Oxysterols: 27-hydroxycholesterol and its radiolabeled analog.

We describe a convenient and stereoselective route to the synthesis of 27-hydroxycholesterol. Also its radiolabeled analog, 22, 23 di [(3)H]-27-hydroxycholesterol with high specific radioactivity (55 Ci/mmol) was synthesized by this method. Julia condensation of steroidal 22-sulfone with aldehyde, led to the addition of the 23-27 carbon side chain building block to the steroid backbone. Formed in this reaction beta-hydroxysulfone moiety was reduced by sodium amalgam generate 22-23 unsaturated bond. Further reduction either by hydrogen or tritium furnished substrates for the synthesis of title compounds.

Trimethaphan versus sodium nitroprusside for the control of proximal hypertension during thoracic aortic cross-clamping: the effects on spinal cord ischemia.

Sodium nitroprusside (SNP) has been used to control the proximal hypertension associated with thoracic aortic cross-clamping (TACC) during thoracic aortic surgery. It worsens neurologic outcome, presumably by further decreasing distal arterial pressure and increasing cerebrospinal fluid (CSF) pressure, thereby worsening the spinal cord perfusion pressure (SCPP). Trimethaphan does not increase CSF pressure. Therefore, the present study investigates the effect of trimethaphan versus SNP to control proximal hypertension during TACC on neurologic outcome. Two groups, each with eight mongrel dogs, were studied. All animals underwent descending TACC for 45 min. The mean proximal aortic blood pressure was maintained at 95-100 mm Hg by the use of SNP or trimethaphan. Distal aortic pressure was allowed to vary. The dogs were neurologically evaluated 24 and 48 h later by a blinded observer. During cross-clamping, there was no difference in mean proximal aortic pressure between groups. After 10 min of cross-clamping, distal aortic pressure was higher (P < 0.01), CSF pressure was lower (P < 0.01), and SCPP was higher (P < 0.005) in the trimethaphan group as compared with the SNP group (group effect). Neurologic outcome as assessed by Tarlov's score was better at 24 and 48 h in the trimethaphan group (P < 0.05). Histopathologic injury trended with worsened neurologic outcome. We conclude that 1) trimethaphan produced higher SCPP than SNP, and 2) neurologic outcome was better in the trimethaphan group.

Aminoalkylindoles: structure-activity relationships of novel cannabinoid mimetics.

Aminoalkylindoles (AAIs) are a novel series of cannabinoid receptor ligands. In this report we disclose the structural features of AAIs which are important for binding to this receptor as measured by inhibition of binding of [3H]Win 55212-2 (5). Functional activity in the mouse vas deferens is also noted and used to distinguish agonists from potential antagonists. The key structural features for potent cannabinoid activity in this series are a bicyclic (naphthyl) substituent at the 3-position, a small (H) substituent at the 2-position, and an aminoethyl (morpholinoethyl) substituent at the 1-position. A 6-bromo analog, Win 54461 (31), has been identified as a potential cannabinoid receptor antagonist. Modeling experiments were done to develop a pharmacophore and also to compare AAI structures with those of classical cannabinoids. The fact that the cannabinoid AAIs arose out of work on a series of cyclooxygenase inhibitors make sense now that an endogenous cannabinoid ligand has been identified which is a derivative of arachidonic acid. Because of their unique structures and physical properties, AAIs provide useful tools to study the structure and function of the cannabinoid receptor(s).

Aminoalkylindole binding in rat cerebellum: selective displacement by natural and synthetic cannabinoids.

A binding assay for WIN 55212-2, an aminoalkylindole (AAI) with antinociceptive activity in rodents, is described. [3H]WIN 55212-2 bound to rat cerebellar membranes with a Kd of 2 nM and a maximum binding of 1.2 pmol/mg of protein. Specific binding in this filtration assay was greater than 90%, saturable, reversible, stereospecific, pH sensitive and heat labile. Binding was decreased by Na+, K+, Li+ and nonhydrolyzable analogs of GTP and increased by Mg++ and Ca++. The density of specific binding sites varied throughout the central nervous system with the highest found in the cerebellum, hippocampus and striatum and the lowest in the medulla/pons and spinal cord. The binding affinities of other AAIs for the WIN 55212-2 binding site correlated with their potencies for inhibiting neuronally stimulated contractions in the isolated mouse vas deferens. Of more than 60 compounds representing recognized neurotransmitter systems, only cannabinoids effectively inhibited binding. The effect of cannabinoids on AAI binding was consistent with competitive inhibition and suggests that AAI activity may be mediated in whole or in part by interaction with cannabinoid receptors. AAIs appear to represent a structurally novel class of compounds with which to study cannabinoid receptors.

Conformationally restrained analogues of pravadoline: nanomolar potent, enantioselective, (aminoalkyl)indole agonists of the cannabinoid receptor.

