ORIENTAL JOURNAL OF CHEMISTRY www.orientjchem.org An International Open Free Access, Peer Reviewed Research Journal ISSN: 0970-020 X CODEN: OJCHEG 2016, Vol. 32, No. (3): Pg. 1539-1543 Ultrasonic-Promoted Selective Reduction of Aldehydes vs. ketones by NaBH 4 /PhCO 2 Na/H 2 O MINA MIRTAGHIZADEH and DAVOOD SETAMDIDEH* Department of Chemistry, Faculty of Sciences, Mahabad Branch, Islamic Azad University, Mahabad. Iran. *Corresponding author E-mail: davood.setamdideh@gmail.com http://dx.doi.org/10.13005/ojc/320329 (Received: February 09, 2016; Accepted: March 29, 2016) ABSTRACT In this study, we have investigated the selective reduction of aldehydes vs. ketones by NaBH 4 /PhCO 2 Na/H 2 O system under ultrasound irradiation. NaBH 4 (1.25 equivalents) and PhCO 2 Na (2 equivalents) is optimized conditions for reduce a variety of aldehydes (1 mmol) in the presence of ketones (1 mmol) to their corresponding alcohols in water as green solvent in high to excellent yields of the product (90-95%). A benzoate-borane complex [PhCO 2 -H 3 B]Na is possibly the active reductant in the reaction mixture. Keywords: NaBH 4 , Selective Reduction, Aldehydes, PhCO 2 Na, Ultrasound. INTRODUCTION Ultrasound irradiation is an exciting new unconventional energy in organic synthesis during the past decade. The promoted organic reaction by ultrasound irradiation has higher yield, shorter reaction time and milder conditions 1 . The Reduction of aldehydes vs. ketones is interesting in organic synthesis 2 . For this achievement several modified borohydrides 2-3 have been reported. Also some reducing systems have been used for this purpose such as: use of low temperatures 4-5 addition of thiols 6 , metal salts 7 , resins 8 and polyethylene glycol 9 . In this context we have investigated the reducing properties of sodium borohydride (NaBH 4 ) in the presence of sodium benzoate (PhCO 2 Na) as co-reagent for the reduction of aldehydes vs. ketones to their corresponding alcohols in water. This reducing system has been promoted by ultrasound irradiation. RESULTS AND DISCUSSION Aldehydes are more reactive than ketones in reduction reactions. But to achieve for more selectivity, the reduction reactions can be done slower. We have examined the reduction reaction of benzaldehyde as model compound with NaBH 4 in aqueous media in the presence and absence of PhCO 2 Na. Our experiments showed that the reduction reaction of 1 eq. benzaldehyde completed