Studies on plant growth-regulating substances. XLIII. 2 -Chloro -3 -phenoxypropionitriles

A number of ring substituted 2-chloro-3-phenoxypropionitriles have been prepared and their plant growth-regulating activity has been assessed in the wheat coleoptile, pea segment and pea curvature tests, and also by spray treatments on tomato and dwarf French bean plants. The activities of these compounds are compared with those of previously studied 2-chloro-3-phenylpropionitriles and the results are discussed in terms of chemical structure/biological activity relationships and mode of action.     

Novel benzodiazepines derivatives as analgesic modulating for Transient receptor potential vanilloid 1

A new series of derivatives of 3-(7-chloro-5-(2-fluorophenyl)-2-oxo-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)propanoic acid were designed and synthesized as analgesic modulating for Transient receptor potential vanilloid 1. They were investigated for TRPV1 antagonistic activity in vitro, analgesic activity and sedative activity in vivo and aqueous solubility. Preliminary studies identified 3-(7-chloro-5-(2-fluorophenyl)-2-oxo-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)-N,N-dimethylpropanamide(Compound 11), as a potent analgesic modulating for TRPV1 with potent activity and good aqueous solubility.     

A molecular modeling approach to in vivo efficacy of triclabendazole.

The structural and electronic features of a narrow-spectrum benzimidazole anthelmintic triclabendazole (TCZ, 6-chloro-5-[2,3-dichlorophenoxy]-2-methylthio-benzimidazole) and its 2 main metabolites triclabendazole sulfoxide (TCZ sulfoxide, 6-chloro-5-[2,3-dichlorophenoxyl]-2-methylsulfonyl-benzimidazole) and triclabendazole sulfone (TCZ sulfone, 6-chloro-5-[2,3-dichlorophenoxy]-2-methylsulfonyl-benzimidazole) have been determined using a combination of quantum mechanics, molecular graphics, and molecular modeling techniques. Using conformational analyses and quantum mechanics, 2 important differences were found between TCZ sulfoxide, the purported active species, and the broad-spectrum benzimidazole anthelmintics. The first distinguishing feature is the shape of the molecule; the substituent at the 2 position of TCZ sulfoxide is nonplanar. All other broad-spectrum benzimidazole anthelmintics, regardless of substituent at the 2 position (methyl carbamate or thiazolyl group), are flat. The second distinguishing feature is the net atomic charge on the substituent at the 2 position of TCZ sulfoxide; it is an order of magnitude larger than the net atomic charges on the other anthelmintics. Thus the nonplanar shape of the methysulfinyl group at the 2 position of TCZ sulfoxide is different (as is its net charge), suggesting that this may be the origin of its narrow spectrum of activity.     

Analogue-based design, synthesis and molecular docking analysis of 2,3-diaryl quinazolinones as non-ulcerogenic anti-inflammatory agents

In our effort to identify potent gastric sparing anti-inflammatory agents, a series of methyl sulfanyl/methyl sulfonyl substituted 2,3-diaryl quinazolinones were designed by analogue-based design strategy and synthesized for biological evaluation. Subsequently, the compounds were evaluated for both cyclooxygenase inhibitions by ovine COX assay and carrageenan-induced rat paw edema assay. All the methyl sulfonyl substituted quinazolinones were exhibited promising anti-inflammatory activity. In particular, 6-bromo-3-(4-methanesulfonyl-phenyl)-2-phenyl-3H-quinazolin-4-one, 7-chloro-3-(4-methanesulfonyl-phenyl)-2-phenyl-3H-quinazolin-4-one, 3-(4-methanesulfonyl-phenyl)-2-(4-methoxy-phenyl)-3H-quinazolin-4-one and 6-bromo-3-(4-methanesulfonyl-phenyl)-2-(4-methoxy-phenyl)-3H-quinazolin-4-one emerged as the most active compounds in the series. The results of ulcerogenic activity assay suggest that these compounds are gastric safe compared to indomethacin. The molecular docking analysis was performed to understand the binding interactions of these compounds to COX-2 enzyme. The results from the present investigation suggests that 2,3-diaryl quinazolinones as a promising template for the design of new gastric safe anti-inflammatory agents, which can be further explored for potential anti-inflammatory activity.     

