Oxidative conversion of hydrazides of carboxylic acids to acids, esters and amides using Cu salts was studied. Acids were obtained in high yields by using a catalytic amount of Cu(OAc)2 at room temperature by bubbling oxygen. Hydrazides were converted to esters by the treatment with Cu(OR)Cl or Cu(OR)2 formed in situ from CuCl2 and sodium alkoxide. Amides were obtained in high yields by the oxidation
Provided is a joined body including: a first member; a second member; and a sintered metal layer that joins the first member and the second member. The sintered metal layer includes a structure that is derived from flake-shaped copper particles which are oriented in approximately parallel to an interface between the first member or the second member, and the sintered metal layer, and the amount of copper contained in the sintered metal layer is 65% by volume or greater on the basis of a volume of the sintered metal layer.