882044-94-2

Upstream product

• 3777-61-5 1,1-diethoxy-2,4-pentadiyne 
• 1576-35-8 toluene-4-sulfonic acid hydrazide 
• 882045-04-7 2,4-pentadiynal 
• 41345-53-3 2,4-pentadiyne-1-ol 
• 114534-23-5 (Z)-1-chloro-5,5-diethoxyprop-1-en-3-yne 

Relevant academic research and scientific papers

Variable Markovnikov orientation and "cis effect" in ene reactions of nitrosocarbonyl intermediates

Nitrosocarbonyl intermediates, generated at room temperature by the mild oxidation of nitrile oxides, undergo clean ene reactions with trisubstituted olefins. Allylic hydrogens on the more congested side of the alkene are exclusively abstracted (the "cis

Reactive carbon-chain molecules: Synthesis of 1-diazo-2,4-pentadiyne and spectroscopic characterization of triplet pentadiynylidene (H-C≡C-C- C≡C-H)

1-Diazo-2,4-pentadiyne (6a), along with both monodeuterio isotopomers 6b and 6c, has been synthesized via a route that proceeds through diacetylene, 2,4-pentadiynal, and 2,4-pentadiynal tosylhydrazone. Photolysis of diazo compounds 6a-c (λ > 444 nm; Ar or N2, 10 K) generates triplet carbenes HC5H (1) and HC5D (1-d), which have been characterized by IR, EPR, and UV/vis spectroscopy. Although many resonance structures contribute to the resonance hybrid for this highly unsaturated carbon-chain molecule, experiment and theory reveal that the structure is best depicted in terms of the dominant resonance contributor of penta-1,4-diyn-3- ylidene (diethynylcarbene, H-C≡C-C-C≡C-H). Theory predicts an axially symmetric (D∞h) structure and a triplet electronic ground state for 1 (CCSD(T)/ANO). Experimental IR frequencies and isotope shifts are in good agreement with computed values. The triplet EPR spectrum of 1 (|D/hc| = 0.6157 cm-1, |E/hc| = 0.0006 cm-1) is consistent with an axially symmetric structure, and the Curie law behavior confirms that the triplet state is the ground state. The electronic absorption spectrum of 1 exhibits a weak transition near 400 nm with extensive vibronic coupling. Chemical trapping of triplet HC5H (1) in an O2-doped matrix affords the carbonyl oxide 16 derived exclusively from attack at the central carbon.