Pranab K. Patra

Organocatalytic synthesis of N-Phenylisoxazolidin-5-ones and a one-pot synthesis of beta-amino acid esters.

A novel N-heterocyclic carbene (NHC)-catalyzed C-N bond formation by the reaction of alpha,beta-unsaturated aldehydes and nitrosobenzene to N-phenylisoxazolidin-5-ones, followed by an acid-catalyzed esterification and Bamberger-like rearrangement in a mild one-pot protocol leads to N-p-methoxyphenyl (N-PMP) protected beta-amino acid esters.

N-Heterocyclic Carbene (NHC)-Catalyzed Direct Amidation of Aldehydes with Nitroso Compounds

NHC-catalyzed direct amidation of aldehydes with nitroso compounds is a powerful method for the synthesis of N-arylhydroxamic acids. A variety of aryl, alkyl, alkenyl, and heterocyclic aldehydes were found to give excellent yields of the corresponding N-arylhydroxamic acids. This chemistry was also extended to the synthesis of chiral N-arylhydroxamic acids by kinetic resolution of alpha-branched aldehydes, a domino amidation-redox amination reaction of acrolein, and a three-component reaction for the synthesis of N-arylaziridines.

A practical improvement of odorless Corey–Kim and Swern oxidations

Methyl 6-morpholinohexyl sulfide (3a, MMS) and methyl 6-morpholinohexyl sulfoxide (7, MMSO) have been employed as efficient odorless substitutes for dimethyl sulfide (DMS) and dimethyl sulfoxide (DMSO) in Corey–Kim and Swern oxidations, respectively. The oxidation products and the byproduct 3a are easily separable by simple aqueous extraction. The Corey–Kim oxidation was studied in various solvents. The utility of the odorless 6-morpholinohexan-1-thiol (2a) in the dealkylation of phenyl ethers and methyl esters is also presented.

Odorless Diphenyl Diselenide and Disulfide: Syntheses and Applications

Bis[4-(trimethylsilyl)phenyl]diselenide (3) and bis[4-(trimethylsilyl)phenyl]disulfide (31) are found to be odorless equivalents of the commonly used diphenyl diselenide and diphenyl disulfide, respectively. The diselenide 3 is shown to be useful in the preparation of odorless selenium(II) chloride 26 and selenium(IV) trichloride 28 that follow similar reactivity patterns to their phenyl derivatives and can be stored refrigerated under dry conditions. The corresponding selenium(II) bromide had to be prepared fresh from 3 before use. It is also shown that the trimethylsilyl group in the sulfide products can be protodesilylated quantitatively using TFA.