�ber das 4-Hydroxy-6,6-dimethyl-5,6-dihydro-2(1H)-pyridinthion bzw.-on und die entsprechenden Tautomeren

Synthesis of new tetrahydropyridinylidene ammonium salts and their antiprotozoal potency

“…: 139°C (Ref. [9] 138°C) corresponds well with the reported one. 5,6-Dihydro-6,6-dimethyl-4-(1-pyrrolidinyl)-thiopyrane-2(1H)-thione (8) This compound was prepared according a reported procedure [14].…”

“…Thiones 3a-3d were transformed to the tetrahydropyridinylidene salts 6a-6d by a S-methylation/reduction procedure using deactivated Raney nickel for the selective reduction process. To vary the 4-amino substituents of 6, it was in some cases easier to prepare thiones 3e-3j via reaction of compound 7 and the appropriate amine 5e-5j [9] followed by abovementioned steps to yield 6e-6j (Scheme 1).…”

“…v = 3149, 3119, 3027, 2944, 2867, 1606, 1555, 1532, 1428, 1411, 1334, 1287, 1268, 1183, 1136 N-(4-Chlorophenyl)-2,2-dimethyl-1,2,3,4-tetrahydropyridin-4-iminium iodide (6j, C 13 H 16 ClIN 2 ) A solution of 2.14 g of 3j (8.7 mmol) in 10 cm 3 of chloroform reacted with 1.5 g methyl iodide (10.5 mmol) dissolved in 10 cm 3 of chloroform to a precipitate which was treated in a total volume of 40 cm 3 ethanol with Raney nickel prepared from 6 g nickel/aluminum alloy and 12 g of caustic soda giving 770 mg (69 %) 6j as light yellow crystals. 6,6-Dimethyl-2-thioxo-4-piperidone (7) This compound was prepared according a reported procedure [9]. Its melting point m.p.…”

Synthesis of Isomeric Isoxazolopyridinones

“…The tautomers 10a, b had already been prepared from the 4-methylaminopyridin-2-one 3 [27]. When measured in DMSO-d 6 , the oximes 11a, b appear in a ratio of 4.3:1 in the 1 H NMR spectrum.…”

Straightforward Pyrimidine Ring Construction: A Versatile Tool for the Synthesis of Nucleobase and Nucleoside Analogues

“…New functional groups were thus introduced on the previously constructed pyrimidines 3-12 by nucleophilic substitution of the methylsulfanyl group. Reactions with hydrogen sulfide in basic medium [13] or hydroxide potassium in alcoholic medium [14] gave, after prototropic equilibrium, 4-thioxopyrimidines 13-22 and 4-oxopyrimidines 23-32, respectively (Scheme 4). These transformations were achieved with good yields (Table 2) and we note that substitution with thiohydroxide can be considered as an S-deprotection of thioamide 1.…”