Time filter

Source Type

Mumbai, India

Patel R.N.,Unimark Remedies Ltd. | Patel R.N.,SLRP Associates LLC
ACS Catalysis | Year: 2011

Chirality is a key factor for the safety and efficacy of many drug products. The production of single enantiomers of drug intermediates has become increasingly important in the pharmaceutical industry. There has been an enormous potential of microorganisms and enzymes derived from there for the transformation of synthetic chemicals with high chemo-, regio-, and enatioselectivities. Recent development in the area of directed evolution has led screen mutants under process conditions to increase activity and selectivity of biocatalysts, thus making the enzymatic process highly efficient and economically feasible. In this review, chemoenzymatic processes are described for the synthesis of chiral intermediates for the development of pharmaceuticals. © 2011 American Chemical Society. Source

Satyanarayana P.,Indian Institute of Chemical Technology | Maheswaran H.,Indian Institute of Chemical Technology | Lakshmi Kantam M.,Indian Institute of Chemical Technology | Chawla H.P.S.,Unimark Remedies Ltd.
Catalysis Science and Technology | Year: 2012

Pregosin's complex Ru(H)(p-cymene)((R)-DTBM-Segphos)(SbF 6) has been shown to be an efficient catalyst for stereoselective asymmetric hydrogenation of 2-benzamido-methyl-3-oxobutanoate to syn-(2S,3R)-methyl-2- (benzamido-methyl)-3-hydroxybutanoate in high diastereoselectivity and enantioselectivity in ethanol. © 2012 The Royal Society of Chemistry. Source

Manvar A.T.,Saurashtra University | Virsodia V.R.,Jubilant Organosys | Upadhyay K.D.,Torrent Research Center | Manvar D.R.,Jubilant Organosys | And 5 more authors.
Molecular Diversity | Year: 2010

In continuation of our research program on new antitubercular agents, this article is a report of the synthesis of 97 various symmetrical, unsymmetrical, and N-substituted 1,4-dihydropyridines. The synthesized molecules were tested for their activity against M. tuberculosis H 37Rv strain with rifampin as the standard drug. The percentage inhibition was found in the range 3-93%. In an effort to understand the relationship between structure and activity, 3D-QSAR studies were also carried out on a subset that is representative of the molecules synthesized. For the generation of the QSAR models, a training set of 35 diverse molecules representing the synthesized molecules was utilized. The molecules were aligned using the atom-fit technique. The CoMFA and CoMSIA models generated on the molecules aligned by the atom-fit method show a correlation coefficient (r 2) of 0.98 and 0.95 with cross-validated r 2(q 2) of 0.56 and 0.62, respectively. The 3D-QSAR models were externally validated against a test set of 19 molecules (aligned previously with the training set) for which the predictive r 2(r 2 pred) is recorded as 0.74 and 0.69 for the CoMFA and CoMSIA models, respectively. The models were checked for chance correlation through y-scrambling. The QSAR models revealed the importance of the conformational flexibility of the substituents in antitubercular activity. Source

Kadivar M.H.,Unimark Remedies Ltd. | Sinha P.K.,Unimark Remedies Ltd. | Kushwah D.,Unimark Remedies Ltd. | Jana P.,Unimark Remedies Ltd. | And 2 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2011

Febuxostat is used in the treatment of hyperuricemia and gout. Several impurities were detected in Febuxostat drug substance. Impurities were identified with the help of LC-MS/MS and were characterized after synthesis by IR and NMR. Reverse phase gradient system was used with Kromasil C18, 150. mm × 4.6. mm, 5 μm particle size column for the separation of impurities. Q-TOF mass spectrometer with electrospray ionization (ESI) source was used and operated in ESI positive mode, which gives exact mass up to four decimal places and fragmentation with mass accuracy, it is useful for the identification of impurities. Four impurities were identified as amide, sec-butyl, des-cyano and des-acid in Febuxostat drug analog. These impurities were further confirmed by NMR and FT-IR spectral data. © 2011. Source

Kushwah D.,Unimark Remedies Ltd. | Patel H.B.,Unimark Remedies Ltd. | Sinha P.K.,Unimark Remedies Ltd. | Jana P.K.,Unimark Remedies Ltd.
E-Journal of Chemistry | Year: 2011

For the determination of accurate quantity of impurities in the samples authentic impurity standards or response factors at a given wavelength must be known. In the presented work a convenient method for determination of relative response factors of impurities has been described without using an authentic impurities standard. An approach for the determination of response factors of the impurities where impurity standard is physically not available was developed and verified using different approaches. One such method was developed and verified by RP-HPLC using Cosmosil C18 MS-II column at UV 238 nm. Two different approaches were employed and the verification of correctness of approach was done using a known related substance of known response factor. © Copyright E-Journal of Chemistry 2004-2011. Source

Discover hidden collaborations