Pyrrolo[1',2':1,2]imidazo[4,5-b]pyridines, pyrrolo- [2',1':2,3]imidazo[4,5-c]pyridines and pyrrolo[2,1-f]purines as potential benzodiazepine ligands

The synthesis of some 7,8,8a,9-tetrahydro-6H-pyrrolo[1',2':1,2]imidazo[4,5-b]pyridin-6-ones, 5,5a,6,7-tetrahydro-8H-pyrrolo[2',1':2,3]imidazo[4,5-c]pyridin-8-ones and 7,8,8a,9-tetrahydro-6H-pyrrolo[2,1-f]purin-6-ones is reported. The structure of the obtained compounds has been assigned by means of 1H-NMR spectra assisted by NOESY measurements. In addition, the ability to displace [3H]-flunitrazepam binding from rat brain membranes is determined. Only the pyrrolopurine derivative 5d binds to the benzodiazepine receptor (BZR) with appreciable potency.     

Studies on substances with antiblastic activity. IX. Anthramycin and analogs. IX. Synthesis of 7-methoxy-8-hydroxy-10,11-dihydro-5H-pyrrolo[2,1-c] [1,4] benzodiazepine and other compounds related to oxotomaymycin

The synthesis of some pyrrolobenzodiazepine derivatives related to oxotomaymycin, an antibiotic recovered together with tomaymycin from fermentation broths of Streptomyces achromogenes var. tomaymycetics, is described. Reaction between 2-nitro-4-benzyloxy-5-methoxybenzylbromide and pyrrole-2-carboxyaldehyde afforded 1-(2-nitro-4-benzyloxy-5-methoxybenzyl)pyrrole-2-carboxyaldehyde. Catalytic reduction of this compound with hydrogen in the presence of Pd/C gave 10,11-dihydro-8-hydroxy-7-methoxy-5H-pyrrolo[2.1-c] [1,4]benzodiazepine. Amides obtained from condensation between 2-nitro-4-benzyloxy-5-methoxybenzoic acid chloride and proline or hydroxyproline were reduced catalytically to 2,3-dihydro-8-hydroxy-7-methoxy-1H-pyrrolo [2,1-c] [1,4]benzodiazepine-5,11 (10H, 11aH)-dione and its 2-hydroxyderivative respectively. The synthesis of 10,11-dihydro-8-hydroxy-9-methoxy-5-pyrrolo [2,1-c] [1,4]benzodiazepine is also reported.     

Studies on quinazolines and 1,2,4-benzothiadiazine 1,1-dioxides. 8.1, 2 synthesis and pharmacological evaluation of tricyclic fused quinazolines and 1,2,4-benzothiadiazine 1,1-dioxides as potential alpha1-adrenoceptor antagonists

A series of 2-substituted methyl 2,3-dihydroimidazo[1, 2-c]quinazolin-5(6H)-ones (4), 3-substituted methyl 2, 3-dihydroimidazo[1,2-c]quinazolin-5(6H)-ones (5), 3-substituted methyl 2,3-dihydro-5H-thiazolo[2,3-b]quinazolin-5-ones (15a,b), 3-substituted methyl 2,3-dihydroimidazo[2,1-b]quinazolin-5(1H)-ones (16a,b), 3-substituted methyl 2,3-dihydro-1H-imidazo[1,2-b][1,2, 4]benzothiadiazine 5,5-dioxides (33a,b), 2-substituted methyl imidazo[1,2-c]quinazolin-5(6H)-ones (42-45a,b), 3-substituted methyl imidazo[1,2-c]quinazolin-5(6H)-ones (50-53a,b), 3-substituted methyl 5H-thiazolo[2,3-b]quinazolin-5-ones (55-56a,b), and 3-substituted methyl 5-(methylthio)-2,3-dihydroimidazo[1,2-c]quinazoline (57) were synthesized as compound 1conformational rigid congeners for pharmacological evaluation as potential alpha1-adrenoceptor antagonists. Compounds 4, 5, 33a,b, 44a,b, 45a,b, 52a,b, 53a,b, and 57 were found to possess high affinity for the alpha1-adrenoceptor. Compounds 5 and 57 were the most highly selective and potent alpha1 antagonists with Ki = 0.21 +/- 0.02 and 0.90 +/- 0.08 nM, respectively. The S-enantiomers of these two compounds (Ki = 0.13 +/- 0.01 nM for (S)-(-)-5; Ki = 1.0 +/- 0.2 nM for (S)-(+)-57) were 144-200-fold more potent than the R-enantiomers (Ki = 26 +/- 8 nM for (R)-(+)-5; Ki = 144 +/- 23 nM for (R)-(-)-57). Compound 4 showed 8-fold higher affinity to alpha1A-AR better than alpha1B-AR. These compounds possessed weak to no activity against the 5-HT1A receptor.     

