Abstract: The present invention provides a crystalline or crystallized acid addition salt of Losartan useful for obtaining highly pure 2-n-butyl-4-chloro-1-[[2′-(1H-tetrazol-5-yl)[1,1′-biphenyl]-4-yl]methyl]-1H-imidazole-5-methanol (Losartan), and a purification method of Losartan that includes production of the crystalline or crystallized acid addition salt.

Abstract: A process for preparing a tert-alkyl carboxylic acid ester represented by the formula (III): wherein R1 is an organic group; and each of R2 and R3 is independently an alkyl group having 1 to 4 carbon atoms, comprising reacting a carboxylic acid represented by the formula (I): R1—COOH  (I) wherein R1 is as defined above, with a vinylidene compound represented by the formula (II): wherein R2 and R3 are as defined above, in the presence of a phosphorus halide. The tert-alkyl carboxylic acid ester can be used as intermediates for pharmaceuticals such as antibiotics.

Abstract: A process for preparing a 2-cyanobiphenyl compound represented by the formula (II): ##STR1## wherein R.sup.1 is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or hydrogen atom, from a phenylmagnesium chloride compound represented by the formula (I): ##STR2## wherein R.sup.1 is as defined above. According to the process, a 2-cyanobiphenyl compound represented by the formula (II) can be economically, simply, industrially and advantageously prepared.

Abstract: A piperidine derivative, which can be used as an intermediate for pharmaceuticals such as paroxetine useful as antidepressants, represented by the general formula (I): ##STR1## wherein R.sup.1 is hydrogen atom, benzyloxycarbonyl group or tert-butoxycarbonyl group; R.sup.2 is hydroxymethyl group, an alkylsulfonyloxymethyl group having an alkyl moiety of 1 to 2 carbon atoms, phenylsulfonyloxymethyl group which may have methyl group at the 4-position, (3,4-methylenedioxyphenyl)oxymethyl group, carboxyl group or --CO.sub.2 R.sup.7 group in which R.sup.7 is an alkyl group having 1 to 5 carbon atoms, and Z is methylene group or carbonyl group.

Abstract: Process for preparing 4'-methyl-2-cyanobiphenyl, comprising, catalytically hydrogenating at least one brominated cyanobiphenyl compound selected from 4'-dibromomethyl-2-cyanobiphenyl and 4'-bromomethyl-2-cyanobiphenyl; and process for regenerating 4'-methyl-2-cyanobiphenyl, comprising, catalytically hydrogenating at least one brominated cyanobiphenyl compound selected from 4'-dibromomethyl-2-cyanobiphenyl and 4'-bromomethyl-2-cyanobiphenyl, contained in a filtrate prepared by brominating 4'-methyl-2-cyanobiphenyl in a solvent; crystallizing 4'-bromomethyl-2-cyanobiphenyl from the resulting reaction mixture; and removing the resulting crystals from the reaction mixture by filtration. 4'-Methyl-2-cyanobiphenyl can be used as starting materials for 4'-bromomethyl-2-cyanobiphenyl.

Abstract: A method for producing 4'-bromomethyl-2-cyanobiphenyl by the step of treating 4'-methyl-2-cyanobiphenyl with Br.sub.2 in a halogenated hydrocarbon solvent or an alkane solvent having 5 to 7 carbon atoms.

Abstract: A process for preparing an optically active 4-hydroxy-2-cyclopentenone of the formula: ##STR1## wherein R.sub.1 is a hydrogen atom or a methyl group, R.sub.2 is an alkyl group, an alkenyl group or an alkynyl group and the asterisk (*) indicates an asymmetric configuration, which comprises subjecting an optically active 4-cyclopentenone-alcohol of the formula: ##STR2## wherein R.sub.1 and R.sub.2 are each as defined above, the asterisk (*) indicates an asymmetric configuration and the substituents R.sub.1 and R.sub.2 take a cis-configuration to rearrangement while maintaining the original steric configuration.

