Abstract: It is intended to provide a process for producing 1-benzyl-4-[(5,6-dimethoxy-1-indanon)-2-ylidene]methylpiperidine represented by the structural formula (I): (I) which is useful as an intermediate material for a pharmaceutical or a solvate thereof in which impurity content is further reduced and operation is simple and suitable for industrial production by reacting 5,6-dimethoxy-1-indanone with 1-benzyl-4-formylpiperidine in a reaction solvent in the presence of a base and then gradually crystallizing a target substance in a reaction mixture in a high temperature region.

Abstract: The present invention provides a novel industrially excellent and ecological process for producing methylcobalamin which is useful as a medicament etc. More specifically, it provides a process for producing methylcobalamin by reducing cyanocobalamin or hydroxocobalamin in the presence of a reducing agent, and then methylating the reductant by adding a water-soluble methylating agent.

Abstract: The present invention provides a novel industrially excellent and ecological process for producing methylcobalamin which is useful as a medicament etc. More specifically, it provides a process for producing methylcobalamin by reducing cyanocobalamin or hydroxocobalamin in the presence of a reducing agent, and then methylating the reductant by adding a water-soluble methylating agent.

Abstract: The present invention provides novel polymorphic crystals (A) to (C) having excellent handling properties and an extremely low content of residual solvent of donepezil used as a precursor for production of donepezil hydrochloride having an excellent action as a medicament, and an industrial process for producing the same.

Abstract: The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo?4,5-b!pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo?4,5-b!pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization. The halogen atom introduced at the 5-position as a protective group against nitration can be eliminated simultaneously in the step which is conducted thereafter. Thus, this process is industrially advantageous.

Abstract: The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1##

Abstract: The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo-[4,5-b]pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization. The halogen atom introduced at the 5-position as a protective group against nitration can be eliminated simultaneously in the step which is conducted thereafter. Thus, this process is industrially advantageous.

Abstract: The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization.

Abstract: The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1##

Abstract: The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo-[4,5-b]pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization. The halogen atom introduced at the 5-position as a protective group against nitration can be eliminated simultaneously in the step which is conducted thereafter. Thus, this process is industrially advantageous.

Abstract: The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization. The halogen atom introduced at the 5-position as a protective group against nitration can be eliminated simultaneously in the step which is conducted thereafter. Thus, this process is industrially advantageous.

Abstract: The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo-[4,5-b]pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization. The halogen atom introduced at the 5-position as a protective group against nitration can be eliminated simultaneously in the step which is conducted thereafter. Thus, this process is industrially advantageous.

Abstract: Polyprenyl carboxylic acid derivatives having the general formula (I): ##STR1## in which n is an integer of from 2 to 4, R.sub.1 represents the hydrogen atom or a protecting group for the carboxylic acid group, and R.sub.2 represents a hydroxymethyl, formyl or carboxyl group, are disclosed. A process for the preparation of the polyprenyl carboxylic acid derivative involving microbiological oxidation using a strain belonging to the genus Nocardia is disclosed. The compounds have anti-ulcer activity and hypotensive activity. The compounds also are useful as intermediates for preparing polyprenyl carboxylic acids of the formula ##STR2## and esters thereof, wherein l is an integer of from 4 to 11. The polyprenyl carboxylic acids and esters thereof have hypotensive activity and anti-ulcer activity.

Abstract: A process is disclosed for the preparation of a compound having the general formula: ##STR1## wherein n is an integer of from 2 to 4, R.sub.1 is an ester-forming moiety effective as a protecting group for a carboxyl group, and R.sub.2 is hydroxymethyl, formyl or carboxyl. The compounds (I) are useful as intermediates for the preparation of polyprenyl compounds having hypotensive and anti-ulcer activity. The process of the invention includes cultivating a microorganism selected from a strain of the genus Nocardia called BPM 1613, FERM-P No. 1609, Corynebacterium equi IAM 1038, Candida lipolytica IFO 0746, and Mycobacterium smegmatis IFO 3083, in a nutritive culture medium, in the presence of a compound having the general formula: ##STR2## wherein R.sub.3 is an ester-forming moiety effective as a protecting group for a carboxyl group, whereby the microorganism utilizes the compound (II) as a carbon source and oxidizes the compound (II), thereby converting the compound (II) into the compound (I).