3- oxo-3,4-dihydro

Chloro-7-methyl-1 H-indazol-3 -yl) -5 -pyridin-3 -yl-thiazole-4-carboxylic acid [3-(5-oxo-4,5-dihydro-lH-pyrazol-4-yl)-propyl]-amide aOJ tQTn o Y-O HN 7 H N... 

The course of methylation of all the thio derivatives with diazomethane was then investigated. These mcthylations generally result in mixtures of substances it may be deduced from the products isolated, however, that this reaction proceeds first at the nitrogen atom (in contrast with alkaline methylation) and only then at the sulfur one. The methylation of the 3-methylmercapto derivative to 4-methyl-3-methylmercapto-5-oxo-4,5-dihydro-l,2,4-triazine (95) is of interest in this connection. 

Methyl 5-Oxo-4,5-dihydro-l f/-l,2-benzodiazepine-3-carhoxylate (4) Single Procedure 125... 

Ethyl 4-(melhoxymethyl)-5-oxo-4,5-dihydro-l//-l,4-diazepine-l-carboxylate (6) results from the thermal isomerization of ethyl 6-(methoxymethyl)-7-oxo-3,6-diazatricyclo[3.2.0.02 4 ]hep-tane-3-carboxylate (5).31... 

Oxo-4,5-dihydro-l//-l,2,4-benzotriazepine-3-carboxylates8can be transformed into the acid chlorides 10 with phosphorus pentachloride and the crude products converted into various amides and esters 11 by treatment with amines and alcohols, respectively. Selected examples are given.347... 

I.3.4.2.4. Heterocumulenes The 1,3-dipolar cycloaddition of substituted ben-zonitrile oxides to the C=N group of chlorocarbonyl isocyanate C1C(0)N=C=0 gives 3-aryl-4-chlorocarbonyl-5-oxo-4,5-dihydro-l,2,4-oxadiazoles 172 in 75%-80% yield (340). A similar reaction with chlorosulfonyl isocyanate, C1S02N=C=0, affords 4-unsubstituted oxadiazolinones 173 (341). 

FMF Chen, K Kuroda, NL Benoiton. A simple preparation of 5-oxo-4,5-dihydro-1,3-oxazoles (oxazolones). Synthesis 230, 1979. 

Die Bestrahlung 1-substituierter 2-Methyl-5-nitro-imidazole in einem Wasser/1,4-Dioxan (9 1)-Gemisch mit einer Quecksilber-Hochdrucklampe fiihrt iiber die Bildung eines 3-Hydrox-imino-5-oxo-4,5-dihydro-imidazols als primares Photoprodukt zu 3-Aminocarbonyl-5-me-thyl-l,2,4-oxadiazolen103 235 ... 

Amino-l,3,4-oxadiazole konnen fur die Einfuhrung heterocyclischer Substituenten iiber eine Ringumwandlung eines anderen labilen Heterocyclus genutzt werden. So reagiert 2-Amino-5-phenyl-l,3,4-oxadiazol mit 4-Benzyliden-2-methyl-5-oxo-4,5-dihydro-l,3-oxazol zu 2-(4-Benzyliden-2-methyl-5-oxo-4,5-dihydro-lH-imidazolo)-5-phenyl-1,3,4-oxadiazol649 (70% Schmp. 258°). 

Tab. 50 s-substituierte a-Amino-carbonsauren aus 4,4-disubstituierten 5-Oxo-4,5-dihydro-1,3-oxazoIen durch Hydrolyse... 

Die Umsetzung von 2-Mercapto-5-oxo-4,5-dihydro-l,3-thiazol mit Carbonyl-Verbindun-gen fiber 4-Alkyliden-2-mercapto-5-oxo-4,5-dihydro-l,3-thiazole zu -Alkyl-a-amino-car-bonsauren1 wurde bisher nicht weiter ausgebaut ... 

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