Yamanouchi Pharmaceutical Company Ltd.

Makoto Yoshida

Toshinari Tamura

Hidenori Iwamoto

Minoru Yamamoto

Shin-ichi Tsukamoto

Soichi Kagami

Hideya Matsuda

A novel crystal form of N.sup..alpha. -[[(S)-4-oxo-2-azetidinyl]-carbonyl]-L-histidyl-L-prolinamide is provided and a process for preparing such crystals. The crystals provided by the present invention are the dihydrate form of the compound which exhibits a specific X-ray powder diffraction pattern, infared absorption spectrum and thermogravimetry-differential scanning calorimetry. The compound in its novel crystal form is useful in the treatment of consciousness disturbances and memory disorders.

Crystalline form III of N.sup..alpha. -[[(S)-4-oxo-2-azetidinyl]-carbonyl]-

Substituted azetidinone compounds are provided which have the formula: ##STR1## wherein one of R.sup.1 and R.sup.2 represents a substituted lower alkyl group, an azido group, an amino group, a lower acylamino group, a mercapto group or a lower alkylthio group and the other represents a hydrogen group, or, both represent hydrogen atoms or lower alkyl groups; R.sup.3 represents a hydrogen atom or a group shown by formula: ##STR2## (wherein X represents ##STR3## (wherein R.sup.5 represents a hydrogen atom or a lower alkyl group) and Y represents a hydroxy group, a lower alkoxy group, an amino group, a mono- or di-lower alkylamino group); R.sup.4 represents a hydrogen atom, a substituted or unsubstituted lower alkyl group or a group shown by formula: --CH.sub.2 CO--A (wherein A represents an amino group or a group shown by formula: ##STR4## (wherein X and Y are as defined above), provided that when R.sup.1 and R.sup.2 are both hydrogen atoms, at least R.sup.4 represents a group other than a hydrogen atom and provided that either R.sup.3 or R.sup.4 represents a group other than a hydrogen atom. The compounds have strong CNS action.

CNS active substituted azetidinone compounds

A novel-4-substituted-2-azetidinone compound shown by the general formula ##STR1## and salts thereof. The compounds of this invention have a strong CNS activity and are useful for improving a disturbance of consciousness in schizophrenia, a head injury, etc., or improving hypobulia, memory loss, etc.

4-substituted-2-azetidinone compound

A novel 4-substituted-2-azetidinone compound shown by the general formula ##STR1## and salts thereof. The compounds of this invention have a strong CNS activity and are useful for improving a disturbance of consciousness in shizophrenia, a head injury, etc., or improving hypobulia, memory loss, etc.

4-substituted-2-azetidinone compound, process of producing the

A novel 4-substituted-2-azetidinone compound shown by the general formula ##STR1## and salts thereof. The compounds of this invention have a strong CNS activity and are useful for improving a disturbance of consciousness in schizophrenia, a head injury, etc., or improving hypobulia, memory loss, etc.

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Saitama, Japan

Makoto Yoshida