• MANDALA ANITHA

      Articles written in Journal of Chemical Sciences

    • FeCl3 catalysed regioselective allylation of phenolic substrates with (𝛼-hydroxy)allylphosphonates

      Mandala Anitha Ramesh Kotikalapudi K C Kumara Swamy

      More Details Abstract Fulltext PDF

      Electrophilic allylation of phenolic substrates including salicylaldehydes with (𝛼-hydroxy) allylphosphonates is presented. It is observed that catalytic FeCl3 is sufficient to accomplish the allylation. Interestingly, the reaction led to the formation of allylphosphonates in addition to vinylphosphonates, depending upon the substituent. The vinylphosphonates obtained here are 𝐸-isomers. More importantly, the reaction occurred regioselectively with respect to the phenolic substrates. Substituted allylphosphonates are formed when salicylaldehyde or (2-hydroxy-phenyl)arylmethanones are used. Conclusive proof for the formation of allylphosphontates as well as vinylphosphonates has been provided by single crystal X-ray crystallography.

    • New reactions of allenes, alkynes, ynamides, enynones and isothiocyanates

      K C KUMARA SWAMY G GANGADHARARAO MANDALA ANITHA A LEELA SIVAKUMARI ALLA SIVA REDDY ADULA KALYANI SRINIVASARAO ALLU

      More Details Abstract Fulltext PDF

      Abstract. This perspective article is related to transformations (both catalytic and non-catalytic) involving allenes, alkynes/enynones/ynamides and isothiocyanates. Part of the work from the author’s group has been reviewed along with some new reactions of (i) allenylphosphonate/allenylphosphine oxide and (ii) a P(III) isothiocyanate. Thus, the allenylphosphine oxide Ph2P(O)C(Ph)=C=CH2 undergoes base (DBU) catalyzed addition to the β-ketophosphonate (OCH2CMe2CH2O)P(O)CH2C(O)CH3 at 90°C to afford the addition product Ph2P(O)C(Ph)=C(Me)CH[C(O)Me][P(O)(OCH2CMe2CH2O)]. In an analogous reaction, with DBU as the base at 140°C, isomeric vinylphosphine oxides (Z)-Ph2P(O)C(Ph)=C(Me)CH2[C(O)Me] and (E)-Ph2P(O)C(Ph)=C(Me)CH2[C(O)Me] were isolated. The E-isomer has been characterized by single crystal X-ray structure determination. In another set of studies, the reaction of P(III) isothiocyanate (OCH2CMe2CH2O)P(NCS) with N-(2-bromomethyl)sulfonamide afforded an unusual product with the formula(OCH2CMe2CH2O)P(O)SCH2CH2NHS(O)2-(C6H4-4-Me) as shown by X-ray structure determination. This result is different from that obtained in the recently reported analogous reaction using phenyl isothiocyanate.

    • Reactivity of ynamides with AlCl3 and ICl: Ready access to (E)-achloroenamides and (E/Z)-a-chloro-b-iodo-enamides

      ALLA SIVA REDDY MANDALA ANITHA SURAJ K C KUMARA SWAMY

      More Details Abstract Fulltext PDF

      AlCl3 acts as a chlorinating agent for ynamides in the presence of stoichiometric amount of water in the environmentally benign solvent dimethylcarbonate, affording efficient access to (E)-a-chloroenamides via hydrochlorination, with water as a protic source. The role of water in the reaction was proven by deuterium labelling experiment. Epoxy-ynamides undergo iodochlorination in addition to the cleavage of the epoxy ring to afford (E/Z)-a-chloro-b-iodo-enamides. Regio- and stereochemical assignments for the products are based on X-ray crystallographic studies.

      Chloroenamides are formed regio- and stereo-specifically via hydrochlorination of ynamides with AlCl3+H2O (1:1) in a dimethyl carbonate; aryl substituted epoxy ynamides afford (iodo)(chloro) enamides upon treatment with ICl.

  • Journal of Chemical Sciences | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2021-2022 Indian Academy of Sciences, Bengaluru.