Haloacetylated Enol Ethers. XVII.1* a Convenient Synthesis of 5-Trichloromethyl-1,2-Dimethyl- 1h-Pyrazolium Chlorides

15N NMR spectroscopy of 3‐substituted 5‐trichloromethyl‐1,2‐dimethyl‐1H‐pyrazolium chlorides

“…The 5-trichloromethyl-1,2-dimethyl-1H-pyrazolium chlorides 1-11 were prepared by the cyclocondensation reaction of 4-alkoxy-1,1,1-trichloro-3-alken-2-ones 9 [CCl 3 C(O)CH C(R 1 )OR, where R 1 D H, Me, Et, n-Pr, nBu, n-Pe, n-Hex, (CH 2 ) 5 NMR spectra 13 C NMR spectra were recorded on a Bruker DPX-400 spectrometer ( 13 C at 100.6 MHz), at 300 K, 1.0 M in D 2 O as solvent. The general reproducibility of chemical shift data is estimated to be better than š0.1 ppm.…”

Polyphosphate im marinen Phosphorkreislauf

“…Our results have shown that the reaction of β‐alkoxyvinyl trihalomethyl ketones and hydrazines generally produces highly regioselective 5‐hydroxy‐4,5‐dihydro‐1 H ‐pyrazoles. Although trihalomethyl pyrazolium chlorides have been synthesized by the cyclocondensation reaction of 4‐alkoxy‐1,1,1‐trichloro‐3‐alken‐2‐ones with 1,2‐dimethylhydrazine [12], they remain rare in the literature. The reactivity of β‐alkoxyvinyl dichloromethyl ketones with amines to obtain enaminones and reactions with different hydrazines in an attempt to obtain the respective 5‐dichloromethylpyrazoles and 5‐dichloromethylpyrazolium has not yet been studied.…”

Brominated Trihalomethylenones as Versatile Precursors to 3‐Ethoxy, ‐Formyl, ‐Azidomethyl, ‐Triazolyl, and 3‐Aminomethyl Pyrazoles

“…The most convenient method to construct halogenated compounds is to use halogen‐containing building blocks as starting material . During the last 20 years, we have developed a general synthesis of 4‐alkoxy‐1,1,1‐trihalo‐3‐alken‐2‐ones , an important halogen‐containing building block, and demonstrated its usefulness in heterocyclic preparations, for example, isoxazoles , pyrazoles, pyrazolium chlorides , pyrrolidinones , pyrimidines , pyridines , thiazines , and diazepines.…”

“…Despite extensive studies on applications of 4‐alkoxy‐1,1,1‐trihalo‐3‐alken‐2‐ones in heterocyclic chemistry , 5‐heteroalkyl substituted 4‐alkoxy‐1,1,1‐trihalo‐3‐alken‐2‐ones and their usefulness in the synthesis of heterocycles have been less explored. These compounds are highly functionalized intermediates, which may be useful for further synthetic conversions.…”