Conformationally restricted glutamic acid derivatives: asymmetric synthesis of 4-substituted 4,5-dihydro-3(2H)-pyridazinones

Diastereoselective Synthesis and Estimation of the Conformational Flexibility of 6-Oxoperhydropyridazine-3-carboxylic Acid Derivatives

“…Alkylation of compounds 3 under solid−liquid PTC conditions took place exclusively at C-4 , (R 2 X, NaOH, (TEBA)Cl, acetonitrile), giving rise to compounds 4 as Z : E mixtures (Table ). However, it was found that compounds 4 were obtained with the same Z : E ratio irrespective of the double bond geometry of the starting materials 3b , thus making unnecessary the separation of isomers ( Z )- 3b,c and ( E )- 3b,c .…”

Synthesis of 5‐(6‐Pyridazinone‐3‐yl)‐2‐glycosylamino‐1,3,4‐thiadiazoles

“…Dihydeopyrida-zinones can be considered as rigid analogues of hydrainolactams. 6 6-Aryl-4,5-dihydro-3(2H)-pyridazinones exhibited a strong platelet aggregation inhibiting action coupled with a hypotensive action. Three para-substituted dihydropyridazinones were conspicuous in exerting a strong hypotensive action on anesthetized rats.…”

N-Heterocyclic Carbene-Catalyzed Oxidative Annulations of α,β-Unsaturated Aldehydes with Hydrazones: Selective Synthesis of Optically Active 4,5-Dihydropyridazin-3-ones and Pyridazin-3-ones

“…Due to their broad and powerful pharmacologic activities, the syntheses of 4,5-dihydropyridazin-3-one and pyridazin-3-one compounds have attracted continuous interest from both organic and medicinal chemists. The most frequently used strategy for the construction of a 4,5-dihydropyridazin-3-one or a pyridazin-3-one ring is based on the condensation of a hydrazine or substituted hydrazines with γ-carbonyl acids or their derivatives. ,,,− Another method for the formation of dihydropyridazin-3-ones or pyridazin-3-ones is to utilize a hydrazone of a 1,2-dicarbonyl compound as a substrate to react with ethyl cyanoacetate, phosphonium ylides of carboxylates, 2-benzylidene­cyano­acetate, or 2-benzylidene­malono­nitrile, followed by intramolecular cyclization. In recent years, several new methods, including the AgNO 3 -catalyzed multicomponent radical reaction of aryldiazonium salts with pent-4-enoate and sodium triflinate, the copper-catalyzed multicomponent reaction of aldehydes with hydrazines and alkynylesters, the KSF-catalyzed multicomponent cyclocondensation of γ-keto acids with thiosemicarbazide and phenacyl bromide, the Brønsted acid assisted Lewis base catalyzed asymmetric reaction between hydrazones and α,β-unsaturated aldehydes, and the reaction between aryldiazonium salts and potassium 2-furan­trifluoro­borate, have been developed for the construction of 4,5-dihydropyridazin-3-ones or pyridazin-3-ones.…”