Dr. Jhillu Singh Yadav – Scientist Par Excellence a Tribute
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Issue in Honor of Dr. Jhillu S. Yadav ARKIVOC 2016 (ii) 1-8 Dr. Jhillu Singh Yadav – Scientist par excellence A Tribute Dedicated to Dr. Jhillu Singh Yadav on the occasion of his outstanding contribution to organic synthetic chemistry I feel privileged to pay tribute to Dr. J. S. Yadav, who has been magnificent as a co-mentor (during my initial career as research fellow) and colleague after I joined the Institute as a scientist. Dr. Yadav was born on the 4th of August, 1950 in Azamgarh, Uttar Pradesh, India. After school in Uttar Pradesh (largest state in India), he Joined Banaras Hindu University, Varanasi (one of the oldest Universities in India) in 1968 and pursued his Bachelors and Masters degrees. He completed his Ph.D in a span of three years from the National Chemical Laboratories, Pune and was awarded a doctorate from Maharaja Sayajirao University of Baroda in 1976 where he was involved in Isolongifolene chemistry under the supervision of Prof. Sukh Dev. He worked as Research Associate at Rice University, Houston, USA and as a postdoctoral fellow at the University of Wisconsin, USA between 1977-1980. He returned to India and joined National Chemical Laboratories as Scientist (1980-1986) and started work on pheromones and fatty acids. In 1986, he moved to the Regional Research Laboratory, Hyderabad (presently known as CSIR- Indian Institute of Chemical Technology) and initiated a new era in the field of synthesis. He became the Director in 2003 and headed the crown institute of CSIR (CSIR-IICT) for 9 years (2003-2012). The scientific career of Dr. Yadav at CSIR-IICT began with a strong focus on asymmetric synthesis. Initially, he was involved in construction of long chain aliphatic compounds containing acetylene moieties. He believed that outstanding achievement in science should benefit society. In order to address the indiscriminate use of harmful pesticides, Dr. Yadav Page 1 ©ARKAT-USA, Inc Issue in Honor of Dr. Jhillu S. Yadav ARKIVOC 2016 (ii) 1-8 pioneered Pheromone Application Technology (PAT) by utilizing insect pheromones, the chemicals released by insects for communication and behavioral response. His contributions in this area had a direct impact whereby insect pheromones were synthesized in the laboratory via unique and viable routes then used to popularize green technology strategies for pest control. Field demonstrations on Ground Nut Leaf Miner (GLM), Brinjal Shoot and Fruit Borer (BSFB), Rice Yellow Stem Borer (YSB) Sugarcane Internode borer (SINB) etc., carried out by Dr. Yadav in collaboration with farmers gained many laurels and the farming community began to appreciate the potential and versatility of PAT. Simultaneously, he established state of the art facilities for conducting pheromone R&D at CSIR-IICT, which was recognized as a National Center for pheromone research in India. In fact, it was a successful beginning to agro practice in Indian farming with a great future as an environmental and ecofriendly alternative to pesticides. Dr. Yadav is one of the most distinguished organic chemists in India. His scientific skills and innovative approaches have paved the way for Indian science to excel in the area of asymmetric synthesis. He nurtured many enthusiastic young scientists in India by developing the art of total synthesis in his group. This exercise was excellent training for budding researchers who excelled in the area of asymmetric synthesis. From the beginning of his research career, he was at the forefront of research in new areas and tackled difficult problems with the deepest insight. His pioneering work on the development of highly enantioselective synthesis of propargyl alcohol derivatives from epoxy alcohol and carbohydrates and subsequent investigations over nearly one decade, marked a milestone in his prolific career that resulted in fundamental contributions to asymmetric chemistry in India (Figure 1). This methodology was illustrated by its application to the total synthesis of several long chain fatty acids such as lipoxin A, Coriolic acid, Octadecanoic acid, Sphingenine, Strongylodiol, and Panaxytriol (Figure 2). His work on the de- oxygenation of epoxy alcohols led to the synthesis of a series of trans-3-hydroxy vinyl compounds (Figure 1). Page 2 ©ARKAT-USA, Inc Issue in Honor of Dr. Jhillu S. Yadav ARKIVOC 2016 (ii) 1-8 R O R' Cl O Tetrahedron 1990, 46, 7033 R' Tetrahedron Lett. 1990, 31, 4495 O O O Cl R a Tetrahedron Lett. c a O 1992, 7973 Tetrahedron Lett. OH 1989, 31, 5455 O R' R R' OH c a R=H, Cl, Cl, J.C.S. Chem Comm. OH a O O 1990, 