Synthesis of allyl O-[sodium(alpha-D-glycero-D-talo-2- octulopyranosyl)onate]-(2-->6)-2-acetamido-2-deoxy-beta-D-glucopyranosi de, a core constituent of the lipopolysaccharide from Acinetobacter calcoaceticus NCTC 10305

Reaction of methyl 2,6-anhydro-2,3-dideoxy-D-manno-2-octenoate 1 with 3-chloroperoxybenzoic acid gave the 2,3-anhydro derivative 2, which was converted into the per-O-acetylated anomeric methyl glycosides of D-glycero-D-galacto-2-octulopyranosylonic acid in good yield. Subsequent inversion of the configuration at C-3 and deprotection afforded sodium (methyl beta-D-glycero-D-talo-2-octulopyranosid)onate. Alternatively, 2 was transformed into methyl (alpha-D-glycero-D-talo-2- octulopyranosyl bromide(onate derivatives. Reaction with methanol or allyl 2-acetamido-2-deoxy- 3,4-O-(1,1,3,3-tetraisopropyldisiloxan-1,3-diyl)-beta-D-g lycopyranoside, promoted by silver triflate, gave good yields of the corresponding orthoester derivatives. Me3Si triflate-catalyzed orthoester rearrangement and removal of the protecting groups afforded sodium O-(methyl alpha-D-glycero- D-talo-2-octulopyranosid)onate and the disacchanide, allyl O-[sodium(alpha-D-glycero-D-talo-2- octulopyranosyl)onate]-(2-->6)-2-acetamido-2-deoxy-beta-D-gl ucopyranoside in high yield.     

Selective inhibition of cyclic AMP-dependent protein kinase by isoquinoline derivatives

A large series of isoquinoline derivatives was synthesised including derivatives of isoquinoline, isoquinolino[3,4-c]furazan, 1,2-dihydro-1-oxoisoquinoline, 6-oxopyrimido[1,2-d]isoquinoline, benzo[c][1,8]-naphthyridine, pyrazino[2,3-c]isoquinoline and benzimidazo[2,1-a]isoquinoline as well as further structurally related isoquinoline derivatives and pyrido-2,3-furazans. Representatives of all of these classes of isoquinolines are potent and selective inhibitors of the cyclic AMP-dependent protein kinase (PKA) catalytic subunit (cAK) from rat liver. The most effective cAK inhibitors are a series of 1,3-di-substituted and 1,3,4-tri-substituted isoquinolines (IC50 values 30-50 nM) (compounds A1, A2, A3, A4 and A5) and 2-ethylcarboxy-3-amino-5,6-dihydro-6-oxobenzo[c] [1,8]naphthyridine (E1) (IC50 0.08 microM). Compounds A1-A5 inhibit cAK in a fashion that is competitive with respect to ATP as substrate. The isoquinoline inhibitors A1-A5 are ineffective or very poor inhibitors of wheat embryo Ca(2+)-dependent protein kinase (CDPK) and rat brain Ca(2+)-dependent protein kinase C (PKC), chicken gizzard myosin light chain kinase (MLCK) and potato tuber cyclic nucleotide-binding phosphatase (Pase). E1 is a moderately effective inhibitor of CDPK and PKC (IC50 values 30 and 61 microM, respectively). The bisisoquinoline-1(2H)-one compound B7 inhibits cAK, CDPK, PKC and MLCK (IC50 values 8, 95, 24 and 7 microM, respectively) as does J1 [2-(p-bromophenyl)pyrrolo-[2,3-c]isoquinoline-5(4H)-one] (IC50 values 2, 50, 44 and 7 microM, respectively). The very potent isoquinoline-derived cAK inhibitors found here involve substitution of the N-containing isoquinoline ring system and these inhibitors show high specificity for cAK.     

