Reaction of ethyl 4-aryl-6-bromomethyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates with N-methylmorpholinium 3-cyano-1,4-dihydro- and 3-cyano-1,4,5,6-tetrahydropyridine-2-thiolates

Design and Synthesis of Pyrido[2,1-b][1,3,5]thiadiazine Library via Uncatalyzed Mannich-Type Reaction

“…HCHO and a set of various primary amines 9 { 1–31 } (Figure ). The required thiolates 7 { 1–47 } are easily accessible by one-pot condensation of aromatic aldehydes, cyanothioacetamide 10 and Meldrum’s acid (2,2-dimethyl-1,3-dioxane-4,6-dione) 11 in the presence of N -methylmorpholine following the consequent cyclization of the isolable Michael adduct, N -methylmorpholinium 5-(3-amino-1-aryl-2-cyano-3-thioxopropyl)-2,2-dimethyl-4-oxo-4H-1,3-dioxin-6-olate 12 , as outlined in Scheme . − As the starting 1,4,5,6-tetrahydropyridine-2-thiolates 7 have been prepared as racemic mixtures of (4 R )- and (4 S )-enantiomers, all the pyrido[2,1- b ][1,3,5]thiadiazine-9-carbonitriles 8 also were obtained as mixtures of (8 R )- and (8 S )-isomers.…”

“…The thiolates 7 { 1–47 } were obtained in a manner analogous to reported procedures − as follows: A 0.5 L round-bottom flask fitted with an overhead stirrer was charged with the corresponding aromatic aldehyde (0.1 mol), cyanothioacetamide 10 (10.0 g, 0.10 mol) and EtOH (100 mL). N -Methylmorpholine (0.8–1.0 mL) was added, and the mixture was stirred for 1 h at 20 °C (yellow/orange crystalline 3-aryl-2-cyanoprop-2-enethioamides may precipitate from the solution).…”

Synthesis of 7-thia-1,4,6,8-tetraazabenzo[de]anthracenes

“…2,4-Diamino-10-(2-furyl)-5-imino-8-oxo-7,8,9,10-tetrahydro-5Н-pyrido [2',3':4,5]thiopyrano [2,3b]pyridine-3-carbonitrile (1b), DMF solvate (2:1). A mixture of thiolate 3b [6,7] (3.0 g, 9.34 mmol), malononitrile dimer 4 [8] (1.85 g, 14.0 mmol) in 96% EtOH (30 mL) was heated under reflux for 25 h. The mixture was then kept for 48 h at 20 °С, and black precipitate was filtered and dried at 60 °С. After recrystallization from DMF, the solvate containing 0.5 molecules of DMF was obtained.…”

Mannich reaction in the synthesis of N,S-containing heterocycles. 14*. Unexpected formation of thiazolo[3,2-a]pyridines in the aminoalkylation of N-methylmorpholinium 4-aryl-3-cyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates by isobutyraldehyde and primary amines

“…Melting points were measured on a Koffler hot bench and are not corrected. The model thiolates 1a-d were prepared by condensation of the corresponding aldehyde, cyanothioacetamide, Meldrum's acid, and N-methylmorpholine by a known method [8][9][10]. N-{4-[(8-Cyano-7-(2-furyl)-2,2-dimethyl-5-oxo-2,3,6,7-tetrahydro-5H-thiazolo[3,2-a]pyridin-3-yl) A mixture of disulfide 7 (0.973 g, 1.88 mmol), prepared from thiolate 1a using method described in [7], isobutyraldehyde (1.20 ml, 13.2 mmol), ptoluidine (0.420 g, 3.92 mmol), and N-methylmorpholine (0.45 ml, 4.10 mmol) in ethanol (12 ml) was refluxed in a flask fitted with a condenser.…”