Inhibitors of acyl-CoA:cholesterol acyltransferase. 1. Identification and structure-activity relationships of a novel series of fatty acid anilide hypocholesterolemic agents

Abstract

A series of fatty acid anilides was prepared, and compounds were tested for their ability to inhibit the enzyme acyl-CoA:cholesterol acyltransferase (ACAT) in vitro and to lower plasma total cholesterol and elevate high-density lipoprotein cholesterol in cholesterol-fed rats in vivo. The compounds reported were found to fall into two subclasses with different anilide SAR. For nonbranched acyl analogues, inhibitory potency was found to be optimal with bulky 2,6-dialkyl substitution. For alpha-substituted acyl analogues, there was little dependence of in vitro potency on anilide substitution and 2,4,6-trimethoxy was uniquely preferred. Most of the potent inhibitors (IC50 less than 50 nM) were found to produce significant reductions in plasma total cholesterol in cholesterol-fed rats. Additionally, in vivo activity could be improved significantly by the introduction of alpha,alpha-disubstitution into the fatty acid portion of the molecule. A narrow group of alpha,alpha-disubstituted trimethoxyanilides, exemplified by 2,2-dimethyl-N-(2,4,6-trimethoxyphenyl)dodecanamide (39), was found to not only lower plasma total cholesterol (-60%) in cholesterol-fed rats but also elevate levels of high-density lipoprotein cholesterol (+94%) in this model at the screening dose of 0.05% in the diet (ca. 50 mg/kg).

Structure-Activity Relationships of N-(3,5-Dimethoxy-4-n-octyloxycinnamoyl)-N'-(3,4-dimethylphenyl)piperazine and Analogues as Inhibitors of Acyl-CoA: Cholesterol O-Acyltransferase.

“…The Structure-Activity Relationships of Regions B and C The amide compounds CI-976 8,18,19) and FR129169 20) ( Fig. 2) are excellent ACAT inhibitors.…”

“…ACAT inhibitory activity decreased in the following order: amino (12)Ͼpiperazino (16)Ͼn-propylamino (11)Լn-butylamino (15)Ͼ Ͼethylamino (14)ϭn-butyl (7)Ͼ Ͼmethylamino (13). Further, ACAT inhibitory activity markedly increased with the introduction of methyl residues to the C-phenyl ring of 12 and 16 (17)(18)(19)(20). In particular, 19, which had a piperazino-linker in region B and methyl residues at positions 2 and 4 in the C-phenyl ring, significantly inhibited the elevation of plasma total cholesterol levels in rats given a high cholesterol diet when administered as a dietary admixture at a concentration of 0.1%.…”

“…Yakuchinone B (1), 17) CI-976 18) and YM750 21) were synthesized according to the previously described method in our laboratories. 4-tert-Butylphenylpiperazine, 2,6-dimethylphenylpiperazine, 3,4-dimethylphenylpiperazine, and 3,5-dimethylphenylpiperazine were prepared from bis(2-chloroethyl)-N-(ethoxycarbonyl)amine and corresponding anilines according to the procedure described by Mishani et al 44) a) In vitro ACAT inhibition was measured using microsomes isolated from rat livers, HepG2, or Caco2.…”

“…17) As shown in Chart 1, phenylalkylamides (11,(13)(14)(15) or anilides (12,17,18) were prepared by alkylation of 8, followed by amidation with appropriate phenylalkylamine or aniline by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) in CHCl 3 .…”

Inhibition of acyl-coenzyme A:cholesterol acyltransferase stimulates cholesterol efflux from macrophages and stimulates farnesoid X receptor in hepatocytes

“…Oleic acid anilide (OAA), a known ACAT inhibitor, was synthesized by one of the authors as described (Roth et al, 1992). [1-14 C]Oleoyl-CoA (56 Ci/mol) and [4-14 C]cholesterol (50 Ci/mol) were purchased from Amersham Biosciences (UK).…”