Synthesis of diverse indole libraries on polystyrene resin - Scope and limitations of an organometallic reaction on solid supports

The synthesis of diverse substituted indole structures on solid supports is described. The immobilization of nitrobenzoic acid onto Merrifield resin and the subsequent treatment with alkenyl Grignard reagents delivered indole carboxylates bound to solid supports. In contrast to results in the liquid phase, ortho,ortho-unsubstituted nitroarenes also delivered indole moieties in good yields. Subsequent palladium-catalyzed reactions (Suzuki, Heck, Sonogashira, Stille) delivered, after cleavage, the desired molecules in moderate to good yields over four steps. The scope and limitations are presented.

Organic azides: an exploding diversity of a unique class of compounds

Since the discovery of organic azides by Peter Griess more than 140 years ago, numerous syntheses of these energy-rich molecules have been developed. In more recent times in particular, completely new perspectives have been developed for their use in peptide chemistry, combinatorial chemistry, and heterocyclic synthesis. Organic azides have assumed an important position at the interface between chemistry, biology, medicine, and materials science. In this Review, the fundamental characteristics of azide chemistry and current developments are presented. The focus will be placed on cycloadditions (Huisgen reaction), aza ylide chemistry, and the synthesis of heterocycles. Further reactions such as the aza-Wittig reaction, the Sundberg rearrangement, the Staudinger ligation, the Boyer and Boyer-Aubé rearrangements, the Curtius rearrangement, the Schmidt rearrangement, and the Hemetsberger rearrangement bear witness to the versatility of modern azide chemistry.

Efficient solid phase synthesis of benzo[1,2,3]thiadiazoles and related structures

The first solid-phase synthesis of benzo[1,2,3]thiadiazoles was achieved by starting from resin bound ortho bromo or iodo triazenes and using a functionalization on cleavage.

Natural Product-Like and Other Biologically Active Heterocyclic Libraries Using Solid-Phase Techniques in the Post-Genomic Era

High-throughput technologies allow the selection of new biological targets for drug discovery in the post-genomic era. These tools increase the need of new methods to rapidly obtain potent small molecules and natural products to discover new lead structures. In particular, the solid-phase synthesis offers a great potential to obtain large compound sets.

Bartoli indole synthesis on solid supports

[reaction: see text] Bartoli indole synthesis has been performed for the first time on solid supports. Starting from Merrifield resin, immobilization of five nitro benzoic acids was performed. Addition of four different alkenyl Grignard reagents and basic cleavage leads to substituted methyl indole carboxylates in excellent purities. Features of this reaction are the stability of halide groups, ester moieties, and tolerance of o,o'-unsubstituted nitro resins. Heck and Sonogashira reactions are also possible with immobilized indoles.

The recent impact of solid-phase synthesis on medicinally relevant benzoannelated nitrogen heterocycles

Benzoannelated heterocycles such as benzodiazepines and indoles can be prepared efficiently through cyclization on solid supports, although no single approach is currently universal for the preparation of all benzoannelated N-heterocycle chemistries. In this review, a number of synthetic strategies for the generation of benzoannelated nitrogen heterocycles using resin-bound substrates have been described. Classical heterocycle forming reactions such as the Fischer indole, the Bischler-Napieralski tetrahydroisoquinoline, the Pictet-Spengler tetrahydro-beta-carboline, the Tsuge, the Nenitzescu and the Richter cinnoline reaction are presented. In addition, the Heck, Sonogashira, Wittig, Diels-Alder, and olefin metathesis reactions have been also used. Multicomponent reactions such as the Grieco three-component assembly have been exploited for the synthesis of heterocycles. Cyclative cleavage from the solid support is particularly suitable for the synthesis of heterocycles while particular emphasis has been focused on the synthesis of libraries and the use of combinatorial chemistry techniques. In addition, the most relevant pharmacological properties of benzoannelated nitrogen heterocycles are included.

Extending due process protections in managed care credentialling to hospital privileges

The Article analyzes two recent state court decisions granting due process rights to physicians deselected from managed care networks. The author applauds these decisions and argues that managed care organizations wishing to deselect a physician should be required to demonstrate (1) that they have a legitimate reason for doing so relating to quality of care, economic factors, or administrative considerations, and (2) that the deselection will not unduly affect the quality of healthcare available in the network. In addition, the author contends that these same due process requirements may be applied to the closely analogous area of hospital staff privileges in situations in which the privileges of hospital-based practitioners are tied to employment, or the grant or termination of exclusive contracts.

Involuntary transfers and discharges of nursing home residents under federal and state law

When, as projected, nearly one out of every four Americans is age sixty-five or more, one out of every four Americans over sixty-five will spend time in a nursing home, and caregiver families scarcely exist, we will no longer be able to avert our eyes from the grim options faced by our senior citizens. Nor will we be able to continue to operate under the comforting but often false illusion that our convenient dispositions are actually serving the best interests of the elderly.

[Pregnancies without complications of patients with jejuno-ileal bypass because of extreme obesity (author's transl)]

Report about 3 pregnancies without complications of patients, who had been treated by jejuno-ileal bypass because of extreme obesity. There is no increased risk for the successful finishing of a pregnancy of these patients. A close cooperation between the treating doctors is necessary to cope with possible problems.

[Stenosis of the celiac artery as cause of chronic recurrent pancreatitis (author's transl)]

Report on three clinical examples of the interrelation between chronic recurrent pancreatitits and external compression which cause a stenosis of the celiac artery. If clarification of the etiology of recurrent pancreatitis with the usual examinations is impossible, angiography is very important. A causal therapy is only possible by means of surgical treatment of the stenosis.