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Metabolites in the kynurenine pathway, generated by tryptophan degradation, are thought to play an important role in neurodegenerative disorders, including Alzheimer's and Huntington's diseases. In these disorders, glutamate receptor-mediated excitotoxicity and free radical formation have been correlated with decreased levels of the neuroprotective metabolite kynurenic acid. Here, we describe the synthesis and characterization of JM6, a small-molecule prodrug inhibitor of kynurenine 3-monooxygenase (KMO). Chronic oral administration of JM6 inhibits KMO in the blood, increasing kynurenic acid levels and reducing extracellular glutamate in the brain. In a transgenic mouse model of Alzheimer's disease, JM6 prevents spatial memory deficits, anxiety-related behavior, and synaptic loss. JM6 also extends life span, prevents synaptic loss, and decreases microglial activation in a mouse model of Huntington's disease. These findings support a critical link between tryptophan metabolism in the blood and neurodegeneration, and they provide a foundation for treatment of neurodegenerative diseases., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Efficient radical cyclization of alkyl iodides to various aromatic systems including pyrrole, indole, isoquinolone, pyridone, and benzene, mediated by dicumyl peroxide, is described. The methodology was used to provide access to 5,6,8,9,10,11-hexahydroindolo[2,1-a]isoquinoline derivatives.

The (-)-S isomer of 5-benzoyl-1,2-dihydro-3H-pyrrolo[1,2-alpha]pyrrole-1-carboxylic acid is about 60 times more potent than the (+)-R isomer in the carrageenan edema test and ca. 230 times more active than the (+)-R isomer in the mouse phenylquinone writhing assay.

The synthesis of several 3-alkylamino-2-hydroxypropyl heteroaryl ethers (13-15, 17, and 18) is described. These compounds were prepared by the alkylamination of the corresponding glycidyl ethers (6-8, 10, and 11), which in turn were obtained from the requisite heteroaryl halides and the sodium salt of glycidol. The above basic ethers exhibited beta-blocking activity, but the potency of the tested compounds was considerably less than that of propanolol. Only 3-tert-butylamino-2-hydroxyl-1-(1,2,4-thiadiazol-5-yl) propyl ether (13) showed some selective myocardial beta-blocking activity.

In order to improve the modest oral activity of PGE2 as an inhibitor of gastric acid secretion, analogs were prepared and tested orally in histamine-challenged rats. Insertion of a double bond at C-4, resulting in the 4,5-allene analog of PGE1, gave a small increase in activity. Introduction of the omega-tetranor-16-phenoxy lower sidechain, a modification known to enhance activity in the PGF series, gave an eight-fold increase in activity. The analog having both modifications (enprostil, 2) showed a six hundred-fold increase in oral antisecretory activity over PGE2, which may reflect a potentiation effect. Modification of enprostil at C-1 (various esters) and at C-11 (11-methyl, 11-deoxy) generally resulted in compounds of high activity while modifications at other sites generally resulted in significant reductions in activity.

5-Acyl-1,2-dihydro-3H-pyrrolo[1,2-a]pyrrole-1-carboxylic acids and the homologous pyridine and azepine derivatives were synthesized and assayed for antiinflammatory and analgesic activity. 5-Benzoyl-1,2-dihydro-3H-pyrrolo-[1,2-a]pyrrole-1-carboxylic acid and the corresponding p-methoxy compound 74 were selected for evaluation as analgesic agents in humans on the basis of their high potency in the mouse phenylquinone writhing assay as well as on their minimal liability to elicit gastrointestinal erosion in rats on chronic administration. Extensive quantitative structure-activity relationship (QSAR) studies of the benzoylpyrrolopyrrolecarboxylic acids have demonstrated that the analgesic (mouse writhing) and antiinflammatory (rat carrageenan paw) potencies of these compounds are satisfactorily correlated with the steric and hydrogen-bonding properties of the benzoyl substituent(s). The 4-vinylbenzoyl compound 95, which was correctly predicted to be highly active in both assays on this basis, is undergoing advanced pharmacological evaluation in animals as a potential antiinflammatory agent.

11-Deoxy-11 alpha,12 alpha-methanoprostaglandin E2 (1b) and the corresponding methyl ester 7a were highly potent, but short acting, bronchodilators both by the intravenous (80 and 10 times PGE2, respectively) and aerosol (2 and approximately 1 times PGE2) routes, as measured by the Konzett-Rössler assay. The 11 beta,12 beta-methano compound 15a was two orders of magnitude less active than 7a. In rhesus monkeys anesthetized by aerosol administration, 1b was 10-50% as potent as, and had a duration of action similar to, PGE1 in the inhibition of methacholine-induced increases in airway resistance. At doses effective in preventing the methacholine response, 1b increased the heart rate (less than or equal to 30%) and precipitated mild upper airway irritation.

The synthesis and activity in the spontaneously hypertensive rat of several 4-(1,2,3,4-tetrahydronaphthyl-2-amino)-1-(4-fluorophenyl)-1-but anones is reported. Maximal antihypertensive activity was associated with 5,6-dimethoxy substitution in the aminotetralin moiety.

The synthesis of nine mono- and difluoro prostaglandins XIII, XV, XXIV, XXVII, XXXII, XXXVIII, XLV, LI and LIV, and two monochloro prostaglandins LVII and LXI, from appropriately protected derivatives of natural PGF2 is described.

5-Aroyl-6-substituted-1,2-dihydro-3H-pyrrolo[1,2-a]pyrrole-1-carbo xylic acids were synthesized and assayed for analgesic and antiinflammatory activity. Several of these compounds, notably the 5-(4-fluoro- and 4-chlorobenzoyl)-6-methyl derivatives 25 and 26 and the 5-(4-methyl-, 4-fluoro-, 4-chloro-, and 4-methoxybenzoyl)-6-chloro congeners 31-34 were of equal or greater potency than indomethacin as antiinflammatory and analgesic agents both in acute and chronic animal models.

Acetic acid derivatives of tricyclic systems, such as 6,11-dihydro-11-oxodibenzo[b,e]thiepin, 4,10-dihydro-4-oxo-thieno[2,3-c][1]benzothiepin, dibenzo[b,f]thiepin, dibenz[b,f]oxepin, etc., were synthesized and assayed for antiinflammatory activity. One of the compounds, 6,11-dihydro-11-oxodibenzo[b,e]thiepin-3-acetic acid (52), was chosen for evaluation in man on the basis of high antiinflammatory activity in both short- and long-term animal assays and a low gastric irritation liability in rats and dogs.

5-Aroyl-6-(methylthio)-1,2-dihydro-3H-pyrrolo[1,2-a]pyrrole-1-carb oxylic acids and 1-methyl-4-(methylthio)-5-aroylpyrrole-2-acetic acids were synthesized and assayed as antiinflammatory and analgesic agents. The majority of these compounds exhibit a surprisingly low level of antiinflammatory activity (rat carrageenan paw) but have considerable potency as analgesics (mouse phenylquinone writing). For example, the p-tolyl-substituted bicyclic and monocyclic compounds 44 and 58 are 301 and 66 times more potent than aspirin (mouse writhing) but only 3.4 and 1.5 times more potent than phenylbutazone in the antiinflammatory screen (rat paw).