Synthesis of cytotoxic indenoisoquinoline topoisomerase I poisons

A number of indenoisoquinolines were prepared and evaluated for cytotoxicity in human cancer cell cultures and for activity vs topoisomerase 1 (top1). The two most cytotoxic indenoisoquinolines proved to be cis-6-ethyl-5,6,12,13-tetrahydro-2,3-dimethoxy-8, 9-(methylenedioxy)-5,11-dioxo-11H-indeno[1,2-c]isoquinoline (21) and cis-6-allyl-5,6,12,13-tetrahydro-2,3-dimethoxy-8, 9-(methylenedioxy)-5,11-dioxo-11H-indeno[1,2-c]isoquinoline (22), both of which displayed submicromolar mean graph midpoints when tested in 55 human cancer cell cultures. Two of the most potent top1 inhibitors were 6-(3-carboxy-1-propyl)-5,6-dihydro-5, 11-dioxo-11H-indeno[1,2-c]isoquinoline (26) and 6-ethyl-2, 3-dimethoxy-8,9-(methylenedioxy)-11H-indeno[1,2-c]isoquinolinium chloride (27), both of which also inhibited top2, unwound DNA, and are assumed to be DNA intercalators. However, two additional potent top1 inhibitors, 6-allyl-5,6-dihydro-2,3-dimethoxy-8, 9-(methylenedioxy)-5,11-dioxo-11H-indeno[1,2-c]isoquinoline (13c) and 5,6-dihydro-6-(4-hydroxybut-1-yl)-2,3-dimethoxy-8, 9-methylenedioxy-5,11-dioxo-11H-indeno[1,2-c]isoquinoline (19a), did not unwind DNA and did not affect top2. Some of the DNA cleavage sites detected in the presence of the indenoisoquinolines were different from those seen with the camptothecins. The cleavage sites induced by the indenoisoquinolines were reversed by salt treatment, which is consistent with the reversible trapping of top1 cleavable complexes by the indenoisoquinolines. In general, the potencies of the indenoisoquinolines as top1 inhibitors did not correlate with their potencies as cytotoxic agents, as some of the most cytotoxic agents had little if any effect on top1. On the other hand, the most potent of the indenoisoquinolines vs top1 were not the most cytotoxic. In several cases, moderate activity was observed for both cytotoxicity and activity vs top1.     

Synthesis and antimicrobial activity of pyrazolo[3',4':4,3]pyrido[6,5-c]pyridazine and thieno[2,3-c]pyridazine derivatives

4-Acetyl-5,6-diphenyl-2(H)pyridazine-3-one (1) was allowed to react with phenyl hydrazine to afford the corresponding hydrazone 2. Hydrazone 2 upon treatment with Vilsmeier's reagent gave pyrazolylpyridazine derivative 3, which was allowed to react with thiosemicarbazide and hydroxyl amine to give the corresponding thiosemicarbazone and oxime 4 and 5, respectively. Treatment of oxime 5 with Ac2O gave the pyrazolylpyridazine carbonitrile derivative 6. Compound 5 reacts with POCl3 to give the corresponding chloro compound 7. The chloro compound 7 was reacted with hydrazine hydrate or aniline to afford pyrazolopyridazodiazepine 9 or pyrazolopyridazopyridazine 10. When compound 1 was allowed to react with POCl3 the chloro derivative 11 resulted. This compound reacts with thiourea, piperidine or hydrazine hydrate to give compounds 12, 14 and 15, respectively. Compound 12 reacted with alpha-haloester or alpha-haloketone to give the thienopyridazines 13a and b, respectively. Most of the newly synthesized compounds were screened for fungicidal and bactericidal activity.     

