Abstract: This invention provides a novel compound expressed by the following formula (1): ##STR1## [wherein R.sup.1 denotes a hydrogen atom or CH.sub.3 CO--, R.sup.2 denotes --COOR.sup.4 (R.sup.4 denotes Na or a methyl group) or ##STR2## (R.sup.5 denotes a hydrogen atom, --COC.sub.6 H.sub.5 or --Si(C.sub.6 H.sub.5).sub.2 C(CH.sub.3).sub.3 and R.sup.3 denotes ##STR3## (R.sup.5 denotes a hydrogen atom, --COC.sub.6 H.sub.5 or --Si(C.sub.6 H.sub.5).sub.2 C(CH.sub.3).sub.3) when R.sup.2 is --COOR.sup.4 (R.sup.4 denotes Na or a methyl group) or denotes --COOR.sup.4 when R.sup.2 is ##STR4## and a method of preparation thereof. The above novel compounds of present invention are useful as a tumor maker, a molecular marker for cells having the ability of differential induction, or an intermediate of the synthesis thereof.

Abstract: An expectorant capable of acting on the rheological properties of sputum and capable of directly promoting the ciliary motion. The expectorant contains N-acetylneuraminic acid or a pharmaceutically active salt thereof.

Abstract: Sialic acid derivatives of the formula: ##STR1## wherein R.sup.1 is hydrogen, trityl, or acyl, R.sup.2 is hydrogen or acyl, R.sup.3 and R.sup.4 are individually glycerolglycoside, dialkylglycerol, alkoxycarbonyl or carboxyl.These compounds may be employed as a useful intermediate for the synthesis of biologically active substances and may be employed as an inhibitor of hydrolytic enzyme, a reagent for affinity chromatography for purifying enzyme, or a synthetic antigen.

Abstract: A novel N-acetylneuraminic acid derivative, represented by the general formula: ##STR1## wherein the R.sup.1 groups are, independently, hydrogen or acetyl; R.sup.2 is a nucleoside residue; and R.sup.3 is carboxyl or methoxycarbonyl.The N-acetylneuraminic acid derivative is useful in inhibiting metastasis of cancer cells. Also provided is a process for the preparation of the derivatives.

Abstract: This invention provides a novel compound having a formula such as ##STR1## This invention also provides a process for preparing such a compound. The novel compound has excellent immunological activity.

Abstract: This invention provides a novel compound having a formula such as ##STR1## This invention also provides a process for preparing such a compound. The novel compound has an excellent immunological activity.

Abstract: Nucleoside or glucose derivatives of N-acetylneuraminic acids are provided, which have immunological activity, are clinically useful, as an immuno suppressive, in particular to treat autoimmune disease such as collagenosis disease without causing any serious side-effects and may be prepared by subjecting a halide of N-acetylneuraminate derivative together with a nucleoside or a glucose to Koenigs-Knorr reaction.