A Nitrogen-Assisted One-Pot Heteroaryl Ketone Synthesis from Carboxylic Acids and Heteroaryl Halides.

A practical and highly effective one-pot synthesis of versatile heteroaryl ketones directly from carboxylic acids and heteroaryl halides under mild conditions is reported. This method does not require derivatization of carboxylic acids (preparation of acid chlorides, Weinreb amides, etc.) or the use of any additives/catalysts. A wide substrate scope of carboxylic acids with high functional group tolerance has also been demonstrated. The results reveal that the presence of an α-nitrogen on the halide substrate greatly improves the desired ketone formation.

Synthesis of isotope-labeled HSP90 inhibitor: [(13) CD3 ] and [(14) C]-TAK-459.

[(13) CD3 ]-TAK-459 (1A), an HSP90 inhibitor, was synthesized from [(13) CD3 ]-sodium methoxide in three steps in an overall yield of 29%. The key intermediate [(13) CD3 ]-2-methoxy-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine was synthesized in two steps from 2,6-dibromopyridine and stable isotope-labeled sodium methoxide. [(14) C]-TAK-459 (1B) was synthesized from [(14) C(U)]-guanidine hydrochloride in five steps in an overall radiochemical yield of 5.4%. The key intermediate, [(14) C]-(R)-2-amino-7-(2-bromo-4-fluorophenyl)-4-methyl-7,8-dihydropyrido[4,3-d]pyrimidin-5(6H)-one, was prepared by microwave-assisted condensation.

Syntheses of C-13 and C-14-labeled versions of the investigational proteasome inhibitor MLN9708.

MLN9708 (ixazomib citrate) is an investigational, orally bioavailable proteasome inhibitor that is under development by Millennium in clinical studies in both hematologic and nonhematologic malignancies. The stable isotope-labeled MLN9708 was required for bio-analytical studies. [(13) C9 ]-MLN9708 (11) was synthesized in seven steps from the uniformly labeled [(13) C6 ]-1,4-dichlorobenzene (3) and [1-(13) C]-acetyl chloride. Because of the presence of two chlorine atoms and a boron atom, compound 6 was further reacted with [(13) C2 ]-glycine to provide an internal standard that is well separated from the parent compound during mass spectrometric analysis. The radiolabeled version was prepared to support metabolite profiling and whole body autoradiography studies in experimental animals. [(14) C]-MLN9708 (19) was synthesized in six steps from commercially available [(14) C]-barium carbonate. The key intermediate, [carboxyl-(14) C]-2,5-dichlorobenzoic acid (14), was prepared by selective lithiation of 1-bromo-2,5-dichlorobenzene (12) followed by carbonation with [(14) C]-barium carbonate. In preparation for a one-time human absorption, distribution, metabolism and excretion (ADME) study, the stability of [(14) C]-MLN9708 and its precursors were also evaluated.

N-(tert-butoxycarbonyl)-N-[(triethylenediammonium)sulfonyl]azanide: a convenient sulfamoylation reagent for alcohols.

A convenient and efficient procedure is described for the sulfamoylation of alcohols using N-(tert-butoxycarbonyl)-N-[(triethylenediammonium)sulfonyl]azanide (1). The ambient temperature stable reagent 1 reacts with phenols as well as primary and secondary alcohols to give high to modest yields. The relative reaction rate of substrates was determined (primary > phenol > secondary ≫ tertiary). The reagent's utility as a selective sulfamoylation reagent with polyols is also demonstrated.

Synthesis of the pyrazolo[4,3-e][1,2,4]triazine family of natural products: nostocine A, fluviol A, and pseudoiodinine.

The first syntheses of any members of the naturally occurring pyrazolo[4,3-e][1,2,4]triazine family are reported, verifying the structures of nostocine A and fluviol A, and leading to the revision of the structure of pseudoiodinine. The revised structure of pseudoiodinine was also established by total synthesis.

Total synthesis of nigellicine and nigeglanine hydrobromide.

[reaction: see text] The first syntheses of the pyridazinoindazolium alkaloids nigellicine and nigeglanine hydrobromide via a common intermediate are described. Ortho-lithiation/acylation and the direct amination of an isatin ring system are the key steps in the synthesis.

Synthesis and properties of 1,6,7,12,13,18,19,24-octamethylacenaphthyleno[b,l]tetraphenylene.

The X-ray crystal structure and photophysical properties of 1,6,7,12,13,18,19,24-octamethylacenaphthyleno[b,l]tetraphenylene, which has been synthesized via a Diels-Alder reaction of 5,6,11,12-tetradehydrodibenzo[a,e]cyclooctene and 6,7-dihydro-6-hydroxy-7,9-dimethyl-8H-cyclopenta[a]acenaphthylene-8-one, are reported.

Anion mediated structural motifs in silver(I) complexes with corannulene.

The synthesis of three new silver(I) complexes with corannulene is reported. In the crystal these complexes form extended networks of Ag(+) ions, corannulene nuclei, and counterions, similar to the networks reported for Ag(+) with other polynuclear aromatic hydrocarbons (PAHs). The preferred Ag(+)-arene interaction is compared with the model developed by Kochi. The crystal motifs can be described by a classification scheme analogous to that developed by Etter for hydrogen-bonded networks in solids. The effect of counterion variation (ClO(4)(-), O(3)SCF(3)(-), BF(4)(-)) is noted to be substantial. Thus, although one can categorize the various networks, it is hard to predict an expected packing pattern on the basis of preferred binding in the metal/organic complex alone.

Asymmetric synthesis of the AB ring system of lactonamycin.

[reaction: see text] An enantiospecific synthesis of the AB fragment of lactonamycin (5) is achieved in eight steps from dimethyl D-tartrate. Ester enolate chemistry features prominently in the sequence.

Synthesis and properties of sym-pentasubstituted derivatives of corannulene.

Alkyl, aryl, and alkynyl as well as heteroatom derivatives of sym-pentasubstituted corannulenes have been synthesized from sym-pentachlorocorannulene. These units form potential building blocks for future work on superstructures based on corannulene. Absorption/emission properties follow expected trends from the parent 1. sym-Pentasubstitution gives rise to variations in the chemical dynamics of bowl inversion. van der Waals attraction is cited to explain an anomalously high barrier to bowl inversion in 10.