Indole derivatives as a new class of steroid 5 alpha-reductase inhibitors

Small-molecule agents for treating skin diseases

Skin diseases are a class of common and frequently occurring diseases that significantly impact daily lives. Currently, the limited effective therapeutic drugs are far from meeting the clinical needs; most drugs typically only provide symptomatic relief rather than a cure. Developing small-molecule drugs with improved efficacy holds paramount importance for treating skin diseases. This review aimed to systematically introduce the pathogenesis of common skin diseases in daily life, list related drugs applied in the clinic, and summarize the clinical research status of candidate drugs and the latest research progress of candidate compounds in the drug discovery stage. Also, it statistically analyzed the number of publications and global attention trends for the involved skin diseases. This review might provide practical information for researchers engaged in dermatological drugs and further increase research attention to this disease area.

Indole based prostate cancer agents

Cancer weakens the immune system which fails to fight against the rapidly growing cells. Among the various types of cancers, prostate cancer (PCa) is causing greater number of deaths in men after lung cancer, demanding advancement to prevent, detect and treat PCa. Several small molecule heterocycles and few peptides are being used as oncological drugs targeting PCa. Heterocycles are playing crucial role in the development of novel cancer chemotherapeutics as well as immunotherapeutics. Indole skeleton, being a privileged structure has been extensively used for the discovery of novel anticancer agents and the application of indole derivatives against breast cancer is well documented. The present article highlights the usefulness of indole linked heterocyclic compounds as well as the fused indole derivatives against prostate cancer.

Advances in the design and discovery of drugs for the treatment of prostatic hyperplasia

INTRODUCTION

Benign prostatic hyperplasia (BPH) is a common medical problem in nearly 80% of geriatric male population severely affecting the quality of life. Several strategies has been suggested in the past for the management of BPH, but only α-blockers and 5α-reductase inhibitors are in clinical use. This review aims to give deep insight into advances in the design and discovery of newer chemical entities as 'druggable' molecule for the management of BPH.

AREAS COVERED

In this review, the authors cover various classes of drugs that have shown their potential for management of BPH. These drugs include α-adrenergic antagonists, 5α-reductase inhibitors, phytochemical agents, phosphodiesterase inhibitor, luteinizing hormone releasing hormone antagonists and muscarinic receptor antagonists. Literature searches were carried out using Google Scholar, SciFinder and PubMed.

EXPERT OPINION

The exact etiology of BPH is unknown; however, several mechanisms may be involved in the progression of the disease. Beside surgery and watchful waiting, medical therapies to treat BPH include α-adrenergic antagonist and 5α-reductase inhibitors. Phytotherapeutic agents are also used in some countries. Various other chemical classes of drugs are proposed for the treatment of the disease, but none of them have reached the clinic. Many classes of drugs are currently undergoing clinical trials such as phosphodiesterase inhibitors, luteinizing hormone releasing hormone antagonists and muscarinic receptor antagonists. The current need is to develop a potent, efficacious and highly selective drug for the treatment of BPH.

Sequential Reactions Promoted by Manganese: Completely Stereoselective Synthesis of (E)-α,β-Unsaturated Amides, Ketones, Aldehydes, and Carboxylic Acids

A complete E-selective synthesis of alpha,beta-unsaturated amides through a sequential reaction of a range of dichloroamides with a variety of aldehydes promoted by Rieke manganese (Mn*) is reported. A mechanism based on a sequential aldol-type reaction and a completely stereoselective beta-elimination is proposed to explain these results. The unsaturated amides obtained are readily and efficiently transformed into alpha,beta-unsaturated ketones, aldehydes, or carboxylic acids without loss of the diastereoisomeric purity of the C-C double bond.

Stereoselective synthesis of (E)-trisubstituted α,β-unsaturated amides and acids

Potassium alkoxides of N-acyl-oxazolidin-2-one-syn-aldols undergo stereoselective elimination reactions to afford a range of trisubstituted (E)-alpha,beta-unsaturated amides in >95% de, that may be subsequently converted into their corresponding (E)-alpha,beta-unsaturated acids or (E)-alpha,beta-unsaturated oxazolines in good yield. syn-Aldols derived from alpha,beta-unsaturated aldehydes gave their corresponding trisubstituted (E)-alpha,beta-unsaturated-amides with poorer levels of diastereocontrol, whilst there was a similar loss in (E)-selectivity during elimination of syn-aldols derived from chiral aldehydes. These elimination reactions proceed via rearrangement of the potassium alkoxide of the syn-aldol to a 1,3-oxazinane-2,4-dione enolate intermediate that subsequently eliminates carbon dioxide to afford a trisubstituted (E)-alpha,beta-unsaturated amide. The (E)-selectivity observed during the E1cB-type elimination step has been rationalised using a simple conformational model that employs a chair-like transition state to explain the observed stereocontrol.

