Synthesis of Indazoles via N-N Bond-Forming Oxidative Cyclization from 2-Aminomethyl-phenylamines

Herein we report a method for the synthesis of indazoles from readily available 2-aminomethyl-phenylamines via N-N bond-forming oxidative cyclization. Inspired by indazole formation initially observed as a side product by N. Coskun et al. we developed a robust protocol to access indazoles in all three tautomeric forms. The method selectively gives access to various 2-substituted 2H-indazoles which are frequently used in drug design, and we also demonstrated its applicability to less studied 3H-indazoles.

Drugging an undruggable pocket on KRAS

The 3 human RAS genes, KRAS, NRAS, and HRAS, encode 4 different RAS proteins which belong to the protein family of small GTPases that function as binary molecular switches involved in cell signaling. Activating mutations in RAS are among the most common oncogenic drivers in human cancers, with KRAS being the most frequently mutated oncogene. Although KRAS is an excellent drug discovery target for many cancers, and despite decades of research, no therapeutic agent directly targeting RAS has been clinically approved. Using structure-based drug design, we have discovered BI-2852 (1), a KRAS inhibitor that binds with nanomolar affinity to a pocket, thus far perceived to be "undruggable," between switch I and II on RAS; 1 is mechanistically distinct from covalent KRASG12C inhibitors because it binds to a different pocket present in both the active and inactive forms of KRAS. In doing so, it blocks all GEF, GAP, and effector interactions with KRAS, leading to inhibition of downstream signaling and an antiproliferative effect in the low micromolar range in KRAS mutant cells. These findings clearly demonstrate that this so-called switch I/II pocket is indeed druggable and provide the scientific community with a chemical probe that simultaneously targets the active and inactive forms of KRAS.

Discovery of a novel series of potent S1P1 agonists

The discovery of a novel series of S1P1 agonists is described. Starting from a micromolar HTS positive, iterative optimization gave rise to several single-digit nanomolar S1P1 agonists. The compounds were able to induce internalization of the S1P1 receptor, and a selected compound was shown to be able to induce lymphopenia in mice after oral dosing.

Furan-2-ylmethylene Thiazolidinediones as Novel, Potent, and Selective Inhibitors of Phosphoinositide 3-Kinase γ

Class I phosphoinositide 3-kinases (PI3Ks), in particular PI3Kgamma, have become attractive drug targets for inflammatory and autoimmune diseases. Here, we disclose a novel series of furan-2-ylmethylene thiazolidinediones as selective, ATP-competitive PI3Kgamma inhibitors. Structure-based design and X-ray crystallography of complexes formed by inhibitors bound to PI3Kgamma identified key pharmacophore features for potency and selectivity. An acidic NH group on the thiazolidinedione moiety and a hydroxy group on the furan-2-yl-phenyl part of the molecule play crucial roles in binding to PI3K and contribute to class IB PI3K selectivity. Compound 26 (AS-252424), a potent and selective small-molecule PI3Kgamma inhibitor emerging from these efforts, was further profiled in three different cellular PI3K assays and shown to be selective for class IB PI3K-mediated cellular effects. Oral administration of 26 in a mouse model of acute peritonitis led to a significant reduction of leukocyte recruitment.

Discovery and development of a new class of potent, selective, orally active oxytocin receptor antagonists

We report a novel chemical class of potent oxytocin receptor antagonists showing a high degree of selectivity against the closely related vasopressin receptors (V1a, V1b, V2). An initial compound, 7, was shown to be active in an animal model of preterm labor when administered by the intravenous but not by the oral route. Stepwise SAR investigations around the different structural elements revealed one position, the arenesulfonyl moiety, to be amenable to structural changes. Consequently, this position was used to introduce a variety of substituents to improve the physicochemical properties. Some of the resulting analogues were found to be superior to 7 both in terms of potency in vitro and aqueous solubility, which translated into significantly improved efficacy in the animal model after intravenous and oral administration. The best compound, 73, potently inhibited oxytocin-induced uterine contractions in nonpregnant rats and reduced spontaneous uterine contractions in late-term pregnant rats.

Effect of a single dose of ibuprofen lysinate before embryo transfer on pregnancy rates in cows

Embryo implantation is a critical step in both cows and humans. The use of ibuprofen lysinate to enhance implantation has been investigated in cattle with the specific aim of improving pregnancy rates after embryo transfer. In this study, heifers (n = 100) were assigned randomly to one of two groups: one group was treated i.m. with 5 mg ibuprofen lysinate kg(-1) body weight 1 h before embryo transfer and a control group received vehicle only. A single embryo was transferred into each recipient cow. There was a significant difference in the number of pregnancies after embryo transfer between cows in the treated (41 of 50; 82%) and control (28 of 50; 56%) groups (P < 0.05). These data indicate that ibuprofen lysinate may be an effective adjunctive treatment for assisted reproduction in cattle. Further studies are needed to clarify whether this effect is associated with the reduction of cyclooxygenase enzyme isoforms during embryo transfer or whether other mechanisms are involved.

Effect of a single dose of ibuprofen lysinate before embryo transfer on pregnancy rates in cows

Embryo implantation is a critical step in both cows and humans. The use of ibuprofen lysinate to enhance implantation has been investigated in cattle with the specific aim of improving pregnancy rates after embryo transfer. In this study, heifers (n = 100) were assigned randomly to one of two groups: one group was treated i.m. with 5 mg ibuprofen lysinate kg(-1) body weight 1 h before embryo transfer and a control group received vehicle only. A single embryo was transferred into each recipient cow. There was a significant difference in the number of pregnancies after embryo transfer between cows in the treated (41 of 50; 82%) and control (28 of 50; 56%) groups (P < 0.05). These data indicate that ibuprofen lysinate may be an effective adjunctive treatment for assisted reproduction in cattle. Further studies are needed to clarify whether this effect is associated with the reduction of cyclooxygenase enzyme isoforms during embryo transfer or whether other mechanisms are involved.

