Abstract: A method for producing 2-methylspiro(1,3-oxathiolane-5,3')quinuclidine, which comprises reacting 3-hydroxy-3-mercaptomethylquinuclidine or a salt thereof and a carbonyl compound in the presence of a catalyst made of at least one member selected from the group consisting of tin halides, oxyacids of phosphorus, phosphorus oxyhalides and organic sulfonic acids, to produce cis-form 2-methylspiro(1,3-oxathiolane-5,3')quinuclidine or a salt thereof.

Abstract: A mercapto-substituted pyridine compound having formula (I): ##STR1## where R.sub.1 and R.sub.2 are alkyl groups, and n is 0 or 1, and salts thereof and a process for preparing the same are disclosed. The mercapto-substituted pyridine compound is useful as an intermediate for preparing a herbicidal compound.The present invention further provides aminocarbonyl-substituted pyridinesulfinic acid (ACPS) or salts thereof as the precursor of aminosulfonyl-substituted pyridinecarbonic acid amide compound (APCA) which is useful as the starting material for agricultural chemicals, medicine, etc. Moreover, the preparation process of the present invention is an industrially advantageous preparation process which is capable of preparing in a series of steps from mercapto-substituted pyridinecarboxylic acid amide compound (MPCA) or aminocarbonyl-substituted halogenopyridine compound (ACHP) to ACPS or salts thereof, and further to APCA.

Abstract: An aminocarbonyl-substituted pyridinesulfinic acid intermediate for production of an herbicide having formula (V): ##STR1## wherein R.sub.3 and R.sub.4 are selected from the group consisting of hydrogen and alkyl groups, or a salt thereof. The aminocarbonyl-substituted pyridinesulfinic acid or salt thereof is useful as the precursor of aminosulfonyl-substituted pyridinecarbonic acid amide, which in turn is useful as the starting material for agricultural chemicals, medicine, etc.

Abstract: A process for preparing a S-substituted phosphorochloridothiolate having the formula: ##STR1## wherein R.sup.1 is a chlorine atom or an alkoxy or phenoxy group which may be substituted, and R.sup.2 is an alkyl, alkenyl, alkynyl, cycloalkyl or phenyl group which may be substituted, which comprises isomerizing an O-substituted phosphorochloridothionate having the formula: ##STR2## wherein R.sup.1 and R.sup.2 are as defined above, in the presence of a Lewis acid catalyst or a phosphorus compound catalyst.

Abstract: The present invention relates to an industrially advantageous process for producing 2-amino-4,6-dichloropyrimidine, which comprises reacting 2-amino-4,6-dihydroxypyrimidine or its salt with phosphorus oxychloride at a temperature of from 50.degree. to 100.degree. C. in the presence of a solvent and an acid removing agent. Further, the yield of 2-amino-4,6-dichloropyrimidine can be improved by hydrolyzing 4,6-dichloro-2-pyrimidinylphosphoramidic dichloride produced as a by-product of the chlorination reaction to form 2-amino-4,6-dichloropyrimidine. The 2-amino-4,6-dichloropyrimidine produced by the process of the present invention is useful as an intermediate for medicines and agricultural chemicals.

Abstract: A novel amino-trifluoromethylpyridine compound selected from the group consisting of 3-amino-5-trifluoromethylpyridine, 2-amino-4-trifluoromethylpyridine, and 2-amino-4,6-bis(trifluoromethyl)pyridine, and, a process for preparing the same by reacting a halogeno-trifluoromethylpyridine compound with ammonia at a temperature of 50.degree. to 200.degree. C. The compound is useful as an intermediate from which a compound effective in controlling various harmful organisms or an effective component compound of medicines can be easily derived.

Abstract: A process for preparing a S-substituted phosphorochloridothiolate having the formula: ##STR1## wherein R.sup.1 is a chlorine atom or an alkoxy or phenoxy group which may be substituted, and R.sup.2 is an alkyl, alkenyl, alkynyl, cycloalkyl or phenyl group which may be substituted, which comprises isomerizing an O-substituted phosphorochloridothionate having the formula: ##STR2## wherein R.sup.1 and R.sup.2 are as defined above, in the presence of a Lewis acid catalyst or a phosphorus compound catalyst.

Abstract: A process for producing a 3-chloro-5-trifluoromethylpyridine derivative comprises reacting a 5-trifluoromethylpyridine derivative having a hydrogen atom at 3-position with chlorine. The process is characterized by reacting said 5-trifluoromethylpyridine derivative with chlorine in a vapor phase in the presence of a catalyst selected from the group consisting of activated carbon and a chloride of a metal element selected from the group consisting of iron, antimony, copper and zinc.