Activation of chemically diverse procarcinogens by human cytochrome P-450 1B1

A human cytochrome P-450 (P450) 1B1 cDNA was expressed in Saccharomyces cerevisiae and the microsomes containing P450 1B1 were used to examine the selectivity of this enzyme in the activation of a variety of environmental carcinogens and mutagens in Salmonella typhimurium TA1535/pSK1002 or NM2009 tester strains, using the SOS response as an end point of DNA damage. We also determined and compared these activities of P450 1B1 with those catalyzed by recombinant human P450s 1A1 and 1A2, which were purified from membranes of Escherichia coli. The carcinogenic chemicals tested included 27 polycyclic aromatic hydrocarbons and their dihydrodiol derivatives, 17 heterocyclic and aryl amines and aminoazo dyes, three mycotoxins, two nitroaromatic hydrocarbons, N-nitrosodimethylamine, vinyl carbamate, and acrylonitrile. Among the three P450 enzymes examined here, P450 lB1 was found to have the highest catalytic activities for the activation of 11,12-dihydroxy-11,12-dihydrodibenzo[a,l]pyrene, 1,2-dihydroxy-1,2-dihydro-5-methylchrysene, (+)-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene, 11,12-dihydroxy-11,12-dihydrobenzo[g]chrysene, 3,4-dihydroxy-3,4-dihydrobenzo[c]phenanthrene, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole, 2-aminoanthracene, 3-methoxy-4-aminoazobenzene, and 2-nitropyrene. P450 1B1 also catalyzed the activation of 2-amino-3,5-dimethylimidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3-methylimidazo[4,5-f]quinoline, 2-aminofluorene, 6-aminochrysene and its 1,2-dihydrodiol, (-)-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene, 1,2-dihydroxy-1,2-dihydrochrysene, 1,2-dihydroxy-1,2-dihydro-5,6-dimethylchrysene, 2,3-dihydroxy-2,3-dihydrofluoranthene, 3,4-dihydroxy-3,4-dihydro-7,12-dimethylbenz[a]anthracene, and 6-nitrochrysene to appreciable extents. However, P450 1B1 did not produce genotoxic products from benzo[a]pyrene, trans- 3,4-dihydroxy-3,4-dihydrobenzo[a]anthracene, trans-8,9-dihydroxy-8,9-dihydrobenzo[a]anthracene, 7,12-dimethylbenz[a]anthracene and its cis-5,6-dihydrodiol, 5-methylchrysene, 11,12-dihydroxy-11,12-dihydro-3-methylcholanthrene, 1,2-dihydroxy-1,2-dihydro-6-methylchrysene, benzo[c]phenanthrene, 2-amino-6-methyldipyridol[1,2-a:3',2'-d]imidazole, 2-acetylaminofluorene, benzidine, 2-naphthylamine, aflatoxin B1, aflatoxin G1, sterigmatocystin, N-nitrosodimethylamine, vinyl carbamate, or acrylonitrile in this assay system. P450 1B1 is expressed constitutively in extrahepatic organs, including fetal tissue samples, and is highly inducible in various organs by 2,3,7,8-tetrachlorodibenzo-p-dioxin and related compounds in experimental animal models. Thus, activation of procarcinogens by P450 lB1 may contribute to human tumors of extrahepatic origin.     

Investigation of the conformational influences on the estrogenic activity of 1,2-bis(2,6-dichloro-4-hydroxyphenyl)ethylenediamines and of their platinum(II) complexes, II: Synthesis and studies on the estrogenic activity of cis- and trans[bis(2,6-dichloro-4-hydroxybenzylamine)]dihaloplatinum(II)-c omplexes

2,6-Dichloro-4-hydroxybenzylamine (1) and its N-methyl (2) and N-ethyl (3) derivatives were synthesized and tested for estrogen receptor affinity as well as for estrogenic activity. In contrast to their related highly active 1,2-bis(2,6-dichloro-4-hydroxyphenyl)ethylenediamines (meso-4 - meso-6) none of the benzylamines showed hormonal activity. The coordination of the benzylamine 1 to platinum did not lead to an estrogenic compound. The reasons for the different activity of [meso- 1,2(bis-2,6-dichloro-4-hydroxyphenyl)ethylenediamine]dichloroplatinum(II ) (meso-4-PtCl2) and cis[bis(2,6-dichloro-4-hydroxybenzylamine)]dichloroplatinum(II) (cis-1-PtCl2), the latter of which can be considered as a ring-opened counterpart of the highly active meso-4-PtCl2, are thoroughly discussed under inclusion of conformational facts. The results of this and the preceding work show, that the pharmacophore meso-1,2-bis(2,6-dichloro-4-hydroxyphenyl)ethylenediamine (meso-4) which is exclusively responsible for the estrogenic activity of meso-4-PtCl2 causes comparable hormonal effects in two different conformations with O-O distances of about 8 A (complex) and of about 12 A (diamine). Therefore, we discuss two binding sites for estrogens in their receptor.     

