@article { ISI:000234092500005, title = {Convenient synthesis of the enantiomerically pure beta-blocker (S)-betaxolol using hydrolytic kinetic resolution}, journal = {Tetrahedron-Asymmetry}, volume = {16}, number = {23}, year = {2005}, month = {NOV}, pages = {3802-3806}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Enantiopure (S)-betaxolol was prepared in an extremely simple and practical way using hydrolytic kinetic resolution of a terminal epoxide by Jacobsen{\textquoteright}s catalyst. High enantiomeric purity (99\% ee) has been achieved and the method is amenable to industrial scale-up. (c) 2005 Elsevier Ltd. All rights reserved.

}, issn = {0957-4166}, doi = {10.1016/j.tetasy.2005.10.028}, author = {Joshi, Ramesh A. and Garud, Dinesh R. and Muthukrishnan, Murugan and Joshi, Rohini R. and Gurjar, M. K.} } @article { ISI:000244054900016, title = {Concise synthesis of beta-blockers (S)-metoprolol and (S)-betaxolol using hydrolytic kinetic resolution}, journal = {Tetrahedron}, volume = {63}, number = {8}, year = {2007}, month = {FEB}, pages = {1872-1876}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Enantiopure (S)-metoprolol and (S)-betaxolol were prepared in an extremely simple and practical way using Jacobsen{\textquoteright}s hydrolytic kinetic resolution of terminal epoxides in isopropanol. (c) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {beta-blockers, betaxolol, Hydrolytic kinetic resolution, metoprolol}, issn = {0040-4020}, doi = {10.1016/j.tet.2006.12.016}, author = {Muthukrishnan, Murugan and Garud, Dinesh R. and Joshi, Rohini R. and Joshi, Ramesh A.} } @article { ISI:000259450800027, title = {Continuous flow nitration of salicylic acid}, journal = {Organic Process Research \& Development}, volume = {12}, number = {5}, year = {2008}, month = {SEP}, pages = {995-1000}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Continuous flow nitration of salicylic acid using HNO3/AcOH was studied in the SS316 tubular microreactor. At specific reaction conditions, complete conversion of the reactant was achieved in less than 7 min. It yielded only mononitro derivatives with a higher selectivity of 5-nitrosalicylic acid. Presence of the lower amount of acetic acid in the reaction mixture was seen to be detrimental, leading to precipitation of the desired product (5-nitrosalicylic acid). Reaction at higher temperatures yielded byproducts. The continuous mode operation using the system comprising the microdevices was demonstrated for 2 h with consistent composition at the outlet.

}, issn = {1083-6160}, doi = {10.1021/op800112u}, author = {Kulkarni, Amol A. and Nivangune, Nayana T. and Kalyani, Vishwanath S. and Joshi, Ramesh A. and Joshi, Rohini R.} } @article { ISI:000269892100029, title = {Continuous flow nitration of benzaldehyde}, journal = {Organic Process Research \& Development}, volume = {13}, number = {5}, year = {2009}, note = {235th American-Chemical-Society National Meeting, New Orleans, LA, APR 06-10, 2008}, month = {OCT}, pages = {999-1002}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

The nitration of benzaldebyde can be carried out in a safe manner in continuous mode using a microreactor system. Choice of a micromixer was seen to affect the performance of this two-phase reaction significantly The reaction time could he brought down to 2 min by increasing the reaction temperature and thereby taking advantage of higher heat transfer area. The simple T-micromixer is seen to be inefficient for two-phase reactions. Further scope of process intensification is also discussed.

}, issn = {1083-6160}, doi = {10.1021/op000129vv}, author = {Kulkarni, Amol A. and Kalyani, Vishwanath S. and Joshi, Ramesh A. and Joshi, Rohini R.} } @article { ISI:000326121800014, title = {Continuous flow multipoint dosing approach for selectivity engineering in sulfoxidation}, journal = {Organic Process Research \& Development}, volume = {17}, number = {10}, year = {2013}, month = {OCT}, pages = {1293-1299}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A continuous synthesis approach with multipoint dosing of one of the reagents is demonstrated for the synthesis of sulfoxide compounds such as proton pump inhibitors. Use of multipoint dosing of the oxidizing agent helped to minimize the possibility of over-oxidation leading to sulfone. Different oxidizing agents were used, and the effect of various parameters (viz. mole ratio of sulfide to oxidizing agent, temperature, residence time, concentration of oxidizing agent, etc.) on the yield of the desired sulfoxide compound was studied. Single-point and multipoint dosing approaches of the oxidizing agent were used for the most promising set of parameters. The performance was compared in terms of conversion of sulfide and the selectivity of the desired sulfoxide. Numbering up approach was used to produce the sulfoxide in a relatively large quantity at laboratory scale with complete conversion and over 99\% selectivity for the sulfoxide.

