Disclosed is a compound represented by formula (1) or a salt thereof wherein: “Base” represents an aromatic heterocyclic group which may have a substituent, or an aromatic hydrocarbon ring group which may have a substituent; A.sup.1 represents a single bond or an alkylene group; R.sup.1 to R.sup.5 represent an atom or a group disclosed in the specification.

A process for the preparation of hydroxocobalamin hydrochloride. More particularly the present application relates to improved process for the preparation of Hydroxocobalamin hydrochloride. In addition the present application also relates to process for the preparation of novel amorphous form. This application particularly relates to a process for the industrial manufacture of hydroxocobalamin hydrochloride from cyanocobalamin. The present application also relates to the improvement in yield with better purity of Hydroxocobalamin hydrochloride.

A process for the preparation of hydroxocobalamin hydrochloride. More particularly the present application relates to improved process for the preparation of Hydroxocobalamin hydrochloride. In addition the present application also relates to process for the preparation of novel amorphous form. This application particularly relates to a process for the industrial manufacture of hydroxocobalamin hydrochloride from cyanocobalamin. The present application also relates to the improvement in yield with better purity of Hydroxocobalamin hydrochloride.

Disclosed are a modified cytidine compound, i.e. a new derivative cytidine generated by adding a guanidyl at position 4 of a cytidine, and a nucleic acid containing the modified compound, for example, RNA. The nucleic acid containing the modified cytidine, especially mRNA, can significantly increase the expression quantity of the mRNA in vivo.

Disclosed are a modified cytidine compound, i.e. a new derivative cytidine generated by adding a guanidyl at position 4 of a cytidine, and a nucleic acid containing the modified compound, for example, RNA. The nucleic acid containing the modified cytidine, especially mRNA, can significantly increase the expression quantity of the mRNA in vivo.

To provide a chiral reagent or a salt thereof.

The chiral reagent has following chemical formula (I). In the formula (I), G.sup.1 and G.sup.2 are independently a hydrogen atom, a nitro group (—NO.sub.2), a halogen atom, a cyano group (—CN), a group of formula (II) or (III), or both G.sup.1 and G.sup.2 taken together to form a group of formula (IV).

##STR00001##

To provide a chiral reagent or a salt thereof.

The chiral reagent has following chemical formula (I). In the formula (I), G.sup.1 and G.sup.2 are independently a hydrogen atom, a nitro group (—NO.sub.2), a halogen atom, a cyano group (—CN), a group of formula (II) or (III), or both G.sup.1 and G.sup.2 taken together to form a group of formula (IV).

##STR00001##

Disclosed herein, inter alia, are silicon containing cleavable linkers and compounds for use in nucleic acid sequencing.

Disclosed herein, inter alia, are silicon containing cleavable linkers and compounds for use in nucleic acid sequencing.

A process for preparing a glycoside compound represented by formula (3), which includes reacting a glycoside compound represented by formula (1) with an ether compound represented. by formula (2) in the presence of an. oxidizing agent and an acid to prepare a glycoside compound represented by formula (3),

##STR00001## where the oxidizing agent is added to a reaction system, followed by adding an acid thereto, where B.sup.a represents a cytosine group which may be optionally substituted with acyl group, or an uracil group, R.sup.1 represents a C1 to C6 alkyl group or a phenyl group, and n is 0 or 1, where an oxidizing agent is selected from N-halogenated succinimide and N-halogenated hydantoin, and an acid is selected from perfluoroalkylcarboxylic acid, alkylsulfonic acid, arylsulfonic acid, periluoroalkylsulfonic acid, and salts thereof, and any combinations thereof, which can provide a synthesis of a desired compound with high purity.