Preparation of (4,4-difluoro-1,2,3,4-tetrahydro-5H-1-benzazepin-5-ylidene)acetamide derivatives as novel arginine vasopressin V2 receptor agonists

Vasopressin and Its Analogues: From Natural Hormones to Multitasking Peptides

Human neurohormone vasopressin (AVP) is synthesized in overlapping regions in the hypothalamus. It is mainly known for its vasoconstricting abilities, and it is responsible for the regulation of plasma osmolality by maintaining fluid homeostasis. Over years, many attempts have been made to modify this hormone and find AVP analogues with different pharmacological profiles that could overcome its limitations. Non-peptide AVP analogues with low molecular weight presented good affinity to AVP receptors. Natural peptide counterparts, found in animals, are successfully applied as therapeutics; for instance, lypressin used in treatment of diabetes insipidus. Synthetic peptide analogues compensate for the shortcomings of AVP. Desmopressin is more resistant to proteolysis and presents mainly antidiuretic effects, while terlipressin is a long-acting AVP analogue and a drug recommended in the treatment of varicose bleeding in patients with liver cirrhosis. Recently published results on diverse applications of AVP analogues in medicinal practice, including potential lypressin, terlipressin and ornipressin in the treatment of SARS-CoV-2, are discussed.

Managing Nocturia in Frail Older Adults

This review discusses the available evidence in the current evaluation and treatment of nocturia in frail older adults. No evidence specifically evaluates the use of behavioral interventions in the treatment of the frail older adult with nocturia, but their use is supported in other cohorts. Behavioral modifications and optimal management of comorbidities remain the first-line treatment for all age groups and should be emphasized in the frail due to their favorable safety profile. No studies specific to the frail older adult support the use of pharmacotherapy. Some evidence exists for the efficacy of several agents in the older adult; however, this is difficult to extrapolate to the frail, and safety concerns abound. Desmopressin may be effective in the older adult, but a high risk of hyponatremia raises concerns for its safety, and therefore it is not recommended in the frail. α-Antagonists may have limited efficacy in men with known benign prostatic hyperplasia (BPH); they are relatively well tolerated, although the risk of orthostatic hypotension in the frail should be considered. β3-agonist trials suggest limited clinical utility. Antimuscarinics are not found to be useful in this cohort and are contraindicated in the frail older adult given the ability of antimuscarinics to cause cognitive impairment, delirium, and falls. No data examine the use of nonsteroidal anti-inflammatory drugs (NSAIDs) in the frail older adult. Additionally, the American Geriatrics Society Beers Criteria recommends against the use of muscarinics in those over the age of 75 years and therefore their use is not supported.

De Novo Synthesis of Benzannelated Heterocycles

Benzannelated heterocycles such as indoles and indazoles are prominent structural motifs found in natural products, pharmaceuticals and agrochemicals. For their synthesis, chemists traditionally either functionalize commercially available heterocycles or resort to transformations that make use of benzene-derived building blocks. Here, we report a powerful cascade reaction that enables the de novo construction of variously substituted indoles, indazoles, benzofurans and benzothiophenes from readily available bicyclo[3.1.0]hexan-2-ones. The transformation can be conducted under mild, non-anhydrous conditions. For the synthesis of indoles, mechanistic studies revealed that the electrocyclic ring-opening of the bicyclic ring-system and aromatization precedes the 3,3-sigmatropic rearrangement.

Synthesis and structure-activity relationships of amide derivatives of (4,4-difluoro-1,2,3,4-tetrahydro-5H-1-benzazepin-5-ylidene)acetic acid as selective arginine vasopressin V2 receptor agonists

A series of (4,4-difluoro-1,2,3,4-tetrahydro-5H-1-benzazepin-5-ylidene)acetamide derivatives was synthesized, and their structure-activity relationships were examined in order to identify potent and selective arginine vasopressin V(2) receptor agonists. Attempts to substitute other chemical groups in place of the 2-pyridilmethyl moiety of 1a led to the discovery that potent V(2) binding affinity could be obtained with a wide range of functional groups. This structural tolerance allowed for the manipulation of other attributes, such as selectivity against V(1a) receptor affinity or avoidance of the undesirable inhibition of cytochrome P450 (CYP), without losing potent affinity for the V(2) receptor. Some representative compounds obtained in this study were also found to decrease urine volume in awake rats.