New investigation of the reaction of 2-amino-2-oxazolines with isocyanates and isothiocyanates. Evidence of a transposition during the second step

Abstract

The reaction of some 2-amino-2-oxazolines with isocyanates and arylisothiocyanates yields 3-monosubstituted or 2,3-disubstituted 2-iminooxazolidines depending on the experimental conditions and on the nature of the electrophile reactants. The structures of a mono- and a disubstituted derivative were established by X-ray analysis. The chemical behaviour of the compounds was investigated by molecular and quantum mechanics calculations. An intramolecular transposition during the second step of the reaction was found. Key words: 2-amino-2-oxazolines, iso(thio)cyanates, transposition. X-ray structure, MOPAC calculations.

Synthesis and Pharmacological Evaluation ofN-Phenyl-N′-[1-[3-(1-aryl-4-piperazinyl)propan-2-ol]]ureas

“…For the tested (3) it seems that two pharmacological profiles could be deduced from these preliminary results. Compounds 3a and 3c exhibited promising antiallergic activity, whereas 3c and 3d showed a potent analgesic activity.…”

“…Recently we reported the reaction of 5-substituted 2-amino-2-oxazolines with phenyl isocyanate studied in terms of comparative nucleophilic potency of the two amidinic nitrogen atoms [3] . Experimental conditions permitting to selective formation of the corresponding 3-phenylcarbamoyl-2-iminooxazolidines and avoidance of their possible rearrangement to the more stable urea isomers were described.…”

Derivatization of (±)-5-[(2-Methylphenoxy)methyl]-2-amino-2-oxazoline, an Imidazoline Binding Sites Ligand, with (+)- (R) -α-Methylbenzyl Isocyanate for Drug Monitoring Purposes

“…Diethyl ether was obtained from Cooper (Melun, France) and was of analytical-grade. The (þ )-(R ) and (2 ) This reaction, based on a procedure already described, 14 …”

Synthesis and Anti-histaminic Evaluation of N-Phenyl-(alkyl)-5-(dialkylamino)methyl-2-amino-2-oxazolines

“…As it was not possible to substitute directly the exocyclic nitrogen atom they were synthesized by an original method starting from the 3-phenyl(alkyl)carbamoyl-2-iminooxazolidines 2 obtained by carbamoylation of the amidine function in 2-amino-2-oxazolines. 9 By hydrolysis in acidic medium 2 led to the corresponding 3-phenyl-(alkyl)carbamoyl-5-(dialkylamino)methyl-2-oxazolidinones 3a -e. That was followed by the opening of the heterocyclic ring leading to N-phenyl(alkyl)-N 0 -[1-{3-(dialkylamino)-propan-2-ol}]ureas 4 and then, the cyclic functionality was regenerated through an intramolecular nucleophilic substitution involving an halogen atom introduced by the reaction of thionyl chloride on 4.…”