}, issn = {1083-6160}, doi = {10.1021/op400138v}, author = {Kulkarni, A. A. and Nivangune, N. T. and Joshi, Rohini R. and Joshi, Ramesh A.} } @article { ISI:000346134300012, title = {Continuous-flow meerwein arylation}, journal = {Journal of Flow Chemistry}, volume = {4}, number = {4}, year = {2014}, month = {DEC}, pages = {211-216}, publisher = {AKADEMIAI KIADO RT}, type = {Article}, address = {PRIELLE K U 19, PO BOX 245,, H-1117 BUDAPEST, HUNGARY}, abstract = {

The continuous-flow Meerwein arylation is demonstrated for a set of few aryl donors (anilines and m-aminoacetophenone) and specific radical acceptors. Homogeneous catalyst (CuBr in HBr and CuCl in HCl) was used to facilitate the reaction. The effect of parameters, viz., temperature, catalyst concentration, residence time, and concentration of the radical acceptor on the yield of the arylated product, was studied. The yield of the aryl derivative obtained by continuous-flow syntheses was always better than the respective experiments in batch mode. Flow synthesis allows easy variation in these parameters and thus allows going close to the maximum possible yields in a system where the relative rates of different reactions create a complex situation. Temperature plays a crucial role by affecting the rates as well as by governing the system homogeneity. The nitrogen bubbles generated in the reaction helped to avoid any channel blockage.

}, keywords = {diazonium salt, flow chemistry, homogeneous catalyst, Meerwein arylation, micromixer, multistep synthesis}, issn = {2062-249X}, doi = {10.1556/JFC-D-14-00023}, author = {Bhaya, Vinay G. and Joshi, Ramesh A. and Kulkarni, Amol A.} } @article { ISI:000361866400009, title = {Continuous-flow nitration of o-xylene: effect of nitrating agent and feasibility of tubular reactors for scale-up}, journal = {Organic Process Research \& Development}, volume = {19}, number = {9, SI}, year = {2015}, month = {SEP}, pages = {1138-1147}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Continuous-flow nitration of o-xylene has been studied with different nitrating agents over a wide range of conditions for different parameters such as temperature, residence time, and concentrations. A nitrating mixture comprising sulfuric acid and fuming nitric acid was seen to yield higher selectivity for the isomer 1,2-dimethyl-3-nitrobenzene over the isomer 1,2-dimethyl-4-nitrobenzene and also a non-negligible quantity of dinitro derivatives of o-xylene. With only fuming nitric acid as the nitrating agent, the reaction was selective for 1,2-dimethyl-4-nitrobenzene over 1,2-dimethyl-3-nitrobenzene. Impurities mainly come from nitration of mononitro derivatives, and this occurs more from nitration of the 3-nitro isomer because of its higher reactivity with nitric acid. An economic analysis of the continuous-flow reactor for the production of 1,2-dimethyl-4-nitrobenzene at 100 and 500 kg/h in a jacketed tubular reactor showed that numbering-up is a more economical approach for higher production capacity. A combination of large- and small-sized tubes depending upon the relative rates of heat generation during a reaction will achieve more profit and a shorter payback period than having the entire reactor made of a single tube size.

}, issn = {1083-6160}, doi = {10.1021/acs.oprd.5b00064}, author = {Sharma, Y. and Joshi, Ramesh A. and Kulkarni, A. A.} } @article {42544, title = {Continuous flow doebner{\textendash}miller reaction and isolation using continuous stirred tank reactors}, journal = {Organic Process Research \& Development}, volume = {20}, year = {2016}, month = {AUG}, pages = {1621{\textendash}1625}, abstract = {

Continuous flow Doebner{\textendash}Miller synthesis of different quinaldines from respective anilines is demonstrated using sulfuric acid as a homogeneous catalyst. The extent of reaction was monitored for various parameters, namely, temperature, residence time, mole ratio of sulfuric acid to substrate, mole ratio of crotonaldehyde to substrate, and so forth. Continuous stirred reactors in series were used as a preferred configuration for this rection that generates byproduct in the form of sticky solid material. The approach has been extended for six different anilines, and the results are compared with batch reactions. Continuous stirred reactors in series with distributed dosing of crotonaldehyde facilitated a continuous flow reaction with lower byproduct formation, increased yields, and continuous workup and is a scalable approach.

}, doi = {10.1021/acs.oprd.6b00179}, author = {Yadav, Maruti B. and Kulkarni, Sourabh and Joshi, Ramesh A. and Kulkarni, Amol A.} } @article {43566, title = {Continuous flow telescopic oxidation of alcohols via generation of chlorine and hypochlorite}, journal = {Reaction Chemistry \& Engineering}, year = {2017}, month = {MAR}, abstract = {A 3-step continuous flow oxidation of alcohols is demonstrated with continuous generation of chlorine as the first step followed by its use for the flow synthesis of high strength sodium hypochlorite. The solution is subsequently used for oxidation of alcohols in the presence of a catalytic amount of the nitroxyl radical {\textquotedblleft}TEMPO{\textquotedblright}, which inhibits oxidation at the aldehyde stage. Selective oxidations of eight different alcohols were demonstrated. To achieve identical yields, the aromatic alcohols containing electron withdrawing groups needed a longer residence time than aliphatic alcohols.}, doi = {10.1039/C6RE00225K}, author = {Sharma, Y. and Moolya, S. and Joshi, Ramesh A. and Kulkarni, Amol A.} }