A Serendipitous Synthesis of 11a-Hydroxy-11,11a-dihydrobenzo[e]indeno[2,1-b][1,4]diazepine-10,12-dione Derivatives by Condensation of 2-Aminobenzamides with Ninhydrin in Water.

Ninhydrin undergoes an unprecedented condensation reaction with various 2-aminobenzamide derivatives in boiling water to afford 11a-hydroxy-11,11a-dihydrobenzo[e]indeno[2,1-b][1,4]diazepine-10,12-dione derivatives. These hitherto unreported products are easily isolated in high yield by a simple filtration step. An interesting "ortho effect" was observed in the condensation reaction of ninhydrin with 2-amino-N-phenylbenzamide derivatives having an ortho- substituent in the N-phenyl moiety wherein the corresponding expected 3'-phenyl-1'H-spiro[indene-2,2'-quinazoline]-1,3,4'(3'H)-triones were obtained.

One-pot synthesis of per-O-acetylated hemiacetals from free sugars in a deep eutectic solvent.

Free sugars reacted with acetic anhydride in a deep eutectic solvent made from choline chloride and ZnCl2 at 90 °C to afford the corresponding peracetates that on further heating to 100 °C underwent selective deacetylation at the anomeric position to furnish the corresponding peracetylated hemiacetals in good yield.

Ferrier reaction in a deep eutectic solvent.

A mild and efficient synthesis of 2,3-unsaturated sugar derivatives has been achieved by conducting the Ferrier reaction in a deep eutectic solvent (DES). A wide range of alcohols including primary, secondary, benzylic, and sugar-derived primary alcohols can be used. Advantages include good yields, shorter reaction times and recyclability of DES.