ABSTRACT
Herein, we developed a new SnCl2-mediated ANRORC (addition of nucleophile, ring-opening, and ring-closure)-like rearrangement for the synthesis of 3-amino-2-substituted-quinazolin-4(3H)-one from 2-(2-nitrophenyl)-5-substituted-1,3,4-oxadiazole. The new method is solvent-dependent and features the use of a green solvent system (i.e., ethanol/water), high yields, and simple workup. The reduced product could be exclusively synthesized by changing the solvent to acetonitrile.
ABSTRACT
We have developed a novel method for the synthesis of benzotriazolyl alkyl esters (BAEs) from N-acylbenzotriazoles and dichloromethane (DCM) under mild conditions. This reaction is one of few examples to show the use of DCM as a C-1 surrogate in carbon-heteroatom bond formation and to highlight the versatility of using DCM as a methylene building block.
ABSTRACT
Michael, Michael-annulation, and oxa-Diels-Alder reactions of carbohydrate derivatives that afford polyoxy-functionalized piperidine derivatives bearing tetrasubstituted carbon at the 3-position of the piperidine ring are reported. Iminium ions generated from carbohydrate derivatives with amines were converted to enamines in situ, which acted as nucleophiles. As a result, substituents were introduced at the 3-position or both 2- and 3-positions of the piperidines bearing polyoxy groups. This strategy will be useful in drug discovery efforts.
ABSTRACT
Mannich reactions of carbohydrate derivatives with ketones that afford polyoxy-functionalized piperidines are reported. Ketone nucleophiles (enamines/enolates) were generated in the presence of the amines used for the formation of the iminium ions of sugar derivatives with or without an additive. Conditions to preferentially generate piperidine derivatives rather than tetrahydrofurans were identified. Products from the reactions of allyl ketones were readily transformed to bicyclic piperidines.