Novel 5-hydroxytryptamine (5-HT3) receptor antagonists. I. Synthesis and structure-activity relationships of conformationally restricted fused imidazole derivatives

We prepared a novel series of conformationally restricted fused imidazole derivatives 4b, 4c and 4d (possessing 4,5,6,7-tetrahydroimidazo[4,5-c] pyridine and substituted 4,5,6,7-tetrahydro-1H-benzimidazole for 4b, 5,6,7,8-tetrahydroimidazo[1,2-a]pyridine for 4c and 5,6,7,8-tetrahydroimidazo[1,5-a]pyridine for 4d as a basic amine part and (2-methoxyphenyl)aminocarbonyl group as an aromatic-carbonyl part). Their activities were then evaluated as an 5-hydroxytryptamine (5-HT3) receptor antagonist which may be useful for the treatment of irritable bowel syndrome (IBS) as well as for nausea and vomiting associated with cancer chemotherapy. The most potent compound was N-(2-methoxyphenyl)-4,5,6, 7-tetrahydro-1H-benzimidazole-5-carboxamide 14 in this series with an ID50 value of 0.32 microgram/kg on the von Bezold-Jarisch reflex in rats and an IC50 value of 0.43 microM on the isolated colonic contraction in guinea pig, approximately ten and two times more potent than ondansetron 1, respectively. The structure activity relationships (SAR) study suggested that the high potency of 14 may be attributed to the suitable position and direction of the N-C-N centroid in the conformationally restricted imidazole ring against the planar (2-methoxyphenyl)aminocarbonyl part in the binding of 14 to the receptor.     

Synthesis of 5-substituted 2'-deoxyuridines

A series of thymidylate synthetase inhibitors was synthesized, some of which were potential irreversible inhibitors. 5-Formyl-2'-deoxyuridine (9) and its dithiolane derivative 11 were prepared by condensation of the bis(trimethylsilyl) derivative of 5-formyluracil dimethyl acetal and the protected chloro sugar followed by saponification of the protective groups. 5-Acetyl-2'-deoxyuridine (15) was prepared in the same way from 5-acetyluracil. Treatment of the diester of 5-allyl-2'-deoxyuridine (17 or 22) with m-chloroperbenzoic acid gave the corresponding epoxide. Dimethylamine removed the ester groups and opened the epoxide to give the amino alcohol 24. The diester of 5-chloromethyl-2'-deoxyuridine (27) treated with methanol or sodium azide gave 5-methoxymethyl- (29) and 5-azidomethyl- (31) 2'-deoxyuridines. Compound 27 also was converted to 5-iodoacetamidomethyl-2'-deoxyuridine by treatment with ammonia, chloroacetyl chloride, base saponification, and finally sodium iodide.     

Facile synthesis of 2-methyl-[4,6-di-O-acetyl-1,2-dideoxy-3-O-(2,3,4,6-tetra-O-acetyl-D-glycopyranosyl)-alpha-D-glucopyrano-[2',1':4,5]-2-oxazolines, key intermediates for the synthesis of oligosaccharides

A simple synthesis of disaccharide oxazolines has been developed. Condensation of methyl 2-acetamido-4,6-O-benzylidene-2-deoxy-alpha-D-glucopyranoside with 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide, followed by removal of the 4,6-O-benzylidene group from the resulting disaccharide derivative, gave crystalline methyl 2-acetamido-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-alpha-D-glucpyranoside which, on acetolysis with acetic anhydride-acetic acid-sulfuric acid, provided 2-methyl-[4,6-di-O-acetyl-1,2-dideoxy-3-O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-alpha-D-glucopyrano]-[2',1':4,5]-2-oxazoline (7). Synthesis of the related alpha-D-mannopyranosyl compound was similarly accomplished. The glycosylating capability of 7 was employed for the synthesis of 6-(benzyloxycarbonylamino)hexyl-2-acetamido-4,6-di-O-acetyl-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-beta-D-glucopyranoside (18). An alternative synthesis of compound 18 is also described.     