Synthesis of Racemic 5-Substituted 1-(2,3-Dihydroxypropyl)-6-azauracils and Their Isosteric Isomers

Abstract

Acyclic nucleoside analogues of antiviral DHPA and HPMPA have been prepared. Coupling of silylated 6-azauracils with benzyl glycidyl ether and stannic chloride followed by the deprotection with boron trichloride gave 1-(2,3-dihydroxypropyl)-6-azauracils (3) in good overall yields. Reaction of silylated 6-azauracil and epichlorohydrin with or without catalytic stannic chloride afforded 1-(2-chloro-3-hydroxypropyl)-6-azauracil (4a) and 1-(3-chloro-2-hydroxypropyl)-6-azauracil (6a) respectively. Coupling of silylated 6-azaisocytosine under the same reaction conditions provided 1-(2,3-dihydroxypropyl)-6-azaisocytosine (9) and 1-(2-chloro-3-hydroxypropyl)-6-azaisocytosine (10) respectively. None of the compounds exhibited significant antiviral activity against herpes simplex viruses.     

Synthesis,structural characterization and in vitro antitumor activity of novel 6-chloro-1,1-dioxo-1,4,2-benzodithiazie derivatives

A series of nonconventional aminium N-(6-chloro-7-R-1,1-dioxo-1,4,2-benzodithiazin-3-yl)arylsulfonamidates 7-15 have been synthesized by the reactions of 6-chloro-7-R-3-methylthio-1,4,2-benzodithiazine 1,1-dioxides with 4-dimethylaminopyridine or Et(3)N and some arylsulfonamides. The free N-(6-chloro-7-methyl-1,1-dioxo-1,4,2-benzodithiazin-3-yl)benzenesulfonamides 16-18 were obtained by treatment of their aminium salts with H(2)SO(4) in boiling acetic acid. The in vitro antitumor activity of the compounds 9, 11-14 and 16-18 has been tested in the antitumor screening of the National Cancer Institute (NCI), and relationships between structure and antitumor activity are discussed. 4-Dimethylaminopyridinium 4-chloro-N-(6-chloro-7-methyl-1,1-dioxo-1,4,2-benzodithiazin-3-yl)benzenesulfonamidate 9 is the prominent of the compounds due to its remarkable activity (log GI(50)<-8.00, log TGI=-5.50) and selectivity for the leukemia SR cell line. For that reason experimental and theoretical analysis of the geometric and electronic properties of 9 was carried out.     

Novel 4,1-benzoxazepine derivatives with potent squalene synthase inhibitory activities.

A series of (3,5-trans)-2-oxo-5-phenyl-1,2,3,5-tetrahydro-4,1-benzoxazepine derivatives were synthesized and evaluated for squalene synthase inhibitory and cholesterol biosynthesis inhibitory activities. Through modification of substituents of the lead compounds 1a and 1b, it was found that 4,1-benzoxazepine-3-acetic acid derivatives with isobutyl and neopentyl groups at the 1-position, the chloro atom at the 7-position, and the chloro and methoxy groups at the 2'-position on the 5-phenyl ring, had potent squalene synthase inhibitory activity. Among such compounds, the 5-(2,3-dimethoxyphenyl) derivative 2t exhibited potent inhibition of cholesterol biosynthesis in HepG2 cells. As a result of optical resolution study of 2t, the absolute stereochemistry required for inhibitory activity was determined to be 3R,5S. In vivo study showed that the sodium salt of (3R,5S)-7-chloro-5-(2,3-dimethoxyphenyl)-1-neopentyl-2-oxo-1,2,3,5-tetrahydro-4,1-benzoxazepine-3-acetic acid 20 effectively reduced plasma cholesterol in marmosets.     

The Influence of the Synthetic Growth Regulator α-Chloro-(β-(3-chloro-o-tolyl) propionitrile on Some Phytochrome-mediated Processes

In intact Sinapis alba seedlings the synthetic growth regulator α-chloro-β-(3-chloro-o-tolyl)propionitrile (PRB-8) inhibits the phytochrome-mediated anthocyanin synthesis, carotenoid synthesis and L-phenylalanine ammonia-lyase activity. This action was compared with that of other auxins and with that of α-chloro-β-(3-chloro-o-tolyl)propionitrile-homologues. From the results it appeared that PRB-8 and some other o-tolyl derivatives are more inhibitive than other known auxins.     

