65133-31-5

Upstream product

• 60272-64-2 2-phenyl-4-methoxycarbonylmethyl-5-oxo-4,5-dihydro-1,3-oxazole 
• 13831-03-3 tert-butyl prop-2-ynoate 
• 100-47-0 benzonitrile 
• 98-88-4 benzoyl chloride 
• 79439-38-6 (+/-)-3-endo-benzamido-5-norbornene-2-endo-carboxylic acid 
• 79439-38-6 (1S,2S,3R,4R)-3-Benzoylamino-bicyclo[2.2.1]hept-5-ene-2-carboxylic acid 
• 55-21-0 benzamide 
• 28562-53-0 4-acetoxy azetidinone 
• 91813-50-2 (1R,2R,7S,8S)-4-Phenyl-5-oxa-3-aza-tricyclo[6.2.1.0^2,7]undeca-3,9-dien-6-one 

Relevant academic research and scientific papers

Gold-catalyzed formal [4π + 2π]-cycloadditions of propiolate derivatives with unactivated nitriles

Gold-catalyzed hetero-[4π + 2π]-cycloadditions of tert-butyl propiolates with unactivated nitriles are described; the resulting 6H-1,3-oxazin-6-ones are not easily accessible via conventional methods. This new finding enables a one-pot gold-catalyzed synthesis of highly substituted pyridines through sequential gold-catalyzed reactions of tert-butyl propiolates with nitriles, and then with electron-deficient alkynes in the same solvent. The utility of these [4 + 2]-cycloadditions is further expanded with various aldehydes, ketones and 2-phenyloxetane, yielding satisfactory yields of cycloadducts.

Flash flow pyrolysis: Mimicking flash vacuum pyrolysis in a high-temperature/high-pressure liquid-phase microreactor environment

Flash vacuum pyrolysis (FVP) is a gas-phase continuous-flow technique where a substrate is sublimed through a hot quartz tube under high vacuum at temperatures of 400-1100 °C. Thermal activation occurs mainly by molecule-wall collisions with contact times in the region of milliseconds. As a preparative method, FVP is used mainly to induce intramolecular high-temperature transformations leading to products that cannot easily be obtained by other methods. It is demonstrated herein that liquid-phase high-temperature/high- pressure (high-T/p) microreactor conditions (160-350 °C, 90-180 bar) employing near- or supercritical fluids as reaction media can mimic the results obtained using preparative gas-phase FVP protocols. The high-T/p liquid-phase "flash flow pyrolysis" (FFP) technique was applied to the thermolysis of Meldrum's acid derivatives, pyrrole-2,3-diones, and pyrrole-2-carboxylic esters, producing the expected target heterocycles in high yields with residence times between 10 s and 10 min. The exact control over flow rate (and thus residence time) using the liquid-phase FFP method allows a tuning of reaction selectivities not easily achievable using FVP. Since the solution-phase FFP method does not require the substrate to be volatile any more -a major limitation in classical FVP-the transformations become readily scalable, allowing higher productivities and space-time yields compared with gas-phase protocols. Differential scanning calorimetry measurements and extensive DFT calculations provided essential information on pyrolysis energy barriers and the involved reaction mechanisms. A correlation between computed activation energies and experimental gas-phase FVP (molecule-wall collisions) and liquid-phase FFP (molecule-molecule collisions) pyrolysis temperatures was derived.

Conversion of N-Acyl-4-acyloxy-β-lactams into 1,3-oxazin-6-ones: Two consecutive pseudopericyclic processes

(equation presented) N-Acyl-4-acyloxy-β-lactams are converted into 1,3-oxazin-6-ones under basic conditions. This transformation is believed to proceed via N-acylazetones, which rearrange to the final products by a sequence of two electrocyclic processes. The calculated (RHF and B3LYP) transrtion structures of both concerted reactions are shown to present characteristic pseudopericyclic orbital topologies.

Synthesis of 2-substituted 1,3-oxazin-6-ones by gas-phase pyrolysis

Acylaminomethylene Meldrum's acid derivatives 5 are prepared either by direct reaction of methoxymethylene Meldrum's acid 4 with primary amides, or by acylation of aminomethylene Meldrum's acid 6. Pyrolysis of the substrates 5 under FVP conditions gives the title compounds 8 in good yields.

STEREOCHEMICAL STUDIES -- 79 SYNTHESIS AND KINETIC STUDY ON THE RETRODIENE DECOMPOSITION OF NORBORNENE-CONDENSED 1,3-OXAZIN-4-ONES

The cis-exo-amino acid 3 with norbornene skeleton was converted into 2-aryl-cis-exo-1,3-oxazin-4-ones 5a-d.These compounds, similarly to the diendo isomers 1a-d studied by us earlier, undergo retrodiene decomposition under mild conditions to give 2-aryl-6

Thermolyse von Oxazolin-5-onen, XI. N-Acylimine und Enamide durch Gasphasenpyrolyse von 4-Alkyl-2-oxazoline-5-onen

On gas phase thermolysis 4-alkyl-2-oxazolin-5-ones 1 undergo CO elimination to yield N-acylimines 2, which rearrange into more stable enamides 3 if α-hydrogens are present.N-Acylimines (e.g. 2a) may be isolated in cases where the rearrangement is prevented by a quarternary C-atom.The 4,4-dialkylsubstituted oxazolinone 1o yields mixtures of N-acylimine 2o and enamide 3o, the amount of the latter increasing at higher pyrolysis temperatures.