Introduction

Organic chemistry, owing to its difficult chemical structural formulas, may be an academic field that the public keeps distance from, even if they have some knowledge of chemistry. However, organic compounds are everywhere around people, ranging from dyes, perfumes, medicines to liquid crystals and organic EL, and are indispensable components of modern daily life. Because organic compounds are common in our daily life, we can catch a glimpse of them in some literary works. Although literature seemed to be far removed from chemistry, I want people to discover organic chemistry in literary works and feel the pleasure of learning both literature and chemistry cultures. My apologies in advance is that, in this paper, organic compounds and people related to them are the main subjects, and the contents of literary works may be misinterpreted.

Takadiastase and chemists in the Meiji era – I am a CAT. (Soseki Natsume)

This famous work is a humorous novel that caricatures the human world from the eyes of a cat. Mr. Kushami, the master of the cat (me), is a big eater despite his weak stomach. Mr. Kushami used to take Takadiastase after a large meal. However, after a while, he stopped taking it. Even if his wife advised him to take it, he stubbornly refused it, saying that it would not work.

Takadiastase is a stomach digestive enzyme and a gastrointestinal drug invented by Dr. Jokichi Takamine, a chemist of the Meiji era. Taka of Takadiastase is originated from Takamine’s name and also from the Greek meaning of “strong” and “the highest.” In fact, Jokichi Takamine and his assistant Keizo Uenishi succeeded in taking the crystalline adrenaline from the adrenal gland for the first time in the world in 1900. Adrenaline is a hormone, a substance that causes sympathomimetic effect and has a vasoconstrictor action. Soseki Natsume and Jokichi Takamine are only connected in the novel, however, in real life, Soseki did have a contact point with a chemist, Kikunae Ikeda. Kikunae Ikeda is known for finding that the umami component of bonito flakes is sodium glutamate (Ajinomoto). He studied in Germany and the UK while he was an assistant professor at the Tokyo Imperial University and lived in the same boarding house as Soseki Natsume in London. In his work Shojosaku Tsuikaidan, Soseki says that encounter with Kikunae was very beneficial to him.

Heliotrope – Sanshiro (Soseki Natsume)

Another work of Soseki Natsume is Sanshiro. Sanshiro Ogawa, who passed the entrance examination to the Tokyo Imperial University and came to Tokyo from Kyushu, is a young country boy who does not have much experience with women. One day, he saw a beautiful young lady, Mineko Satomi, on the banks of a pond in the university campus (present Sanshiro pond) by chance. Although Sanshiro falls in love with Mineko, she is a sly, cunning woman, so Sanshiro continues to be at the mercy of her. One day, when he went out to buy a shirt, Mineko, who was also out for shopping, sought his opinion about perfume. As he picks a bottle of heliotrope to recommend to her, Mineko agrees to buy it. When she is going to marry another man and parts from Sanshiro, Mineko’s handkerchief with strong scent comes in front of Sanshiro’s face, and she says “Heliotrope.”

Heliotrope is a generic term for plants of the genus heliotropium and is called perfume grass. The perfume heliotrope chosen by Sanshiro is a synthetic fragrance called heliotropin with fragrance of the heliotrope plant. Heliotropin is an aromatic aldehyde-based perfume, synthesized from naturally existing safrole. In this novel, heliotrope seems to be used as props to distract Sanshiro’s heart. People believe that aroma can be a tool to tempt the opposite sex and continue to pursue natural fragrances. For example, since muscone (musk) emanating from the male seminal vesicle of the musk deer has a power to attract the female, some people are driven by the desire to acquire this, hoping to be able to seduce the opposite sex.

Shikonin, Alizarin – The Anthology of Myriad Leaves (Nukata no Okimi, Ooamanomiko)

As aroma has an effect of attracting people, color also attracts people. A color has a meaning that expresses the state of the surface of things, but it also has a meaning that is related to affections between men and women. Here, I introduce the work on the affection of Nukata no Okimi and Ooamanomiko as well as the source of color, namely, pigment, in the Anthology of Myriad Leaves. Nukata no Okimi and Ooamanomiko were in a romantic relationship, but she was pledged to be the wife of Emperor Tenji who is the older brother of Ooamanomiko. Although Nukata no Okimi became a married woman, her feelings towards the former lover, Ooamanomiko, do not change. In the Anthology of Myriad Leaves, there is a phrase that Nukata no Okimi wrote for Ooamanomiko.

“You are going back and forth in the field covered by colorful gromwell and in the imperial hunting fields marked off with sacred ropes, waving your sleeves at me. It is awful if the field guard finds you acting like that.”

As a response, Ooamanomiko says, “I cannot have a bitter feeling towards you who is as beautiful as gromwell. If I have a bitter feeling, I can never be so crazy about you while knowing that you are a married woman.” You can read the painful feelings of the two for romance which will not be fulfilled.