843, 5071 Cl R' R' O a R R' b R=H, , Chain Tetrahedron Lett. Cl NHR" 2001, 42, 3909 O c R' Tetrahedron Lett. Organic synthons O 1995, 36, 5071 b a O R ON R' NNHTs a R' I Tetrahedron Lett. Tetrahedron Lett. O 1995, 36, 307 2001, 42, 6385 R' Cl Tetrahedron Lett. 1997, 38, 4479 a) LINH or LDA or n-Buli. b) RMgX. c) Cp TiCl/Zn 2 2 Figure 1. Synthesis of chiral allyl and propargyl alcohols. Page 3 ©ARKAT-USA, Inc Issue in Honor of Dr. Jhillu S. Yadav ARKIVOC 2016 (ii) 1-8 OH OH CO2Me CO H CO2Me OH 2 OH OH OH OH Trihydrox octadecanoic acid Lipoxin-A Didehydrocoriolic acid Tetrahedron Lett. 1990, 31, 4349 Tetrahedron Lett. Tetrahedron Lett. 1992, 48, 4465 OH 1988, 39, 143 C H HO 12 25 OH NH2 OH 6-Hydroxy-4E-sphingenine CO H 2 Tetrahedron Lett. 2003, 2983 HO H 9(S)-HETE & 9 (R) 5 Tetrahedron 1998, 54, 3929 OH Virol C OH R' Synthesis 2003, 2699 OH O HO OH COOR R' R HO O HO O R = Cl, =Cl, Triyne carbonate L-660,631 Panaxytriol Tetrahedron Lett. 1990, 31, 5077. Tetrahedron 2002, 58, 4955 X HO HO H Y (R) Strongylodiol - A Tetrahedron Lett. 2002, 43, 1739 OH RR' HO HO C H CO2R 13 27 HO X= OH, Y=H NH2 OH X=H, Y= OH R=H, R'=OH, (D)-Erythro HO Trihydroxyeicosa Trienoic acid R=OH, R'=H, (L)-Threo Tetrahedron Lett. 1994, 35, 641. Sphingosines Trihydroxyeicosa Trienoic acid Tetrahedron Lett. 1993, 34, 1191 Tetrahedron Lett. 1992, 33, 135 Figure 2. Applications of allyl and propargyl alcohols. Dr. Yadav’s papers dealing with intermolecular [4 + 3] cycloaddition followed by desymmetrization giving rise to five contiguous chiral centers in a highly diastereoselective manner, paved the way to major developments in the utilization of this protocol for the total synthesis of a variety of complex biologically active natural products with multiple chiral centers such as Rifamycin, Discodermolide, Scytophycin, Siphonarin, Methynolide, Azaspiric Acid, Callystatin, Saliniketal A&B, Venturicidin X, Crocacin etc., (See Figure 3 for few structures). Page 4 ©ARKAT-USA, Inc Issue in Honor of Dr. Jhillu S. Yadav ARKIVOC 2016 (ii) 1-8 MeO OO OMe OAc OH OH OH OH O NH2 O O O OMeOMe H OH OH O N N H Discodermolide O OH O OMe Me O Tetrahedron Lett. 2001, 42, 4713 O R OH O O O O Scytophycin Tetrahedron lett. 2002, 43, 7147 Rifamycin JCS. Chem.commun, 1995, 55 O O R Tetrahedron Lett. 1995, 36, O O 7717 OH OH HO O R = H, Saliniketal R = OH, OBn OBn Saliniketal B J. Org. Chem. 2009, 74, 8822 OH O O O O O O O O O OHHO OHOH O NH OH OBn O Tetrahedron Lett. 1995, 36, 7717 Tirandamycin HO Siphonarin O Tetrahedron 2009, 65, 3545 J. Org. Chem. 2012, 77, 9628 O O O O OO HO O O O OH Me Me Me Me Me O Membrenone C Tetrahedron Lett, 2006, 1603 OH Methynolide O OH Callystatin O J. Org. Chem. 2007, 5882 Tetrahedron lett. 2011, 52, 4269 Maurenone Synlett 2007, 1957 Figure 3 Dr. Yadav was the first to develop directed-Prins cyclization protocol for the synthesis of 2,4,6-syn-trisubstituted tetrahydropyran derivatives under environmentally benign conditions and further transformations for the formation of anti-1,3-diol, that lead to the total synthesis of a number of highly complex natural products such as Crocacin A, Salicylihalamides A & B, Apicularen A, Tetrahydrolipstatin (Figure 4) which amply demonstrated the value of his approach. Page 5 ©ARKAT-USA, Inc Issue in Honor of Dr. Jhillu S. Yadav ARKIVOC 2016 (ii) 1-8 O Me OH OH N Me OH O Ph O O (-)-Sedamine Prelactone C Tetrahedron Lett. 2N OH Tetrahedron Lett. 2005 Basiliskamide A & B 2006, 47,4397, 2006 46, 2133 Tetrahedron Lett. 2008, 5427 NH NHCHO OH O O O O O OH O O R' CH3 n-C11H23 R CHO + (-)-Salicylihalamides A and B (-)-Tetrahydrolipstatin HO R'' Synthesis 2007, 1070 Tetrahedron Lett. , 47, 4995 Acid 2006 O catalyst, Nu Nu OAc OAc O Me Me R' NH2 Cryptocarya diacetate OMeOMe Me O R O R'' Tetrahedron Lett. 2007 Crocacin C Major isomer 1469 Synlett, 2007, 2049 OH OH O Me O O O Diospongin A Prelactone B Synlett, 2007, 2045 Tetrahedron Lett 2005, OO TBSO 46, 2133 O O O O 10 OH O O O OH TBSO O OH C4H9 (-)- Tarchonanthuslactone OH Pheromone Tetrahedron, 2007, 2689 Muconin Tetrahedron Lett. 2006, 47, 4397 Tetrahedron Lett. 2014, 55, 3860 Figure 4 Through his vast expertise in the Chemistry of Natural Products, many programmes and projects were explored on the utility of natural products for human health care at different CSIR laboratories under the project title “Bioactives from Natural Products”. The herbal drug standardization programme and Golden Triangle Partnership Programmes on Ayurvedic Products & Bhasmas benefited many Ayurvedic industries such as M/S Arya Vaidya Sala (AVS), Kottakkal; Indian Medicines and Pharmaceuticals Corporations Limited (IMPCL), Mohan; Hamdard Research Foundation, New Delhi.