Wako Pure Chemical Industries, Inc.

Takeda Pharmaceutical Company Limited

Tsutomu Tani

Yoshio Hata

Kohei Yamamoto

Takashi Aoki

Reiji Miyahara

Motoshige Sumino

Atsunori Sano

Tsutomu Miyagawa

Takuhiro Kimura

Kazuo Maruhashi

A process for producing a lactic acid polymer of 15,000 to 50,000 in weight-average molecular weight, the content of polymeric materials having not more than about 5,000 in weight-average molecular weight therein being not more than about 5% by weight, characterized by hydrolyzing a high molecular weight lactic acid polymer, placing the resultant solution comprising the hydrolyzed product under a condition capable of precipitating the objective lactic acid polymer, separating the precipitated lactic acid polymer and collecting them. The lactic acid polymer is useful as a matrix for sustained-release preparations. The sustained-release microcapsule preparation encapsulating a physiologically active substance can fully prevent the initial excessive release of the physiologically active substance from the microcapsules and keep a stable release rate over a long period of time.

Lactic acid polymer and process for producing the same

A process for producing an aminoalkylsulfonic acid of formula [2]:  wherein Rand Rare each independently hydrogen, alkyl, aryl or aralkyl; and Rand Rare each independently hydrogen or alkyl, comprising reacting an aminoalkylsulfonate salt of formula [1]:  wherein M is alkali metal, organic ammonium or ammonium ion; and Rto Rare as described above, an aqueous solution thereof, or a solution dissolving any one of them in a water-soluble organic solvent, selected from alcohols having 1 to 3 carbon, carboxylic acids having 2 to 12 carbon and dimethylformamide, with an organic acid; and a method of salt exchange for an aminoalkylsulfonate salt of formula [1']:  wherein M&#x2032; is alkali metal, organic ammonium or ammonium ion; and Rand Rare as described above, comprising reacting the aminoalkylsulfonate salt formula [2] with a hydroxide of formula [6]:M&#x2032;OH[6] wherein M&#x2032; is as described above, in alcohol or water.

Process for producing of an aminoalkylsulfonic acid and a method of salt exchange for a salt thereof

Novel and improved simple process for preparing a 1,2-pyrazolidine-4-yl-disulfide compound represented by the following formula: ##STR1## wherein R.sup.1 and R.sup.2 are, independently each other, a hydrogen atom or an amino-protecting group. This compound may be prepared by reacting a compound of the formula: ##STR2## wherein R.sup.3 is an acid anion residue group, and R.sup.1 and R.sup.2 have the same meanings as above, with a disulfide compound selected from the group consisting of an alkali metal disulfide, an alkali earth metal disulfide, an ammonium disulfide and a tri-alkylammonium disulfide.

Process for preparing 1,2-pyrazolidine-4-yl-disulfide compound

4-Halogeno-2-alkoxyimino-3-oxo fatty acid can be produced by one-pot and one-step by reacting a halogenating agent with a 2-alkoxyimino-3-oxo fatty acid ester in an ether solvent or a mixed solvent of an ether solvent and an inert organic solvent such as carbon tetrachloride, benzene, toluene, etc.

Process for producing 4-halogeno-2-alkoxyimino-3-oxo fatty acid

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Kawagoe, Japan

Tsutomu Tani