Synthesis of 3-tert-alkyl-2,4-imidazolidinediones

Abstract

was added, and after 2 h the white Mannich-base precipitate was collected by filtration and washed with water. This solid was dissolved in dimethylformamide to induce decarboxylation and stirred for 1 h. The solvent was then evaporated under reduced pressure, and the resulting oil was dissolved in ethyl acetate and washed with 20% citric acid, water, and saturated sodium chloride. The organic layer was dried over magnesium sulfate, filtered, and evaporated to an oil. Crystallization from diethyl ether/hexane afforded pure 7: 0.032 g (23%); mp 105-108 °C; [apD -34.7°( c

Versatile Synthesis of Free and N‐Benzyloxycarbonyl‐Protected 2,2‐Disubstituted Taurines

“…Amino acids 3a – e were prepared from amino nitriles 2a – e in acceptable‐to‐good yields according to a modified literature method 20. Amino acid 3f was prepared from 5,5‐diphenylhydantoin,23 which was obtained from benzil and urea in good yield 24. The analytical data of all known compounds are identical to those reported in the literature.…”

“…After successful synthesis of 2‐amino‐2‐phenylpropanesulfonic acid ( 8a ) and its N ‐benzyloxycarbonyl derivative 9a from acetophenone, a series of commercially available ketones 1 were converted into α,α‐disubstituted α‐amino acids 3 by Strecker amino acid synthesis. 2,2‐Diphenylglycine ( 3f ) was prepared from sodium hydroxide hydrolysis of 5,5‐diphenylhydantoin,23 which was synthesized from benzil and urea 24. After reduction with sodium borohydride–iodine and subsequent N ‐acylation with benzyl chloroformate, N ‐benzyloxycarbonyl‐protected 2,2‐disubstituted vicinal amino alcohols 5 were obtained in good yields.…”

Synthesis of Adamantyl-Containing Compounds - Structure Elements of Rotaxanes and Supramolecular Polymers

“…In the second step Carbonyl Chloride II was introduced into the exchange reaction with Sodium Azide in Toluene at its boiling temperature for 2 hours and gave the corresponding 3,5-dimethyladamantane-1-carbonylazide (III), which is then refluxed in Toluene without isolation until the complete allocation of Nitrogen. Azide undergone Curtius rearrangement into the 1-isocyanato-3,5-dimethyladamantane (IV), which was purified by vacuum distillation to yield up to 95% of the original acid: Methods described in the literature on the Curtius reaction involve the step of isolation and desiccation of the intermediate Azide, followed by its heating [17]. Heating of large amounts of Azide, even at low temperature with the strict observance of safety is potentially an explosive process.…”

N-Substituted S-Alkyl Carbamothioates in the Synthesis of Nitrogen-containing Functional Derivatives of the Adamantane Series

“…Isocyanates are commonly prepared by phosgenation of amines or by Curtius rearrangement from acyl azides [ 25 ]. Most of the methods for the preparation of adamantan-1-yl isocyanate include the aforementioned treatment of 1-aminoadamantane hydrochloride with phosgene [ 26 , 27 ] or triphosgene [ 28 ] and the implementation of Curtius rearrangement [ 29 ], including with the preliminary preparation of 1-azidoadamantane from adamantane-1-carboxylic acid [ 13 , 30 ] or its acid chloride [ 31 – 35 ]. Alternative synthetic approaches to adamantan-1-yl isocyanate involve the cleavage of 1,3-dehydroadamantane in sulfuric acid in the presence of sodium cyanate [ 36 ], the reaction of 1-bromoadamantane with the silver salt of nitrocyanamide [ 37 ], and thermolysis of 2-(adamantan-1-yl)-5-methyl-1,3-oxothiolane [ 38 ].…”