Quantitative analysis of 3‐OHB[a]P and (+)‐anti‐BPDE as biomarkers of B[a]P exposure in rats

The aim of this study was to develop an analytical method for the determination the levels of metabolites of benzo[a]pyrene (B[a]P), 3‐hydroxybenzo(a)pyrene (3‐OHB[a]P) and (+)‐anti‐benzo(a)pyrene diol‐epoxide [(+)‐anti‐BPDE, combined with DNA to form adducts], in rat blood and tissues exposed to B[a]P exposure by high‐performance liquid chromatography with fluorescence detection (HPLC/FD), and to investigate the usefulness of 3‐OHB[a]P and (+)‐anti‐BPDE as markers of intragastrical exposure to B[a]P in rats. The levels of 3‐OH‐B[a]P and B[a]P‐tetrol I‐1 released after acid hydrolysis of (+)‐anti‐BPDE in the samples were measured by HPLC/FD. The calibration curves were linear (r² > 0.9904), and the lower limit of quantification ranged from 0.34 to 0.45 ng/mL for 3‐OHB[a]P and from 0.43 to 0.58 ng/mL for (+)‐anti‐BPDE. The intra‐ and inter‐day stability assay data suggested that the method is accurate and precise. The recoveries of 3‐OHB[a]P and (+)‐anti‐BPDE were in the ranges of 73.6 ± 5.0 to 116.5 ± 6.3% and 73.3 ± 8.5 to 141.2 ± 13.8%, respectively. A positive correlation was found between the concentration of intragastrical B[a]P and the concentrations of 3‐OH‐B[a]P and (+)‐anti‐BPDE in the blood and in most of the tissues studied, except for the brain and kidney, which showed no correlation between B[a]P and 3‐OHB[a]P and between B[a]P and (+)‐anti‐BPDE, respectively. A sensitive, reliable and rapid HPLC/FD was developed and validated for analysis of 3‐OHB[a]P and (+)‐anti‐BPDE in rat blood and tissues. There was a positive correlation between the concentration of 3‐OHB[a]P or (+)‐anti‐BPDE in the blood and the concentration of 3‐OHB[a]P or (+)‐anti‐BPDE in the most other tissues examined. The concentration of 3‐OHB[a]P or (+)‐anti‐BPDE in the blood could be used as an indicator of the concentration of 3‐OHB[a]P or (+)‐anti‐BPDE in the other tissues in response to B[a]P exposure. These results demonstrate that 3‐OHB[a]P and (+)‐anti‐BPDE are potential biomarkers of B[a]P exposure, which would also be useful to assess the carcinogenic risks from B[a]P exposure. Copyright © 2015 John Wiley & Sons, Ltd.     

Chemical selectivity of nucleobase adduction relative to in vivo mutation sites on exon 7 fragment of p53 tumor suppressor gene

Damage to p53 tumor suppressor gene is found in half of all human cancers. Databases integrating studies of large numbers of tumors and cancer cell cultures show that mutation sites of specific p53 codons are correlated with specific types of cancers. If the most frequently damaged p53 codons in vivo correlate with the most frequent chemical damage sites in vitro, predictions of organ-specific cancer risks might result. Herein, we describe LC-MS/MS methodology to reveal codons with metabolite-adducted nucleobases by LC-MS/MS for oligonucleotides longer than 20 base pairs. Specifically, we used a known carcinogen, benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) to determine the most frequently adducted nucleobases within codons. We used a known sequence of 32 base pairs (bp) representing part of p53 exon 7 with 5 possible reactive hot spots. This is the first nucleobase reactivity study of a double stranded DNA p53 fragment featuring more than 20 base pairs with multiple reactive sites. We reacted the 32 bp fragment with benzo[a]pyrene metabolite BPDE that undergoes nucleophilic substitution by DNA bases. Liquid chromatography-mass spectrometry (LC-MS/MS) was used for sequencing of oligonucleotide products from the reacted 32 bp fragment after fragmentation by a restriction endonuclease. Analysis of the adducted p53 fragment compared with unreacted fragment revealed guanines of codons 248 and 244 as most frequently targeted, which are also mutated with high frequency in human tumors. Codon 248 is mutated in non-small cell and small cell lung, head and neck, colorectal and skin cancer, while codon 244 is mutated in small cell lung cancer, all of which involve possible BDPE exposure. Results suggest the utility of this approach for screening of adducted p53 gene by drugs and environmental chemicals to predict risks for organ specific cancers.     

