#3: Prof.Takeshi Kitahara: The harmony of chemistry and biology: synthesis

#3: Prof.Takeshi Kitahara: The harmony of chemistry and biology: synthesis

The third interview of this series is with Professor Takeshi Kitahara from the School of Pharmacy at Teikyo Heisei University (also Professor Emeritus at the University of Tokyo), introduced to us by Professor Tohru Fukuyama at our first Chem-Station interview. Professor Kitahara has been well-known since the development of “Danishefsky’s diene” from his postdoc days, but he was also heavily involved in the total synthesis of compounds related to the fields of plant physiology, plant hormones, and plant protective agents during his stay at the University of Tokyo. Based on his distinguished achievements, he was awarded the Japan Academy Prize in 2010. Please read on to find out more about him on a personal level!

Q: What made you choose chemistry as a career? If you were not a chemist, what would you like to be, and why?

A: I guess my answer here is an answer to both of these questions combined. Also, before I start my story, I refer you to a short text I wrote (entitled “Life full of accidental encounters: the path I chose”) that summarizes my lecture (entitled “When I awakened to a life in academia”) at a 2002 symposium for the Academic Guidance Center in the Department of Arts and Sciences at the University of Tokyo; this can be found on the internet at http://park.itc.u- tokyo.ac.jp/agc/news/32/kitahara.html.

I grew up in the mountains on a countryside during the times when Japan was poor, but I was then blessed with the golden opportunity of attending university. Although I loved language arts and history, I knew that it would be hard to make a living studying these topics. I also liked the physical sciences and chemistry in particular, and I believed that I could ride the national wave of technological development at the time to gain financial freedom. So rather than pursuing chemistry out of pure passion, there were some “impure motives” under the circumstances of my upbringing.

Ever since I was a boy, I have been confident that I am second to none in terms of proficiency in reading books. I was a sickly child, and back in Grade 8, when I got sick and stayed home for 2 weeks, I read Sima Qian’s “Records of the Grand Historian” over and over until I practically memorized the entire book. Thereafter, I read various texts regarding Chinese history, and I am proud to admit that I love history. If I were to choose a career now, I might indeed choose history. I would like to study in depth not only Chinese history but also events regarding the Silk Road, Turkey and its surrounding areas, as well as the rise and fall of various empires that stood as the meeting point of the East and the West.

 

Q: Currently, what kind of research are you conducting? Moreover, how do you foresee its future development?

A: I am currently at a stage where I just give lectures in general or organic chemistry at various universities following my mandatory retirement. Therefore, I must say that I am not actively participating in research at the forefront of science. There are, however, two projects that I really want to continue studying, and so the company where I consult has agreed to collaborate with me on these topics: 1) development of the synthesis and function of mugineic acid and related compounds, which serve as agents that aid plant growth in barren, alkaline soil; 2) identification of the structure and function of pheromones that govern sexual and other behaviors in goats (collaborative research with a veterinary physiologist).

 

Q: If you could have dinner with any famous person from the past, who would it be, and why?

A: Out of Japanese people, I would choose “The Wise Monarch, Harunori Uesugi” (called Yōzan Uesugi in his early days) from the Edo era; out of the rest of the world, it would be “The All-Rounded Genius, Leonardo da Vinci” from the Renaissance era. When I was in elementary school, I read a lot about important historical figures, leaving me with a strong impression (the books at the time, however, may have been slightly exaggerated or overdramatic). Among many, the two people mentioned above really captivated me. I was a child born to poor farmers, so an adopted child like Yōzan (albeit to the ruler of a fief) rebuilding the finances of a nearly collapsed fief (unlike modern society that makes the rich richer and the poor poorer) really inspired me. As an adult, I re-read some of Yōzan’s legends (one of my favorites is Shūhei Fujisawa’s “Urushi-no-mi-no-minoru-kuni”), but my opinion of him is unchanged. As for Da Vinci, I have only seen his authentic works at the Louvre (including the Mona Lisa, of course), but I have read stories about the agony he suffered while painting “The Last Supper” (the painting at Ōtsuka Museum of Art in Tokushima, Japan, was beautiful!), and I want to hear what his thought process was during the creation of this masterpiece.

 

Q: When was the last time you performed an experiment in the laboratory, and what was it about?

A: I have performed experiments until the age of 50 or so. The last reaction I ran was to synthesize allosamidin’s sugar-like moiety, allosamizoline (allosamidin is a chitinase inhibitor). I took a glucosamine derivative, a 6-iodo methyl acetal, and reductively cleaved it with zinc to make a substituted vinylcyclopentanecarbaldehyde. We were aiming for a large-scale synthesis of the target molecule, and while a graduate student did the front-line work, I provided large amounts of one of the synthetic intermediates. Using purified zinc and ethanol, the reaction worked well on a small scale but not on a large scale. Varying the rate of stirring, rigorously purifying the zinc, and slightly modifying the solvent did not lead to better results. I then drastically changed the solvent to THF, with a small amount of water as the proton source (1.5 % v/v; the finding of this number is an interesting story on its own, but I will not bore you with the details here). This led to an 80% yield on small scale, and slightly under 70% on a large (2 to 30 gram) scale.

 

Q: If you were stranded on a desert island, which book or song/piece of music would you like to have with you? Please single out your favorite example.

A: I would have problems choosing a single book, but I can name one author—I love Shūhei Fujisawa’s historical fiction. It is unfortunate that there is no one to mimic his style of writing since his death. Since I cannot bring myself to choose just one of his works, I would bring all of them and re-read them one by one. Otherwise, I would like to re-read a famous collection of 18 texts that includes “Records of the Grand Historian”, all works by W. Somerset Maugham, “Analects of Confucius”, and everything written by Sōseki Natsume. Is it against the rules that I choose so many? As for music, I would choose to bring all “nostalgic enka hits” CD sets from the post-war era and “forever Baroque music” CD sets. I would need them both.

 

Q: Do you have any suggestions as to whom we should interview next?

A: I would like to nominate a valued friend from my Pittsburgh days as well as my lifetime rival, Mugio Nishizawa; however, as you have already written at Chem-Station, he has already passed away. I have many other suggestions, but I nominate three of my closer friends and colleagues: Professors Kōichi Narasaka,

Tsutomu Katsuki, and Tamio Hayashi.

 

Biographical sketch of Takeshi Kitahara:

Professor at Teikyo Heisei University, as well as Professor Emeritus at the University of Tokyo. He is well-known for his numerous contributions to the total synthesis of biologically active natural products. He is a recipient of the Japan Academy Prize in 2010.

 

Japanese version written here on date; 8.27.2010

 

 

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