Nhk Spring Co., Ltd.

Suntory Limited

Shiratori Pharmaceutical Co., Ltd.

Hideaki Sakai

Atsushi Yoneoka

Tadashi Kanai

A wave spring includes an annular body in which crests and valleys are alternately and continuously formed in a circumferential direction. At least a portion of the annular body in the circumferential direction is a joined portion. The joined portion of the annular body is a flat portion extending in a plane orthogonal to a center axis of the annular body.

Wave spring

The disc spring is a disc spring for being fitted on a rotary shaft and includes: an annular body portion; a claw portion protruding inward in a radial direction from an inner peripheral edge of the body portion, wherein the claw portion gradually extends toward one side in an axial direction as it goes inward in the radial direction, and at least a tip part of the claw portion is provided with a hole.

Disc spring

(6R)-Tetrahydro-L-biopterin of the following formula: ##STR1## is prepared by catalytically reducing L-erythrobiopterin or an acyl derivative thereof in the presence of an amine, at pH 10-13 and with a platinum-base catalyst and when one or more acyl groups still remain, then removing the acyl groups. (6R)-Tetrahydro-L-biopterin is effective for the treatment of certain serious neuroses and malignant hyperphenylalaniemia. The present invention has succeeded in preparing (6R)-tetrahydro-L-biopterin at a high asymmetric ration R/S and moreover with a high yield. Since the process of this invention makes use of an amine as a base, the process is free from admixture of any inorganic salt and can hence provide high-purity crystals with ease.

Growing community of inventors

Yokohama, Japan

Hideaki Sakai