Efficient Synthesis of Optically Pure (+)‐Bezene Diol Epoxide and (+)‐Conduramine A‐1

In this paper, we develop a concise approach to (+)‐benzene diol epoxide and (+)‐conduramine A‐1 based upon the utilization of the C₂‐symmetric L‐tartaric acid as a chiral building block.     

Three New Abietane‐type Diterpenes from the Bark of Cryptomeria japonica

Three new abietane‐type diterpenoids, 7β‐acetoxy‐12‐methoxyabieta‐8,11,13‐triene‐6α,11‐diol ( 1 ), 7α‐acetoxy‐12‐methoxyabieta‐8,11,13‐triene‐6α,11‐diol ( 2 ), and 6α‐acetoxy‐12‐methoxyabieta‐8,11,13‐triene‐7α,11‐diol ( 3 ), as well as two known abietane‐type diterpenoids, 12‐methoxyabieta‐8,11,13‐triene‐6α,7β,11‐triol ( 4 ) and 6α‐acetoxy‐12‐methoxyabieta‐8,11,13‐triene‐7β,11‐diol ( 5 ), were isolated from the MeOH extract of the bark of Cryptomeria japonica. Their structures were determined by analysis of spectroscopic data and comparison of NMR data with those of related metabolites.     

Stereoselective Synthesis of cis,cis‐Configured Perhydroquinoxaline‐5‐Carbonitrile from Cyclohex‐2‐en‐1‐ol

cis,cis‐Configured perhydroquinoxaline‐5‐carbonitrile 10 was synthesized stereoselectively by ditosylation of trans,cis‐2,3‐dihydroxycyclohexane‐1‐carbonitrile 4 and subsequent reaction with ethylenediamine. The diol precursor 4 was stereoselectively obtained by regioselective opening of the epoxide 3 with KCN in water avoiding hazardous Et₂AlCN.     

Synthesis of (±)‐Trinervitadiene‐2,3‐diol

The first synthesis of trinervita‐1(15),8(19)‐dien‐2β,3α‐diol ( 2a ) and its 2α‐isomer 2b , which have been isolated from termite soldiers, where they are used as defense chemicals, is documented starting from geranylgeranioic acid in 33 steps. The route for construction of the key intermediate of the trinervitane skeleton 8 has been developed previously (Scheme 1). Noteworthy features include the efficient construction of the trinervitane framework from the corresponding bicyclic 7(16)‐secotrinervitane skeleton and Me₃SiCl (TMSCl)‐induced ring‐opening of tetrasubstituted epoxide to give the corresponding allyl alcohols (Scheme 7). The synthetic route developed in the present study seems applicable to the syntheses of other trinervitane‐type natural products.     

Synthesis and Characterization of β—Cyclodextrin Bonded Metal Porphyrins

Reactions of 5-(p-aminophenyl)-10,15,20-triphenyl porphyrin (1) with Ru3(CO)12 or M(OCOCH3)2 (M=Ni,Mn) afforded metalloporphyrins(4-6),respectively.6-Deoxy-6-io-do-β-cyclodextrin(2) and mono(6-O-trifluoromethanesulfonyl) permethylated β-cyclodextrin(3) reacted with complexes 4-6 to give β-cyclodextrin bonded metal porphyrins (7-9) and permethylated β-cyclodextrin bonded me-tal porphyrins (10-12) respectively.These new complexes were identified by MS,IR,UV-visible and ^1H NMR spectra,and elemental analysis.     

Cracking the genetic code(s) with a modular determinative degree: An algebraic approach

We introduce a new “modular” (compositional and positional) determinative degree for the four bases U, C, A, and G to define a “Dinucleotide charge number” for the dinucleotides, which discriminates between the two octets of dinucleotides: M₁ and M₂. These two components are exchanged under a transformation, which, we show, implements the Rumer symmetry. We invoke also the base “size index” of Rosen as a complementary determinative degree for the third‐base component of a codon. Next, we define the address functions for the 64 codons (amino acids), which are functions only of the composition and position of these codons in the genetic table. With these ingredients, we build an algebraic classification of the amino acids in the genetic code and some of its nonstandard versions as a preliminary application. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003     

