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European Journal of Medicinal Chemistry Oct 2022Boceprevir is an HCV NSP3 inhibitor that was explored as a repurposed drug for COVID-19. It inhibits the SARS-CoV-2 main protease (M) and contains an α-ketoamide...
Boceprevir is an HCV NSP3 inhibitor that was explored as a repurposed drug for COVID-19. It inhibits the SARS-CoV-2 main protease (M) and contains an α-ketoamide warhead, a P1 β-cyclobutylalanyl moiety, a P2 dimethylcyclopropylproline, a P3 tert-butylglycine, and a P4 N-terminal tert-butylcarbamide. By introducing modifications at all four positions, we synthesized 20 boceprevir-based M inhibitors including PF-07321332 and characterized their M inhibition potency in test tubes (in vitro) and 293T cells (in cellulo). Crystal structures of M bound with 10 inhibitors and cytotoxicity and antiviral potency of 4 inhibitors were characterized as well. Replacing the P1 site with a β-(S-2-oxopyrrolidin-3-yl)-alanyl (Opal) residue and the warhead with an aldehyde leads to high in vitro potency. The original moieties at P2, P3 and the P4 N-terminal cap positions in boceprevir are better than other tested chemical moieties for high in vitro potency. In crystal structures, all inhibitors form a covalent adduct with the M active site cysteine. The P1 Opal residue, P2 dimethylcyclopropylproline and P4 N-terminal tert-butylcarbamide make strong hydrophobic interactions with M, explaining high in vitro potency of inhibitors that contain these moieties. A unique observation was made with an inhibitor that contains a P4 N-terminal isovaleramide. In its M complex structure, the P4 N-terminal isovaleramide is tucked deep in a small pocket of M that originally recognizes a P4 alanine side chain in a substrate. Although all inhibitors show high in vitro potency, they have drastically different in cellulo potency to inhibit ectopically expressed M in human 293T cells. In general, inhibitors with a P4 N-terminal carbamide or amide have low in cellulo potency. This trend is reversed when the P4 N-terminal cap is changed to a carbamate. The installation of a P3 O-tert-butyl-threonine improves in cellulo potency. Three molecules that contain a P4 N-terminal carbamate were advanced to cytotoxicity tests on 293T cells and antiviral potency tests on three SARS-CoV-2 variants. They all have relatively low cytotoxicity and high antiviral potency with EC values around 1 μM. A control compound with a nitrile warhead and a P4 N-terminal amide has undetectable antiviral potency. Based on all observations, we conclude that a P4 N-terminal carbamate in a boceprevir derivative is key for high antiviral potency against SARS-CoV-2.
Topics: Antiviral Agents; Carbamates; Carbutamide; Humans; Lactams; Leucine; Nitriles; Proline; Protease Inhibitors; SARS-CoV-2; COVID-19 Drug Treatment
PubMed: 35839690
DOI: 10.1016/j.ejmech.2022.114596 -
British Journal of Pharmacology and... Dec 1957The glucose uptake of the rat diaphragm has been determined in the presence of the plasma of young volunteers before and after administration of carbutamide without and...
The glucose uptake of the rat diaphragm has been determined in the presence of the plasma of young volunteers before and after administration of carbutamide without and with added insulin. The increase in the glucose uptake of the rat diaphragm due to the added plasma above that in the medium alone has been termed plasma effect. The increase in the glucose uptake of the rat diaphragm with plasma and added insulin above that with only insulin in the medium has been termed plasma+insulin effect. There was a significant increase in the plasma effect and the plasma+insulin effect after carbutamide administration. The increase in the plasma+insulin effect was significantly greater than the increase in the plasma effect. From these observations it has been suggested that carbutamide potentiates the action of insulin peripherally. Observed facts about carbutamide do not contradict this mechanism of action.
Topics: Animals; Biological Transport; Carbohydrate Metabolism; Carbutamide; Diaphragm; Glucose; Humans; Hypoglycemic Agents; Insulin; Muscles; Plasma; Rats
PubMed: 13489177
DOI: 10.1111/j.1476-5381.1957.tb00168.x -
British Journal of Pharmacology Mar 19981. The structure activity relationships for the insulin secretagogues N-benzoyl-D-phenylalanine (NBDP) and related compounds were examined at the sulphonylurea receptor...
