The role of ammonia in promoting ammonia borane synthesis

Mechanistic studies point toward added ammonia acting as a reagent while promoting the high-yielding synthesis of pure ammonia borane from sodium borohydride and ammonium salts.

Amine–boranes bearing borane-incompatible functionalities: application to selective amine protection and surface functionalization

The first general open-flask synthesis of amine–boranes with inexpensive and readily available reagents, such as sodium borohydride, sodium bicarbonate, water, and the desired amines is described.

Role of dual time fluorodeoxyglucose (FDG) positron emission tomography-computed tomography in identifying co-existing inflammatory and malignant disease: Who holds it (FDG) longer?

18-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) is an integral part of imaging in the follow-up of head and neck malignancies. Very often distinguishing inflammatory/infective from malignant recurrence cannot be made confidently with standard uptake value (SUV) alone, as inflammatory lesions have shown to have a very high SUV, and in some cases both can co-exist. In such doubtful cases, dual time PET-CT (3-5 h delayed) is of paramount importance in confidently differentiating inflammatory/infective from a malignant cause.

Asymmetric synthesis of γ-aryl-substituted GABA derivatives via a highly diastereoselective Rh-catalyzed boronic acid addition at room temperature

A highly diastereoselective Rh-catalyzed boronic acid addition to enantiopure sulfinylimines at room temperature providing γ-aryl GABA derivatives has been described.

Facile synthesis of 1-trifluoromethylalkenes via the decarboxylation of α-trifluoromethyl-β-lactones

DCC-mediated cyclodehydration of α-trifluoromethyl-β-hydroxy acids provides α-trifluoromethylated β-lactone intermediates, without loss of stereoselectivity. These lactones undergo facile decarboxylation providing a simple route to obtain both alkyl and aryl 1-trifluoromethyl alkenes in excellent yields and stereoselectivity.

In celebration of the 80th birthday of Professor Ei-ichi Negishi

Photo credit © Steve Scherer, Purdue University.

Ammonia-mediated, large-scale synthesis of ammonia borane

The presence of NH₃ allows a high concentration, ambient temperature synthesis of ammonia borane from sodium borohydride in air using reagent-grade THF.

Diastereoselective synthesis of α-(aminomethyl)-γ-butyrolactones via a catalyst-free aminolactonization

An auto-catalytic domino reaction involving an aza-Michael reaction, proton transfer, and lactonization furnishing α-aminomethyl-γ-butyrolactones in near quantitative yields and excellent diastereoselectivity is described.

Synthetic α-(aminomethyl)-γ-butyrolactones and their anti-pancreatic cancer activities

Aminated α-methylene-γ-butyrolactones, which are readily synthesized with facile control of the diastereoisomerism, provide an economical and commercially-viable alternative to the use of aminated natural products. These aminoloactones, which exhibit excellent activity against three pancreatic cancer cell lines when measured at 10 μM-Panc-1, MIA PaCa-2, and BxPC-3-and are comparable to or better than parthenolide and dimethylaminoparthenolide (DMAPT, LC-1). It has also been shown that there is an effect on the biological activity depending on the identity of the amine.

Enantioselective synthesis of anti- and syn-β-hydroxy-α-phenyl carboxylates via boron-mediated asymmetric aldol reaction

A reagent-controlled, diastereo- and enantioselective synthesis of anti- and syn-β-hydroxy-α-phenyl carboxylates has been achieved by the proper choice of solvent, temperature, alkoxy group, and amine for the diisopinocampheylboron-mediated asymmetric enolization-aldolization of phenylacetates. The pure diastereomers can be readily separated by column chromatography.