Synthesis and Oxidation of N‐Aminoglyconolactams: A Synthesis of Mannostatin A

The N‐amino‐ribono‐1,5‐lactam 4 was prepared in two high‐yielding steps from the known methanesulfonate 2 . Oxidation of 4 with t‐BuOCl in the presence of 2,6‐lutidine afforded the tetrazene 6 (63%). Oxidation with MnO₂ gave the deaminated lactam 7 (40%), which was also obtained, together with the lactone 8 , upon oxidation of 4 with PhSeO₂H. Oxidation with Mn(OAc)₃/Cu(OAc)₂ provided the lactam 7 as the major and the dimer 9 as the minor product. Oxidation of 4 with 3 equiv. of Pb(OAc)₄ in toluene at room temperature gave two cyclopentanes, viz. the acetoxy epoxide 10 and the diazo ketone 11 in a combined yield of 78%. Oxidation with Pb(OBz)₄ provided 11 and the crystalline benzoyloxy epoxide 12 . The crystal structure of 12 was established by X‐ray analysis. The N‐amino‐glyconolactams 41, 46 , and 51 were prepared similarly to 4 . Their oxidation with Pb(OAc)₄ provided the diazo ketones 56, 57 , and 58 as the only isolable products. Oxidation of the N‐amino‐mannono‐1,5‐lactam 55 with Pb(OAc)₄ in the presence of DMSO gave the sulfoximine 59 . Mannostatin A, a strong α‐mannosidase inhibitor, was synthesized from the acetoxy epoxide 10 (obtained in 48% from 4 ) in seven steps and in an overall yield of 45%.     

Grafting onto carbon black by the reaction of reactive carbon black having epoxide groups with several polymers

The grafting of functional polymers onto carbon black surface by the reaction of epoxide groups introduced onto the surface was investigated. The introduction of epoxide groups was achieved by the reaction of the phenolic hydroxyl and carboxyl groups on carbon black with chloromethyloxirane in the presence of sodium hydroxide. The amount of epoxide groups introduced onto the channel black Neospectra II was equal to 0.40 meq/g. The epoxide groups were reacted with polypropylene glycol, silicone diol (SDO), silicone diamine (SDA), and polyethyleneimine to give polymer-grafted carbon blacks. For example, the percentage of grafting of SDO (M_n = 1.0 × 10³) and SDA (M_n = 3.9 × 10³) reached to 23.6 and 67.2%, respectively. The percentage of grafting increased with the molecular weight (M_n) of the polymers, while the number of grafted chain (G_n) decreased. In the case of SDO, the relationship between M_n and G_n was found to be G_n = 4.68 × 10^?2 M. The carbon black obtained from the reaction gave stable colloidal dispersions in tetrahydrofuran and the stability of dispersion increased with an increase in the percentage of grafting.     

Lycopodium Alkaloids from Huperzia serrata

Three new lycopodium alkaloids, huperserramines A–C ( 1 – 3 , resp.), along with 15 known ones, lycopodine‐6α,11α‐diol ( 4 ), lycoposerramine H ( 5 ), lycoposerramine I ( 6 ), lycopodine‐6α‐ol ( 7 ), lycoposerramine M ( 8 ), diphaladine A ( 9 ), lycoposerramine K ( 10 ), lycoposerramine W ( 11 ), huperzine M ( 12 ), luciduline ( 13 ), phlegmariuine N ( 14 ), huperzine A ( 15 ), huperzine B ( 16 ), lycodine ( 17 ), and lycoposerramine R ( 18 ), were isolated from the whole plant of Huperzia serrata. Their structures were established by spectroscopic methods, including 2D‐NMR and MS analyses. All the isolates were evaluated for their inhibitory effects on acetylcholinesterase (AChE) and α‐glucosidase. As a result, lycopodine‐6α,11α‐diol ( 4 ) exhibited more potent α‐glucosidase inhibitory activity (IC₅₀ 148±5.5 μM ) than the positive control acarbose (IC₅₀ 376.3±2.7 μM ).     