Comparative pharmacophore development for inhibitors of human and rat 5-alpha-reductase

There are a number of diseases where the 5-alpha-reductase (5AR) enzyme is of therapeutic interest as a drug target. Currently the crystal structure for 5-alpha-reductase is unavailable, thus ligand-based pharmacophore techniques are beneficial in the drug development process. We have developed pharmacophores to aid inhibitor design for both human types I (preliminary) and II 5-alpha-reductase isozymes and also the rat type II isozyme. To our knowledge, these are the first published pharmacophores for inhibitors of the human type I and rat type II enzymes. A comparison between isozymes and the previously published human type II isozyme pharmacophore is also presented.

Novel lead generation through hypothetical pharmacophore three-dimensional database searching: discovery of isoflavonoids as nonsteroidal inhibitors of rat 5 alpha-reductase

A hypothetical pharmacophore of 5 alpha-reductase inhibitors was generated and served as a template in virtual screening. When the pharmacophore was used, eight isoflavone derivatives were characterized as novel potential nonsteroidal inhibitors of rat 5 alpha-reductase. This investigation has demonstrated a practical approach toward the development of lead compounds through a hypothetic pharmacophore via three-dimensional database searching.

4-(Benzoylindolizinyl)butyric acids; novel nonsteroidal inhibitors of steroid 5alpha-reductase. III

A novel series of indolizinebutyric acids with various benzoyl substituents was synthesized to develop nonsteroidal inhibitors of steroid 5alpha-reductase, and the structure-activity relationships in this series were studied. We previously reported the structure-activity relationships in a series of indolebutyric acids as well as the discovery of the novel nonsteroidal 5alpha-reductase inhibitor, FK143. We have now made other modifications to this compound to improve in vivo inhibitory activity. By altering the heterocyclic nucleus and changing the benzoyl substituent we have succeeded in identifying the strongly active compound, FK687, (S)-4-[1-[4-[[1-(4-isobutylphenyl)butyl]oxy]benzoyl]indolizin-3-yl]butyric acid, which displays strong in vitro inhibitory activity against the human enzyme and in vivo inhibitory activity against the castrated young rat model. This compound should be a useful agent for the treatment of benign prostatic hyperplasia.

N-substituted 4-(5-indolyl)benzoic acids. Synthesis and evaluation of steroid 5alpha-reductase type I and II inhibitory activity

The synthesis of N-alkyl and N-arylalkyl substituted 4-(5-indolyl)benzoic acid derivatives as inhibitors of steroid 5alpha-reductases is described. For the human type II isozyme a benzyl substituent (IC50 6.20 microM) and for the human type I isozyme a cyclohexanemethyl substituent (IC50 2.10 microM) on the indole nitrogen proved to be most efficacious, thus providing interesting leads for the development of drugs for the treatment of benign prostatic hyperplasia (BPH).

Indole and benzimidazole derivatives as steroid 5alpha-reductase inhibitors in the rat prostate

A novel series of indole and benzimidazole derivatives were synthesized and evaluated for their inhibitory activity of rat prostatic 5alpha-reductase. Among these compounds, 4-¿2-[1-(4,4'-dipropylbenzhydryl)indole-5-carboxamido]phenoxy¿buty ric acid (15) and its benzimidazole analogue 25 showed potent inhibitory activities for rat prostatic 5alpha-reductase (IC50 values of 9.6+/-1.0 and 13+/-1.5 nM, respectively), with the potency very close to that of finasteride. Compound 30, in which the moiety between the benzene ring and amide bond was replaced by quinolin-4-one ring, showed almost equipotent activity (IC50= 19+/-6.2nM) with the correspondent amide derivative 13. This result was consistent with the previous observation that the coplanarity of this moiety might contribute to the potent inhibitory activity.