Heterocyclic steroids-part-VI: Studies on the total syntheses of racemic A-nor-3-thiaestra-1,5(10),6,8,14-pentaen-17(e)-OL and A-nor-3-thiaestra-1,5(10),8,14-tetraen-17(e)-OL

4-Oxo-4,5,6,7-tetrahydrothianaphthene(I) is converted into racemic A-nor-3-thiaestra-1,5(10),6,8,14-pentaen-17(e)-01(IX) and A-nor-3-thiaestra-1,5(10),8,14-tetraen-17(e)-01 (VIII).     

Studies of novel pentacyclic heterocyclic steroids: Part XXI. Total synthesis of racemic benz[3,4]-6-oxaestra-1,3,5(10),8-tetraen-17 beta-ol

1-Oxo-4-oxa-1,2,3,4-tetrahydrophenanthrene is converted into racemic benz[3,4]-6-oxaestra-1,3,5(10),8-tetraen-17 beta-ol in 45% yield.     

Heterocyclic steroids-part ix: Studies on the total synthesis of racemic a-nor-5,7-bisthiabstra-1,5 (10), 8, 14-tetraen-17(e)-ol

1,6-Bisthia-4,5,6,7-tetrahydroinden-4-one (I) was converted to racemic A-nor-3,7-bisthiaestra-1,5 (10),8,14-tetraen-17(e)-o1 (VI).     

Heterocyclic steroids-part VIII: Studies on the total synthesis of racemic 2-phenyl-7-methyl-3-oxa-A-nor-14 beta-estra-1,5(10),6,8-tetraen-17 alpha-ol.

2-Phenyl-6-methyl-4-oxo-4,5,6,7-tetrahydrobenzofuran (II) is converted into racemic 2-phenyl-7-methyl-3-oxa-A-nor-14 beta-estra-1,5(10),6,8-tetraen-17 alpha-ol (VIII).     

Total synthesis of heterocyclic steroids,part VI. synthesis of (±)-3-methoxy-6-aza-12-thia-12-dioxo-B-nor-14β-estra-1,3, 5(10),8-tetraen-17α-OL

With 7-hydroxy-7a-methyl-4-oxo-cyclopenta(b)tetrahydrothiopyran-1-dioxide (III) as the CD part, the synthesis of the title compound (II) was achieved by the Fischer indole synthesis.     

Totally synthetic steroid heterocycles. Part X. Synthesis of racemic a-nor-3.16-dithia- and 2-methyl-a-nor-3-oxa-16-thia-d-homo-1, 5(10),8,14-estratetraen-17a-ols

As a part of synthetic modifications directed toward biologically active 16-thia-d-homoestrogens, synthesis of the title steroids via the Torgov-Wendler route is described.     

Total synthesis of heterocyclic steroids,part VII. Synthesis of (±)-8,13-diaza-3-thia-A-norgona-1,5(10)-dien-17-one

The total synthesis of (±)-8,13-diaza-3-thia-A-norgona-1,5(10)-dien-17-one (XII) was achieved starting from 2-(2-thienyl) ethylamine (VII) and 3-succinimidopropionyl chloride (IX) as the A and D ring precursors respectively.     

Formation of 5-[17beta-2H]androstene-3beta,17alpha-diol from 3beta-hydroxy-5-[17,21,21,21-2H]pregnen-20-one by the microsomal fraction of boar testis

After incubation of 3beta-hydroxy-5-[17,21,21,21-2H]-pregnen-20-one with the microsomal fraction of boar testis, the metabolites were analyzed by gas chromatography and gas chromatography-mass spectrometry. The following metabolites were identified: 3beta,17alpha-dihydroxy-5-[21,21,21-3H]pregnen-20-one, 3beta-hydroxy-5-androsten-17-one, 5-androstene-3beta,17beta-diol, and 5-[17beta-2H]androstene-3beta,17alpha-diol. The presence of a 2H atom at the 17beta position of 5-androstene-3beta,17alpha-diol was confirmed by oxidizing the steroid with 3beta-hydroxy-steroid dehydrogenase of Pseudomonas testosteroni to obtain 17alpha-hydroxy-4-[2H]androsten-3-one and then by oxidizing the latter steroid with chromic acid to obtain nonlabeled 4-androstene-3,17-dione. Among these metabolites, the first three can be interpreted to be synthesized by a well documented pathway, including 17alpha-hydroxylation followed by side chain cleavage as follows: 3beta-hydroxy-5-[17,21,21,21-2H]pregnen-20-one leads to 3beta,17alpha-dihydroxy-2-[21,21,212H]-pregnen-20-one leads to 3beta-hydroxy-5-androsten-17-one leads to 5-androstene-3beta,17beta-diol. On the other hand, 5-androstene-3beta,17alpha-diol, which contained a 2H atom at the 17beta position, is not likely to be synthesized via above mentioned pathway in which nonlabeled 3beta-hydroxy-5-androsten-17-one is formed as the first C19-steroid. It seems that an alternate side chain cleavage mechanism leading from pregnenolone to 17alpha-hydroxy-C19-steroid exists in boar testis.     