In the novel written by Yasushi Inoue, Nukata no Okimi (original title), there is a passage that says, “Nukata heard that roots of gromwell are used for a purple dye, but when she was watching small white flowers, she could not imagine purple.” Gromwell’s roots contain purple pigment called shikonin. Akanesasu is a poetic epithet of purple, but Akane (madder) itself is also a plant, and a red dye called alizarin is extracted from its roots. Shikonin and alizarin are chemically quinone dyes. I feel romance as the poems read by a man and a woman of ancient Japan have something to do with substances of a common chemical structure by a curious coincidence. Incidentally, the story of the triangular relationship between Ooamanomiko, Nakanoooenooji (Emperor Tenji) and Nukata no Okimi is performed at Takarazuka Revue Company under the title, “Akanesasu Purple Flower.”

Crocetin, Indigo, Carthamin – The Pillow Book (Sei Shonagon)

I would like to introduce another classic work on pigment. In the essay of Sei Shonagon, titled Makura no Soshi (The Pillow Book), there is a following passage: “Hakama is cool in thick purple and moegi color (yellowish green). Futaai (a shade of deep purple) is nice in summer. When it is extremely hot, light green is great as it looks cool.” Surely, it describes a hobby about color of costume.

Moegi means bright green, the color of green onion bursting out. This color is prepared by mixing blue indigo pigment with yellow gardenia pigment. The pigment of deep blue is indigo, and, in modern times, it is industrially synthesized using aniline as a raw material. The pigment of gardenia is crocetin, which is a compound in which seven carbon-carbon double bonds are linked in a straight line. As the number of carbon-carbon double bonds increases, the color gradually turns reddish. For example, lycopene as a red color of tomato and watermelon and β-carotene as an orange color of carrot are known as an eleven-connected compound. Astaxanthin contained in cosmetics (ASTALIFT) is also a member of these groups and is said to have an antioxidant effect. Futaai is blue-violet dyed by indigo after dyed with safflower. The red pigment of safflower is carthamin. The color of the safflower’s flower is yellow and contains the yellow pigment safflor yellow and the red pigment carthamin. Although carthamin contained in safflower is only about 1%, it can be separated from safflor yellow using the difference in solubility in water.

Tyrian purple (6,6’-dibromoindigo) – Tyrian Purple Fantasy (Yoshiko Shibaki)

This is a story concerning color as the title says. Keiko lives in Tokyo and works for the editorial department of a publisher. One day, Yasuo, her mother’s half-brother from Kyoto, visited Kamakura. Yasuo is a lecturer at a university in Kyoto and is studying a dye of tyrian purple that can be obtained from murexes. Keiko is attracted by Yasuo and also attached to the charm of tyrian purple. It is a very tricky story as Keiko and Yasuo fall in love with each other as a man and a woman, even though they are related by blood as an uncle and a niece.

Tyrian purple is 6,6’-dibromoindigo (the number 6 indicates the place where bromine is bonded to indigo) and has a structure in which two bromine groups are bonded to indigo which can be obtained from indigo plants. As the bromine groups bond to indigo, the color changes from blue to deep purple. 6,6’-dibromoindigo is a very precious and rare pigment. Only 1 gram can be obtained from 1,000 murexes . Probably because of that, tyrian purple was also called emperor purple and favored by people with power. Even in ancient Japan, the dark purple is designated as the color of the highest rank (Daitoku) in the system of the twelve grades of cap rank, and it is the color of the clothes of the highest-ranked person. Although only a small amount of tyrian purple can be produced in nature, easy synthetic methods have been proposed by studies on organic synthetic chemistry. By cutting the carbon-bromine bond of this compound and performing a cross-coupling reaction with another organic compound, it is possible to give a function to indigo and it is expected to be applied to a sensitizer of solar cells, etc.

Conclusion

So far, I showed you a part of the world of organic chemistry in classical to modern literature. I could only introduce only a few works here due to a character limit, but I have found organic chemistry in about 50 literary works, including classics and serious literature as well as mystery novels and science fictions. Some of my students also studied it as a theme of their graduate research. The results are posted on my website.

New Catalytic Organic Reaction Laboratory in the Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University

Shinichi Fukuzawa／Professor, Faculty of Science and Engineering, Chuo University
Area of Specialization: Organic Synthetic Chemistry

Shinichi Fukuzawa was born in Niigata Prefecture in 1956. He graduated from the Faculty of Engineering, Kyoto University, in 1979.
He completed the doctoral program in the Graduate School of Engineering, Kyoto University in 1984. He holds a PhD in engineering (Kyoto University).
In 1991, he became Assistant Professor of the Chuo University Faculty of Science and Engineering, and took up the current position in 1999.
His current research topics include organic synthetic chemistry and organometallic chemistry (development of new methods, and new reactants/new catalysts for stereo-selective and diversity synthesis).
His written works include Basic Master Series: Organic Chemistry (co-authored, Ohmsha, 2011) and more. He has published more than 150 papers.