Regio- and Stereospecific Syntheses of syn- and anti-1,2-Imidazolylpropylamines from the Reaction of 1,1‘-Carbonyldiimidazole with syn- and anti-1,2-Amino Alcohols

The Direct Conversion of α-Hydroxyketones to Alkynes

Alkynes are highly important functional groups in organic chemistry, both as part of target structures and as versatile synthetic intermediates. In this study, a protocol for the direct conversion of α-hydroxyketones to alkynes is reported. In combination with the variety of synthetic methods that generate the required starting materials by forming the central C-C bond, it enables a highly versatile fragment coupling approach toward alkynes. A broad scope for this novel transformation is shown alongside mechanistic insights. Furthermore, the utility of our protocol is demonstrated through its application in concert with varied α-hydroxyketone syntheses, giving access to a broad spectrum of alkynes.

A room temperature copper catalyzed N-selective arylation of β-amino alcohols with iodoanilines and aryl iodides

An efficient method is described for the synthesis of N-(2-aminophenyl)-2-hydroxyethylamines via a copper catalyzed N-selective arylation of β-amino alcohols with iodoanilines. The corresponding coupling products are useful intermediates for the synthesis of a variety of N-2-hydroxyethyl-substituted benzimidazoles, benzimidazolones, and iminobenzimidazoles. We found that 2-iodoaniline only arylates certain amino alcohols but not amines lacking a hydroxyl group. We also demonstrate the arylation of sterically demanding β-amino alcohols, such as ephedrine and prolinol with aryl iodides at room temperature.

Synthesis of novel ursolic acid heterocyclic derivatives with improved abilities of antiproliferation and induction of p53, p21waf1 and NOXA in pancreatic cancer cells

A series of new heterocyclic derivatives of ursolic acid 1 were synthesized and evaluated for their antiproliferative activity against AsPC-1 pancreatic cancer cells. Compounds 24-32, with an α,β unsaturated ketone in conjugation with an heterocyclic ring in ring A have improved antiproliferative activities. Compound 32 is the most active compound with an IC(50) of 1.9 μM which is sevenfold more active than ursolic acid 1. Compound 32 arrests cell cycle in G1 phase and induces apoptosis in AsPC-1 cells with upregulation of p53, p21(waf1) and NOXA protein levels.

Semisynthetic ursolic acid fluorolactone derivatives inhibit growth with induction of p21(waf1) and induce apoptosis with upregulation of NOXA and downregulation of c-FLIP in cancer cells

A series of ursolic acid ((1S,2R,4aS,6aR,6aS,6bR,8aR,10S,12aR,14bS)-10-hydroxy-1,2,6a,6b,9,9,12a-heptamethyl-2,3,4,5,6,6a,7,8,8a,10,11,12,13,14b-tetradecahydro-1H-picene-4a-carboxylic acid) derivatives with a 12-fluoro-13,28β-lactone moiety were synthesized using the electrophilic fluorination reagent Selectfluor. The antiproliferative effects of these novel compounds were evaluated in AsPC-1 pancreatic cancer cells, and the structure-activity relationships (SARs) were evaluated. Of the compounds synthesized, ursolic acid derivatives carrying a heterocyclic ring, such as imidazole or methylimidazole, and cyanoenones were among the more potent inhibitors of AsPC-1 pancreatic cancer cell growth. 2-Cyano-3-oxo-12α-fluoro-urs-1-en-13,28β-olide, compound 20, was the most effective inhibitor with IC(50) values of 0.7, 0.9 and 1.8 μM in pancreatic cancer cell lines AsPC-1, MIA PaCa-2 and PANC-1, respectively. This compound also exhibited better antiproliferative activities against breast (MCF7), prostate (PC-3), hepatocellular (Hep G2) and lung (A549) cancer cell lines, with IC(50) values lower than 1 μM. The mechanism of action by which these compounds exert their biological effect was evaluated in AsPC-1 cells using the most potent inhibitor synthesized, compound 20. At 1 μM, the cell cycle arrested at the G1 phase with upregulation of p21(waf1). Apoptosis was induced at an inhibitor concentration of 8 μM with upregulation of NOXA and downregulation of c-FLIP. These data indicate that fluorolactone derivatives of ursolic acid have improved antiproliferative activity, acting through arrest of the cell cycle and induction of apoptosis.

Synthesis of novel C17 steroidal carbamates. Studies on CYP17 action, androgen receptor binding and function, and prostate cancer cell growth

We have exploited the reaction of 1,1'-carbonylbis(2-methylimidazole) (CBMI) with several 17beta-hydroxy androstanes to synthesize a series of novel C17 steroidal carbamates. Structural elucidation features have been provided for the final compounds based on 1D and 2D NMR techniques, IR spectroscopy, and related literature. The new compounds were tested for inhibition of human cytochrome 17alpha-hydroxylase-C17,20-lyase (CYP17) and androgen receptor (AR) binding and function effects. Their inhibitory potential against PC-3 cell proliferation was also evaluated. Compounds 11 and 23 were found to inhibit CYP17 with IC50 values of 17.1 and 11.5 microM, respectively. The carbamate moiety at C17 allowed tight binding of the synthesized compounds to both wild-type (wt-) and mutated AR. When bound to the mutated AR, the compounds were found to have a dual effect, stimulating transcription at low concentrations while almost fully blocking it at the higher concentrations tested, in the presence of the natural androgen dihydrotestosterone (DHT). Compounds 8 and 12 were the most active against PC-3 cell proliferation with EC50 values of 2.2 and 0.2 microM, respectively.

N,N‘-Carbonyldiimidazole-Mediated Cyclization of Amino Alcohols to Substituted Azetidines and Other N-Heterocycles

Amino alcohols are important synthons for N-heterocycles. We have developed an efficient method to activate hydroxyl groups, which avoids the use of toxic reagents and tolerates a wide variety of functional groups. Our strategy has been applied to the synthesis of functionalized p-methoxyphenyl-protected azetidines, pyrrolidines, and piperidines. The required amino alcohols were synthesized according to an optimized proline-catalyzed Mannich protocol. An azetidine analogue of ezetimibe was synthesized to demonstrate the potential for the synthesis of drug-like molecules.

3-[6-(2-Dimethylamino-1-imidazol-1-yl-butyl)-naphthalen-2-yloxy]-2,2-dimethyl-propionic acid as a highly potent and selective retinoic acid metabolic blocking agent

3-[6-(2-Dimethylamino-1-imidazol-1-yl-butyl)-naphthalen-2-yloxy]-2,2-dimethyl-propionic acid and analogs were designed and synthesized as highly potent and selective CYP26 inhibitors, serving as retinoic acid metabolic blocking agents (RAMBAs), with demonstrated in vivo efficacy to increase the half-life of exogenous atRA.

Potent and selective [2-imidazol-1-yl-2-(6-alkoxy-naphthalen-2-yl)-1-methyl-ethyl]-dimethyl-amines as retinoic acid metabolic blocking agents (RAMBAs)

A series of [2-imidazol-1-yl-2-(6-alkoxy-naphthalen-2-yl)-1-methyl-ethyl]-dimethyl-amines were designed and synthesized as CYP26 inhibitors, serving as retinoic acid metabolic blocking agents (RAMBA's).