Acetyl tetrahydroquinoline

Yadav et al. explored the reaction of substituted anilines with 3,4,6-tri- O-acetyl-D-glucal to offer the tetrahydroquinoline moieties.134 Most yields are around 80% with excellent distereoselectivity and the reaction was carried out in water (Eq. 12.61). The primary disadvantages are that both CeCb and Nal are required in stoichiometric amounts. 

The tetrahydroquinoline-2,5-dione (46) is obtained when the 2-cyanoethylcyclohexane-1,3-dione is treated with acetyl chloride in chloroform, or phosphorus tribromide in pyridine (76JOC636). In contrast, the cyclohexane-1,3-dione (47) can be converted into an isoquinolin-... 

A three component coupling reaction of A-acetyl-2-azetine, aromatic imines and aromatic amines allows a rapid stereoselective entry to 2,3,4-trisubstituted tetrahydroquinolines, via fused tricyclic azetidines 1 <02CC444>. Fused heterocycles 1 were formed through an aza Diels-Alder reaction between aromatic imines and A-acetyl-2-azetine, which acts as an enamide substrate. This strategy has been used for the formal synthesis of luotonin A <02TL5469>. 

The use of l-acetyl-2-phenylhydrazine [APH (VI)] and saccharin resulted in a somewhat slower reaction rate than with DMPT unless a catalytic amount of copper was added. In this study the concentration of CHP was found to be very important where the molar ratio of CHP/APH was less than 1. Where the ratio was greater than 1, the rate was independent of CHP [12]. These papers [11,12] have been reviewed [13]. The accelerating effect of the salts of saccharin and 6-methyl-1,2,3,4-tetrahydroquinoline (VII), 1,2,3,4-tetrahydroquinoline (IV), or 1,2,3,4-tetrahydroquinaldine (VIII) on the anaerobic polymerization of methyl methacrylate were studied. No organic peroxides were required for these polymerizations [14]. 

The Bischler-Napieralski synthesis of l-methyl-3,4-dihydroisoquinoline (18) from N-(2-phenylethyl)acetamide (19) in the presence of heat and acid (72) was not predicted by the Electrophilic Aromatic module of CAMEO this module of CAMEO predicted instead the formation of methyl 2-acetyl-phenethylamine, 20 (Scheme 5). In a related case, CAMEO predicted (when the Electrophilic Aromatic module was chosen) that 4-anilino-butan-2-one (21) would undergo intramolecular cyclization to form 4-hydroxy-4-methyl-tetrahydroquinoline, 23 (Scheme 6). Apparently, CAMEO correcdy perceives the eneamine character of 21 as necessary for this reaction to occur. It was noted in this case that ring formation, as predicted by CAMEO, depended upon the presence of mineral acid, but did not occur if a Lewis acid (e.g., stannic chloride) was selected instead as the reagent. It is known, however, that intramolecular cyclization of 21 does occur in the presence of a Lewis acid and yields 4-methyl-quinoline, 22, as product (74). 

A mixture of N-acetyl-4-oxo-1,2,3,4-tetrahydroquinoline-2-carboxylic acid, anhydrous Na-acetate, and acetic anhydride refluxed 0.5 hr. in dimethylformamide -> kynurenic acid. Y 90%. C. Jordanides, A. 729, 244 (1969). 

In efforts to develop industrial processes for the manufacture of nicotinic acid, Russian workers have studied the electrolytic oxidation of alkylpyridines and quinolines (X-74) using neutral or acidic media and platinum and lead anodes. Reactions occurred at 40 to 100° with high current efficiencies, but reported yields are low (Desired products appeared, of course, in the anolyte compartment. In the catholyte compartment, on the other hand, quinoline substrate was, inter alia, reduced to 1,2,3,4-tetrahydroquinoline (X-7S), isolated as the. /V-acetyl derivative. 

ZnClg added to a mixture of 2-benzoyl-4-chloro-N-methylaniline, methyl vinyl ketone, and methylene chloride, and stirred 1 hr. at room temp. 3-acetyl-6-chloro-4-hydroxy-l-methyl-4-phenyl-l,2,3,4-tetrahydroquinoline. Y 74%. F. e. s. A. Walser, G. Zenchoff, and R. I. Fryer, J. Heterocyclic Chem. 13, 131 (1976). 

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