STUDIES ON PLANT GROWTH-REGULATING SUBSTANCES. XIII CHLORO- AND METHYL-SUBSTITUTED PHENOXYACETIC AND BENZOIC ACIDS

The physiological activity of complete series of mono- and di-substituted chloro-and methyl-phenoxyacetic and benzoic acids have been investigated using the wheat cylinder, pea segment and pea curvature tests. In the phenoxyacetic acids, high activity was associated with substitution in the 3-, 4-, 2:4-, 2:5- and 3:4-positions and in general, chlorine had a greater effect than methyl in conferring activity.
With the benzoic acids, 2:3-, 2:5- and 2:6-, disubstitution gave active compounds, the chloro-derivatives again being the more active. The 2:5-compound was the most active in the dichloro- series, all members of which were less active than the 2:3:6-trichloro- and 2:3:5:6-tetrachloro-acids. Benzoic acids substituted in the 4- position were either inactive or exhibited only weak growth-promoting activity.
The results are discussed in relation to recent theories which attempt to relate growth-promoting activity with the position of substituents in the aromatic ring.     

Synthesis and anticancer activity of 2-amino-8-chloro-5,5-dioxo[1,2,4]triazolo[2,3-b][1,4,2]benzodithiazine derivatives

A new series of 1-(6-chloro-1,1-dioxo-1,4,2-benzodithiazin-3-yl)-4-arylsemicarbazides (4-16) were obtained. Intramolecular ring closure in semicarbazides 4-16 upon treatment with phosphorus oxychloride resulted in the formation of 2-amino-8-chloro-5,5-dioxo[1,2,4]triazolo[2,3-b][1,4,2]benzodithiazines 17-29 with potential antitumor activity. The structures of these compounds were confirmed on the basis of elemental analysis, spectral data and X-ray analysis. Compounds 17-29 were screened at the US National Cancer Institute (NCI) for their activities against a panel of 59 tumor cell lines, and relationships between structure and antitumor activity in vitro are discussed. The benzodithiazines 18, 19, 23, 28 and 29 were inactive, whereas the other compounds exhibited reasonable activity against numerous human tumor cell lines. The prominent compound 17 showed significant activity against the leukemia SR cell line (log GI(50)=-7.67, log TGI=-6.90 and log LC(50)=-4.77).     

Enzymatic and chemical preparation of 5-amino-4-chloro-2-(2,3-dihydroxyphen-1-yl)-3(2H)-pyridazinone

A hypothetical intermediate of the microbial degradation of pyrazon, 5-amino-4-chloro-2(2,3-dihydroxyphen-1-yl)-3(2H)-pyridazinone, was prepared by enzymatic and chemical treatment of 5-amino-4-chloro-2(2,3-dihydroxy-cyclohexa-4,6-dien-1-yl)-pyridazinone. The properties of the metabolite are described.     

Synthesis and biological evaluation of 2-chloro-3-[(thiazol-2-yl)amino]-1,4-naphthoquinones

A series of novel, substituted 2-chloro-3-[(thiazol-2-yl)amino]-1,4-naphthoquinones have been prepared and shown to exhibit promising concentration-dependent activity against human SH-SY5Y cells, Plasmodium falciparum, Mycobacterium tuberculosis and P. aeruginosa. Substituent effects on observed bioactivity have been explored; the para-fluorophenyl derivative 3d exhibited activity across the range of the bioassays employed, indicating the potential of the 2-chloro-3-[(4-arylthiazol-2-yl)amino]-1,4-naphthoquinone scaffold in the development of novel, broad spectrum therapeutics.     

Inhibition of 2,3-oxidosqualene cyclases.

Monocyclic and tricyclic compounds possessing a nitrogen atom situated at a position corresponding to the carbenium ion of high energy intermediates or transition states involved during cyclization of 2,3-oxidosqualene to tetra- and pentacyclic triterpenes have been synthesized. These compounds were tested as inhibitors of 2,3-oxidosqualene cycloartenol, lanosterol-, and beta(alpha)-amyrin-cyclases in vitro and in vivo, and their affinity was compared to that of formerly synthesized 8-aza-bicyclic compounds [Taton et al. (1986) Biochem. Biophys. Res. Commun. 138, 764-770]. A monocyclic N-alkyl-hydroxypiperidine was shown to be the strongest inhibitor of the series upon cycloartenol-cyclase (I50 = 1 microM) from maize embryos but was much less effective on the beta(alpha)-amyrin-cyclases from Rubus fruticosus suspension cultures or pea cotyledons. In contrast, 13-aza-tricyclic derivatives displayed little inhibition on 2,3-oxidosqualene cycloartenol-, lanosterol-, and beta(alpha)-amyrin-cyclases. The obtained data exemplify the differences existing in the cyclization process between cycloartenol- (lanosterol-) cyclases on one hand and beta(alpha)-amyrin-cyclases on the other. The results are discussed with respect to current mechanisms postulated for 2,3-oxidosqualene cyclization. Because of its activity in vivo and in vitro the monocyclic N-alkyl-hydroxypiperidine appears to be a potent and promising tool to study sterol biosynthesis regulation.     

