Synthesis of imides, N-acyl vinylogous carbamates and ureas, and nitriles by oxidation of amides and amines with Dess-Martin periodinane

A direct and efficient total synthesis of the tubulin-binding agents ceratamine A and B; use of IBX for a remarkable heterocycle dehydrogenation

The total synthesis of the tubulin-binding agents ceratamine A and B is reported, along with des-methyl analogs, via a synthetic route that is high-yielding and operationally efficient. The synthetic route involved a Beckmann rearrangement to form an azepine ring precursor, a Knoevenagel condensation to install the benzylic side chain, and an effective imidazole annulation onto an alpha-aminoketone precursor with a protected S-methylisothiourea. Final dehydrogenation proved remarkably facile using IBX.

Hypervalent iodine reagents as a new entrance to organocatalysts

The catalytic utilization of hypervalent iodine reagents, largely in consideration of economical and environmental viewpoints, is a most attractive strategy due to their unique features as extremely useful oxidants, with mild, safe, and environmentally friendly characteristics. In addition to a system based on electrochemical reoxidation conditions, new reliable catalytic methods have emerged in recent years that can broaden the scope of the catalytic concept. For these contributions, a catalytic strategy is now available for performing many representative types of oxidative bond-forming reactions and alcohol oxidations mediated by hypervalent iodines, some of which even include key transformations for natural product synthesis. A suitable choice of terminal oxidants, e.g., m-chloroperbenzoic acid (mCPBA) or Oxone, for generation of active hypervalent iodine(iii) or (v) species from iodoarenes in situ, has led to recent rapid expansion in this field. This feature article highlights the historical background and the efforts made to realize the catalytic utilization of these reagents, especially with focus on iodine(iii).

NaIO4-oxidized carbonylation of amines to ureas

Oxidative carbonylation of amines using NaIO(4) as the oxidant and NaI as a promoter affords good to excellent yields of ureas from primary amines in the absence of transition metal catalysts.

Convergent synthesis and biological activity of the WXYZA'B'C' ring system of maitotoxin

The WXYZA'B'C' ring system ( 1) of maitotoxin (MTX) was synthesized in a convergent manner via successive coupling of the W, Z, and C' ring fragments through construction of the XY and A'B' ring systems. The synthetic segment 1 blocked the hemolytic activity elicited by MTX.

Microwave-assisted synthesis of N-substituted cyclic imides and their evaluation for anticancer and anti-inflammatory activities

A number of N-substituted cyclic imides 3a-e, 5a-e, 7a-d, and 9a-e have been synthesized in very high yields, by condensation of various diacids 2, 4, 6, and 8 with different amines under microwave irradiation. These compounds were screened for anticancer and anti-inflammatory activities, and compounds 3c, 3e, 5c, 9c, and 9d exhibited anticancer activity against colon (COLO 205) cancer better than 5-fluorouracil and mitomycin-C, and compound 9b exhibited anti-inflammatory activity better than standard drug phenyl butazone.

Coenzyme A biosynthesis: an antimicrobial drug target

Pantothenic acid, a precursor of coenzyme A (CoA), is essential for the growth of pathogenic microorganisms. Since the structure of pantothenic acid was determined, many analogues of this essential metabolite have been prepared. Several have been demonstrated to exert an antimicrobial effect against a range of microorganisms by inhibiting the utilization of pantothenic acid, validating pantothenic acid utilization as a potential novel antimicrobial drug target. This review commences with an overview of the mechanisms by which various microorganisms acquire the pantothenic acid they require for growth, and the universal CoA biosynthesis pathway by which pantothenic acid is converted into CoA. A detailed survey of studies that have investigated the inhibitory activity of analogues of pantothenic acid and other precursors of CoA follows. The potential of inhibitors of both pantothenic acid utilization and biosynthesis as novel antibacterial, antifungal and antimalarial agents is discussed, focusing on inhibitors and substrates of pantothenate kinase, the enzyme catalysing the rate-limiting step of CoA biosynthesis in many organisms. The best strategies are considered for identifying inhibitors of pantothenic acid utilization and biosynthesis that are potent and selective inhibitors of microbial growth and that may be suitable for use as chemotherapeutic agents in humans.

An efficient approach to the stereocontrolled synthesis of enamides

[reaction: see text] A fast, flexible, and efficient approach for the stereocontrolled synthesis of enamides has been developed starting from lactams and amides through the use of imides. This new approach provides access to enamide systems not easily or currently accessible through other approaches.