An economic synthesis of 1,2,3,4-tetra-O-acetyl-5-thio-D-xylopyranose and its transformation into 4-substituted-phenyl 1,5-dithio-D- xylopyranosides possessing antithrombotic activity

D-Xylose was converted via 1,2-O-isopropylidene-alpha-D-xylofuranose (4) into 3-O-benzoyl-5-S-benzoyl-1,2-O-isopropylidene-alpha-D-xylofuranose which, after methanolysis, acetylation and subsequent acetolysis afforded 1,2,3,4-tetra-O-acetyl-5-thio-alpha-D-xylopyranose (14) in an overall yield of 36%. Reaction of 4 with thionyl chloride gave a mixture of the diastereomeric cyclic sulfites, the structures of which were established by X-ray crystallography. Their oxidation with sodium periodate afforded the corresponding cyclic sulfate 23. Treatment of 23 with potassium thioacetate gave the potassium salt of 5-S-acetyl-1,2-O-isopropylidene-alpha-D-xylofuranose 3-O-sulfonic acid (26) which, after methanolysis, acetylation and subsequent acetolysis afforded 14 in an overall yield of 56%. Treatment of 4 with sulfuryl chloride gave a mixture containing 5-chloro-3-O-chlorosulfonyl-5-deoxy-1,2-O-isopropylidene-alpha-D- xylofuranose, 3,7,9,11-tetraoxa-4-thia-10-dimethyl-tricyclo[6,3,0, 0(2,6)]undecane S-dioxide and 23 in a 2:3:7 ratio. Tetraacetate 14 was converted into the alpha-1-bromide 18 as well as into the alpha-1-O-trichloroacetimidate 17. These three compounds were used as donors for the glycosylation with 4-cyanothiophenol, affording the 4-cyanophenyl 2,3,4-tri-O-acetyl-1,5-dithio-alpha- (29) and beta-D-xylopyranoside (30) in different ratios, depending on the reaction conditions. When donor 18 was used in the presence of potassium carbonate, besides 29 and 30 two aryl C-glycosylated-thioglycosides, i.e. 4-cyano-2-(2,3,4-tri-O-acetyl-5-thio-beta-D-xylopyranosyl)phenyl 2,3,4-tri-O-acetyl-1,5-dithio-alpha- and beta-D-xylopyranoside (32 and 33) as well as 4-cyano-2-(2,3,4-tri-O-acetyl-5-thio-beta-D-xylopyranosyl)phenyl disulfide 34 could be isolated as byproducts. Deacetylation of 30 with sodium methoxide in methanol afforded, besides 4-cyano-phenyl 1,5-dithio-beta-D-xylopyranoside (1), the corresponding 4-[(methoxy)(imino)methyl]phenyl glycoside 2. The 4-cyano group of 1 was converted into the 4-aminothiocarbonyl, the 4-(methyl-thio)(imino)methyl, the 4-amidino and the 4-(imino)(hydrazino)methyl group. All of these glycosides showed a significant antithrombotic activity on rats.     

Synthesis and evaluation of 4-amino-substituted 7-methoxy (and 7-hydroxy)- 11-methyl (and 5,11-dimethyl)-10H-pyrido [2,3-b] carbazoles and 4-amino- substituted 11-methyl (and 5,11-dimethyl)-10H-pyrido[3',4':4,5] pyrrolo [3,2-g] quinolines, two new series related to antitumor ellipticine derivatives

2-Acetyl-4-chloro-3-lithiopyridine ethylene glycol ketal (6b) was reacted with 3-formyl-5-methoxy-1-methyl-indole (9) and 3-formyl-1-methyl-1H-pyrrolo [3,2-c] pyridine (12), giving the corresponding expected alcohols. Reduction of these intermediates with triethylsilane trifluoroacetic acid and subsequent cyclodehydration then led to 4-chloro-7-methoxy-10,11-dimethyl-10H-pyrido [2,3-b] carbazole (8a) and the corresponding 7-aza-analog (8b). The synthesis of 4-chloro-11-methyl (and 5,11-dimethyl)-10-unsubstituted derivatives of these two series was performed through an independent pathway, involving condensation of conveniently substituted 2-amino carbazoles (17) and 7-amino-5H-pyrido [4,3-b] indoles (18) with 5-(ethoxymethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione, thermal cyclization of the resulting compounds with concomitant decarboxylation to the corresponding tetracyclic fused-4-quinolone systems and final chlorination with phosphorus oxychloride. Nucleophilic substitution of various 4-chloro derivatives was then easily performed in an excess of the required dialkylamino alkylamines at reflux and 4-amino substituted-7-hydroxy-10H- pyrido [2,3-b] carbazoles (25d-e) were obtained from 7-methoxy precursors (25a-b), by demethylation with boron tribromide in methylene chloride at -65 degrees C or with boiling 47% hydrobromic acid. Cytotoxicity determination of all new aminosubstituted derivatives and in vivo antitumor evaluation of the most active compounds clearly show that these two series of ellipticine analogs closely related to highly active products are devoid of antitumor properties in two experimental models shown to be sensitive to ellipticines. The place of the pyridinic nitrogen atom in these series has thus been demonstrated to play a crucial role in antitumor activity.     