Purification and characterization of haloalcohol dehalogenase from Arthrobacter sp. strain AD2.

An enzyme capable of dehalogenating vicinal haloalcohols to their corresponding epoxides was purified from the 3-chloro-1,2-propanediol-utilizing bacterium Arthrobacter sp. strain AD2. The inducible haloalcohol dehalogenase converted 1,3-dichloro-2-propanol, 3-chloro-1,2-propanediol, 1-chloro-2-propanol, and their brominated analogs, 2-bromoethanol, as well as chloroacetone and 1,3-dichloroacetone. The enzyme possessed no activity for epichlorohydrin (3-chloro-1,2-epoxypropane) or 2,3-dichloro-1-propanol. The dehalogenase had a broad pH optimum at about 8.5 and a temperature optimum of 50 degrees C. The enzyme followed Michaelis-Menten kinetics, and the Km values for 1,3-dichloro-2-propanol and 3-chloro-1,2-propanediol were 8.5 and 48 mM, respectively. Chloroacetic acid was a competitive inhibitor, with a Ki of 0.50 mM. A subunit molecular mass of 29 kDa was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. With gel filtration, a molecular mass of 69 kDa was found, indicating that the native protein is a dimer. The amino acid composition and N-terminal amino acid sequence are given.     

Prodrug-oriented molecular design of neonicotinoids: preparation of imidacloprid-related 5,5-dimethoxy-1,3-diazacyclohexane derivatives and their insecticidal activity

Prodrug-oriented molecular design was attempted for the potent acyclic neonicotinoid insecticide, clothianidin (1-(2-chloro-5-thiazolylmethyl)-3-methyl-2-nitroguanidine). Molecules bearing a CH2COCH2 bridge linking the 1,3-NH ends of clothianidin or their acetals would possibly be hydrolyzed, regenerating the mother compounds. This strategy was used to prepare seven acetals of clothianidin-based molecules that combined 2-chloro-5-thiazolylmethyl, 6-chloro-3-pyridylmethyl or 3-tetrahydrofurfuryl with a nitroimine, cyanoimine or nitromethylene group. The key intermediate, 1,3-diamino-2,2-dimethoxypropane, was prepared from the dihydroxyacetone dimer in four steps. A selected acetal showed a characteristic nerve-impulse pattern for neonicotinoids on an excised American cockroach ganglion, although the neuroblocking activity was fairly low. Some acetals were highly insecticidal against the pea aphid at 0.8-20 ppm 7 days after a spray treatment, this being in a contrast to their far weaker activity by injection into American cockroaches. The biological results suggest that the intrinsic insecticidal activities of the acetals are weak, but would exhibit enhanced activity if hydrolyzed in an external environment.     

Degradation of 2-methylbenzoic acid by Pseudomonas cepacia MB2.

We report the isolation of Pseudomonas cepacia MB2, believed to be the first microorganism to utilize 2-methylbenzoic acid as the sole carbon source. Its growth range included all mono- and dimethylbenzoates (with the exception of 2,5- and 2,6-dimethylbenzoates) and 3-chloro-2-methylbenzoate (but not 4- or 5-chloro-2-methylbenzoate) but not chlorobenzoates lacking a methyl group. 2-Chlorobenzoate, 3-chlorobenzoate, and 2,3-, 2,4-, and 3,4-dichlorobenzoates inhibited growth of MB2 on 2-methylbenzoate as a result of cometabolism to the corresponding chlorinated catechols which blocked the key enzyme catechol 2,3-dioxygenase. A metapyrocatechase-negative mutant, MB2-G5, showed accumulation of dimethylcatechols from 2,3- and 3,4-dimethylbenzoates, and phenols were detected in resting-cell transformation extracts bearing the same substitution pattern as the original substrate, presumably following thermal degradation of the intermediate dihydrodiol. 2-Methylphenol was also found in extracts of the mutant cells with 2-methylbenzoate. These observations suggested a major route of methylbenzoate metabolism to be dioxygenation to a carboxy-hydrodiol which then forms a catechol derivative. In addition, the methyl group of 2-methylbenzoate was oxidized to isobenzofuranone (by cells of MB2-G5) and to phthalate (by cells of a separate mutant that could not utilize phthalate, MB2-D2). This pathway also generated a chlorinated isobenzofuranone from 3-chloro-2-methylbenzoate.     