1. The structure activity relationships for the insulin secretagogues N-benzoyl-D-phenylalanine (NBDP) and related compounds were examined at the sulphonylurea receptor level by use of cultured HIT-T15 and mouse pancreatic beta-cells. The affinities of these compounds for the sulphonylurea receptor were compared with their potencies for K(ATP)-channel inhibition. In addition, the effects of cytosolic nucleotides on K(ATP)-channel inhibition by NBDP were investigated. 2. NBDP displayed a dissociation constant for binding to the sulphonylurea receptor (K(D) value) of 11 microM and half-maximally effective concentrations of K(ATP)-channel inhibition (EC50 values) between 2 and 4 microM (in the absence of cytosolic nucleotides or presence of 0.1 mM GDP or 1 mM ADP). 3. In the absence of cytosolic nucleotides or presence of GDP (0.1 mM) maximally effective concentrations of NBDP (0.1-1 mM) reduced K(ATP)-channel activity to 47% and 44% of control, respectively. In the presence of ADP (1 mM), K(ATP)-channel activity was completely suppressed by 0.1 mM NBDP. 4. The L-isomer of N-benzoyl-phenylalanine displayed a 20 fold lower affinity and an 80 fold lower potency than the D-isomer. 5. Introduction of a p-nitro substituent in the D-phenylalanine moiety of NBDP did not decrease lipophilicity but lowered affinity and potency by more than 30 fold. 6. Introduction of a p-amino substituent in the D-phenylalanine moiety of NBDP (N-benzoyl-p-amino-D-phenylalanine, NBADP) reduced lipophilicity and lowered affinity and potency by about 10 fold. This loss of affinity and potency was compensated for by formation of the phenylpropionic acid derivative of NBADP. A similar difference in affinity was observed for the sulphonylurea carbutamide and its phenylpropionic acid derivative. 7. Replacing the benzene ring in the D-phenylalanine moiety of NBDP by a cyclohexyl ring increased lipophilicity, and the K(D) and EC50 values were slightly lower than for NBDP. Exchange of both benzene rings in NBDP by cyclohexyl rings further increased lipophilicity without altering affinity and potency. 8. This study shows that N-acylphenylalanines interact with the sulphonylurea receptor of pancreatic beta-cells in a stereospecific manner. Their potency depends on lipophilic but not aromatic properties of their benzene rings. As observed for sulphonylureas, interaction of N-acylphenylalanines with the sulphonylurea receptor does not induce complete inhibition of K(ATP)-channel activity in the absence of inhibitory cytosolic nucleotides.
Topics: ATP-Binding Cassette Transporters; Adenosine Triphosphate; Animals; Calcium; Carbutamide; Cell Line, Transformed; Cricetinae; Cyclohexanes; Glyburide; Guanosine Diphosphate; Islets of Langerhans; Male; Mice; Nateglinide; Phenylalanine; Potassium Channels; Potassium Channels, Inwardly Rectifying; Receptors, Drug; Sulfonylurea Receptors; Tritium
PubMed: 9559882
DOI: 10.1038/sj.bjp.0701686 -
California Medicine Nov 1956Of a group of 32 patients with diabetes, 26 had a favorable modification of the disease in response to administration of butyl-sulfonyl-urea. All but one of the patients...
Of a group of 32 patients with diabetes, 26 had a favorable modification of the disease in response to administration of butyl-sulfonyl-urea. All but one of the patients who had good response were past the age of 38. All diabetic patients included in this group were those with little or no tendency to ketosis after cessation of insulin administration. No toxic manifestations were noted except for a slight decrease in leukocytes in one case.
Topics: Carbutamide; Diabetes Mellitus; Ketosis; Sulfanilamide; Sulfanilamides; Sulfonamides; Tolbutamide; Urea
PubMed: 13364673
DOI: No ID Found -
British Journal of Pharmacology and... Sep 1959The fall in blood sugar with carbutamide (BZ55) 24 hr. after the maintenance dose of insulin (28.1%+/-2.9 s.e) in rabbits made severely diabetic with alloxan was...
The fall in blood sugar with carbutamide (BZ55) 24 hr. after the maintenance dose of insulin (28.1%+/-2.9 s.e) in rabbits made severely diabetic with alloxan was significantly different from the change in the blood sugar with the same drug given 72 hr. (6.8%+/-2.0) or distilled water given 24 hr. (7.7%+/-1.3) respectively after the last dose of insulin. It is postulated that the drug acts by liberating bound insulin in the plasma.
Topics: Alloxan; Animals; Blood Glucose; Carbutamide; Diabetes Mellitus; Humans; Hypoglycemic Agents; Insulin; Rabbits
PubMed: 13792172
DOI: 10.1111/j.1476-5381.1959.tb00261.x -
British Medical Journal Feb 1958
Topics: Carbutamide; Humans; Schizophrenia
PubMed: 13499958
DOI: 10.1136/bmj.1.5067.381 -
The Journal of Clinical Investigation Feb 1977It has been suggested previously that chlorpropamide and other hypoglycemic sulfonylureas interfere with hepatic triglyceride breakdown. Since ketogenesis from...
