Phosgene quinolines

A solution of 34 cc (0.5 mol) of liquid phosgene in 150 cc of absolute ether is reacted while cooling with a mixture of sodium chloride and ice, first with 62 grams (0.5 mol) of 1-ethinyl cyclohexanoM and then with 64 cc (0.5 mol) of quinoline. The precipitated quinoline chlorohydrate is filtered off and the filtrate is reacted with ammonia in ether. 

The oxazolo[4,5-/z]quinolin-2(3//)-ones (89) and 2,5-disubstituted oxazolo[4,5-/i]quinolines (90) were prepared as new antiallergic agents by oxazole ring annelation conducted by condensing 7-amino-8-hydroxyquinoline intermediates with phosgene, o-ester, or imidate reagents (Scheme 7)... 

Carbon-sulfur bond formation by oxidative cyclization of a thiourea derivative using bromine will in the case of (521) furnish a thiazolo[/,/]quinoline (522 Z = NH). The same imine is obtained from 8-mercapto-l,2,3,4-tetrahydroquinoline on treatment with cyanogen bromide with phosgene the 2-oxo derivative (522 Z = 0) is formed (63JOC2581). 

Quinoline red dyestuffs which are prepared by quaternization with benzalchloride, diphenyldichloromethane, phosgene, or 1,2-dibromo-ethane exist only as form 25 (see Fig. 13). 

Previously only a few condensed 1,3,4-oxadiazoles were known. Pyrido[2,l-6]l,3,4-oxadiazol-2-one and the quinoline analog are obtained by the action of phosgene on l-aimnopyrid-2-one and 1-aminoquinol-2-one, respectively.118 These compounds display a mesoionic character. Furthermore, imidazolo[2,1 -6] 1,3,4-oxadiazoles... 

Preparative Methods The title reagent is prepared by reaction of (IR, 2S)-2-phenyl-l-cyclohexanol with excess phosgene in the presence of quinoline to afford a chloroformate which is treated directly with hydrazine monohydrate (0.5 equiv) to afford di-(—)-(IR, 25)-2-phenyl- 1-cyclohexyl diazanedicarboxy-late. Oxidation of the diazanedicarboxylate to the diazenedicarboxylate is then readily effected using N-bromosuccinimide and pyridine (eq 1). 

N-Substituted acetanilides (69), the original substrates studied by Vilsmeier (see Scheme 1), are highly reactive compounds for quinoline formation. Thus, quinolinium salts (70) derive from the action of phosgene,55 while 2-quino-lones (71) are readily formed by Vilsmeier formylation of the same sub-strates." b 7 The formylation of IV-phenylacetanilides (69 R1 = Ph) was initially misinterpreted,58 but has now been shown to be a highly efficient route to l-phenyl-2-quinolones.57... 

Barton devised a new method for the oxidation of primary alcohols to aldehydes involving in the first step conversion to the alkyl chloroformate (1) by adding a solution of the alcohol in ether to ether saturated with phosgene (15-20% w./v.) the solvent is removed at reduced pressure. If the alcohol is hindered, quinoline is added as catalyst and the quinoline hydrochloride removed by filtration. The next step, reaction with dimethyl sulfoxide, is attended with evolution of carbon... 

This material is preferabiy prepared, with the label in a different position, from the reaction of quinoline with CH 3 CH jOCOCl [1725]. This is itself prepared by the reaction of specifically labelled ethanol with unlabelled phosgene ... 

A fused pyrimidin-2-one may be prepared in good yield by heating a 1,3-diamine with urea. Phosgene reacts at ambient temperature with a 2-imino-amine to form a fused pyrimidin-2-one. Quinoline-1,8-diamine and carbon disulphide react to give a yield of 89% of the pyrimidinethione. 

The preparation of berbines (Scheme 38) through treatment of 1-benzyl-1,2,3,4-tetrahydro-iso-quinolines with phosgene gas to yield the iV-chloroformyl derivatives (208) is another example of the use of intramolecular Friedel-Crafts reactions in the construction of quinolizidine systems. These intermediates gave berbin-8-ones (209) by intramolecular ring closure in the presence of several Lewis acid catalysts (Scheme 38) <85T169>. 

Dicyanopyridine has been prepared from the corresponding quinolinic acid diamide with phosgene in 64% yield [1051]. Asparagine and glutamine react with... 

Various vinyl isocyanides 1521-1525 are prepared from oximes (for example, 1519) by reductive formylation and dehydration of the resulting vinyl formamides (for example, 1520) with phosgene in 40-97% yield [1167]. For the dehydration step, DABCO proved to be the most effective base among acid scavengers (EtsN, pyridine, and quinoline were also used). 

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