Zinc, insulin and diabetes

Miso, a widely used Japanese fermented food was analysed for its lactic acid bacterial count on bromocresol purple agar. The binding of eight different foodborne carcinogenic heterocyclic amines to 25 bacterial isolates from miso were investigated. The heterocyclic amines used were 3-amino-1,4-dimethyl[5H]pyrido(4,3-b)indole (Trp-P-1), 3-amino-1-methyl[5H]pyrido(4,3-b)indole (Trp-P-2), 2-amino-6-methyldipyrido(1,2-a:3'2'-d)imidazole (Glu-P-1), 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP), 2-amino-dimethylimidazo(4,5f)quinoline (IQ), 2-amino-3,4-dimethylimidazo(4,5-f) quinoline (MeIQ), 2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline (MeIQx), and 2-amino-3-methyl-9H-pyrido(2,3)indole (MeA alpha C). The lyophilized cells of all of the isolates exhibited high binding activity towards Trp-P-1, Trp-P-2, MeA alpha C, and PhIP, while Glu-P-1 and IQ were not effectively bound. Of the isolates tested, the strongest and weakest binders were identified as Pediococcus acidilactici 1 and 2, respectively. Lyophilized cell wall fractions, heat-treated cells, and the cytoplasmic contents of P. acidilactici 1 and 2 were analysed for their ability to bind to different mutagens. Pure cell wall and peptidoglycan showed greater binding activity than the bacterial cells. Cytoplasmic content also showed some binding, but it was much less effective. The impact of enzymes (amylase, protease, cellulase, chitinase, muraminase, and peptidase) and acetylation of Trp-P-1 and IQ on the binding action of bacteria and cell wall material were also analysed to understand the possible processes involved in the binding of lactic acid bacteria to carcinogenic heterocyclic amines.     

Synthesis of [5'-11C]ribonucleoside and -2'-deoyribonucleoside derivatives from D-ribose

An approach to the synthesis of 2'-deoxy[5'-13C]ribonucleosides was achieved by the coupling reaction of a nucleic acid base derivative with D-[5-13C]ribose derivative (8). Compound 8 was derived from D-ribose (1) by way of methyl 2,3-di-O-benzyl(Bn)-D-ribofuranoside (2), 2,3-di-O-Bn-D-ribose diethyl dithioacetal (3), 2,3-di-O-Bn-D-ribose dibenzyl acetal (4), and 4-aldehydo-2,3-di-O-Bn-D-erythrose dibenzyl acetal (5), which was then successively subjected to Wittig reaction using Ph3P13CH3I-BuLi, highly stereoselective hydroxylation with OsO4 to give 2,3-di-O-Bn-D-ribose dibenzyl acetal (7), debenzylation with H2-Pd/C. The resulting 8 was subjected to coupling reaction with a nucleic acid base to give [5'-13C]ribonucleosides. The products were derived into the corresponding 2'-deoxy[5'-13C]ribonucleoside derivatives by the established manner.     

Design of antineoplastic agents based on the "2-phenylnaphthalene-type" structural pattern. 4. Synthesis and biological activity of 2-chloro-3-(substituted phenoxy)-1, 4-naphthoquinones and related 5,8-dihydroxy-1,4-naphthoquinones

The intermediate in the preparation of 1,3,7, 10-tetrahydroxybenzo[b]naphtho[2,3-d]furan-6,11-dione (2), 2-chloro-5,8-dimethoxy-3-(3,5-dimethoxyphenoxy)-1,4-naphthoquinone (8h), and corresponding hydroxyl, methoxyl, and acetoxyl analogues was found to possess interesting inhibitory activities in a number of cytotoxic test systems. Activities were also noticed in some 5, 8-dihydroxy-1,4-naphthoquinone derivatives. A structure-activity discussion of compounds of this series is presented. The newly uncovered biological activity of 2-chloro-3-(substituted phenoxyl)-1, 4-naphthoquinones and 2,3-bis(substituted phenoxy)-1, 4-naphthoquinones may suggest an approach for the development of new classes of antineoplastic agents.     