Physiological studies on pea tendrils. XIII. Respiration is necessary for contact coiling

When 9 day old light grown pea ( Pisum sativum L. cv. Alaska 2B) plants are irrigated for 4–6 days with 50 μ M 4-chloro-5-(dimethylamino)-2-(α, α, α-trifluoro- m -totyl)-3(2H)-pyridazinone, designated San-6706, the new leaves and tendrils grow morphologically normal, but with neither chlorophyll nor the ability to carry out photosynthesis. Excised tendrils from these plants coil in response to rubbing as well as those from water irrigated controls. Tendrils from San-6706 irrigated plants, which have been dark adapted for 2 or 3 days, proceed to coil when illuminated, just as do those from water irrigated plants. Rubbing of dark adapted tendrils results in an increased respiration rate over the first hour or two, when most of the coiling response occurs. Inhibitor studies indicate that blockage of oxidative phosphorylation, but not of the alternative, cyanide-insensitive, path of respiration, results in a failure of tendrils to coil in response to mechanical perturbation. It is concluded that the normal path of respiration, perhaps via ATP production, may be necessary for thigmosensory perception leading to contact coiling in pea tendrils.     

Synthesis and biological activity of 5-fluorotubercidin

The electrophilic fluorination of 4-chloropyrrolo[2,3-d]pyrimidine (1) was studied culminating a 59% conversion of compound 1 to 4-chloro-5-fluoropyrrolo[2,3-d]pyrimidine (2) using Selectfluor. This transformation proceeded via the 4-chloro-5,6-dihydro-5-fluoro-6-hydroxypyrrolo[2,3-d]pyrimidine (3) in a 9:1 trans:cis ratio. The trans isomer of compound 3 was studied by 1H NMR and 19F NMR, and the 5-H tautomer (4) was observed as another intermediate. A modified Vorbruggen procedure of compound 2 and tetra-O-acetylribose gave 4-chloro-5-fluoro-7-(2,3,5,-tri-O-benzoyl-beta-D-ribofuranosyl)pyrrolo[2,3-d]pyrimidine (6) in a 65% yield. Treatment of compound 6 with ammonia (l) in dioxane gave 5-fluorotubercidin (7). No antibacterial activity was observed. An MTT assay (Promega) against Huh-7 liver cells, normal mouse spleen cells stimulated with Con A (a T-cell mitogen), and normal mouse spleen stimulated with LPS (a B-cell mitogen) showed no significant toxicity. Increased activity of 7 over tubercidin was observed against L-1210 cells and toxicity in fibroblast cells was reduced.     

Synthesis and cytotoxicity evaluation of pyridin[2,3-f]indole-2,4,9-trione and benz[f]indole-2,4,9-trione derivatives

3-Ethoxycarbonyl-3-methyl-1N-substrituted-2,3-dihydro-pyridin[2,3-f]indole-2,4,9-trione [9(a-d)] and 3-ethoxycarbonyl-3-methyl-N-substrituted-2,3-dihydro-benz[f]indole-2,4,9-trione [10(a-i)] derivatives were synthesized from 7-chloro-6-(1,1-diethoxycarbonyl-ethyl)-5,8-quinolinedione (7) and 2-chloro-3-(1,1-diethoxycarbonyl-ethyl)-1,4-naphthoquinone (8), respectively, using a variety of alkyl- and arylamines. The cytotoxic activities of the synthesized compounds were evaluated by a Sulforhodamine B (SRB) assay against the following tumor cell lines: A459 (human non-small cell lung), SK-OV-3 (human ovarian), SK-MEL-2 (human melanoma), XF498 (human CNS), and HCT 15 (human colon). Almost all the derivatives mentioned above had a more potent cytotoxic effect against SK-OV-3 than etoposide. In particular, 3-ethoxycarbonyl-3-methyl-N-(4-aminophenyl)-2,3-dihydro-benz[f]indole-2,4,9-trione (10h) exhibited greater activity against all the tumor cell lines, and its cytotoxic effect against SK-OV-3 was especially higher than doxorubicin.