hydroxy 3 nitromethylindolin 2 ones of formula application_number US 201313921957 A description the present invention pertains to improved and novel method of preparing oxindole derivatives having substituents attached in the 3 position the so obtained nitroalcohols are valuable synthetic intermediates for several organic transformations especially in the synthesis of 1 2 amino alcohols the 3 substituted 3 hydroxy oxindole derivatives provided in the present invention can be generally termed as henry adduct and its importance is g chen x j hao q y sun j ding chemical papers 2010 64 673 677 by way of a non limiting example the 3 substituted 3 hydroxy oxindole derivatives provided in the present invention may be used in the general scheme as shown below the foregoing and other features of the present invention will be fully understood from the detailed description of illustrative examples according to certain embodiments compounds of the invention are represented by general formula as described below r 1 h x 1 at c 7 position or x 2 at c 5 position x 2 h f cl br i no 2 ch 3 ocf 3 when r h then r 1 x 1 at c 7 position or x 2 at c 5 position when r ch 3 c 3 h 5 c 7 h 6 u2014 x then r 1 h when r c 7 h 6 u2014 x then r 1 x 2 at c 5 position when x h cl or br then r 1 cl at c 5 position the compounds of this invention are prepared by reacting isatin or substituted isatin of general formula i with nitromethane in aqueous medium to give corresponding 3 hydroxy 3 nitromethylindolin 2 ones ii in high yields according to the.