Identification of subdomain IB in human serum albumin as a major binding site for polycyclic aromatic hydrocarbon epoxides

Covalent adducts between serum albumin and low molecular weight organic electrophiles are formed with a high degree of regioselectivity mostly for nucleophilic amino acid residues located in subdomains IIA and IIIA. Previous studies have indicated that diol epoxide metabolites of polycyclic aromatic hydrocarbons (PAH) may target residues in a different subdomain. The regioselectivity of PAH epoxide and diol epoxide binding was examined in this study by reaction of human serum albumin in vitro with the racemic trans,anti-isomers of 7,8-dihydrobenzo[a]pyrene-7,8-diol 9,10-epoxide (1), 2,3-dihydrofluoranthene-2,3-diol 1,10b-epoxide (2), 1,2-dihydrochrysene-1,2-diol 3,4-epoxide (5), 6-methyl-1,2-dihydrochrysene-1,2-diol 3,4-epoxide (6), 5-methyl-1,2-dihydrochrysene-1,2-diol 3,4-epoxide (7), 3,4-dihydrobenzo[c]phenanthrene-3,4-diol 1,2-epoxide (8), 11,12-dihydrobenzo[g]chrysene-11,12-diol 13,14-epoxide (9), and 11,12-dihydrodibenzo[a,l]pyrene-11,12-diol 13,14-epoxide (10) and the racemic epoxides cyclopenta[cd]pyrene 3,4-epoxide (3) and benzo[a]pyrene 4,5-epoxide (4) followed by determination of the linkage site. Adducted albumin was digested enzymatically, and digests were chromatographed by reversed-phase HPLC to purify peptide adducts, which were analyzed by electrospray ionization collision-induced dissociation (CID) tandem mass spectrometry. Product ion spectra revealed that adducts fragmented predominantly by cleavage of the peptide-PAH bond with retention of charge by the peptide as well as by the hydrocarbon. Peptide sequences were determined by MS/MS analysis of the peptide ions formed by in-source CID to cleave the adduct bond. Longer peptide sequences established site selectivity by virtue of their uniqueness, while shorter sequences revealed the reactant amino acid within the site. Epoxide 4 and diol epoxides 1, 2, 5, and 6 reacted predominantly with His146; epoxide 3 and diol epoxides 7-9 reacted predominantly with Lys137. Both residues are situated in subdomain IB. The binding site for 10 could not be determined uniquely, but one of the several possibilities was Lys159, which is also located in subdomain IB. The results, taken together with previous findings, demonstrate that the reaction of polycyclic aromatic hydrocarbon epoxides with human serum albumin is highly selective for a small number of residues in subdomain IB.     

Evidence for a 1,2-hydride shift in the microsomal metabolism of the heterocycle L-158,338, a nonpeptide angiotensin II receptor antagonist

L-158,338 is an imidazo[4,5-b]pyridine derivative that is a potent and highly selective angiotensin II receptor antagonist. Rat liver microsomal metabolism of [C6-3H]L-158,338 gave a major metabolite that was monohydroxylated at the C6 position of the imidazo-pyridine but showed partial retention of the radiolabel. This biotransformation necessitated a shift of the radiolabel from the C6 position to another site within the molecule. We have investigated the mechanism of this biotransformation using 3H-, 3H/14C-, and 2H-labeled L-158,338. Metabolites were identified by FAB/MS, LC/MS, and 1H-NMR. Results of these studies show that the microsomal metabolism of L-158,338 to its C6-monohydroxylated derivative was mediated by a 1,2 hydride shift.     

The incidence of post-operative wound infection in orthopaedic surgery

The alkylation of 7,8-dihydroimidazo[1,2-a]-1,3,5-triazine-2,4-(3H,6H)-dithione [I] with 2-chloro-N-arylacetamides gave 2-alkyltio derivatives [III]. Further reactions of 2-(alkyltio)-7,8-dihydroimidazo[1,2-a]-1,3,5-triazine-4(6H)- thiones [III] or [IV] with aryl isothiocyanates, sulfochlorides or 2-bromo-1-phenylethanone afforded corresponding B-substituted products [V,VI,VII].