Synthesis of 3,6α,16α-trihydroxy-1,3,5(10)-estratrien-17-one 6-hemisuccinate and [6,73H]-3,16α-dihydroxy-1,3,5(10)-estratrien-17-one

The preparation of high specific activity ³H labeled 16α-hydroxyestrone and of the 6-hemisuccinate of the ketol metabolite of estradiol is described. The synthetic procedures which were required to produce these essential ingredients of a radioimmunoassay for 16α-hydroxyestrone required multistep syntheses because of the multifunctional and labile nature of the metabolite.     

Microbial transformation of 13-ethyl-3-methoxy-8,14-seco-gona-1,3,5(10),9(11)-tetraene-14, 17-dione to its 17-beta hydroxy derivative by Pichia farinosa in pilot plant fermentors

Parameters for microbial transformation of 13-ethyl-3-methoxy-8, 14-seco-gona-1,3,5 (10), 9(11)-tetraene-14,17-dione to its 17 beta-hydroxy derivative by P. farinosa have been standardised in pilot plant fermentors. The yield of the pure crystalline compound was 80%.     

Facile formation of hydrophilic derivatives of 5H-8,9-dimethoxy-5-[2-(N,N-dimethylamino)ethyl]-2,3-methylenedioxydibenzo[c,h] [1,6]naphthyridin-6-one (ARC-111) and its 12-aza analog via quaternary ammonium intermediates

Several new TOP1-targeting agents were prepared using as intermediates the N,N,N-trimethyl quaternary ammonium salts of either ARC-111 or its 12-aza analog (ARC-31), 3 and 4, respectively. Direct displacement of the quaternary ammonium group with water, imidazole, alkylethylenediamines, or polyhydroxylated alkylamines provides a convenient means for furthering the structure-activity relationships associated with these non-camptothecin TOP1-targeting agents.     

Synthesis of N3,5'-cyclo-4-(beta-D-ribofuranosyl)-vic-triazolo[4,5-b]pyridin-5-one and its 3'-deoxysugar analogue as potential anti-hepatitis C virus agents

We recently discovered a novel compound, identified as N3, 5-cyclo-4-(beta-D-ribofuranosyl)-vic-triazolo[4,5-b]pyridinin-5-one, with anti-hepatitis C virus (HCV) activity in vitro. The structure was confirmed by chemical synthesis from 2-hydroxy-5-nitropyridine. It showed anti-HCV activity with EC50= 19.7 microM in replicon cells. Its 3'-deoxy sugar analogue was also synthesized, but was inactive against HCV in vitro.     

1-[3-Aminobenzisoxazol-5'-yl]-3-trifluoromethyl-6-[2'-(3-(R)-hydroxy-N-pyrrolidinyl)methyl-[1,1']-biphen-4-yl]-1,4,5,6-tetrahydropyrazolo-[3,4-c]-pyridin-7-one (BMS-740808) a highly potent, selective, efficacious, and orally bioavailable inhibitor of blood coagulation factor Xa

Attempts to further optimize the pyrazole factor Xa inhibitors centered on masking the aryl aniline P4 moiety. Scaffold optimization resulted in the identification of a novel bicyclic pyrazolo-pyridinone scaffold which retained fXa potency. The novel bicyclic scaffold preserved all binding interactions observed with the monocyclic counterpart and importantly the carboxamido moiety was integrated within the scaffold making it less susceptible to hydrolysis. These efforts led to the identification of 1-[3-aminobenzisoxazol-5'-yl]-3-trifluoromethyl-6-[2'-(3-(R)-hydroxy-N-pyrrolidinyl)methyl-[1,1']-biphen-4-yl]-1,4,5,6-tetrahydropyrazolo-[3,4-c]-pyridin-7-one 6f (BMS-740808), a highly potent (fXa Ki=30 pM) with a rapid onset of inhibition (2.7x10(7) M-1 s-1) in vitro, selective (>1000-fold over other proteases), efficacious in the AVShunt thrombosis model, and orally bioavailable inhibitor of blood coagulation factor Xa.     

