Synthetic studies toward mitomycins. 1. Total synthesis of deiminomitomycin A

Metal-free syntheses of new azocinesviaaddition reactions of enaminones with acenaphthoquinone followed by oxidative cleavages of the corresponding vicinal diols

A one-pot, clean and green procedure is described for the syntheses of new azocine derivatives via addition reactions of enaminones with acenaphthoquinone followed by periodic acid-mediated oxidative cleavages of the corresponding vicinal diols. Various derivatives of azocine were prepared and well characterized. The excellent yields, simple synthesis procedure, lack of a need to carry out any tedious work-up and column chromatography, metal-free catalysis, and mild reaction conditions are important features of this protocol.

One-pot metal-free periodic acid-mediated syntheses of azocine rings with high yields under mild reaction conditions via the addition reactions of enaminones and acenaphthoquinone.

Enantioselective Synthesis of (+)-Mitomycin K by a Palladium-Catalyzed Oxidative Tandem Cyclization

The mitomycins, a family of bioactive natural products, feature a compact 6/5/5-fused polycyclic ring structure densely decorated with highly reactive and/or fragile quinone, amino ketal, and aziridine as well as carbamate moieties. It is this striking feature that has defeated numerous synthetic attempts towards these apparently small molecules, rendering them one of the most formidable targets for total synthesis. We herein report the first enantioselective synthesis of (+)-mitomycin K, a representative of G series mitomycins. The key step of this synthesis is an enantioselective oxidative cyclization catalyzed by a palladium/(+)-sparteine system that had previously been developed by our group. The robustness of this method bodes well for further applications in the asymmetric total synthesis of natural products, particularly those with characteristic 6/5/5-fused pyrroloindole skeletons.

Syntheses of Cyclic Guanidine-Containing Natural Products

Naturally occurring guanidine derivatives frequently display medicinally useful properties. Among them, the higher order pyrrole-imidazole alkaloids, the dragmacidins, the crambescidins/batzelladines, and the saxitoxins/tetradotoxins have stimulated the development of many new synthetic methods over the past decades. We provide here an overview of the syntheses of these cyclic guanidine-containing natural products.

A procedure for transforming indoles into indolequinones

A procedure that converts a series of structurally diverse, readily available indole derivatives to their corresponding indolequinones is described. The three-step route commences with an iridium catalyzed C-H borylation to give a 7-borylindole that upon oxidation-hydrolysis affords the 7-hydroxyindole. Subsequent oxidation provides the indolequinone.

Synthesis of 7a-phenyl-1a,7a-dihydro-benzopyrano[2,3-b]azirin-7-ones via photoisomerization reaction

An environmentally friendly and novel protocol has been developed for the synthesis of 7a-phenyl-1a,7a-phenyl-benzopyrano[2,3-b]azirin-7-ones in moderate to high yieldsviathe photoisomerization of 4-phenyl-5-(2-hydroxyphenyl)isoxazoles.

Efficient synthesis of some new antiproliferative N-fused indoles and isoquinolines via 1,3-dipolar cycloaddition reaction in an ionic liquid

Triethylammonium acetate (TEAA) as a new, recyclable and environmentally friendly reaction medium for the intramolecular[3+2] cycloaddition reaction.

Preparation of Methyl (2-hydroxynaphthalen-1-yl)(aryl)methyl/benzylcarbamate derivatives using magnesium (II) 2,2,2-trifluoroacetate as an efficient catalyst

Multicomponent condensation reactions of aldehydes, 2-naphthol and methyl/benzyl carbamate have been done by using magnesium 2,2,2-trifluoroacetate [Mg(OOCCF3)2] as an efficient catalyst. This methodology results in the synthesis of a variety of methyl (2-hydroxynaphthalen-1-yl)(aryl)methyl/benzylcarbamate derivatives in high yields. Despite their importance from pharmacological and synthetic points of view, comparatively few methods for the preparation of 1-carbamatoalkyl 2-naphthol derivatives have been reported via multicomponent reactions of aldehydes, 2-naphthol and carbamate using acidic catalysts. Magnesium 2,2,2-trifluoroacetate [Mg(OOCCF3)2] has been prepared from the reaction of trifluoroacetic acid and magnesium chloride. The prepared catalyst has been characterised through a powder X-ray diffraction pattern.

Palladium-catalyzed regiocontrolled alpha-arylation of trimethylsilyl enol ethers with aryl halides

Inter- and intramolecular arylations of trimethylsilyl enol ethers with aryl halides are accomplished regiospecifically in the presence of a palladium catalyst and tributyltin fluoride in refluxing benzene or toluene. The optimal catalyst system called for the use of Pd2(dba)3 and tri-tert-butylphosphine in ca. 1:2 ratio. Aryl iodides, bromides, and chlorides are all effective arylation partners in this reaction. [reaction: see text]

Mitomycin antitumour agents: A review of their physico-chemical and analytical properties and stability

The review enumerates the physico-chemical and analytical properties of mitomycin antitumour antibiotics, of which mitomycin C is the most important representative. After a short overview of the position of the compounds in oncology the following subjects will be discussed: structural features, prototropic properties, spectroscopy (UV-VIS, ORD, CD, IR, NMR, MS), chromatography and electrochemistry. The chemical stability and aspects of the mechanism of action of the compounds are also discussed. The last part of the review surveys the analysis of mitomycin C in biological fluids.