Theoretical studies on triaryamine‐based p‐type D‐D‐π‐A sensitizer

Development of triaryamine‐based nonmetallic dye sensitizers is a hot topic in the solar cell research. A series of triaryamine‐based dyes WS1 – WS7 were designed with W1 as the prototype. Density functional theory (DFT) and time‐dependent‐DFT calculations were used to investigate the effects of the attached donor D on the absorption spectra and electronic properties of the dyes. The light‐harvesting efficiency (LHE), hole injection force (ΔG_inj), dye regeneration force (ΔG_reg), and charge recombination force (ΔG_CR) for all the dyes were predicted. The insertion of D not only results in a red shift in the absorption spectra for all dyes but also achieves a broader absorption for visible light. Compared with that of the prototype, the absorption peak of the dye WS7 has a red shift of 95 nm and an oscillator strength increase of 29%. The absorption peak of WS7 is wider and stronger, and the absorption range extends to 900 nm. The LHE and ΔG_reg values of WS7 are 0.991 and ?1.49 eV, respectively. On overall evaluation, WS7 is a promising candidate of a p‐type dye sensitizer with good light absorption and dye regeneration efficiency.     

Synthesis and Structure of Novel Double Flexible Spacer Bridged Biscalix[4]arenes

25, 25′, 27, 27′‐Bis(1,3‐dioxypropane)‐bis(5, 11, 17, 23‐tetra‐tert‐butylcalix[4]arene‐26,28‐diol) (4) and 25, 25′, 27, 27′‐bis(1, 4‐dioxybutane)‐bis (5, 11, 17, 23‐tetra‐tert‐butylcalix‐[4]arene‐26, 28‐diol) (5) were synthesized by the reaction of p‐tert‐butylcalix[4]arene (1) with preorganized 25, 27‐bis(3‐bromoproxyl)calix[4]arene‐26, 27‐diol (2) and 25, 27‐bis(3‐bromobutoxyl)calix[4]arene‐26, 27‐diol (3) in the presence of K₂CO₃ and KI. Compounds 4 and 5 were characterized with X‐ray analysis and the selectivity of 4 and 5 toward K⁺ over other alkali metal ions, alkaline metal ions as well as NH₄⁺ were investigated with an ion‐selective electrode.     

Quantitative study of stereospecific binding of monoclonal antibody to anti-benzo(a)pyrene diol epoxide-N-dG adducts by capillary electrophoresis immunoassay

The stereospecific binding of monoclonal antibody (mAb) 8E11 to anti-benzo(a)pyrene diol epoxide (BPDE)-dG adducts in single nucleoside, long oligonucleotide, and genomic DNA were quantitatively evaluated using noncompetitive and competitive capillary electrophoresis (CE) immunoassays. Two single-stranded TMR-BPDE-90mers containing a single anti-BPDE-dG adduct with defined stereochemistry and a fluorescent label at 5′-end were used as fluorescent probes for competitive CE immunoassay. To quantitatively evaluate the binding affinity through competitive CE immunoassays, a series of equations were derived according to the binding stoichiometry. The binding of mAb 8E11 to trans-(+)-anti-BPDE-dG displays strongest affinity (K_b: 3.57 × 10⁸ M⁻¹) among all four investigated anti-BPDE-dG mononucleoside adducts, and the cis-(−)-anti-BPDE-dG displays lowest affinity (K_b: 1.14 ×10⁷ M⁻¹). The binding of monoclonal antibody (mAb) 8E11 to BPDE-dG adducts in long DNA (90mer) preferentially forms the complex with a stoichiometry of 1:1, and that mAb 8E11 displays a slightly higher affinity with trans-(+)-anti-BPDE-90mers (K_b: 6.36 ± 0.54 × 10⁸ M⁻¹) than trans-(−)-anti-BPDE-90mers (K_b: 4.52 ± 0.52 × 10⁸ M⁻¹). The mAb 8E11 also displays high affinity with BPDE-dG adducts in genomic DNA (K_b: 3.74 × 10⁸ M⁻¹), indicating its promising applications for sensitive immuno-detection of BPDE-DNA adducts in genomic DNA.     

From α‐carbamoyl‐α‐cyano­oxiranes to 3‐halogenopyruv­amides

The crystal structures of the first stable α‐diol from the α‐halogenopyruv­amide series, 3‐chloro‐2,2‐di­hydroxy‐3‐phenyl­propan­amide, C₉H₁₀­ClNO₃, and three products [3‐(4‐chloro­phenyl)‐2‐cyano‐2,3‐epoxy­propan­amide, C₁₀H₇­ClN₂O₂, 3‐bromo‐2‐cyano‐2‐hydroxy‐3‐p‐tolyl­propan­amide, C₁₁H₁₁Br­N₂O₂, 3‐bromo‐2‐oxo‐3‐p‐tolyl­propan­amide, C₁₀H₁₀­BrNO₂] obtained during the systematic synthesis of α‐halogenopyruv­amides are reported. The crystal structures are dominated by hydrogen bonds involving an amide group. The stability of the geminal diol could be ascribed to hydrogen bonds which involve both hydroxyl groups.     

