@article { ISI:000230909100041, title = {Self-assembly with degenerate prototropy}, journal = {Journal of Organic Chemistry}, volume = {70}, number = {16}, year = {2005}, month = {AUG}, pages = {6461-6467}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

This work describes a rational approach for addressing the prototropy-related problems in heterocycle-based self-assembling systems by the use of degenerate prototropy. As a proof of principle, the utility of degenerate prototropy is demonstrated herein by developing heterocycle-based AADD-type self-assembling modules that exist as {\textquoteleft}{\textquoteleft}single set of protameric pair (duplex){\textquoteright}{\textquoteright} in both solution and solid states. These self-assembling modules are quickly accessible in good yield by reacting 2-amino-5,5-disubstituted-1H-pyrimidine-4,6-diones, available in one step by the condensation of (x,a-dialkyl malonates and free guanidine, with isocyanates. Evidence from NMR spectroscopy, ESI mass spectrometry, and single-crystal X-ray diffraction studies confirmed the formation of molecular duplexes. The effect of electronic repulsion in duplex formation is also investigated. Their ready synthetic accessibility, remarkably high propensity to crystal formation, and the novel property of degenerate prototropy would make these novel self-assembling molecules promising candidates for many proposed applications.

}, issn = {0022-3263}, doi = {10.1021/jo0508705}, author = {Baruah, Pranjal K. and Gonnade, Rajesh G. and Phalgune, U. D. and Sanjayan, G. J.} } @article {Shanbhag, title = {Enantioselective syntheses of (-)-pinellic acid, alpha- and beta-dimorphecolic acid}, journal = {Tetrahedron}, volume = {63}, number = {32}, year = {2007}, month = {AUG}, pages = {7624-7633}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

An efficient enantioselective convergent approach for the synthesis of (-)-pinellic acid 1, alpha- and beta- dimorphecolic acid (2 and 3) from 1,9-nonane diol is described. The synthetic strategy features Sharpless asymmetric hydroxylation, Sonogashira coupling and Birch reduction. (C) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {asymmetric dihydroxylation, influenza, Sonogashira coupling}, issn = {0040-4020}, doi = {10.1016/j.tet.2007.05.047}, author = {Baruah, Pranjal K. and Gonnade, Rajesh G. and Sanjayan, Gangadhar J.} } @article {45}, title = {Enforcing periodic secondary structures in hybrid peptides: a novel hybrid foldamer containing periodic gamma-turn motifs}, journal = {Journal of Organic Chemistry}, volume = {72}, number = {2}, year = {2007}, month = {JAN}, pages = {636-639}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, abstract = {

{This note describes the design, synthesis, and conformational studies of a novel hybrid foldamer that adopts a definite compact, three-dimensional structure determined by a combined effect of the special conformational properties of the foldamer constituents. The striking feature of this de novo designed foldamer is its ability to display periodic gamma-turn conformations stabilized by intramolecular hydrogen bonds. Conformational investigations by single-crystal X-ray studies, solution-state NMR, and ab initio MO theory at the HF/6-31G*

}, keywords = {ammonia-TPD, benzylation reaction, Ce-Al-MCM-41, Friedel-Crafts alkylation, pyridine-FrIR}, issn = {0935-9648}, doi = {10.1021/jo062032w}, author = {Baruah, Pranjal K. and Sreedevi, N. K. and Gonnade, Rajesh G. and Ravindranathan, Sapna and Damodaran, Krishnan and Hofmann, Hans-Joerg and Sanjayan, Gangadhar J.} } @article { ISI:000252757100013, title = {Sheet-forming abiotic hetero foldamers}, journal = {Chemical Communications}, number = {6}, year = {2008}, month = {DEC}, pages = {712-714}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Abiotic hetero oligomers, adopting a well-defined extended self-assembled sheet-like structure, derived from conformationally constrained aliphatic and aromatic amino acid residues repeating at regular intervals are reported.

}, issn = {1359-7345}, doi = {10.1039/b713229h}, author = {Baruah, Pranjal K. and Sreedevi, Naduthottiyil K. and Majumdar, Baisakhi and Pasricha, Renu and Poddar, Pankaj and Gonnade, Rajesh G. and Ravindranathan, Sapna and Sanjayan, Gangadhar J.} } @article { ISI:000380138100025, title = {Bronsted-acid-mediated divergent reactions of betti bases with indoles: an approach to chromeno[2,3-b]indoles through intramolecular dehydrogenative C2-alkoxylation of indole}, journal = {European Journal of Organic Chemistry}, number = {20}, year = {2016}, month = {JUL}, pages = {3441-3448}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

Divergent reactions of various 1-(aminoalkyl) naphthols and 2-(aminoalkyl) phenols (commonly known as Betti bases) with indoles under Bronsted acid catalysis is reported. With the reaction strategies, one can efficiently synthesize important indole derivatives such as 3-(alpha,alpha-diarylmethyl)indoles and chromeno[2,3-b]indoles. Furthermore, we disclose here a new C-C bond-cleavage reaction, in which naphthol and phenol behave as leaving groups to produce diarylmethanes. Inexpensive reagents such as p-toluenesulfonic acid monohydrate and molecular iodine are used to catalyze the reactions. No metal catalyst is required. The starting material of the reactions, Betti bases, are easily prepared from a three-component reaction of naphthol/phenol, aldehydes, and secondary amines. The mechanisms for the reactions are established through some control experiments. Quinone methide is the key intermediate for all the reactions reported herein.

}, keywords = {Betti bases, C-O bond formation, Dearylation, Fused-ring systems, nitrogen heterocycles}, issn = {1434-193X}, doi = {10.1002/ejoc.201600546}, author = {Deb, Mohit L. and Pegu, Choitanya Dev and Deka, Bhaskar and Dutta, Prantu and Kotmale, Amol S. and Baruah, Pranjal K.} }