Abstract: Disclosed are process for producing a compound having NPYY5 receptor antagonism and useful crystals. A process for producing a compound represented by the formula (IV): wherein R1 is substituted or unsubstituted alkyl, R2 is substituted or unsubstituted alkyl, and n is 1 or 2, or the like, which comprises reacting a compound represented by the formula (II): wherein R1 and n are as defined above, and X is a leaving group, or the like and a compound represented by formula (III): wherein R2 is as defined above, or the like.

Abstract: A process for the preparation of a compound of the formula (I′): which comprises reacting in a solvent a compound of the formula (III): wherein X is halogen, with p-tolylacetylene, a copper (I) salt, a catalyst, and a base, and then treating the resulting reaction mixture with an acid.

Abstract: A process for the preparation of compound (I′): which is characterized by reacting in a solvent a compound of the general formula (III): (wherein X is halogeno) with p-tolylacetylene, a cuprous salt, a catalyst, and a base, and then treating the resulting reaction mixture with an acid.

Abstract: A method for reduction of an allyl alcohol-type compound, specific to its allylic hydroxyl group, being carried out without any side reactions such as reduction of other portions of the compound or allylic rearrangement, which comprises treating the compound with trialkylsilane in the presence of AlX.sub.3, wherein X refers to a halogen atom.

Abstract: This invention relates to a synthesis method favorable for the industrial production of a benzoic acid derivative having a retinoid activity of the general formula: ##STR1## wherein the derivative can be obtained by a simple procedure in safety with high yield.Specifically, this invention relates to a synthesis method characterized in that only one vessel is needed for several reactions in the different steps of subjecting acetanilide as a starting material, which is readily available and safe to handle, to Friedel-Crafts reaction with 2,5-dimethyl-2,5-dichlorohexane; subjecting the thus obtained compound to acyl exchange reaction with monomethyl ester terephthalic chloride, followed by hydrolysis; and recrystallizing from a mixture of methanol and water.Moreover, the crystals in novel form obtained by the synthesis method of this invention are suitable for formulation, because the amount of solvents remaining therein after recrystallization is small and the grain size thereof is uniform.