Eisai Chemical Co., Ltd.

Eisai Company, Limited

Chiaki Seki

Kimio Hamamura

Masayuki Konishi

Norio Minami

Kenji Hayashi

Noriyasu Hirose

Toshio Matsunami

Noriyoshi Iwata

Kouzou Morita

Tetsuo Iwama

Hiroshi Inoue

Yuh Horikawa

Takashi Yoshimura

A process is provided for the preparation of .alpha.-tocopherol. According to the process, a condensation reaction between trimethylhydroquinone and a specific phytol derivative or isophytol is conducted in the presence of any one of the following solvents:

Process for the preparation of .alpha.-tocopherol

A hydroquinone derivative (I) represented by the following formula: ##STR1## wherein R.sup.1 is a hydrogen atom, acetyl group or benzoyl group, such hydroquinone derivative being useful as an intermediate for chroman derivatives useful as a blood sugar-lowering agent.

Butenyl hydroquinone derivatives

Disclosed herein are a quinone derivative represented by the following formula: ##STR1## wherein R.sup.1 and R.sup.2 are identical with or different from each other and mean individually a lower alkyl or lower alkoxy group, or may form an aromatic ring together, R.sup.3 denotes a lower alkyl group, n stands for 0 or an integer of 1-9, and a linkage --- is a single or double bond, such as a vitamin K derivative or coenzyme derivative; and a process for the preparation of the quinone derivative at a high yield without forming any geometric isomer; as well as a 1,4,4.sub.a,8.sub.a -tetrahydro-4.sub.a .alpha.-alkenyl-1.alpha.,4.alpha.-methanonaphthalene-5,8-dione derivative which is useful as an intermediate for the preparation of the quinone derivative.

Tetrahydro-alkenyl-methanonaphthalene-5,8-dione derivatives

Disclosed herein are a quinone derivative represented by the following formula: ##STR1## wherein R.sup.1 and R.sup.2 are identical with or different from each other and mean individually a lower alkyl or lower alkoxy group, or may form an aromatic ring together, R.sup.3 denotes a lower alkyl group, n stands for 0 or an integer of 1-9, and a linkage--is a single or double bond, such as a vitamin K derivative or coenzyme Q derivative; and a process for the preparation of the quinone derivative at a high yield without forming any geometric isomer; as well as a 1,4,4.sub.a,8.sub.a -tetrahydro-4.sub.a .alpha.-alkenyl-1.alpha.,4.alpha.-methanonaphthalene-5,8-dione derivative which is useful as an intermediate for the preparation of the quinone derivative.

Process for the preparation of quinone derivative

The present invention relates to intermediates useful for the preparation of vitamin K derivatives.

1,4,4.sub.a 5,8,9.sub.a

A process for the industrial preparation of the quinone derivative represented by the following general formula: ##STR1## which is an intermediate for chroman derivatives useful as a blood sugar lowering agent, and novel intermediates, encompasses the following: (1) Oxidation of the corresponding hydroquinone derivative, and (2) Hydrolysis of the corresponding acyl hydroquinone derivative with a Claisen alkali, followed by the oxidation of resulting hydrolyzate.

Oxidative process for the preparation of allyl quinone derivatives

Disclosed herein are a quinone derivative represented by the following formula: ##STR1## wherein E.sup.1 and E.sup.2 are identical with or different from each other and mean individually a lower alkyl or lower alkoxy group, or may form an aromatic ring together, E.sup.3 denotes a lower alkyl group, n stands for 0 or an integer of 1-9, and a linkage ------ is a single or double bond, such as a vitamin K derivative or coenzyme Q derivative; and a process for the preparation of the quinone derivative at a high yield without forming any geometric isomer; as well as a 1,4,4.sub.a,8.sub.a -tetrahydro-4.sub.a .alpha.-alkenyl-1.alpha.,4.alpha.-methanonaphthalene-5,8-dione derivative which is useful as an intermediate for the preparation of the quinone derivative.

Process for the preparation of a quinone derivative

Disclosed herein are a naphthoquinone derivative represented by the following formula: ##STR1## wherein R.sup.1 means a hydrogen atom or methyl group, R.sup.2 is a hydrogen atom or methyl group, n stands for 0 or an integer of 1-9, and a linkage is a single bond or double bond with the proviso that if n is an integer of 2-9, the linkages may be identical with or different optionally from each other, such as a vitamin K derivative; and a process for producing the naphthoquinone derivative at a high yield without forming any geometric isomer; as well as 1,4,4.sub.a,5,8,9.sub.a -hexahydro-4.sub.a .alpha.-alkenyl-1.alpha.,4.alpha.-methanoanthraquinone derivatives and 1,4,4.sub.a,5,8,9.sub.a -hexahydro-1.alpha.,4.alpha.-methanoanthraquinone derivatives which are useful as intermediates for the preparation of the naphthoquinone derivatives.

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Aichi Prefecture, Japan

Chiaki Seki