Dérivés de l'imidazo[2,l-b]thiazole. IX. Comportement du phénacyl-3 dihydro-5,6 imidazo[2,1-b]thiazole et du phénacylidène-3 tétrahydro-2,3,5,6 imidazo[2,1-b]thiazole vis-à-vis du chlorhydrate d'hydroxylamine

The reaction of hydoxylamine hydrochloride with two imidazothiazoles, having a ketonic carbonnyl group, leads to two types of compounds according to the quantity of the sodium acetate used. 3-Phenacyl-5,6-dihydroimidazo[2,1-b]thiazole hydrochloride gives logically the corresponding oxime, isolated in salt form or as a base depending upon the quantity of sodium acetate added. Furbase depending upon the quantity of sodium acetate added. Furthermore, a systematic allylic rearrangement was observed with migration of thiazole double bond to the adjacent nuclear position. 3-Phenacylidene-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole gave directly in the absence of sodium acetate, a rearranged oxime salt. On the other hand, in the presence of sodium acetate, we obtained a hgydroxylamine which was characterized by a double bond in the 2,3-position of the thiazole ring. It is noteworthy that no transformation of the hydroxylamine into the oxime or vice-versa occurs whatever the pH of the solution. These different compounds have no fungistatic activity in contrast to the corresponding ketones.     

Dérivés de l'imidazo[2,1–b] thiazole. IV. Réarrangements au cours de la condensation de β-dicétones α-bromées avec l'amino-2 thiazole et la mercapto-2 imidazoline

Formation of 2-acetyl- (ro benzoyl-) imino-3-acetonyl- (or phenacyl-)-thiazolines and l-acetyl- (or benzoyl-)-2-acetonyl- (or phenacy l)-thioimidazolines by the action of α-halogenated β-di-ketones on 2-aminothiazole and 2-mercaptoimidazoline has been observed. These compounds resulted by nucleophilic attack followed by rearrangement and then cleavage of the intermediate carbinolamine. A dissymmetrical βdiketone rearranged unequivocally.     

Nouvelle synthèse des pyrido[4,3-b]quinoléines substituées sur leur sommet 1

A three step synthesis of pyrido[4,3-b]quinolines is reported. Thus, treatment of 2-hydroxy-4-arylaminopyridines under Vilsmeir-Haack conditions directly afforded 1-oxo-1,2-dihydropyrido[4,3-b]quinolines. Chlorination of these compounds gave the corresponding 1-chlorinated derivatives which were then substituted by various primary and secondary amines.     

Derives de l'imidazo(2,1-b)thiazole—III : Transpositions au cours de la condensation d'acetylacetates d'ethyle α et ω halogenes avec l'ethylenethiouree

Rearrangement accompanies condensation of α and ω halogenated acetylacetic ethyl esters with 2-mercapto imidazoline, giving 5,6-dihydroimidazo(2,1-b) thiazoles with lateral chains substituted in position 2 or 3. ¹³C NMR was used to prove structures of rearranged products.     

Détermination du Site de Protonation de l'Azido-2 thiazole et du Thiazolo[2,3-e]tétrazole à Partir de la Largeur des Raies des Signaux Protoniques

The signals of protons bonded to carbon atoms in α position to the pyridinic nitrogen atom in thiazole and in γ position in thiazolo[2,3-e]tetrazole are broadened. This broadening disappears on irradiation at the ¹⁴N resonance frequency, on cooling, and in an acidic medium (in which the protonation sites in both molecules can be determined).     

Synthèse d'une nouvelle depsidone dérivée de l'acide furfurique,le diméthoxy-3,8-(diméthoxy-2,4-méthoxycarbonyl-5-diméthyl-3,6-benzyl)-9-triméthyl-1,4,6-oxo-11-11H-dibenzo[b,e]dioxépinne[1,4]carboxylate-7 de méthyle

Synthesis of a New Depsidone, Derivative of Furfuric Acid: Methyl 3,6-dimethoxy-9-(2,4-dimethoxy-5-methoxycarbonyl-3,6-dimethylbenzyl)-1,4,6-trimethyl-11-oxo-11H-dibenzo[b,e] [1,4]dioxepin-7-carboxylate The total synthesis of the title compound 1b is described. Starting from simple orcinol and β-orcinol units, the benzophenone 4 has been prepared. Using a biomimetic reaction, the intramolecular oxydative coupling, lead to the grisadienedione 25 . By thermal interconversion and permethylation, the depsidone 1b has been obtained.