CCXVII.—The nitro- and amino-derivatives of 4-phenylglyoxaline

Abstract

CCXVI1.-The Nitroand Amino-derivatives of 4-Phen y lgly oxaline. By REGINALD LIKDSAY GRANT and FRANK LEE PYJIAN. THE laws of substitution in the glyoxaline nucleus, and the properties conferred by it upon substituents in the 2-and 4-(or 5-) positions have been the subjects of previous papers by one of us and Dr. R. G. Fargher, and are being further investigated in these laboratories. The present work was carried out with the object of contributing to our present scanty knowledge of the somewhat unstable 4-aminoglyoxalines. The simplest member of the series is unknown, and the only substance which is known certainly to belong to this class is 4-amino-5-methylglyoxaline (Fargher, T., 1920, 117, SSS), although the same author (Zoc. cit.) has shown that the reduction product of 4-p-bromobenzeneazo-2-phenylglyoxaline (Fargher and Pyman, T., 1919, 115, 258) is probably 5-amino-4-(5'-bromo-2'-aminophenyl)-2-phenylglyoxaline. It was thought that a 4-amino-derivative of a 5-phenyl (or substituted pheny1)-glyoxaline might be stable and consequently 4-phenylglyoxaline was chosen as the starting material. This substance has been prepared previously by Pinner (Ber., 1902, 35, 3~2

H3-Receptor Antagonists: Synthesis and Structure−Activity Relationships of Para- and Meta-Substituted 4(5)-Phenyl-2-[[2-[4(5)-imidazolyl]ethyl]thio]imidazoles

“…General Method of Preparation of Substituted 4(5)-Phenyl-2-mercaptoimidazole Derivatives (2a − l). Substituted 4(5)-phenyl-2-mercaptoimidazole derivatives (Scheme : 2a , 2b , 2c − g , and 2i − k ) were prepared from the corresponding ω-aminoacetophenones and KSCN following the general method of Norris 39 (in CH 3 COOH) or that of Pyman (in water). For p - and m -carbamoyl derivatives ( 2h and 2l ), the cyclization was performed from p - and m -cyano-ω-aminoacetophenone, giving 4(5)-(4-cyanophenyl)-2-mercaptoimidazole and 4(5)-(3-cyanophenyl)-2-mercaptoimidazole, respectively; these were then hydrolyzed to the respective carbamoyl derivatives by addition of water, according to the method of Snyder …”

Nonpeptide Somatostatin Agonists with sst4 Selectivity: Synthesis and Structure−Activity Relationships of Thioureas

“…23 24 (2.00 g, 6.24 mmol), CS2 (5.08 g, 66.7 mmol), and DCC (1.29 g, 6.24 mmol) in THF (45 mL) yielded an oil. Flash chromatography on silica gel using hexane/ EtOAc/Et3N (70:30:1) as the solvent gave 1.35 g (60%) of 32 as an oil: 1 (34). 25 (4.00 g, 10.8 mmol), CS2 (8.80 g, 115 mmol), and DCC (2.32 g, 10.8 mmol) in THF (140 mL) afforded an oil.…”

“…The foam was triturated with MeOH/water to yield a white solid. Recrystallization from CH2Cl2/Et2O afforded 659 mg (48%) of 47 as a white, crystalline solid: mp 112-113.5 °C; 1 34 (521 mg, 2.25 mmol) and Et3N (455 mg, 4.49 mmol) in THF (30 mL) was stirred under nitrogen for 2 h, and the reaction mixture was treated dropwise with 35 (1.00 g, 2.25 mmol) in THF (15 mL). The reaction mixture was heated at 45 °C for 48 h and filtered, and the solvent was evaporated under reduced pressure.…”

The Substitution of Linked Aromatic Ring Systems.

“…Though this last sweeping generalization is not absolutely correct (15, 36), there is no doubt that this consistency of type of directive action of any ring system has now been proved beyond question. Even in the three isomeric phenylpyridine systems (C6H6 -C6H4N), in which the great readiness of the pyridine ring to undergo tautomeric change has specially favored the transmission of alternating polarity effects, this same constancy of type of action is generally preserved (16), and the same rule seems to apply to other linked aromatic-heterocyclic compounds containing two rings both of aromatic character (18,37,38,48). The very strong meta directing influence of the nitrogen atoms acting as "positive poles" within the heterocyclic ring is never greater than the general ortho-para directive influence of the whole ring system.…”