Synthesis, characterization, and anticonvulsant activity of enaminones. Part 5: Investigations on 3-carboalkoxy-2-methyl-2,3-dihydro-1H-phenothiazin-4[10H]-one derivatives

A new series of anticonvulsant 3-carboalkoxy-2-methyl-2,3-dihydro-1H-phenothiazin-4[10H]-ones is herein reported. 2-Aminothiophenols underwent cyclocondensation with 4-carboalkoxy-5-methylcyclohexane-1,3-diones in refluxing dimethylsulfoxide (DMSO) to yield 3-carboalkoxy-2-methyl-2,3-dihydro-1H-phenothiazin-4[10H]-ones, 4a–k. In the case of the carbo-tert-butoxy derivatives (4c and 4k) prolonged reaction times led to the isolation of the respective 3-unsubstituted-2-methyl-2,3-dihydro-1H-phenothiazin-4[10H]-ones (4l and 4m) instead. Significant anticonvulsant activity was displayed by these analogues, most particularly 4k, which was active at 30 mg/kg intraperitoneally (ip) in mice in the maximal electroshock seizure (MES) evaluation, with no toxicity noted at dosages up to 300 mg/kg. Oral (po) rat evaluation of 4k in the MES evaluation provided an ED₅₀ of 17.60 mg/kg, with no toxicity noted at dosages up to 500 mg/kg, providing a protective index (PI = TD₅₀/ED₅₀) > 28.40. These compounds represent the first reported series of phenothiazines which possess anticonvulsant activity.     

Design,synthesis, biological evaluation,homology modeling and docking studies of (E)-3-(benzo[d][1,3]dioxol-5-ylmethylene) pyrrolidin-2-one derivatives as potent anticonvulsant agents

A series of (E)-3-(benzo[d][1,3]dioxol-5-ylmethylene)pyrrolidin-2-one derivatives were designed, synthesized, and evaluated for their anticonvulsant activities. In the preliminary screening, compounds 5, 6a–6f and 6h–6i showed promising anticonvulsant activities in MES model, while 6f and 6g represented protection against seizures at doses of 100?mg/kg and 0.5?h in scPTZ model. The most active compound 6d had a high-degree protection against the MES-induced seizures with ED₅₀ value of 4.3?mg/kg and TD₅₀ value of 160.9?mg/kg after intraperitoneal (i.p.) injection in mice, which provided 6d in a high protective index (TD₅₀/ED₅₀) of 37.4 comparable to the reference drugs. Beyond that, 6d has been selected and evaluated in vitro experiment to estimate the activation impact. Apparently, 6d clearly inhibits the Na_v1.1 channel. Our preliminary results provide new insights for the development of small-molecule activators targeting specifically Na_v1.1 channels to design potential drugs for treating epilepsy. The computational parameters, such as homology modeling, docking study, and ADME prediction, were made to exploit the results.     

Gonadotropin release following oral delivery of luteinizing hormone-releasing hormone and its superactive analogue (des-Gly10 [D-Ala6] LHRH ethylamide) to 17β-oestradiol-primed coho salmon, Oncorhynchus kisutch (Walbaum)

The permeability of the coho salmon, Oncorhynchus kisutch (Walbaum), gut to orally administered LHRH and LHRHa (des-Gly¹⁰ [D-Ala⁶] LHRH ethylamide) was examined over a 360 min time-course. Both forms of LHRH were detected in the blood plasma of treated fish within 30 min of delivery. Retained biological activity of the absorbed LHRH was also assessed. Oral delivery of LHRH or LHRHa to 17β-oestradiol-primed coho resulted in a significant ( P < 0.01) release of gonadotropin (GtH) when compared to saline intubated, 17β-oestradiol-primed animals. The dose response of 17β-oestradiol-primed coho salmon to orally delivered LHRHa revealed that maximal GtH release occurred at doses between 2.0 and 20 μg LHRHa per g body weight.     

Novel antioxidant agents deriving from molecular combinations of vitamins C and E analogues: 3,4-dihydroxy-5(R)-[2(R,S)-(6-hydroxy-2,5,7,8-tetramethyl-chroman-2(R,S)-yl-methyl)-[1,3]dioxolan-4(S)-yl]-5H-furan-2-one and 3-O-octadecyl derivatives

Molecular combinations of two antioxidants (i.e., ascorbic acid and the pharmacophore of α-tocopherol), namely the 2,3-dihydroxy-2,3-enono-1,4-lactone and the chromane residues, have been designed and tested for their radical scavenging activities. When evaluated for their capability to inhibit malondialdehyde (MDA) production in rat liver microsomal membranes, the 3,4-dihydroxy-5R-2(R,S)-(6-hydroxy-2,5,7,8-tetramethylchroman-2(R,S)yl-methyl)-1,3]dioxolan-4S-yl]-5H-furan-2-one (11a–d), exhibited an interesting activity. In particular the 5R,2R,2R,4S and 5R,2R,2S,4S isomers (11c,d) displayed a potent antioxidant effect compared to the respective synthetic α-tocopherol analogue (5) and natural α-tocopherol or ascorbic acid, used alone or in combination. Moreover, the mixture of stereoisomers 11a–d also proved to be effective in preventing damage induced by reperfusion on isolated rabbit heart, in particular at the higher concentration of 300 μM. In view of these results our study represents a new approach to potential therapeutic agents for applications in pathological events in which a free radical damage is involved. Design, synthesis and preliminary biological activity are discussed.