Discovery of inhibitors of human renin with high oral bioavailability.

Knowledge of the sequence of a bioactive protein (angiotensinogen) and the availability of a natural product inhibitor lead (pepstatin) were the starting point for discovery of potent penta- and hexapeptide renin inhibitors. Study of the metabolism and disposition of these substances forced the discovery of simpler inhibitors leading to the discovery of oral activity in Terlakiren (22). Modification of physical properties led to the synthesis of aminopiperidine 30, which was identified by oral efficacy profiling. Structural modification to give enzymatic stability produced the bioavailable benzylsuccinate inhibitor 34. Its bioactive monomethylamine metabolite (35, CP-108,671) was subsequently found to have uniformly high oral bioavailability and activity in various species including primates.

Computer graphics modelling of human renin. Specificity, catalytic activity and intron-exon junctions.

A model has been constructed using computer graphics for human renin based on the sequence derived from that of the gene and the 3-dimensional structure defined at high resolution for other homologous aspartic proteinases. Human renin can adopt a 3-dimensional structure close to that of other aspartic proteinases, in which amino acids corresponding to intron-exon junctions in the gene are at surface regions in the 3-dimensional structure. As expected, the essential catalytic residues are retained and the nearby residue 304 is alanine as in the mouse sequence, supporting the idea that Asp 304 of other aspartic proteinases may contribute to the low pH of their optimal activity. There are interesting differences at subsite S3' which may contribute to the specificity of human renin. Certain residues at the surface of the enzyme adjacent to the active site cleft are unique to renins and may play a role in recognition and binding of angiotensinogen.

Structure-activity studies of configurationally rigid arylprostaglandins.

Potent, albeit nonselective, smooth-muscle stimulant activity has been previously reported for 16-phenoxy- and 17-phenylprostaglandins, a finding that led to the design and development of the tissue-selective uterine stimulant sulprostone. As an extension of this work, analogues incorporating the 16-phenoxy and 17-phenyl substituents into the rigid indanyl, tetrahydronaphthyl, dihydrobenzofuryl, and dihydrobenzopyranyl ring systems were prepared and evaluated for uterine stimulant activity in vitro and diarrheal effects in vivo. Since these cyclic groups, with the exception of the indanyl, contain a chiral center, both optical antipodes were prepared. These studies demonstrate that ring size, heteroatom, and absolute configuration at C-16 are important determinants for potency and selectivity.

N-(Methanesulfonyl)-16-phenoxyprostaglandincarboxamides: tissue-selective, uterine stimulants.

In an effort to develop tissue-selective prostaglandin analogues resistant to the metabolic inactivating pathways of the natural materials, hybrid compounds modified both at C-1 with a sulfonimide moiety and in the n-amylcarbinol side chain with substituted phenoxy groups were synthesized and evaluated in a variety of in vitro models. Several of these analogues exhibited potent, tissue-selective, uterine stimulant activity, a finding subsequently confirmed in clinical studies with one member of this series, N-(methanesulfonyl)-16-phenoxy-omega-tetranor-PGE2-carboxamide (CP-34089/ZK-57671, sulprostone).

Selective and potent analgetics derived from cannabinoids.

Based on the hypothesis that analgetic activity is a dissociable feature of the cannabinoid molecule, we examined modifications of the side chain, the phenolic moiety, and, most significantly, structures that lack the benzopyran functionality present in THC and (--)-9-nor-9 beta-hydroxyhexahydrocannabinol (HHC). A new grouping, the 1-methyl-4-phenylbutyloxy C-3 side chain, elaborates a unique lipopholic region. Replacement of the phenol substituent produced several derivatives which retain analgetic activity in the codeine potency range. Introduction of a weakly basic nitrogen at C-5 and deletion of the axial methyl group in the B ring, two structural changes forbidden by traditional cannabinoid SAR, resulted in a unique family of benzoquinolines with potent analgetic activity. The prototype of this series, levonantradol, exhibits potent and stereospecific analgetic and antiemetic activity.

Potent analgetics derived from 9-nor-9 beta-hydroxyhexahydrocannabinol.

Based on the report of morphine-like analgetic activity of 9-nor-9 beta-hydroxyhexahydrocannabinol (HHC), we undertook a study of structural modifications of the C-3 side chain of HHC to optimize the analgetic activity. We ultimately examined four distinct classes of side chains: (1) alkyl (la-lc), (2) arylalkyl (ld-lh), (3) alkoxy (li-lj) and (4) arylalkyloxy (lk-lo). Three of these derivatives (lb, lf, ll) possessed analgetic activity 10X morphine. These studies demonstrate that the C-3 side chain of HHC can be modified in a structure-dependent fashion to yield potent, nonopioid analgetics. In addition, the effect of the 1 methyl-4-phenylbutyloxy side chain is unique among the side chains examined.

A tissue-selective prostaglandin E2 analog with potent antifertility effects.

N-methanesulfonyl 16-phenoxy-omega-tetranor PGE2 is a prostaglandin analog which is markedly more tissue selective than PGE2. This compound is 10-30 times more potent than PGE2 in animal models which are considered relevant to antifertility effects in humans. In pharmacological tests which are believed to be predictive for side effects in humans, the compound has potency either equal to or less than that of PGE2.

Studies in antifertility agents: part XV.

PIP: Synthesis of hexa- and octa-hydrophenanthrene derivatives, specifically that of 1,2-trans-7-hydroxy-1-phenyl-1,2,3,4,9,10-hexahydrophenanthrene-2-carboxylic acid, are reported. 2 alternative methods of creating this compound are described in step-by-step detail, and diagrams depicting the chemical structures are provided. These hydrophenanthrene derivatives were synthesized to discover if, as do the related compounds cis-bisdehydrodoisynolic acid and cyclohexanecarboxylic acid, they exhibited marked estrogenic and postcoital antifertility control activities. Derivatives reported here were tested for their anti-implantation activity in mated albino rats; none of them prevents implantation at a 10-millig/kilog dose.^ieng

Studies in antifertility agents. 8. Seco steroids. 2. 5,6-Secoestradiol and some related compounds.

Three ring beta-secoestradiols, 2alpha,3beta- and 2beta,3beta-2-ethyl-3-(p-hydroxyphenyl)-6beta-methyl-trans-bicyclo[4.3.0]nonan-7beta-ols, have been synthesized and some of them shown to possess significant antiimplantation activity in rats.