS) of the fire, provide a mechanism by which the fire can pass over firebreaks and are the leading cause of structure ignitions. Despite this key role in driving wildfire dynamics and hazards, difficulties in collecting firebrands in the field and preserving their physical condition (e.g. dimensions and temperature) have limited the development of knowledge of firebrand dynamics. In this work we present a new, field-deployable diagnostic tool, an emberometer, designed to provide measurement of firebrand fluxes and information on both the geometry and the thermal conditions of firebrands immediately before deposition by combining a visual and infrared camera. A series of laboratory experiments were conducted to calibrate and validate the developed imaging techniques. The emberometer was then deployed in the field to explore firebrand fluxes and particle conditions for a range of fire intensities in natural pine forest environments. In addition to firebrand particle characterization, field observations with the emberometer enabled detailed time history of deposition (i.e. firebrand flux) relative to concurrent in situ fire behaviour observations. We highlight that deposition was characterised by intense, short duration “showers” that can be reasonably associated to spikes in the average fire line intensity. The results presented illustrate the potential use of an emberometer in studying firebrand and spot fire dynamics.

Synthesis of Highly SubstitutedN-Hydroxyindoles through 1,5-Addition of Carbon Nucleophiles to In Situ Generated Unsaturated Nitrones

2006 ◽  
Vol 118 (32) ◽  
pp. 5490-5494 ◽  
Author(s):  
K. C. Nicolaou ◽  
Anthony A. Estrada ◽  
Sang Hyup Lee ◽  
Graeme C. Freestone
Keyword(s):  
Carbon Nucleophiles

scholarly journals Indium-Catalyzed Direct Conversion of Lactones into Thiolactones Using a Disilathiane as a Sulfur Source

2018 ◽  
Author(s):  
Yohei Ogiwara ◽  
Ken Takano ◽  
Shuhei Horikawa ◽  
Norio Sakai
Keyword(s):  
Elemental Sulfur ◽  
Direct Conversion ◽  
Pharmaceutical Chemistry ◽  
Sulfur Source ◽  
Efficient Synthesis ◽  
Previous Reaction ◽  
Indium Catalyst

Indium-catalyzed reaction of lactones and a disilathiane leading to thiolactones is described. The direct synthesis of thiolactones from lactones with an appropriate sulfur source is one of the most attractive approaches in organic and pharmaceutical chemistry. In this context, we found an indium-catalyzed direct conversion of lactones into thiolactones in the presence of elemental sulfur and a hydrosilane via formation of the disilathiane in-situ. On the basis of the previous reaction, the application utilizing the disilathiane as a sulfur source was performed herein for the efficient synthesis of a variety of thiolactone derivatives from lactones by an indium-catalyst.

Efficient Synthesis of Diospyrol via Suzuki-Miyaura and Modified in situ Cross-Coupling

Synthesis ◽  
2005 ◽  
Vol 2005 (17) ◽  
pp. 2934-2938
Author(s):  
Somsak Ruchirawat ◽  
Poolsak Sahakitpichan ◽  
Nopporn Thasana
Keyword(s):  
Cross Coupling ◽  
Efficient Synthesis

scholarly journals Efficient synthesis of ponasterone A by recombinant Escherichia coli harboring the glycosyltransferase GTBP1with in situ product removal

RSC Advances ◽  
2017 ◽  
Vol 7 (37) ◽  
pp. 23027-23029 ◽  
Author(s):  
Bingfeng Li ◽  
Xuejun He ◽  
Bo Fan ◽  
Jianlin Chu ◽  
Bingfang He
Keyword(s):  
Escherichia Coli ◽  
Bacillus Pumilus ◽  
Recombinant Escherichia Coli ◽  
Efficient Synthesis ◽  
In Situ Product Removal ◽  
Product Removal ◽  
Ponasterone A

A glycosyltransferase GTBP1fromBacillus pumilusBF1 was isolated.

Sign in / Sign up

Export Citation Format

Share Document