Pravadoline (1) is an (aminoalkyl)indole analgesic agent which is an inhibitor of cyclooxygenase and, in contrast to other NSAIDs, inhibits neuronally stimulated contractions in mouse vas deferens (MVD) preparations (IC50 = 0.45 microM). A number of conformationally restrained heterocyclic analogues of pravadoline were synthesized in which the morpholinoethyl side chain was tethered to the indole nucleus. Restraining the morpholine diminished the ability of these pravadoline analogues to inhibit prostaglandin synthesis in vitro. In contrast, mouse vas deferens inhibitory activity was enhanced in [2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl] pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-(4-methoxyphenyl)methano ne (20). Only the R enantiomer of 20 was active (IC50 = 0.044 microM). An optimal orientation of the morpholine nitrogen for MVD inhibitory activity within the analogues studied was in the lower right quadrant, below the plane defined by the indole ring. A subseries of analogues of 20 and a radioligand of the most potent analogue, (R)-(+)-[2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]pyrrolo [1,2,3-de]-1,4-benzoxazin-6-yl](1-naphthalenyl)methanone (21) were prepared. Inhibition of radioligand binding in rat cerebellar membranes was observed to correlate with functional activity in mouse vas deferens preparations. Binding studies with this ligand (Win 55212-2) have helped demonstrate that the (aminoalkyl)indole binding site is functionally equivalent with the CP-55,940 cannabinoid binding site. These compounds represent a new class of cannabinoid receptor agonists.

Antinociceptive (aminoalkyl)indoles.

The (aminoalkyl)indole (AAI) derivative pravadoline (1a) inhibited prostaglandin (PG) synthesis in mouse brain microsomes in vitro and ex vivo and exhibited antinociceptive activity in several rodent assays. In vitro structure-activity relationship studies of this new class of PG synthesis inhibitors revealed a correspondence in three respects to those reported for the arylacetic acids: (1) "alpha-methylation" caused an increase in PG inhibitory potency, (2) the (R)-alpha-methyl isomer was more active than the S isomer, (3) the hypothesized aroyl group conformation of the 2-methyl derivatives corresponded to the proposed and reported "active" conformations of the aroyl and related aromatic acetic acid derivatives. The 1H NMR chemical shift of the C-4 hydrogen of pravadoline in comparison to the deshielding seen with 50, which lacks a substituent at C-2, suggested that the carbonyl group of pravadoline is located near C-2 but is located near C-4 in 50. Associated with this conformational change of the carbonyl group of 1a is a diminution of PG synthetase inhibitory activity. The results of UV and difference nuclear Overhauser studies of the two compounds were consistent with these conformational assignments. The low eudismic ratios of the alpha-methyl derivatives and the observation that the side chain may be extended by three methylene groups without significant loss of PG inhibitory potency suggests that this class of inhibitors bound less strongly and less selectively to the active site of PG synthetase than do the arylacetic acids. Two AAIs, 1a and 30, were found to be metabolized to the corresponding acetic acid derivatives, both of which inhibited PG synthesis. An exception to the observation that the antinociceptive activity of the AAIs was associated with PG synthetase inhibitory activity was the 1-naphthoyl derivative 67 since neither it nor its acetic acid metabolite 74 inhibited PG synthesis. Yet 67 was antinociceptive in four different rodent assays. This naphthoyl derivative, like opioids, also inhibited electrically stimulated contractions in the mouse vas deferens (MVD) preparation. Unlike opioids, however, the inhibition was not antagonized by naloxone. A subseries of AAIs was identified, of which 67 was prototypic. These compounds lacked PG synthetase inhibitory activity, but their inhibitory potency in MVD preparations correlated roughly with their antinociceptive potency in vivo. Pravadoline was also inhibitory in the MVD. Its antinociceptive activity, therefore, may be a consequence of both its PG synthetase inhibitory potency and another antinociceptive mechanism, the latter associated with its inhibitory potency in the MVD.(ABSTRACT TRUNCATED AT 400 WORDS)

Antiandrogenic steroidal sulfonylpyrazoles.

The steroidal sulfonylpyrazole 1 bound to the rat ventral prostate androgen receptor in vitro; it inhibited testosterone propionate induced increases in ventral prostate weight in vivo in the castrated, immature male rat with an ED50 of 15 mg/kg po. Compound 1 lacked androgenic activity in vivo in contrast to the parent steroidal pyrazole 5, which was both androgenic and antiandrogenic. The 2'- and 5'-methylsulfonyl isomers 6 and 6a did not bind to the androgen receptor. Introduction of an alkylsulfonyl at the N-1'-position has served, therefore, to isolate the intrinsic antiandrogenic properties of the steroidal heterocycle free of apparent hormone agonist properties. Structure-activity relationship studies revealed that a methylsulfonyl group at N-1' together with a C-17 alpha-substituent were the optimal combination for in vitro androgen receptor binding, in vivo antiandrogenic potency, and a lack of androgenic activity.