Structural changes in the heart and carotid arteries in hypertensive patients associated with cardiovascular risk factors

OBJECTIVE

To estimate the relationship between structural changes in the heart and in the carotid arteries in hypertensives and to analyze the correlations between these structural changes and cardiovascular risk factors.

METHODS

We studied 76 subjects (39 men and 27 women, mean age 45+/-7 years) with mild-to-moderate untreated and uncomplicated hypertension. All of the subjects underwent ambulatory blood pressure monitoring, M-mode echocardiography for evaluation of their left ventricular mass and B-mode high-resolution ultrasonography to determine their carotid arterial wall thickness.

RESULTS

The mean intimal plus medial thickness of the common carotid artery was found to be related significantly and independently to the left ventricular mass indexed by the body surface area. In multivariate analysis, age and the high-density lipoprotein cholesterol level were related strongly to the intimal plus medial thickness, whereas the clinic systolic blood pressure, average night-time systolic blood pressure and glycemia were the most important determinants of the left ventricular mass index. Logistic regression analysis suggested that the thickness of the posterior left ventricular wall was a stronger predictor of the carotid intima-medial thickness than were age and the high-density lipoprotein cholesterol level.

CONCLUSION

The carotid wall thickness and left ventricular mass of hypertensives are related independently; nevertheless the main determinants of structural cardiac and vascular changes are probably different.

Protective effects of carvedilol, a vasodilating beta-adrenoceptor blocker, against in vivo low density lipoprotein oxidation in essential hypertension

Low density lipoprotein (LDL) oxidation plays a crucial role in the development and progression of atherosclerosis and is enhanced in patients with essential hypertension. This finding has stimulated a search for antihypertensive drugs with high intrinsic antioxidant properties. We investigated the antihypertensive and antioxidant effects of carvedilol, a new vasodilating beta-adrenoceptor blocking agent in a group of patients with mild to moderate essential hypertension after 4-month treatment. Carvedilol administration markedly increased the resistance to oxidation of LDL isolated from treated patients to values comparable to those of control, nonhypertensive subjects. This effect was achieved despite a significant loss in LDL-associated vitamin E. The increased resistance of LDL to oxidation promoted by carvedilol was not related to the normalization of previously increased blood pressure (BP). Indeed, the administration of other conventional antihypertensive drugs, capable of decreasing arterial BP but without high intrinsic antioxidant properties, to a control group of matched hypertensive patients failed to ameliorate LDL oxidation parameters. Carvedilol treatment also reduced the extent of in vivo LDL oxidation, as reflected by the decrease in antioxidized LDL autoantibody titer. This effect as well was detected only in the group of carvedilol-treated hypertensive patients and not after the simple reduction in BP obtained with antihypertensive drugs different from carvedilol.

Pharmacokinetics of a sustained release formulation of pyridoxal phosphate of buflomedil after single or repeated oral doses in healthy volunteers

The pharmacokinetics of a sustained release (SR) formulation of pyridoxal phosphate of buflomedil (Pirxane retard) has been studied after oral administration to healthy volunteers using among else a gaschromatographic dosage method. After oral administration of 400 mg of the SR formulation, pyridoxal phosphate of buflomedil has a much slower kinetics compared to the normal formulation (tmax:approx. 1.5 h) reaching the maximum plasma concentration, which was about 467 ng/ml, in about 3 h. After 24 h the concentrations were still about 1/10 (48 ng/ml) the maximum value. 24-h urinary excretion was about 21% of the administered dose. Repeated administration of the SR formulation for 7 days in single daily doses of 400 mg gave steady state plasma levels (ca. 250 ng/ml) 12 h after the administration without statistically significant variations. The plasma concentrations of the drug measured daily after reaching the steady state were similar one to the other. The tolerability was very good and no local or systemic side effects of any kind were reported.

[Intranasal absorption of various calcitonin spray preparations]

In a cross-over study performed on 10 patients the intranasal absorption of calcitonin contained in three formulation spray was evaluated. One of them contained biliary acid (sodium taurocholate) as the absorption promoting factor while the other two drugs did not. The dosage of calcitonin in blood was effected by means of radioimmunoassay using salmon calcitonin marked with I126 in competition to the one present in the sample for a limited quantity of specific antibodies for salmon calcitonin. The minimum measurable quantity of calcitonin is 10 pg and the response is linear including values between 20% and 80%. It is observed that the plasmatic concentration of calcitonin dosed in different times after administration of the drug containing sodium taurocholate are always significantly higher (Student "t" test for unpaired data, p less than 0.005) than the measurements after administration of the other two drugs. They are about 8 times higher at the first half an hour, about 6 times after an hour and again double at the second hour. The AUC calculated for sodium taurocholate containing drug (1629 pg/ml/h) results significantly higher in relation to the other two drugs (1133 and 926 pg/ml/h) indicating a better bio-availability of calcitonin contained in that spray. The relative bioavailability between calcitonin spray with sodium taurocholate and the other two drugs in reference resulted to 144% and 176%. The presence of a transmucosal absorption promoting factor at the level of a nasal mucosa, represented in this case by sodium taurocholate, enhances significantly the absorption and the bioavailability of calcitonin present in the formulation spray.