A semi‐synthetic analog of the cembranoid sarcophine

The title mol­ecule, 2(R)‐[(1E,3E,7S,8S,11E,13R)‐13‐hydroxy‐4,8,12‐tri­methyl‐7,8‐epoxy­cyclo­tetradeca‐1,3,11‐trien‐1‐yl]­propane‐1,2‐diol, C₂₀H₃₂O₄, is a semi‐synthetic analog of sarcophine, the natural cembranoid of marine origin, isolated from the soft coral Sarcophyton glaucum. The conformation of the 14‐membered ring differs substantially from that of sarcophine. The two OH groups of the propane‐1,2‐diol moiety form an unusual weak intramolecular hydrogen bond with an O⋯O distance of 2.788 (2) Å, and the mol­ecules are linked into double chains by intermolecular hydrogen bonds with O⋯O distances of 2.772 (2) and 2.849 (2) Å.     

Synthesis and Antifungal Bioactivity of Methyl 2-Methoxyimino-2-{2-[(substituted benzylidene)aminooxymethyl]phenyl}acetate and 2-Methoxyimino-2-{2-[(substituted benzylidene)aminooxy-methyl]phenyl}-N-methylacetamide Derivatives

Ten methyl 2‐methoxyimino‐2‐{2‐[(substituted benzylidene)aminooxymethyl]phenyl}acetate and 2‐methoxy‐ imino‐2‐{2‐[(substituted benzylidene)aminooxymethyl]phenyl}‐N‐methylacetamide derivatives were synthesized. Structures of the new compounds were characterized by IR, ¹H NMR and GC‐MS data. These compounds at 10 µg/mL were tested in vitro against five pathogenic fungi, namely, Sclerotonia, Botrytis cinerea Pers, Gibberella zeae, Rhizoctorua solani and Pyricularia oryzae. Compounds G₅ , G₆ , G₇ and G₈ showed potent antifungal activities against Botrytis cinerea Pers, G₇ against Gibberella zeae and G₇ , G₈ against Rhizoctorua solani, respectively.     

C-Galactosylceramide diastereomers via Sharpless asymmetric epoxidation chemistry

C-Glycoside analogs of α-galactosylceramide (KRN7000) were synthesized in 19 linear steps with Sharpless asymmetric epoxidation as a key reaction. Opening of a hydroxy epoxide with sodium azide provided an anti vicinal azido diol with inversion of configuration at the azide-bearing carbon while opening with Ti(O-i-Pr)₂(N₃)₂ gave syn vicinal azido diol with retention. The latter, unusual outcome could be rationalized either by invoking Ti-catalyzed intramolecular double S_N2 inversion or by epoxide opening/intramolecular delivery of azide from the Ti complex.     

Dolabellane Diterpenoids from the Higher Plant Aglaia odorata

Two new dolabellane diterpenoids, (1R,3R,7E,11S,12R)‐dolabella‐4(16),7‐diene‐3,18‐diol ( 1 ) and (1R,3E,7R,11S,12R)‐dolabella‐3,8(17)‐diene‐7,18‐diol ( 2 ), and the known (1R,3E,7E,11S,12R)‐dolabella‐3,7‐dien‐18‐ol ( 3 ) were isolated from Aglaia odorata, along with twelve other known compounds. Their structures were elucidated on the basis of spectroscopic data. This is the first time that dolabellane‐type diterpenoids were detected in higher plants.     

Stereoselective Synthesis of the Non‐Lactonic Portion of (Z)‐Cryptofolione and Approaches towards Its Conversion to (Z)‐Cryptofolione

The stereoselective synthesis of the non‐lactonic part of the natural G₂ checkpoint inhibitor, (Z)‐cryptofolione, has been accomplished. Butane‐1,4‐diol was used as the starting material, and the stereogenic centers were generated through L ‐proline‐catalyzed α‐aminoxylation and Maruoka asymmetric allylation. We attempted to convert this non‐lactonic moiety to (Z)‐cryptofolione via olefin cross‐metathesis reaction, but by this approach another naturally occurring lactonic compound, goniothalamin, was obtained.