Dorian P. Nelson

Bio: Dorian P. Nelson is an academic researcher from Merck & Co.. The author has contributed to research in topics: Aryl & Suzuki reaction. The author has an hindex of 6, co-authored 9 publications receiving 402 citations.

An improved protocol for the preparation of 3-pyridyl- and some arylboronic acids.

Abstract: 3-Pyridylboronic acid was prepared in high yield and bulk quantity from 3-bromopyridine via a protocol of lithium-halogen exchange and "in situ quench". This technique was further studied and evaluated on other aryl halides in the preparation of arylboronic acids.

Efficient Synthesis of a GABAA α2,3-Selective Allosteric Modulator via a Sequential Pd-Catalyzed Cross-Coupling Approach

Abstract: A practical synthesis of 2-[3-(4-fluoro-3-pyridin-3-yl-phenyl)-imidazo[1,2-a]pyrimidin-7-yl]-propan-2-ol (1), an oral GABAA α2/3-selective agonist, is described. The five-step process, which afforded 1 in 40% overall yield, included imidazopyrimidine 2 and pyridine boronic acid 4 as key fragments. The synthesis is highlighted by consecutive Pd-catalyzed coupling steps to assemble the final free base 1 in high yield and regioselectivity. A novel method for Pd removal in the final step is also described.

Process for the preparation of CCR-2 antagonists

Abstract: The present invention provides an efficient synthesis for the preparation of ((1R,3S)-3-isopropyl-3-{[3-(trifluoromethyl)-7,8-dihydro-1,6-naphthyridin-6(5H)-yl]carbonyl}cyclopentyl)[(3S,4S)-3-m ethoxytetrahydro-2H-pyran-4-yl]amine and its succinate salt. The present invention additionally provides an efficient syntheses for the preparation of intermediates (3R)-3-methoxytetrahydro-4H-pyran-4-one; (1S,4S)-4-(2,5-dimethyl-1H-pyrrol-1-yl)-1-isopropylcyclopent-2-ene-1-carboxylic acid; and 3-(trifluoromethyl)-5,6,7,8-tetrahydro-1,6-naphthyridine; and for the preparation of the precursor (3S,4S)-N-((1S,4S)-4-isopropyl-4-{[3-(tri-fluoromethyl)-7,8-dihydro-1,6-naphthyridin-6(5H)-yl]carbonyl}cyclopent-2-en-1-yl)-3-methoxytetrahydro-2H-pyran-4-amine. The invention additionally resides in the superior properties of the succinate salt of ((1R,3S)-3-isopropyl-3-1{[3-(trifluoromethyl)-7,8-dihydro-1,6-naphthyridin-6(5H)-yl]carbonyl}cyclopentyl)[(3S,4S)-3-methoxytetrahydro-2H-pyran-4-yl]amine

Aryl-aryl bond formation by transition-metal-catalyzed direct arylation.

Abstract: The biaryl structural motif is a predominant feature in many pharmaceutically relevant and biologically active compounds. As a result, for over a century 1 organic chemists have sought to develop new and more efficient aryl -aryl bond-forming methods. Although there exist a variety of routes for the construction of aryl -aryl bonds, arguably the most common method is through the use of transition-metalmediated reactions. 2-4 While earlier reports focused on the use of stoichiometric quantities of a transition metal to carry out the desired transformation, modern methods of transitionmetal-catalyzed aryl -aryl coupling have focused on the development of high-yielding reactions achieved with excellent selectivity and high functional group tolerance under mild reaction conditions. Typically, these reactions involve either the coupling of an aryl halide or pseudohalide with an organometallic reagent (Scheme 1), or the homocoupling of two aryl halides or two organometallic reagents. Although a number of improvements have developed the former process into an industrially very useful and attractive method for the construction of aryl -aryl bonds, the need still exists for more efficient routes whereby the same outcome is accomplished, but with reduced waste and in fewer steps. In particular, the obligation to use coupling partners that are both activated is wasteful since it necessitates the installation and then subsequent disposal of stoichiometric activating agents. Furthermore, preparation of preactivated aryl substrates often requires several steps, which in itself can be a time-consuming and economically inefficient process.

C-H bond functionalization: emerging synthetic tools for natural products and pharmaceuticals

Abstract: The direct functionalization of C-H bonds in organic compounds has recently emerged as a powerful and ideal method for the formation of carbon-carbon and carbon-heteroatom bonds. This Review provides an overview of C-H bond functionalization strategies for the rapid synthesis of biologically active compounds such as natural products and pharmaceutical targets.

Direct transition metal-catalyzed functionalization of heteroaromatic compounds

Abstract: During the last two decades there has been considerable growth in the development of catalytic reactions capable of activating unreactive C–H bonds. These methods allow for the synthesis of complex molecules from easily available and cheaper precursors in a fewer number of steps. Naturally, the development of C–H activation methods for direct functionalization of heterocyclic molecules, invaluable building blocks for pharmaceutical and synthetic chemistry and material science, has received substantial attention as well. This critical review summarizes the progress made in this field until November 2006 (117 references).