It has been suggested previously that chlorpropamide and other hypoglycemic sulfonylureas interfere with hepatic triglyceride breakdown. Since ketogenesis from endogenous hepatic lipid stores is a measure of hepatic triglyceride hydrolysis, ketogenesis derived from endogenous lipids as well as ketogenesis derived from exogenously added isotopic oleate was determined in isolated hepatocytes from fasted rats in an attempt to identify the nature of the direct effects of sulfonylureas on hepatic lipid metabolism. Ketogenesis from endogenous lipids was inhibited by 1 mM chlorpropamide, while ketone production from exogenous oleate did not change. The effect of chlorpropamide on hepatic triglyceride metabolism was further studied in the isolated perfused liver of normal rats in the presence of a continuous [3H]oleate infusion and in isolated liver cells incubated in the presence of [3H]oleate. In liver perfusion experiments, 1 mM chlorpropamide enhanced the incorporation of tritium into triglycerides (but not other lipid classes) and increased both liver triglyceride content and triglyceride secretion. Using isolated cells similar effects could be demonstrated at 0.5 mM chlorpropamide. Chlorpropamide, tolbutamide, and carbutamide, all of which inhibited endogenous ketogenesis in isolated liver cells, also inhibited lysosomal triglyceride lipase activity in rat liver homogenates. The drugs were not inhibitory towards alkaline lipase activity. Demethylglycodiazin (2-benzolsulfonamid--5-(beta-hydroxyethoxy)-pyrimidin), which did not inhibit endogenous ketogenesis in isolated liver cells, did not affect lysosomal lipase activity. The lysosomotropic drug chloroquine was markedly antiketogenic when tested in liver cells. The reduction in endogenous ketogenesis, the enhanced accumulation of liver triglycerides, and the stimulation of hepatic triglyceride output by chlorpropamide are ascribed to an interference of the drug with hepatic triglyceride breakdown. The present results also suggest that the lysosomes play a significant role in hepatic lipolysis.
Topics: Animals; Chlorpropamide; Hydrogen-Ion Concentration; In Vitro Techniques; Ketone Bodies; Lipase; Liver; Lysosomes; Male; Oleic Acids; Rats; Sulfonylurea Compounds; Triglycerides
PubMed: 13085
DOI: 10.1172/JCI108628 -
British Journal of Pharmacology and... Sep 1957Tolbutamide and carbutamide given orally to fasted rats cause a rise in the liver glycogen content 1(1/2) to 3(1/2) hr. after administration of the drugs. Glycogen...
Tolbutamide and carbutamide given orally to fasted rats cause a rise in the liver glycogen content 1(1/2) to 3(1/2) hr. after administration of the drugs. Glycogen accumulates preferentially in the right lobe. Subcutaneously injected tolbutamide has the same effect. Both sulphonylureas cause inhibition of glucose-6-phosphatase activity of rat liver homogenates in vitro, but at drug concentrations comparable with those found in plasma of treated patients the degree of inhibition is less than 10%. Livers from treated rats show normal glucose-6-phosphatase activity. The glucose uptake of the isolated rat diaphragm is unaffected by the sulphonylureas added in vitro. Diaphragms from treated rats show normal glucose uptake in the presence or absence of insulin. The inferences to be drawn from these results are discussed in the light of previous work. It is concluded that the sulphonylureas exert hypoglycaemic action by inhibiting glycogenolysis and it is suggested that they might do so by inhibiting release of glucagon from the pancreas.
Topics: Animals; Carbohydrate Metabolism; Diaphragm; Fasting; Glucagon; Glucose-6-Phosphatase; Glycogen; Hypoglycemic Agents; Insulin; Liver; Liver Glycogen; Rats; Tolbutamide
PubMed: 13460243
DOI: 10.1111/j.1476-5381.1957.tb00147.x -
Quarterly Bulletin. Northwestern... 1957
Topics: Carbutamide; Child; Diabetes Mellitus; Diabetes Mellitus, Type 1; Humans; Infant; Sulfanilamide; Sulfanilamides; Urea
PubMed: 13408442
DOI: No ID Found -
British Medical Journal Jan 1957
Topics: Blood Platelets; Carbutamide; Diabetes Mellitus; Leukocyte Count; Leukopenia; Sulfanilamide; Sulfanilamides; Thrombocytopenia; Urea
PubMed: 13383229
DOI: 10.1136/bmj.1.5012.199