Various analogues of a new antidiabetic agent, pioglitazone (AD-4833, U-72107), were synthesized in order to study in more detail the structure-activity relationships of this class of drug. 5-(4-Pyridylalkylthiobenzyl)-2,4-thiazolidinediones (I), thia-analogues of pioglitazone, were prepared via Meerwein arylation of the alkylthioanilines (IV). 5-(4-Pyridylalkoxybenzylidene)-2,4-thiazolidinediones (IIa) and related heterocyclic analogues (IIb) were synthesized by Knoevenagel condensation of the aldehydes (VIII) with the corresponding azolidinones. Compounds I and II were evaluated for hypoglycemic and hypolipidemic activity in genetically obese and diabetic yellow KK (KKAy) mice. Several 5-[4-[2-(2-pyridyl)ethoxy]-benzylidene]-2,4- thiazolidinediones (IIa) were equipotent to pioglitazone. However, the thia-analogues (I) and the benzylideneheterocycles (IIb) had decreased activity. Catalytic hydrogenation of the 5-benzylidene analogue (14) was found to be a convenient new synthetic method for pioglitazone. The configuration of 14 is also discussed.

Effects of 5-[4-(1-methylcyclohexylmethoxy)benzyl]-thiazolidine-2,4-dione (ADD-3878, U-63,287, Ciglitazone) on glucose and lipid metabolism were examined in various animal models. ADD-3878, administered as a dietary admixture (30-186 mg/kg/day) to obese-diabetic yellow KK (KK-Ay) mice, markedly suppressed the diabetic syndromes (hyperglycemia, hypertriglyceridemia, and hyperinsulinemia), accompanied by the reduction of insulin resistance as manifested by improvement of overall insulin sensitivity in either the insulin tolerance test or the steady-state blood glucose test. Chronic administration of ADD-3878 for as long as 12 wk to young yellow KK mice, which were in the early stage of diabetes and obesity, depressed age-dependent rises in blood glucose, plasma triglyceride, and insulin without exerting any effect on obesity. When orally administered to obese Zucker-fatty rats, ADD-3878 decreased plasma insulin and triglyceride in a dose-dependent manner (5-100 mg/kg/day). The treated rats showed increased tolerance and decreased insulin secretion in response to oral glucose. The glycemic response to insulin and the steady-state plasma glucose were also normalized in the treated rats. Chronic administration of ADD-3878 to young fatty rats for as long as 12 wk decreased the dose-dependent rises in blood glucose, plasma triglyceride, and insulin without exerting any effect on body weight. ADD-3878 had no effect on glucose and lipid metabolism of young Sprague-Dawley rats and mild streptozotocin-diabetic rats. However, in old Sprague-Dawley rats that were moderately insulin resistant and hyperlipidemic compared with young ones, ADD-3878 decreased plasma triglyceride and insulin and improved insulin sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Two novel classes of 2,4-thiazolidinediones and 2,4-oxazolidinediones with an omega-(azolylalkoxyphenyl)alkyl substituent at the 5-position were prepared and their antidiabetic effects were evaluated in two genetically obese and diabetic animal models, KKA(y) mice and Wistar fatty rats. A large number of the 2,4-thia(oxa)zolidinediones showed potent glucose- and lipid-lowering activities. The antidiabetic activities of the 2,4-oxazolidinediones were superior to those of the 2,4-thiazolidinediones. Among the compounds, both enantiomers of 5-[3-[4-[2-(2-furyl)-5-methyl-4-oxazolylmethoxy]-3-methoxyphenyl]propyl]-2,4-oxazolidinedione (64), one of the most interesting compounds in terms of activity, were synthesized by using an asymmetric O-acetylation of the corresponding alpha-hydroxyvalerate (26) with immobilized lipase, followed by cyclization of the oxazolidinedione ring. (R)-(+)-64 showed more potent glucose-lowering activity (effective dose (ED)25 = 0.561 mg/kg/d) than (S)-(-)-64 (ED25 > 1.5 mg/kg/d) or pioglitazone (ED25 = 6 mg/kg/d) in KKA(y) mice. It also exhibited a 10-fold more potent antidiabetic activity (ED25 = 0.05 mg/kg/d) than pioglitazone (ED25 = 0.5 mg/kg/d) in Wistar fatty rats. The antidiabetic effects of this compound are considered to be due to its potent agonistic activity for peroxisome proliferator-activated receptor gamma (EC(50) = 8.87 nM).

In the course of our study aimed at developing new types of DMARDs (disease-modifying antirheumatic drugs), we found that quinoline derivative 1a had a potent anti-inflammatory effect in an adjuvant arthritis (AA) rat model, starting from the potent bone resorption inhibitors justicidins as the lead compounds. Further modification of 1a was performed, and various quinoline and quinazoline derivatives having a heteroaryl moiety on the alkyl side chain at the 2-position of the skeleton were prepared. These compounds were evaluated for anti-inflammatory effects using the AA rat model. Most of these compounds, especially those having an imidazole or a triazole moiety on the 2-alkyl chain, exhibited a potent effect. Among the compounds synthesized, ethyl 4-(3,4-dimethoxyphenyl)-6,7-dimethoxy-2-(1,2, 4-triazol-1-yl-methyl)quinoline-3-carboxylate (12d), having an ED50 value of 2.6 mg/kg/day (anti-inflammatory effect in an AA rat model, po), was selected as a candidate for further investigation. In vitro, 12d inhibited mitogen-induced proliferation at 10(-7)-10(-5) M but not prostaglandin E2 production at 10(-5) M. Moreover, 12d preferentially inhibited the IFN-gamma production by Th1-type clones over the IL-4 production by Th2-type clones. This preferential suppression of Th1 cytokine production is considered the essential immunomodulating action of 12d for the present. Synthesis and structure-activity relationships for this novel series of quinoline and quinazoline derivatives are detailed.

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