Abstract: A process for preparing cyclopentenone derivatives of the formula: ##STR1## wherein R.sup.1 is hydrogen, lower alkyl or lower alkenyl, R.sup.2 is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, substituted or unsubstituted aryl or substituted or unsubstituted ar(lower)alkyl and A is the residue of a nucleophilic agent from which a hydrogen atom is excluded, which comprises reacting a 3-hydroxy-4-cyclopentenone compound of the formula: ##STR2## wherein R.sup.1 and R.sup.2 are each as defined above with a nucleophilic agent of the formulaA--H (III)wherein A is as defined above.The cyclopentenone derivatives of the formula (I) are useful as pharmaceuticals, agricultural chemicals, perfumes and as intermediates for the preparation of agricultural chemicals, pharmaceuticals and perfumes.

Abstract: A process for producing a compound of the formula: ##STR1## wherein R.sub.1 is a hydrogen atom, an alkyl group or an alkenyl group and R.sub.2 is an alkyl group, an alkenyl group or an alkynyl group, which comprises treating a compound of the formula: ##STR2## wherein R.sub.1 and R.sub.2 are each as defined above and R is a hydrogen atom or a lower alkyl group in the presence of an acidic substance and water.

Abstract: A method for producing an optically active 2,2-dimethylcyclopropanecarboxylic acid useful as an intermediate for dehydropeptidase I inhibitors, medicines and agricultural chemicals, which comprises reacting an optically active diphenylethylamine represented by the formula, ##STR1## wherein R.sub.1 and R.sub.2 are each a hydrogen atom or a lower alkyl group, with 2,2-dimethylcyclopropanecarboxylic acid in a solvent to achieve the optical purification of said acid.

Abstract: An amine of the formula, ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each hydrogen, alkyl or the like and n is 1, 2 or 3, including .alpha.-phenyl-.beta.-(p-tolyl)-ethylamine, which is useful as an optically resolving agent, an intermediate of medicines and the like, is effectively produced by a novel process comprising hydrolysis of the corresponding nitrile of the formula, ##STR2## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and n are the same as above, followed by alkali-decomposition of the resulting amide of the formula, ##STR3## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and n are the same as above. An amide including the above one is effectively produced by hydrolysis of the corresponding nitrile in the presence of a base and hydrogen peroxide using an organic quaternary ammonium salt and/or a tertiary amine as a catalyst.

Abstract: 2-Cyclopentenone esters of the formula: ##STR1## wherein R.sup.1 is hydrogen, lower alkyl or lower alkenyl, R.sup.2 is lower alkyl, lower alkenyl, lower alkynyl, or cycloalkyl, cycloalkenyl or substituted or unsubstituted aryl and R.sup.3 is hydrogen or lower alkyl are prepared in high yields by reacting the corresponding racemic or optically active 4-cyclopentenone of the formula: ##STR2## wherein R.sup.1 and R.sup.2 are each as defined above and R.sup.3 is hydrogen or acyl with at least one lower aliphatic carboxylic acid and/or metal or amine salts thereof.

Abstract: A 4-cyclopentenone of the formula: ##STR1## wherein R is a lower alkyl group, a lower alkenyl group or a lower alkynyl group and R' is a hydroxyl group or an aliphatic acyloxy group, provided that in case of the dl-form, R' is not a hydroxyl group and also that the substituent R at the 2-position and the methyl group at the 3-position take a cis-configuration in the dl-, d- or l-form.

Abstract: A novel process for preparing 2-cyclopentenones of the formula: ##STR1## wherein R.sub.1 is hydrogen, alkyl or alkenyl and R.sub.2 is alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl, which comprises esterifying a mixture of a 3-hydroxy-4-cyclopentenone of the formula: ##STR2## wherein R.sub.1 and R.sub.2 are each as defined above and a 4-hydroxy-2-cyclopentenone of the formulas: ##STR3## wherein R.sub.1 and R.sub.2 are each as defined above with an aliphatic carboxylic acid to give a mixture of the 4-hydroxy-2-cyclopentenone (III) and the cyclopentenone ester of the formula: ##STR4## wherein R.sub.1 and R.sub.2 are each as defined above and R is hydrogen or C.sub.1 -C.sub.4 alkyl and subjecting the resulting mixture to reduction.