The bicyclo[7.3.0]dodecadiyne core structure of the antitumor agents neocarzinostatin, kedarcidin, C-1027 and maduropeptin can be readily constructed by an intramolecular aldol reaction to form the C-8C-9 bond only if the C-6,7 triple bond is complexed as its η2Co2(CO)6-acetylene adduct.

The aryl ether system of the maduropeptin chromophore artifact 1 was constructed via an aldol type condensation (7+6, Schemes 1 and 2, 7+19, Scheme 4), but attempted synthesis and ring closure of aldehyde 25 (Scheme 4) to afford the enediyne core of 1 failed.

A retrosynthetic analysis (Scheme 1) of maduropeptin chromophore artifact 1 defined compounds 2 and 3 as required building blocks. The construction of 2 was achieved starting from the 2,5-dimethyl derived aromatic acid 8 and the d-serine derived δ-lactone 12 (Scheme 2), whereas the synthesis of...

Efficient enantioselective syntheses of the functionalized phenol and diethynylcyclopentene moiety of the maduropeptin chromophore were achieved. Their CsF-mediated coupling yielded a sterically congested aryl propargyl ether. The subsequent intramolecular Sonogashira coupling reaction between t...

We herein report the synthesis of aromatic analogues of the maduropeptin chromophore. Compounds 16a, 16b and 17 were conveniently prepared starting from 2-ethynylbenzaldehyde through a modified Nozaki-Hiyama reaction

Publisher SummaryThis chapter focuses on the latest studies conducted on kedarcidin and maduropeptin, the two 9-membered enediyne containing chromoproteins recently isolated and characterized at Bristol-Myers Squibb. Kedarcidin, neocarzinostatin, and maduropeptin are members of a growing class o...

SummaryThe antigens for the MNS blood group system are Glycophorins A and B (GPA,GPB), products of the GPA gene family. The existence of close to 40 variant phenotypes of this blood group system has been documented by serological analyses.Here is summarized the molecular basis for a large number...

Publisher SummaryThis chapter describes the synthesis of ribulose 1,5-bisphosphate. The synthesis of ribulose 1,5-bisphosphate (RuBP) is accomplished by two routes: (1) glucose 6-phosphate and (2) adenosine monophosphate. These routes provide procedures suitable for preparing several hundred gra...

The radioactive acid-insoluble material, Product I, which was formed by rat-liver nuclear preparation from labeled NAD or labeled ATP with nicotinamide mononucleotide, has been partially purified. It has a peak at 3 S with sucrose density-gradient centrifugation, and a density of around 1.57 wit...

The effects of the P2-purinoceptor antagonist, suramin, on ADP-induced increases in human platelet cytosolic calcium concentration ([Ca2+]i) and inhibition of prostaglandin E1 (PGE1)-stimulated adenylate cyclase activity were investigated. Suramin (50–200 μM) acted as an antagonist of ADP-indu...

Publisher SummaryThis chapter discusses the polymerization of the adenosine 5'-diphosphate-ribose moiety of nicotinamide adenine dinucleotide (NAD). The polymerization is catalyzed by certain aggregated enzyme preparations. This enzymatic polymerization is accompanied by a release of the ni...

The effects of extracellular divalent cations on the responses of human platelets to adenosine 5′-diphosphate (ADP) and on its inhibition by the competitive antagonist adenosine 5′-triphosphate (ATP) were investigated. Two responses were studied, shape change and the inihibition of prostagland...

Publisher SummaryThe chapter presents approaches of studying dynamic changes in intracellular Cl– in living neurons with the laser scanning confocal microscope (LSCM) and a fluorescent Cl– indicator, 6-methoxy-N-ethylquinolinium iodide (MEQ). The chapter discusses the brain slice preparation. ...

With increasing concerns about future oil depletion and plastic pollution, bioplastics saw an increasing interest from scientists and industrials. Among bioplastics, the polyhydroxyalkanoates (PHA) are a promising family of polyester which are both biosourced and biodegradable. Biosynthesized by...

The syntheses and resolutions of enantiomerically enriched 4-phenyl, 4-tert-butyl, and 4-isopropyl pipecolic acids are described. Optically active diastereomers were prepared by diastereomeric salt formation with the chiral base, l-tyrosine hydrazide, to provide Cbz or Boc protected 4-cis-d-pipe...

Formic acid-mediated cyclization reactions of N-(3-alkenyl)-N-(methoxycarbonyl)-acetoxyglycine esters are described. The major reaction products are 4-formyloxypipecolic acid derivatives, formed with low stereoselectivity at C-4. The several subtle features of the cyclization process are satisfa...

Diels–Alder adducts of 1,2-dihydropyridine with maleic and acrylic acid derivatives were stereospecifically converted by way of RuO4 oxidation into new r-2,c-3,c-4,c-5-piperidinetetracarboxylic acid, r-2,t-3,t-4,c-5-piperidinetetracarboxylic acid, r-2,c-3,c-5-piperidinetricarboxylic acid, and r...

A fluorescent analog of cis-diamminedichloroplatinum(II), cis-bis(6-aminoquinoline)dichloroplatinum(II), was prepared from K2[PtCl4] and 6-aminoquinoline (AQL). HPLC of the thiourea derivative of the new complex showed that it has the cis-configuration. The Pt-AQL complex and the parent ligand A...

An efficient and stereoselective synthesis of d-iminolyxitol, a potent α-galactosidase inhibitor, is achieved in 11 steps over 45% overall yield from N-Boc-O-Bn-d-serine. The key step involves the OsO4-catalyzed syn-selective dihydroxylation reaction of the acyclic γ-amino-α,β-unsaturated (Z...

An efficient and easy formal [2+2] cycloaddition (Michael–Dieckmann-type reaction) on methyl 2-acetamidoacrylate with ketene diethyl acetal gave the cyclobutane core. Two kinds of 2-substituted cyclobutane amino acids have been obtained from this compound by means of stereocontrolled interconve...