ChemInform Abstract: Ethyl Chloroformate/DMF in Organic Synthesis. Part 1. A Novel Reagent for Ring Closure of 5‐Amino‐1‐aryl‐4‐imidazolecarboxamides to Their Hypoxanthine Derivatives.
2
Citation
0
Reference
10
Related Paper
Abstract:
Abstract The reaction between the 5‐amino‐4‐imidazolecarboxamides (I) and a mixture of DMF (II) and ethyl chloroformate proceeds under comparatively mild conditions to afford the hypoxanthine derivatives (III) instead of the expected xanthines.Keywords:
Ethyl chloroformate
Hypoxanthine
Chloroformate
Closure (psychology)
Chloroformate
Ethyl chloroformate
Carbamate
Cite
Citations (14)
Chloroformate
Ethyl chloroformate
Diastereomer
Tetrahydrofuran
Chiral derivatizing agent
Cite
Citations (51)
Chloroformate
Ethyl chloroformate
Ethyl ester
Cite
Citations (15)
Chloroformate
Benzimidazole
Imidazole
Ethyl chloroformate
Aqueous medium
Cite
Citations (26)
A simple and rapid method for the separation of amino acids by capillary zone electrophoresis using 9(2carbazole)ethyl chloroformate (CEOC) as derivatization agent was developed. The effect of some key factors such as pH, temperature and concentration of buffer, on the separation of amino acid derivatives was investigated. 12 amino acids were separated with satisfactory results.
Chloroformate
Ethyl chloroformate
Carbazole
Cite
Citations (1)
A new chloroformate fluorescence reagent, 2-(9-carbazol)-ethyl -chloroformate(CEOC), is used for the analysis of amino acids. In a one-step procedure, CEOC reacts with amino acids to form stable derivatives. Maximal yields of derivatization are observed with the amount of the derivant reagent being equal to 4 times of amount of amino acids. The method in conjunction with a gradient elution offers a baseline separation on a reversed_phase Hypersil BDS C18 column. The fluorescent derivatives are detected with a fluorescence monitor at λex of 293 nm and λem of 365 nm. The average detection limits reaches 22.8 fmol.
Ethyl chloroformate
Chloroformate
Gradient elution
Cite
Citations (0)
Chloroformate
Ethyl chloroformate
Cite
Citations (37)
Nitriles react with methyl or ethyl chloroformate (2a,b) and antimony(V) chloride to give high yields of N-methyl-, or N-ethylnitrilium hexachloroantimonates 3,4. With butyl chloroformate (2c) N-(1-methylpropyl)nitrilium salts 6 are obtained. These products arise from a 2-butyl cation, which is formed prior to alkylation of the nitrile. Isobutyl chloroformate (2d), (2-tert-butylcyclohexyl) chloroformate (2e), menthyl chloroformate (2f), 2,2-dimethylpropyl chloroformate (2g), and 3-methylbutyl chloroformate (2h) react with nitriles to give N-tert-alkylnitrilium salts, 11,13,15,19, which were characterized by hydrolysis to amides. With phenyl chloroformate (2i) benzonitriles react in a 1 :2 ratio to furnish 2-phenoxy-1,3,5-oxadiazinium salts 21.
Chloroformate
Ethyl chloroformate
Cite
Citations (20)
Mixed anhydrides of N‐tert. ‐butoxycarbonyl‐, N ‐benzyloxycarbonyl‐ and N ‐9‐fluorenylmethoxycarbonylamino acids were prepared using isopropyl chloroformate, and purified by edulcoration. They were more stable than the corresponding anhydrides obtained using ethyl and isobutyl chloroformates. Aminolysis of the anhydrides by an amino acid ester proceeded efficiently, the amount of urethane generated by reaction at the carbonate moiety being the same as that generated from the other anhydrides. Racemization attending the coupling of N ‐benzyloxycarbonylglycylamino acids by the mixed anhydride method using isopropyl chloroformate was one third to one quarter of that observed for the same couplings using ethyl and isobutyl chloroformate.
Chloroformate
Ethyl chloroformate
Isopropyl
Moiety
Racemization
Cite
Citations (21)
Ethyl chloroformate
Trimethylsilyl
Chloroformate
Cite
Citations (36)